NEWS SPECIAL & STAINLESS STEEL STRUCTURAL · Laiwu Steel produced 2.37Mt of iron and 3.33Mt of steel in the first half 2011. The steelmaker had earli-er set its annual steel production

STEEL TIMES IN

TERN

ATIO

NA

L – Octo

ber 2011 – Vol.35 N

o.7

October 2011 – Vol.35 No.7 – www.steeltimesint.com

NEWS SPECIAL & STAINLESS STEEL STRUCTURAL

Continuous casting – Page 33

NewsNews – Japanese Fastmet recycling plant opens 4

Statistics & Events – August global crude steel output up 9.8% 8

USA Update – Steel industry could provide the ignition to an economic recovery 10

Latin America Update – Latin America de-industrialisation and the Chinese threat 12

Japan Update – Restructuring at home, investment abroad 16

Structural steelsTarget Zero: – Reducing the carbon footprint of buildings 17

Automation and control at the Merchant product mill at Durgapur Steel Plant 20

Special and stainless steelsDry mechanical vacuum pumps in use for VOD and VD-OB processes 23

Applying statistical theory to bearing steel failure modes 29

Vasa Museum replacing 5000 wrought iron bolts 32

Continuous castingA report on the 7th European Continuous Casting Conference 33

The influence of ceramic sprayed caster rolls on the internal quality of slab 37

OthersEnergy saving and environmental protection: Tenova’s latest technologies 41

Automatic head-end cutting at Rourke HSM 45

History: Pioneers of the Steel Industry: Part 5: Open Hearth & Bessemer 48

Steel Times International – October 2011 – 3

Contents

ISSN 0143-7798

October 2011Vol.35/No.7

Front cover imagecourtesy of Tenova

EDITORIAL

EditorTim Smith PhD, CEng, MIMTel: +44 (0) 1737 [email protected]

Deputy EditorGreg MorrisTel:+44 (0) 1737 855132

Production EditorAnnie Baker

SALESInternational Sales ManagerPaul [email protected]: +44 (0) 1737 855116

Area Sales ManagerAnne [email protected]: +44 (0) 1737 855139

Group Sales ManagerKen [email protected]: +44 (0) 1737 855042

Marketing ExecutiveAnnie O’[email protected]: +44 (0) 1737 855012

Advertisement ProductionMartin [email protected]

SUBSCRIPTIONElizabeth BarfordTel +44 (0) 1737 855028Fax +44 (0) 1737 855034Email [email protected]

Steel Times International is published eight

times a year and is available on subscription.

Annual subscription: UK £155.00

Other countries: £222.00 (US$342) (€269)

2 years subscription: UK £279.00

Other countries: £399.60 (US$615.60) (€484.20)

Single copy (inc postage): £35.00

Email: [email protected]

Published by:

Quartz Business Media Ltd,

Westgate House, 120/130 Station Road,

Redhill, Surrey, RH1 1ET, England.

Tel: +44 (0)1737 855000

Fax: +44 (0)1737 855033/855034

www.steeltimesint.com

Steel Times International (USPS No: 020-958) is published

monthly except Feb, May, July, Dec by Quartz Business

Media Ltd and distributed in the US by DSW, 75 Aberdeen

Road, Emigsville, PA 17318-0437. Periodicals postage paid

at Emigsville, PA. POSTMASTER send address changes to

Steel Times International c/o PO Box 437, Emigsville, PA

17318-0437.

Printed in England by: Pensord, Tram Road, Pontlanfraith,

Blackwood, Gwent NP12 2YA, UK

©Quartz Business Media ltd 2011


Structural – Page 17 Stainless & special steel – Page 32

October 2011 – Vol.35 No.7 – www.steeltimesint.com

NEWS SPECIAL & STAINLESS STEEL STRUCTURAL

History – Page 48

4 – October 2011 – Steel Times International

News in Brief World News www.steeltimesint.com

VISIT: www.steeltimesint.comTo see a full list of news and features.


Vietnam seeks partnersThe Vietnam Steel Corporation isseeking strategic partners followingits reorganisation as a joint venture.Under the equitisation process, 29%of the firm would be offered to for-eign strategic investors, leaving theState with a controlling interest of65%, said General Director Le PhuHung.“Next month, we will learn moreabout interest from some majorJapanese steelmakers, includingNipon Steel, JSE, Tokyo Steel, KobeSteel, Mitsubishi and Marubeni-Itochu,” said Hung. “We plan to complete our search forforeign strategic partners in thefourth quarter of next year.”Vietnam Steel has already receivedfeelers from Russian investorsincluding Novolipetsk SteelCorporation and Evraz Group.

SMS secures orderZiehwerk Plettenberg fromPlettenberg, Germany, has placed anorder with SMS Meer, Germany, forthe supply of a bright steel centre.Plettenberg produces bright steel inthe diameter range from 8 to80mm. The new centre with thecore components peeling machineand straightener is designed for adiameter range from 10 to 54mm.

Laiwu Steel profit down 27% Laiwu Steel Co, a listed unit ofShandong Iron and Steel Group CoLtd, posted RMB198M ($31.0M) netprofit for the first half 2011.However, this was down 27.09%from the first half 2010. Laiwu Steel produced 2.37Mt ofiron and 3.33Mt of steel in the firsthalf 2011. The steelmaker had earli-er set its annual steel productiontarget at 6.65Mt.Revenue rose 21.14% to RMB22.819bn ($3.57bn) for H1, while itsfull-year target is RMB40.6bn($6.36bn). Source: China Metals e-mail [email protected]

Distribution expansionUK group Clugston DistributionServices, has invested in eight newcurtain sided lorry trailers. Four are4.2m high, two are 4.5m high, withthe remaining two being specialist‘Euroliners’, introduced to supportthe company’s growing business inthe steel sector. The investment willalso lead to eight new jobs beingcreated.The trailers compliment the special-ist steel trailers operated byClugston from its Scunthorpe andDriffield, UK distribution centres.

Arceloridles sitesArcelorMittal will temporary idle itsEAF and two rolling mills at its longsteel production site in Rodangeand Schifflange, Luxembourg.

In a measure that will affect 450employees, it said the decision wasmade in the light of weak demandin the Northern European con-struction sector.

“This is a temporary measure andthe decision will be re-evaluated atthe end of 2011,” ArcelorMittalsaid in a statement. “All measureswill have an effect on 450 employ-ees who will be put into the internalredeployment cell.”

At the Rodange and Schifflangesite ArcelorMittal produces longcarbon steel products includingreinforcement bars, crane rails andspecial sections.

The steelmaker had announcedin September that it would shut twoblast furnaces in October, one at itsplant in Eisenhuettenstadt,Germany, and one at its Florangeplant in France, due to weaker steeldemand in Europe.

In 2010, ArcelorMittal produced92.629Mt of steel, of which 37%was produced in Western Europeand 11% in Central and EasternEurope.

Australia’s Fortescue MetalsGroup, the world’s fourth largestiron ore miner, said its productionwas strong in its fiscal Q1 of 2011-12.

More than 12Mt of iron ore wasshipped during the three monthsending September 30.

Fortescue said the shipments,which included third-party ship-ments, were the highest quarterly

level achieved by the company. Fortescue also transports and

ships ore mined by BC Iron, whichhas a 50% stake in Fortescue’sNullagine joint venture mine.

The company said it is still sellingall of its production with no cancel-lation or deferral of cargoes, and itssales price averaged $US160/t,‘subject to final adjustments’ for itsmost recent shipments.

Japanese steelmakers Nippon SteelCorporation (Nippon Steel) andKobe Steel said commercial opera-tion was launched at their steel milldust recycling plant in Himeji,Hyogo Prefecture using Kobe’sFastmet rotary hearth technology.

In October 2008, the companiesdecided to establish a joint venturecalled Nittetsu Shinko MetalRefine to recycle steel mill dust and

turn it into direct reduced iron.Construction of the 220kt/y treat-ment plant began in May 2010.

The joint venture plans to pro-duce competitive iron units by recy-cling steel mill dust, a by-productfrom the steelmaking process. Thisrecycling business is expected toprove effective to deal with thesharp increase in steel demand andescalating raw material prices.

German steelmaker ThyssenKruppsaid its joint venture unit in Chinaand Chinese producer Ansteel wereexamining a proposal to build acoated auto sheets production linein southwest China.

Ansteel signed an agreementwith the Chongqing DevelopmentZone, south of Sichuan Province.Tagal, the joint venture of Ansteeland ThyssenKrupp Steel Europe inDalian, will also take part in ‘theintensive, open-ended examina-tion,’ the Duisburg-based companysaid.

Tagal operates two 400kt/y hotdip galvanizing lines in Dalian.

The Chongqing municipal gov-ernment said that the German steelgroup would invest into a $1.1bnauto sheet project in LiangjiangNew Area consisting of two phases.

The first phase will consist of ahot-dip galvanized sheet line andcost $300M, the government reportsaid. The second phase, involving$800M in investment, will consistof a cold-rolling line and a down-stream steel processing line, itadded.

TKS plans Chineseauto sheet venture

Fortescue reportsstrong ore growth

Shougang Group has signed a jvwith New Zealand groupLanzaTech to construct a demon-stration plant at one of Shougang’ssteel mills in China.

The partners say the intention isto quickly scale the JV demonstra-tion plant to a fully commercialfacility at a Shougang steel mill.

LanzaTech’s clean energy tech-nology ferments a variety of gasresources, including those emittedthrough steelmaking, to producelow carbon fuels. Its technology isparticularly attractive because ithas no impact on food security orland use

Beijing-based Shougang is oneof the largest steel producers inChina. It is looking globally fortechnology that will help reducethe environmental impact of steelmaking.

Shougang President WangQinghai said the JV symbolizesShougang’s desire to break theparadigm of heavy industry being akey contributor to carbon emis-sions.

ShougangNZ plan

Japanese Fastmetrecycling plant opens


News in BriefWorld Newswww.steeltimesint.com


Finex orderSiemens VAI Metals Technologiesreceived an order from PoscoEngineering & Construction (PoscoE&C), for its third Finex plant.Posco E&C is a subsidiary companyof the Korean steel producer Posco.The ironmaking facility will be builtat Posco’s Pohang steelworks andproduce 2Mt/y of hot metal on thebasis of directly charged low-costiron ore fines and predominantlynon-coking coal. The Finex plant is set to be complet-ed in 2013 and will allow 4Mt/t ofhot metal to be produced using theFinex process at Posco.

Jiexiu iron commissioningJiexiu Xintai Iron & Steel Co Ltdfrom Jiexiu, Shanxi Province, hascommissioned its section mill forsteel beams supplied by SMS Meer,Germany. The mill will be used to roll beamsin the size range from 200 to1000mm. The plant has a capacityof 1.2Mt/y. The plant at Jiexiu Xintai is the ninthsection mill to be supplied to Chinaby SMS Meer. The heavy beam millis equipped with universal rollstands of CCS (Compact CartridgeStand) design.

Chongqing relocationChongqing Iron and Steel has closedits facilities in southwest ChongqingMunicipality as part of the compa-ny’s relocation programme. In a fil-ing to the stock exchange, the dual-listed company said its productionactivities and office would be relo-cated in the economic and technicaldevelopment zone of Changshoudistrict in Chongqing. The companysaid the relocation programme is inline with the requirements of envi-ronmental protection and industriallayout and planning set by themunicipal government.

Apprentice schemeUK group Sheffield Forgemastershas taken on 68 apprentices to addto its specialist engineering work-force.SFIL will train the apprentices overthe coming year, the majority intheir second and third-years, but 17of which are new school and collegegraduates studying for specialistcareers and roles in all departmentsacross the 64-acre Brightside Lanesite, Sheffield, UK.This year more than 200 peopleapplied for 17 vacancies, provingthat apprenticeships are a soughtafter route for future employees.


ArcelorMittal startsLiberia ore operation

ArcelorMittal has started commer-cial iron ore production from itsmining operations in Liberia.

The launch of commercial miningoperations represents an importantmilestone in the recovery ofLiberia’s economy, which was dev-astated by 14 years of civil war.

ArcelorMittal first entered thismarket in 2005, realising the poten-tial of the country’s rich mineral

resources to facilitate repair of thecountry’s industrial and social infra-structure.

By 2012, it aims to ship 4Mt/y ofiron ore from Liberia. A first testshipment has already taken place.

The company has so far spent$800M in repairing roads and infra-structure, as well as reconstructing a240km railway, port, hospital andschool.

JSW Steel said its 10Mt/y facility inKarnataka may come to a com-plete closure due to an acute short-age of iron ore.

The company also resorted to amassive production cut of 70% inthe Vijayanagar plant in Karnatakadue to shortage of iron ore afterthe Supreme Court imposed a banon mining in the state.

“We may have to shut entirely(Vijayanagar plant)... There is agood possibility of that (closure) ifthe situation does not improve,”

JSW Vice Chairman and MDSajjan Jindal said. An e-auctionroute for supply of the raw materi-al in Karnataka was put in place bythe Supreme Court in September.

JSW is also looking to revise itsproduction forecast downwardsfor the current fiscal due to contin-uous shortage of the iron ore.

The company requires about1.65kt of iron ore to produce 1ktof steel, Jinal said, although he didnot give the details of revised pro-duction forecast (see below).

StripcoexpandsStripco is to expand its site inMishawaka, Indiana, USA.

The flat rolled steel processorand cold rolled strip producer willadd three new annealing bases anda building large enough to morethan double existing annealingcapacity. Rad-Con will provide the100% hydrogen batch-annealingequipment.

Stripco will also continue its useof hydrogen-recycling technologyin the expanded facility.

Each new annealing baseaccommodates 100t with a stackheight of 205 inches. Coils can beup to 0.375inches thick, 72 incheswide, and weigh 50000 lbs.

Construction has begun on thenearly 10000ft2 addition toStripco’s existing precision coldroll strip facility.

JSW to shut Karnataka facility?

Indian iron ore banThe Indian Supreme court hasordered the cessation of miningand transportation operations inChitradurga and Tumkur districtsof Karnataka.

This follows a ban on mining inthe Bellary district imposed on 29July.

The court in its order said thatthe reclamation and rehabilitationof ecology in the area devastatedby reckless mining will have to gotogether with economic activityinvolving industry and there had tobe a balance between the two.

The ban follows the recommen-dation of the Central EmpoweredCommittee (CEC), which foundillegal iron ore mining in these dis-tricts was resulting in environmen-tal damage.

However, the court said a stock-pile of 25Mt of iron ore could bereleased so that steelmakers arenot starved of the steelmaking rawmaterial.

Visit www.steeltimesint.com andsearch on Karnataka for more onthis story as well as other news andfeatures.

SeverstalexpandsSeverstal, Russia’s second largeststeelmaker, will invest about$1.5bn to $2bn/y to raise outputand mine more raw materials,feeding its own plants whileexpanding sales at home andabroad.

It is seeking to almost tripleiron-ore output from last year to38.2Mt by 2020 as it starts miningin Latin America and Africa, thecompany said. Coking-coal vol-umes will rise to 17.9Mt from7.3Mt, helping Severstal increasesteel output by a third to 19.6Mt itsaid.

The company has snapped upiron ore deposits in Brazil andWest Africa as it seeks to counterrising raw-material costs.

After selling three unprofitablesteel mills in the US in March andseparating its Italian Lucchini unitlast year, Severstal has followedcompetitors in tapping emergingmarkets, where demand growthhas outpaced expansion elsewhere.

The company agreed inDecember to form a joint venturewith NMDC Ltd in India,Severstal and NMDC have agreedto invest $3.1bn to build a steelplant in the southern state ofKarnataka.

In May, Severstal agreed to buy25% of SPG Mineracao, whichowns iron-ore exploration licencesin northern Brazil and has anoption to buy a further 50%.

It also controls an iron-ore proj-ect in Liberia.


World News www.steeltimesint.com



Romaniacold mill

Posco, the world’s fourth-largeststeel producer, is seeking toincrease its presence in South Asiaby acquiring shares in an Asiansteel company.

The Korean steel giant hasclinched a deal with Al TuwairqiHolding Co of Saudi Arabia to buya 15.34% stake in Tuwairqi SteelMills Ltd for $15M.

Al Tuwairqi is working to build aproduction complex in Karachi,the country’s financial capital.TSML plans to begin commercialproduction in January with acapacity of 1.28Mt/y of direct-reduced iron, Posco said.

DRI, also known as sponge iron,is produced by using gases gener-ated from natural gas or coal. Itsiron-rich characteristic makes a

high-efficient substitute for scrapmetal in the electric arc furnacesystem.

Posco aims high as the deal willenable the steel mill to rake in div-idends and expand its businessscope in the world’s sixth mostpopulous country with more than180 million people.

“Pakistan’s steel industry has ahigh growth potential,” said ChungJoon-yang, chief executive.

“Through the contract, Poscowill gain a foothold in Pakistan andboost business opportunities foraffiliates involving construction,engineering and information andtechnology and others.”

Posco estimates Pakistan’s steeldemand at 12Mt in 2020, up morethan 70% from 7Mt last year.

Posco to buy share inAsian steelmaker

Wusteel in Canadianmining partnership Wuhan Iron and Steel Corp(Wusteel) has signed a miningdevelopment cooperation agree-ment with Canadian Century IronMines.

The partnership will exploit theCanadian company’s iron ore proj-ects in North America.

It was the latest move in theChinese steelmaker’s overseasmining expansion. Wusteel willtake advantage of the abundantiron ore resources of CanadianCentury, while providing financialsupport, technical expertise andhuman resources to the partner-ship.

Wusteel received regulatoryapproval from the Canadian gov-ernment to take the stake inCanadian Century, a junior compa-ny that operates the mineral prop-

erties Duncan Lake, Attikamagen,and Sunny Lake in Quebec.

To secure iron ore supply,Wusteel has been taking stakes inoverseas mines, in addition to buy-ing the raw material from the threeglobal mining giants, Vale, RioTinto and BHP Billiton.

In addition to CanadianCentury, Wusteel is also in closecooperation with Canadian minersincluding Adriana Resources andConsolidated Thompson IronMines.

Last August the companyreceived the first shipment of ironore from its $400M investment inthe MMX Brazilian mine, whichplaced the Chinese steelmaker asthe second-largest shareholder ofMMX and secured a 20-year ironore purchases and sales agreement.

NamechangeEurofer’s General Assembly haschanged the official name of theorganisation from the ‘EuropeanConfederation of Iron and SteelIndustries’ to “The European SteelAssociation”. The name Euroferremains.

The mission of the organisationremains unchanged. The newname reflects the structure of themembership of the associationwhich is composed primarily of thesteel producers themselves as wellas the national steel associations.

The organisation’s activities willremain the same in terms of coop-eration amongst the national steelfederations and companies in allmatters contributing to the devel-opment of the European steelindustry.

It continues to represent thecommon interests of its memberstowards the European institutionsand international organisations.The logo has been adapted inaccordance with the new name ofthe organisation.

Mobileanalysis

The Tubular Products Division ofArcelorMittal commissioned itsnew cold-formed mill in its Lasi,Romania facility.

The line was constructed toincrease efficiency and reducecosts to service the domestic andregional markets. With a capacityof 120kt/y the mill will comply withEuropean standards in terms ofproduct quality, efficiency andoverall operation.

The mill allows for the success-ful decommissioning of six highcost and outdated lines.

ArcelorMittal Tubular ProductsLasi is the largest producer of lon-gitudinal welded steel tubes inRomania. The cold form line sizerange from 60.3mm to 193.7mmin circular and 50 x 50mm up to150 x 150mm square with a wallthickness from 2.00 to 10.00mm.

It provides tubular applicationsfor mechanical and constructiontubing including sprinkler systems,pressure pipes and conveyor rolls.

Baosteel GuangdongSteel acquisition

The Paul Wurth Group hassecured a number of orders inIndia for engineering and supply ofits Bell Less Top charging systems.

JSW Steel has ordered the MidiBLT system for its Blast FurnacesNo. 1 and 2 (sized at 8 and 8.4mhearth diameter respectively) at itsVijayanagar Works at Toranagallu,Karnataka state.

Essar Steel has bought the MidiBLT chute drive for its 10.5mdiameter hearth furnace at itsHazira works, Gujarat state.

Blast Furnace No. 3 at SAIL’sDurgapur, West Bengal steel plant(with an 8.6m diameter hearth)will be upgraded from double bellcharging to the CF (Central Feed)BLT system, a type designed formid-sized furnaces.

Equipment supply, installationand commissioning of all of thementioned Paul Wurth chargingsystems are scheduled to takeplace in 2012.

Paul WurthIndianorders

The latest version of Spectrotestfrom Spectro Analytical is the onlymobile OES Spectrometer capableof segregating Duplex steels byNitrogen content.

It is also the only one that canmeasure carbon in steels down to0.1% without the need for argonflushing.

The Plasma Generator digitalspark control defines and controlsthe energy in the plasma, whichimproves precision, reproducibilityand measuring speed. The sampleprobe is new too: it is lighter, slim-mer and more convenient to usewhen space is restricted.

Baosteel Group will change itsplan to restructure the southChina-based Guangdong Iron andSteel Group Corp, and now makethe company a wholly-owned sub-sidiary.

Baosteel signed a restructuringagreement with the State ownedAssets Supervision andAdministration Commission(SASAC) of the provincial govern-ment of Guangdong. The local

government will transfer its 20%equity in Guangdong Steel, afterwhich Baosteel will wholly own thesteelmaker, according to the agree-ment.

Based on the previous proposal,Baosteel was to pay $4.49bn totake an 80% stake in theGuangdong Steel while the provin-cial SASAC would take 20%.Source: China Metals e-mail [email protected]


Events Diarywww.steeltimesint.com


News and Statistics

VISIT: www.steeltimesint.comTo see a full listing of industryevents click on ‘events diary’

NOVEMBER 2011

OCT 31-NOV 2 Metcoke 2011Pittsburgh, USAwww.metcokeworldsummit.com

1-3 21st Century RailYork, UKhttps://www.eventsforce.net/iom/frontend/reg/thome.csp?pageID=64791&eventID=172&eventID=172

3-4 Electric Steel 2011Pittsburgh, USAhttp://www.intertechpira.com/elec-tric-steel-2011.aspx

9-11 5th IT for Steel ConferenceHangzhou, Chinaemail [email protected]

10 Stahl 2011Dusseldorf, Germanywww.stahl2011.de

13-15 ILAFA 2011Rio de Janerio, Brazilwww.ilafa.org/ingles/events/Paginas/ILAFA52.Inicio.aspx

15-18 Metal Expo 2011Moscow, Russiawww.metal-expo.ru/en/

22-23 2nd Regional Iron andSteel Investment SummitIstanbul, Turkeywww.ebysummits.com

22-24 Indian Steel ConferenceMumbai, Indiawww.crugrou.com

NOV 27- DEC 01Fray International SymposiumCancun, Mexicowww.flogen.com/FraySymposium/index.php

DECEMBER 2011

12-14 15th Middle East Iron &Steel ConferenceGrand Hyatt Hotel, Dubaiwww.metalbulletin.com/events

14-16 Energy Efficiency in theSteel Industry conferenceRanchi, Indiahttp://eesi2011.com/

JANUARY 2012

25-26 Annual Regional Iron andSteel Investment SummitIstanbul, Turkeywww.ebysummits.com

For full listing of monthly statistics by country visit www.worldsteel.org/?action=stats&type=steel&period=latest

August global crudesteel output up 9.8%World crude steel production forthe 64 countries reporting to theWorld Steel Association was125Mt in August 2011. This is9.8% higher than August 2010.

China’s crude steel productionfor August 2011 was 58.8Mt, anincrease of 13.8% compared toAugust 2010.

Elsewhere in Asia, Japan pro-duced 8.9Mt of crude steel inAugust 2011, a slight increase of0.1% compared to the same monthlast year. South Korea’s crude steelproduction for August 2011 was5.5Mt, a 19.3% increase comparedto August 2010.

India produced 6.16Mt up 7.4%

on August 2010.In USA, crude steel production

grew 13.8% compared to August2010 to 7.35Mt and, comparedwith August 2009, by 35.8%.

Output in the 27 EU countrieswas 12.7Mt in August, up 4.3% onAugust 2010 and up 21.1% onAugust 2009. Other Europeancountries (including Turkey) pro-duced 3.021Mt in August anincrease of 6.9% on August 2010.

The complete table of crudesteel production by country isavailable as a download fromhttp://www.worldsteel.org/?action=stats&type=steel&period=latest.

China steel outputrises on price hikeChina’s output of crude steel mayreach around 706Mt in 2011, farexceeding the prediction of 660Mtforecast at the beginning of theyear, according to the China Ironand Steel Association (CISA).

The latest prediction was madeon the basis of the crude steel out-put in the first half of this yearwhen the country’s crude steeloutput reached 350Mt, up 9.6%from a year earlier.

China’s daily output of crudesteel has stayed high since this yearwith the steel price going up amidrobust demand from the construc-tion sector. China’s daily output ofcrude steel fell slightly to1.9053Mt in the August 21-31period, according to industry esti-mates released by CISA. The fig-

ure is 2.13% lower than the dailyoutput in the August 11-20 periodof 1.947Mt. Throughout August,daily crude steel output averaged1.9351Mt, up 1. 16% from the pre-vious month, said CISA.

The rising price for steel hasimproved the performance ofsteelmakers, which have beenstruggling in loss or meagre profit,although any profit remains verylow. China’s steel industry is in adilemma of high production andlow profit, noted by Zhu Jimin,president of the CISA. Meanwhile,the level of steel production ismaking difficulties in the country’seffort to phase out obsolete pro-duction capacities. Source: China Metals e-mail [email protected]

NLMKcontractLOI Thermprocess has received acontract from Russian steel com-pany NLMK.

It will supply an HPH bell-typeannealing plant, which includes 23annealing bases, 12 gas-fired heat-ing hoods and 10 cooling hoodsincluding all the necessary ancillaryfacilities for the company’s Lipetskplant.

A total of 40 outmoded, ineffi-cient HNx bell-type furnaces areto be replaced with a view to sig-nificantly increasing productionand improving material quality.

The project is to be implement-ed in two stages, with the firststage due for completion in thefirst quarter of 2013 and the sec-ond in the third quarter of 2013.

The new HPH bell-type anneal-ing furnaces will be used to annealcold-rolled coils of low-carbon andlow-alloy thin sheet up to 1850mmwide and a maximum thickness of2.6mm. Each base will have a max-imum stack height of 5600mm anda maximum stack weight of 150t.The capacity of the entire plant isto be 480kt/y.

UK Iron & Steel statistics compilationUK’s Iron and Steel StatisticsBureaux (ISSB) has published itscompilation of UK steel industrystatistics for 2010.The 35 Tables and two chartsinclude data from 2005 to 2010 inthe majority of cases covering:

Raw Materials;Energy;Ironmaking;Steelmaking; Steel Products;Price Indices; and UK Trade.

Available in hard copy or in dig-ital format ‘United Kingdom Iron &Steel Industry Annual Statistics2010’, A4 soft cover can be pur-chased from:

ISSB Ltd, 1 Carlton HouseTerrace, London SW1Y 5DB UKTel (0)20 7343 3900 Fax (0)20 7343 3901 e-mail [email protected] http://www.issb.co.uk Price £220

Posco inTurkishopeningPosco has broken ground on its$350M cold-rolled stainless steelplant in Izmit, Turkey as part of itsefforts to become a leading stain-less steel maker in the region.

The plant, scheduled to be com-pleted in April 2013, will have acapacity of 200kt.

It is the steel giant’s secondinvestment in Turkey, following thelaunch of its Posco-Turkey NiluferProcessing Center (TNPC), autosteel processing centre, in BursaProvince last year.

Currently, the Pohang-basedcompany, which can produce near-ly 3Mt/y of stainless steel, is sittingthird in terms of annual produc-tion capacity behind Acerinox andTaiyuan Iron and Steel, which havecapacities of 3.4Mt/y and 3Mt/y.

The mill will be establishedwithin the Izmit industrial com-plex, about 100km east of Istanbuland its proximity to Derince Portwill make it easy to bring in stain-less hot-rolled plates, from PohangSteelworks.


USA Update

Experts have been urging the US administration to demonstrate the ‘political will’ to strengthen the nation’s steel industry which,in turn, would provide the badly-needed ignition to an economic recovery amidst fears that a double-dip recession could hit thenation and further weaken the manufacturing sector. By Manik Mehta, New York

SOME experts even point out that formervisionary entrepreneurs such as AndrewCarnegie, Charles Schwab and J P Morgantook initiatives to strengthen the steel industrywhich gave a strong impetus to the economyand made the United States the world’s leadingeconomic power.

Steel’s wide-ranging applications in a varietyof industries such as cars, infrastructure andlogistics contributed immensely to America’srise in the world. The plethora of industriesthat rely on steel for survival is mind-boggling.

Take the case of Gary, Indiana, which hasbecome almost synonymous with the steel plantcalled Gary Steel Works, which at one time wasthe world’s largest and most productive steelplant.

However, the steel industry’s falling star castits dark shadow on Gary in the 1970s.Disadvantaged by rising costs and a labourforce accustomed to generous benefits, thesteel industry lost its competitive edge as moreand more foreign suppliers forayed into the USmarket.

The tectonic shift in the global steel industry,with six of the world’s top ten producers locat-ed in Asia, notably China, South Korea, Japanand India, runs parallel to the weakening of theUS steel industry.

Despite persistent high unemployment,resulting in a severe loss of consumer confi-dence, the crisis situation also offers opportuni-ties. For one, steel companies still have plentyof cash reserves which largely remain unusedbecause of economic uncertainties. But theproblem lies in the gloom that is widespread inthe country, with politicians and industry lead-ers failing to see the opportunities.

At the start of his presidency, Barack Obamahad pledged to allocate huge sums to mod-ernise the country’s antiquated infrastructure.He needs to demonstrate his resolve andlaunch a massive programme that will upgradethe infrastructure and, in turn, re-energize thenation’s steel industry.

Imports fallThere was also a drop in the steel imports dur-ing July over the previous month. Indeed, Julyimports declined 4.5% compared to June,according to official US data. “Imports fromCanada and imports of semi-finished productsdeclined in July compared to June reflectingweakening conditions in July as prices softenedin response to steel market supply and demandconditions as some previously shuttered and as

well as new mills began ramping up productionamid general concerns about the health of theoverall economy,” said David Phelps, the presi-dent of the American Institute for InternationalSteel (AIIS).

But from January to July 2011, imports were21.9% above the level of the year-earlier period.Putting things in perspective, Phelps comment-ed: “While there are reasons to be concernedabout the direction of the overall economy forthe remainder of 2011, the improvement inmarket conditions in 2011 compared to 2010continue in important steel markets such as oiland gas, pipelines, heavy equipment and autos.Underlying economic factors seem to continueto suggest that demand in those sectors will sus-tain the steel market at these modestlyimproved levels from the much weaker 2010.”

In absolute figures, total steel imports forJuly 2011 touched 2.583 million short tonscompared to 2.708Mstons the previous month,a 4.5% decline, and a 6.5% increase over June2010. During the first seven months of theyear, imports surged 21.9% over the year-earli-er period – from 14.131Mstons in January-July2010 period to 17.228Mstons in the correspon-ding period of 2011.

Imports are, nevertheless, coming under theadministration’s scanner as the steel industrycontinues to exert pressure to stop what iseuphemized as the ‘import flood’. The adminis-tration is keen to reduce its huge foreign tradedeficit and believes that import reduction couldlead to job creation in the country, a priority forthe Obama administration.

The Department of Commerce (DoC)recently made what it is called a ‘preliminaryjudgement’ that it would impose high tariffs onparts of steel-wheel hubs and galvanized steelwires imported from China. The argument forthis decision is to offset the subsidies whichChina gives to its exporters. The DoC has alsoput in place anti-subsidy duties on drill pipes.Reacting to the DoC’s action, China deniedgiving subsidies to its exporters and fiercelyopposed the high tariffs, calling it ‘trade pro-tectionism’. The anti-subsidy duty rate on steelwheel hubs is between 26 and 47%, while theduty on galvanized steel wires is between 22and 49%. Chinese experts such as Song Hongof the Department of International Trade at theChinese Academy of Social Sciences, have beenquoted in the Chinese media as saying that theUS administration had imposed high counter-vailing duties on Chinese steel products at thebehest of the United Steelworkers’ Union.

The fear behind such moves is to protect exist-ing jobs, particularly in the manufacturing sec-tor. There has been a steady erosion of employ-ment in the manufacturing sector in the UnitedStates. In 1965, manufacturing accounted for53% of the American economy. By 2004, it wasdown to 9%. Two million more manufacturingjobs were lost in the recession that startedtowards the end of 2007, according to the USBureau of Labour statistics data.

Saving jobs is the number one priority ofPresident Barack Obama whose popularitycurve has plummeted. Some pundits say thatObama can even lose the chance of being re-elected unless he brings about aWirtschaftswunder (‘economic miracle’).

Little idle capacityThe American Iron and Steel Institute (AISI)revealed that US steel plants had utilized 76.8%of available raw-steel production capacity in thefirst week of August. Although this percentageis close to the highest level in 2011, it still fallsshort of the near 90% reached in 2008.

Meanwhile, Nucor Corp. has said that it canreplace steel grades currently sourced fromJapan. The company, which is finalising trialruns for advanced high-strength steels, said thatthe automobile industry’s demands for lighter-weight steel would help Nucor get businessfrom a Japanese car manufacturing companythat currently buys materials from Japan.

Nucor’s argument is that its replacementmaterial will help the customer overcome thecumbersome logistical problem of cheaplytransporting steel coils from Japan to stamperson the east coast of the United States. Nucorclaimed that its advanced high-strength steelgrade can reduce the lead times, lower thefreight costs and help provide a lean manufac-turing approach.

Car manufacturers in the United States areresorting to lighter-weight alternatives to tradi-tional steel as the industry prepares for morestringent fuel-economy standards.

Nucor would replace a hot-roll dual phase590 product manufactured in Japan, that isused primarily on frames, rear compartmentcomponents, steel wheels and gussets for A-pil-lars, with its own product. Dual phase 590 is atype of advanced high-strength steel that hashigh formability characteristics and is strongenough to absorb energy during a crash.

The product would complement the compa-ny’s existing product mix using existing capital,according to industry sources. �

Steel industry could provide the ignitionto an economic recovery

– July imports show a decline over June


causing a decline in competitiveness, volatilityof revenues due to exposure to commodityprices for exports, government mismanagementof resources and sometimes unstable regimes.The ‘Dutch disease’ provokes side effects,because the exchange rate appreciation impactsa set of factors, fostering substantial moneyinflows and a spiral of prices, wages and costincreases.

However, de-manufacturing is not necessari-ly associated with primarisation of exports. Onthe one hand, the industrial share concerningemployment and added value can fall as a con-sequence of losing competitiveness in compari-son with other countries (regressive process).On the other hand, the industrial share regard-ing employment and added value can dropbecause of relocation towards other nationswith labour intense or lower added value man-ufacturing (a progressive process). De-industri-alisation is not bad per se, once the country isalready rich.

De-manufacturing in Latin America hasintensified in recent years, harming the genera-tion of high quality jobs and domestic steel con-sumption (Fig 1). Its participation in GDP hasdiminished from 17.1% to 15.7% in just adecade. Fig 2 shows that the same trend hasalso occurred in the four selected countries, butthe tendency is stronger in Mexico, where the


LA Update

Latin American de-industrialisation and the Chinese threat

ALTHOUGH the Chinese threat to the LatinAmerican steel industry is not a new issue, itsimportance has increased substantially in recentyears. The direct and indirect steel tradebetween China and the region was discussed ina previous article in 2007 (STI, Nov-Dec 2007vol 31 No 8, p12).

As well as releasing an annual statisticalreport on bilateral indirect steel trade betweenLatin America and China, the Latin AmericanIron and Steel Institute (ILAFA) decided todevelop an in-depth study on: a) the manufac-turing performance in the region; b) theincreasingly share of primary products in theexport mix; c) the relationship between thesefactors and the trade balance with China. Thereport focused on four countries: Argentina,Brazil, Colombia and Mexico. Each nationalstudy was written by a distinguished local econ-omist and this author played the general co-ordinating role.

De-industrialisation (or, to be more precise,de-manufacturing) in many cases is associatedwith a higher proportion of primary products(‘primarisation’) in the export mix. This can bea symptom of the so-called ‘Dutch disease’ –the paradox where countries abundant in non-renewable natural resources such as mineralsexperience slower economic growth – causedby a combination of exchange rate appreciation

The falling share of manufacturing’s contribution to GDP in Latin American countries and the replacement of this by exports ofprimary products (raw materials) are key features for Latin American economies in general, and for their steel companies in particular. The Chinese threat – via indirect exports of steel to the region – is of great concern to Latin American steelmakers. By Germano Mendes de Paula*

*Professor in Economics, Federal University of Uberlândia, Brazil. Email [email protected]

contribution of manufacturing in GDP has fall-en almost 3% during the past decade.

Among these four nations, Brazil andColombia have accumulated strong exchangerate appreciation since 2005 in comparison withthe US dollar (Fig 3). In Argentina, the situa-tion is more complex, depending on themethod of calculating inflation. It has also reg-istered a considerable appreciation against theUS dollar since 2003, but the multilateral realexchange rate is still relatively devaluated, dueto its large trade with Brazil (with a strongappreciation of the Brazilian Real against theUS dollar). In Mexico, the real exchange rategradually returned to the level observed justbefore the macro-financial crisis that occurredin November 1994.

It is important to highlight that primary prod-ucts have been growing in their share in LatinAmerican exports, increasing from 49.8% in2005 to 54.7% in 2010. There are some relevantdifferences among the nations examined. InBrazil and Colombia, the replacement of exportsof manufactured goods by exports of primaryproducts it is clearly seen (Fig 4), but there is lit-tle evidence of this in Argentina and Mexico.

Trade with ChinaThe bilateral trade with China is a key factor inunderstanding de-manufacturing and the pri-


Shar

e in

GD

P (%

)

Shar

e in

GD

P (%

)

US$

vs

Loca

l cur

renc

y

Shar

e M

anuf

actu

red

good

s in

exp

orts

(%

)

Fig 3 Exchange rate appreciation of local currencies against US dollarSource: own elaboration based on various sources.Note: Argentina and México (1999 = 100), Brazil and Colombia (January 1999= 100). For Colombia the real effective exchange rate was used

Fig 4 Share of manufactured products in exports of selected LatinAmerican countries (%) (2005-2010)Source: ECLAC, own estimation

Fig 1 Share of manufacturing in Latin American GDP (%)Source: ECLAC, own estimation

Fig 2 Share of manufacturing in GDP by country (2000-2010)Source: National Institute of Statistics


LA Update

marisation of exports in Latin America. Fig 5demonstrates that Chinese exports to LatinAmerica grew from $35.6bn in 2005 to$111.1bn in 2010, generating an increasingtrade surplus with the region.

Fig 6 shows that Latin America net exportsof primary products and natural resource-basedgoods to China increased from $12.8bn in 2005to $53.6bn in 2010. More importantly, theregion’s net imports of manufactured productsfrom China, in the same period, increased from$29.3bn to $92.8bn. Thus, there is the reap-pearance of the ‘colonial regime’, experiencedin the past between Latin America and its for-mer Iberian colonisers.

Regarding the metal-mechanical value chain– which is very important in domestic steel con-sumption – the flow is almost unidirectional in

favour of China. In 2010, China exported$59.5bn of such products to the four selectedLatin American countries and imported just$2.0bn (Fig 7). Therefore, the relationshipbetween export of such goods and imports wasalmost thirty times greater for imports. For thefour individual nations, the ratio was: Colombia(3535 times); Argentina (209 times); Mexico(31 times); Brazil (21 times).

Metal-mechanical products were responsiblefor 71% of all imports from China, for the fourselected Latin American countries in 2010.Thus, Chinese exports to the region are verymuch concentrated in steel intensive goods.This asymmetric trade balance for these prod-ucts will grow in the coming years being theoutcome of the goal determined by the Chinesegovernment, underpinned by subsidies to its

steelmakers. Considering that fabrication ofproducts with a high content of steel has beengrowing faster than crude steel output in China(Fig 8), we may expect further growth inexports of manufactured goods from China tothe world, including to Latin America.

Chinese foreign direct investment in LatinAmerica is evidently motivated by exploitingraw materials. The main goal – explicitly shownin the ‘Steel Industrial Policy’ launched in 2005and the 12th 5-Year Development Plan releasedthis year – is to increase China’s control of min-eral resources abroad. However, in some trans-actions, host governments have set certain(implicit or explicit) restrictions. If the Chineseinvestments in Latin America goes ahead, thetendency towards the primarisation of exportswill be even more intense.

US$

bn

US$

bn

US$

bn

Inde

x 20

05 =

100

Fig 5 Bilateral trade Latin America-China (US$bn)Source: ECLAC

Fig 6 Net exports from Latin America to China, by type of products(US$bn) Source: ECLAC, own estimation.Primary products include intense natural resources manufactured goods

Fig 7 Bilateral trade between the four selected Latin Americacountries and China of metal-mechanical products (US$ bn)Source: ADIMRA, Funcex, ALADI, World Trade Atlas Note: Latin America = Argentina, Brazil, Colombia and Mexico

Fig 8 Annual production in China of steel and steel intense goods(2005 = 100)Source: Statistical Yearbook of Chinese Steel Industry 2010, Bloomberg


Latin American consumption downsized for 2011

In its most recent forecasts, ILAFA believesthat apparent steel use in the region will grow4.7% in 2011, a downwards revision comparingto the 7.1% expansion that was expected at thebeginning of the year. Apparent steel use thisyear is expected to reach 62.1Mt.

This is due to a less bright outlook from var-

ious Latin American countries because of theunstable global economic scenario, combinedwith less than expected results for the firstsemester 2011.

During the first 8 months of 2011 the regionproduced 32.85Mt of crude steel of whichBrazil produced 73%.

Latin American consumption SecondQuarter 2011

It is estimated that apparent steel use reached14.9Mt during the second quarter 2011, 3%more than the previous quarter, but 1% lessthat similar period in 2010.

In contrast, during the second semester 2008

apparent steel use contracted 38%, as a resultof the global crisis.

Since then levels have recovered slightly,reaching a maximum of 15Mt during the sec-ond and the third quarter of 2010.

ILAFA-52The Latin American Iron and SteelCongress and expo 2011 takes placethis year in Rio de Janeiro, Brazil onNovember 13 – 15 at the Windsor BarraHotel.

Topics will cover Development &Sustainability; Industrial Strategies;The Global Economy and the WorldSteel Market and BRIC CountriesOutlook.

Download the General Programme ofActivities from:http://www.ilafa.org/CongresoILAFA52/English/Paginas/default.aspx


JAPAN Update

Restructuring at home, investment abroad

ACCORDING to the Board of Investment(BOI) of Thailand, the number of approvednew foreign direct investments (FDIs) byJapanese firms increased by 65% to 241 in thefirst six months of 2011 and the amount (value)for these increased 2.3 times compared to thefirst half of 2010. Automobiles, auto parts andsteel are examples of sectors that accelerateFDIs in Thailand. But, it is not only south-east-ern Asian countries and China which are desti-nations for FDIs by Japanese industries, butalso emerging economies such as Brazil, Russiaand India.

Nissan Motors announced both the buyoutof Russian AvtoVAZ partnered with Renault aswell as a plan to build a new car assembly plantin Brazil. The company also plans to commenceproduction of electric cars in China. Nissanaims at increasing its global sales to 7 millionunits by 2016 with a total investment of 2 tril-lion yen (US$25bn). This is a challenging figurefor the company compared to its current globalsales of 4.2 million units. Nissan intends tokeep its current domestic production capacityof one million units, but the restructuringefforts will inevitably depend on the market sit-

uation in Japan where the country’s populationis declining. Given the recently acceleratedappreciation of the yen, many manufacturingcompanies including in the steel sector hurry toinvest more in foreign countries.

TinplateJFE Steel was reported to increase its globalproduction capacity of tinplate to an annual4.4Mt by 2020, almost a 50% increase over thecurrent figure. Demand for tinplate is growingin emerging economies such as India as theincome levels of households increases, thisresulting in an increase in demand for cannedfoods and beverages.

The company plans to build several 200-300kt/y tinplating facilities in various locationsin countries such as India, Vietnam and theMiddle East. The total cost for the capacityexpansion will be around 20 billion yen(US$250M). Most of the new investments areplanned to be implemented as joint ventureswith domestic firms.

Nippon Steel also has a plan to make agreenfield investment for tinplating and anneal-ing facilities at the city of Wuhan in China in ajoint venture with China’s Wuhan Steel.Investment cost for the venture is estimated tobe around 24 billion yen (US$ 300M), andstart-up is expected in 2013.

The current world tinplate demand is esti-mated to be around 18Mt/y, but it could reach25Mt in 2020, according to JFE.

Only four major integrated steel producers in

Asia; – Nippon Steel, JFE, POSCO andBaoshang, – have capacities to produce highquality cold rolled sheets for further processingto tinplate.

TubeSumitomo Metals plans to increase its capacityof high-grade seamless tube production on aglobal scale with a joint venture in Brazil.

Vallourec (France), Sumitomo Trading andSumitomo Metals are reported to start com-mercial operation of their integrated steel tubeproduction facility in Brazil later this year.

The new venture will produce 1Mt of crudesteel from its blast furnace and roll 600kt ofseamless tubes when it reaches full-scale capac-ity in late 2012. Currently Sumitomo Metalshas a capacity of 1.2Mt of seamless tube pro-duction in Japan, and the new Brazilian venturewill add over 300kt (half the total volume of theventure) to the company’s overall productioncapacity of high priced seamless tubes.

Sumitomo plans to realize a better product mixby producing both high-grade and medium-grade products in Brazil and to shift its domes-tic production to the highest value products asa means of seeking more effective use of itsproduction capability in Japan.

Sumitomo is also expected to start procuringthick plates produced in the new plate mill inThailand, where the venture is led by CanadoilGroup with participation by Sumitomo. Of the1.2Mt of steel plates produced on the easternseaboard of Thailand, Sumitomo expects toprocure 300kt/y, mainly for use in shipbuilding.With this Thai venture, the company expects toshift its plate production capacity in Japan tomuch higher end products for use in oil-drillingfacilities.

EAF ReorganisationAt home, Japanese steel companies have accel-erated their efforts on further restructuringdomestic production lines, particularly in the

electric steelmaking sector (EAF).Currently there are 35 EAF steel producers

in Japan, all of which supply long products suchas small diameter bars and shapes mainly forthe domestic construction market. As the busi-ness environment for construction in Japan hasbecome increasingly severe due to continualstagnation in the construction market, EAF

steel producers are finding it necessary to reor-ganize their operations. It is estimated thatalmost half the production capacity of EAF pro-ducers was redundant in 2010 with a utilisationrate of only about 50%. For small bars, domes-tic demand was estimated to be 7.5Mt in 2010,while the total capacity of 30 companies for thisproduct reached between 14 and 15Mt/y.Recently, the price margin between small bar

products and steel scrap – the major inputmaterial for EAF steel producers – has shrunkto be around 30 thousand yen (US$375), lessthan half the margin at the end of 2008. Thismakes it difficult for most of the Japanese EAFsteel companies to make any profit.

On May 31, JFE Steel announced that itplans to integrate all four affiliated electric-arcfurnace steel companies in the JFE group byApril 2012. These are JFE Bars & Shapes,Daiwa Steel, Toyohira Steel, and Tohoku Steel.This is understood as a significant effort toaccelerate the revitalizing of the stagnant busi-nesses of Japanese EAF steel producers. Totalcrude steel capacity by these four companies isestimated to be 3.8Mt, but in 2010 70% ofcapacity was in use producing 2.67Mt.

The Tsunami triggered by the Great EastJapan earthquake on March 11 badly damagedthe facilities of Tohoku Steel and JFE Bars &Shapes. Among the group’s EAF operationshalted by the Earthquake, Tohoku Steel will notresume production but will retain its sales func-tion. JFE Bars & Shapes Kashima Works andDaiwa Steel Tobu Works, both of which manu-facture reinforcing bars, will supply products toTohoku Steel.

JFE Bars & Shapes Sendai Works in MiyagiPrefecture, which also had to halt production,restarted operations of its steel bar plant inmid-July and wire rod plant in early August.The steelmaking plant and billet mill came online sequentially in mid-August, and overallproduction was expected to return to pre-earth-quake levels by October.

It is understood that JFE’s plan to integrateits EAF businesses will enable the group toremain a viable producer of reinforcing steelbars. The merger will make the new company

the largest of all Japanese EAF producers.Given continued high appreciation of rawmaterial prices, along with the yen, and thiscombined with the sluggish demand for steel inthe domestic construction market, the Japaneseintegrated steel companies will continue theirefforts on improving their business performanc-es using various strategies.

Since March 11 when the Great East Japan Earthquake hit the country, Japanese companies have been busy rebuilding their damaged production facilities and highly integrated supply chains. However, they have not forgotten their global aspirations, afactor accelerated by the continual appreciation of the yen since spring. While the surge of raw material prices continues, theJapanese steel industry continues its efforts on restructuring at home and increasing new ventures abroad. By Nobuhisa Iwase*

* An independent steel economist, Karuizawa, Japan, Email [email protected]

“the number of approved new foreign direct investments (FDIs) by Japanese firmsincreased by 65% to 241 in the first six months of 2011”

“Currently there are 35 EAF steel producers in Japan, all of which supply long products”

“It is estimated that almost half the production capacity of EAF producers was redundantin 2010 with a utilisation rate of only about 50%.”


Structural steels

Target Zero: – Reducing the carbon footprint of buildings

The British Constructional Steelwork Association, Tata Steel and others spent two and a half years and £1M on a study to determine the most cost effective combinations of materials and technologies needed to make low and zero carbon buildingspossible. Known as Target Zero, five case studies have now been completed and indicate the building structure has minimal

impact on regulated carbon emission ie those arising from heating and lighting etc but not from contents eg freezers.

IN a bid to reduce carbon in buildings, the UKgovernment and other leading bodies haveidentified a stage-by-stage approach, with aview to ultimately reaching zero carbon levels.

This is a new era for the construction indus-try as governments’ world-wide move to for-malise their carbon emission targets for thefuture and introduce legislation to ensureimplementation of new, challenging standards.

Target Zero is a UK initiative set up in 2008to help provide feasibility levels and design guid-ance, to show what measures can be taken, howmuch they will cost and what the results are like-ly to be. By sharing a wider knowledge throughthis free resource, designers, architects, engi-neers and material suppliers can work togethertowards achieving zero carbon in new buildings.

The Target Zero project is led by the TataSteel and the British Constructional SteelworkAssociation, with the aim of providing a seriesof fully costed guidance reports on the designand construction of sustainable, low and zerocarbon buildings in the UK, made freely avail-able to the industry.

The work has been undertaken by a group oforganisations which are leaders in the field ofsustainable construction, including AECOM,Cyril Sweett and the Steel ConstructionInstitute (SCI). Working with clients BalfourBeatty, Prologis, Asda, Development Securitiesand Peel Leisure, base case buildings weredefined based on actual buildings.

Five non-domestic building types were select-ed – school; warehouse; supermarket; office andmixed-use building and reports prepared.

Using recently constructed, typical buildingsas benchmarks, Target Zero investigated threespecific, priority areas of sustainable construc-tion on each:

The three areas considered in each reportare:– Embodied energy (the carbon footprint

when something is built);– Operational energy (where the highest car-

bon emissions are) and how to reduce it; and– BREEAM (Building Research Establishment

and Environmental Assessment Model) the industry standard for measuring sustainabili-ty and how to achieve higher BREAAM rat-ings at lower costs.

From this, Target Zero can help constructorsto assess the cost of achieving the highest threelevels in BREEAM, ‘Very Good’, ‘Excellent’and ‘Outstanding’, and the steps needed to betaken to achieve them.

Reports on all five building types have nowbeen completed and can be downloaded fromwww.targetzero.info.

This information is invaluable guidance atthe beginning of a new construction project. Itshows what can be achieve within the budgetset, how cost effective various carbon-reducingmeasures are and what the outcomes are likelyto be.

This guidance is all in line with the zero car-


bon targets set by the UK government.As a resource, Target Zero provides the best

and most accurate information currently avail-able but ultimately, detailed design has to beundertaken by the design team, but Target Zerooffers a very good way of establishing limita-tions and options right from the start.

Case Study – Timber vs Steel FrameGlued laminated timber (Glulam) has beenaround since at least 1870, being used in theconstruction of a school in Southampton, UKthat year.

The material is constructed by gluing togeth-er multiple small pieces of timber thereby mak-ing use of a non-premium product and enablingcurved beams to be produced unavailable innatural wood.

Target Zero compared the use of glulambeams against steel in a supermarket building,taking Asda’s Stockton-on-Tees food storewhich opened in May 2008 and is a portal steelframe building as its test case.

Comparing the embodied carbon on manu-facturing the two types of beam, Target Zeropronounced in favour of steel which was calcu-lated to have 16% less carbon in its manufac-ture and end-of-life treatment.

The result contradicts a similar assessmentcarried out in 2002 for Oslo airport whichassessed steel beams as having six times moreembedded carbon than glulam beams, the steelrequiring three to four times more energy tomake and using six to 12 times more fossil fuel.

However, the key is in the treatment at endof life. In the Oslo analysis it is assumed theglulam beams are incinerated and the heat cap-tured, while Target Zero say 80% of glulam goesto landfill at end-of-life, 16% is recycled and 4%is incinerated.

The most recent estimates from TRADA(Timber Research and DevelopmentAssociation) and WRAP (Working together fora world without waste) indicate that over 10Mtof waste timber each year end up in landfill inthe UK. In 2008, TRADA updated a reporttitled ‘Recovering and Minimising WoodWaste’. This states the 10Mt figure as well as anestimate that 80% of timber waste goes to land-fill, 16% is recycled and 4% incinerated. Thatlarge amounts of timber from demolition go tolandfill is supported by the data BRE use intheir calculations in the Green Guide

Examining the supermarket building as awhole, the difference in embodied carbonbetween glulam beams and a steel framedbuilding is only 2.1% in favour of steel as muchof the embodied carbon in a building is presentin the foundations and floor slabs.

The use of glulam beams, however, was cal-culated to add 2.4% to the cost of construction.

However, from a supermarkets point of view,the public perception of using a sustainablematerial such as timber over one which may beconsidered an energy intensive material such assteel or concrete means the supermarket maywell opt for the glulam choice. Indeed, Tescohave done just so in their Manchester storewhich opened in 2009 which they claim to bethe ‘most energy efficient ever supermarket’.

BREEAM assessmentBREEAM (Building Research EstablishmentEnvironmental Assessment Method) is theleading and most widely used environmentalassessment method for buildings in the UK.

The estimated capital cost uplift of the basecase supermarket was:

– 0.24% to achieve BREEAM ‘Very Good’– 1.76% to achieve BREEAM ‘Excellent’– 10.1% to achieve BREEAM ‘Outstanding’.

The BREEAM assessment examines allaspects of the energy balance of a building – notjust the structural elements but also its contentsand location. Thus, for example, the efficiencyof lighting, ventilation, heating, air tightness,use of land (eg brownfield vs greenfield),equipment within the building (eg refrigera-tion), and how easy it is to reach the building(eg cycle ways) are, among others, taken intoaccount and credits allocated to each and ascore totalled.

Materials selectionWhere BREEAM focuses on materials selec-tion, the research showed that there is an inher-ent weighting within the tool used to calculatethe score. This weighting is used in addition toweighting each element by area. The weightingsare shown in Table 1.

Element External walls Windows Roof Upper floors

Weighting 1.00 0.30 0.85 0.28

Table 1 BREEAMweighting factors formaterial selection

A building’s structure has little impact onits regulated carbon emissions

target zero_Layout 1 10/10/11 10:01 AM Page 1


The table shows that external walls and roofsare highly weighted. An assessment of alterna-tive materials specifications showed that:• The external walls of the Asda supermarket

achieve an ‘A’ rating in the Green Guide to Specification using steel composite profiledpanels, with an opportunity to achieve an A+ rating by using cedar boarding.

• The aluminium curtain walling only achievesa Green Guide ‘D’ rating and requires a dif-ferent glazing solution to achieve higher rat-ings, eg uPVC window frames or timber, which is likely to be considered impractical on this type of building.

• The aluminium standing seam roof con-

struction used achieves an ‘A’ rating. This could be raised to an ‘A+’ rating by substi-tuting the outer skin of the roof with coatedsteel sheet.

• The upper floor slab achieves an ‘A’ (back-of-house) or ‘A+’ (mezzanine retail floor) rating for the case study building.

A score is calculated under credit Mat 1 inthe materials section of BREEAM.

For the case study building, the first two (offour) Mat 1 credits were achieved by using thebase case building specification.

To achieve the third credit the windowswould need to be upgraded, for example, usingtimber to achieve an A+ rating. This is estimat-ed to incur an increased capital cost of £20 000.

Structural steels


The fourth Mat 1 credit can be easily achievedby substituting the aluminium standing seamroof with a steel-based construction.

For the case study building, the full four Mat1 credits can be achieved by selecting A+ mate-rials for the external walls and the roof with allthe other elements achieving only an E rating.

Table 2 compares the costs of implementingthe Glulam option and the steel frame optionagainst a base case steel frame portal building.

Influence of structure on operatingemissionsDynamic thermal modelling of the supermarketbuilding showed Option 2 would emit 3.8%more CO2 a year than the base comparisonsteel portal frame building due to greaterrequirements in space heating as a result of theinclusion of northlights.

While these allow diffused light to enter themiddle of the supermarket while reducing theamount of direct solar radiation, and improvesthe consistency and uniformity of the lightwhile reducing the risk of overheating, a sec-ondary effect is to increase the surface-to-vol-ume ratio of the supermarket. This requiresmore space heating during cold seasons. Thenet effect of this approach is to increase theBuilding Emission Rate (BER) by2.1kgCO2/m2y ie 3.8% relative to the base case.

The Glulam Option 1 emits just 0.2kgCO2/y(0.4%) more than the base case building due tothe need to increase the roof height and so vol-ume to heat to accommodate the deeper beamsrequired when using Glulam.

LCA dataThe most appropriate steel data were providedby the World Steel Association which are basedon average production data in year 2000. Theworldsteel LCA study is one of the largest andmost comprehensive LCA studies undertakenand has been independently reviewed to ISOstandards 14040 and 14044.

For non-metallic building materials the GaBiLCI database was used. Table 3 summarisesthe total lifecycle CO2 emissions and the end-of-life assumptions made.

The results of the five case-studies so farundertaken indicate that a building’s structurehas almost no impact on its regulated carbonemissions.

When it comes to choosing the structuralmaterial it is better to choose the best materialfor the purpose the building is to fulfil. It is farmore effective to reduce CO2 emissions duringthe use of the building, for example byinstalling low energy lighting, Table 4.

External solutions such as wind turbines,heat sinks and photovoltaic panels are also wor-thy of consideration, although their effective-ness is site specific.

Applied to a supermarket site, low energylighting, for example, can save £758k over 25years net present value (NPV) and reduce CO2emissions by 22% compared with the basebuilding.

Even higher comes a wind turbine, a 330kWturbine reducing CO2 emissions by 27.16% andsaving £1.4M over 25 years while photovoltaicssave 14.4% of CO2 emissions worth £170k over25 years (taking into account the UK govern-ment’s feed-in-tariff where owners are paid forthe electricity generated.

Contact

Target Zero Project, Tel +44 (0)1709 825 544

e-mail [email protected] www.targetzero.info

Structural Description Structure Total Total Differenceoption Unit cost Building Building related to

(£/m2 of Cost Unit cost base caseGIFA*) (£) (£m2 of GIFA) building (%)

Base Steel frame 107 16.4M 1746 –

Case Building Suspended concrete floor slab

CFA piles

Upper floor concrete slab on metal deck

Mezzanine: light gauge steel supporting timber decking

Option 1 Glulam frame 141 16.8M 1789 +2.4

(Glulam) Suspended concrete floor slab

CFA piles (concrete)


Mezzanine: Glulam beams supporting timber decking

Option 2 Steel frame 117 16.3M 1735 -0.6

(Steel Frame) Suspended concrete floor slab

Steel H- piles


Mezzanine: light gauge steel supporting timber decking

Northlight roof profile in retail area

*GIFA = Gross Internal Floor Area Source: Target Zero

Table 2 Comparative costs of alternative structural designs

Material End-of-life assumption Total lifecycleemissions (tCO2eq/t)

Fabricated steel sections 99% closed loop recycling 1% landfill 1.009

Steel purlins 99% closed loop recycling 1% landfill 1.317

Organic coated Sheet 94% closed loop recycling 6% landfill 1.693

Rebar 92% closed loop recycling 8% landfill 0.820

Glulam 16% recycling,4% incinerated; 80% landfill 1.10

Concrete (C25) 77% Open loop recycling, 23% landfill 0.132

Concrete (C30/37) 77% Open loop recycling, 23% landfill 0.139

Concrete (C40) 77% Open loop recycling, 23% landfill 0.153

Plywood* 16% recycling, 4% incinerated; 80% landfill 1.05

Plasterboard 20% recycling, 80% landfill 0.145

Aggregate 50% recycling, 50% landfill 0.005

Tarmac 77% recycling, 23% landfill 0.020

* Excludes CO2 uptake or CO2 emissions from biomass

Source: Target Zero

Measure Cost over CO2 saved Whole lifebase Bld (%) (%) saving over 25y (£y)

330kW wind turbine 4.24 27.16 1440

High Eff Lighting 0.27 22.0 758

Photovoltaics 10.44 14.4 170.5

Heat Pump 0.25 5.0 82.3

Improved Chillers 0.30 4.56 80

Motion Sensors 0.08 4.0 106

Ventilation Efficiency 0.06 2.37 68.7

Refrig heat recovery 0.17 1.83 6.0

Optimised Glazing 0.00 0.06 0.10

Source Summarised from Target Zero

Above: Table 3Embodied carboncoefficients for principle materialsused

Table 4 summarisesthe options, costsand savings ofvarious energy saving measures.

target zero_Layout 1 10/10/11 10:01 AM Page 2


Structural steels

Automation and control at the Merchantproduct mill at Durgapur Steel Plant

THE Merchant mill of SAIL’s Durgapur SteelPlant (DSP), India is a continuous mill. It hastwo cooling beds and bar shears, each consist-ing of seven drives.

A Comprehensive PLC (ProgrammableLogic Controller) network based automationsystem (Fig 1) was conceived, developed andimplemented for the cooling beds and barshears of the mill.

Two PLCs and six remote I/Os(Inputs/Outputs) with modified operator deskshave been commissioned in the Bar Shears andalso Control Pulpit #10 (CP).

All eight nodes are connected through a coldredundant distributed communication fibreoptic network eliminating all multicore controlcables.

Any change in control philosophy can be eas-ily achieved through soft logic in place of earli-er complex hard wired relay based control cir-cuits which were difficult to modify, maintainand troubleshoot. The system design also pro-vides plenty of scope for future expansion andenhancement of operations.

The system, commissioned in November2009, has been working satisfactorily providingbenefits in terms of a reduction in the numberof cobbles, mill delay from electrical problemsand has increased mill availability. Also a yieldimprovement has been observed.

The Merchant mill at DSP is used to reducethe section size and section profile of billet. Themill is designed to roll and finish bar of 25m,20m and 16m lengths in a thermo-mechanical-ly-treated (TMT) condition. Any breakdown ofthe control mechanism leads to mill stoppagesand the generation of cobbles.

Cooling beds 1 and 2 use various mecha-nisms to transport the bar such as kick off, carryover, shuffle bar eccentric, shuffle bar lifting,run on table etc. The existing system has provi-

A 10% increase in output at the Merchant bar mill has been achieved by introducing a more reliable network and easier to troubleshoot automation system on the crop shear and cooling beds of the mill.

By A Prasad*, V Kumar*, S Singh*, I Banerjee*, A Prasad*, P Gupta*, PA Aneesh*, TK Dutta*, S Ilangovan*, Y Ramesh**, S Majumdar**, KK Thakur**, AK Aich**

sions for running in automatic and manualmode but poor reliability of its field sensingdevices and control systems frequently result inproblems leading to delays and production loss.

Presently, in the bar shears area, variousmechanisms for cutting the bunch of bars areoperated independently.

In the absence of any online diagnostics toolsand indications, the time taken for fault findingincreases and also the existing hardwired cablenetwork frequently causes problems.

The newly commissioned system has moni-toring and control of various mechanism of thecooling beds and bar shear area of the millthrough two distributed PLCs, six Remote I/Obased modules and programming terminals forthe purpose of programming, trouble-shootingand monitoring of process status.

Three remote combined I/O/Operator deskswere also commissioned for the auto/manualoperation of cooling beds and bar shears drives.One HMI (Human Machine Interface) stationhas been created for online monitoring, histori-cal data storage and analysis of faults occurringduring operation.

ApproachThe objective of the project undertaken was tofacilitate a reduction in mill downtime and pro-vide an improved maintenance managementsystem. To achieve this the following issueswere considered for implementation:

Improved operation through:– Display of equipment status and process

information in HMI stations;– Introduction of automatic control of kickoff

drives.

Improved electrical maintenance manage-ment through:


*Authors are with Research & Development Centre for Iron & Steel, Steel Authority of India Ltd, Ranchi, India.

**Authors are with Durgapur Steel Plant, Steel Authority of India Ltd, Durgapur, India. Contact Author at [email protected]

– Instantaneous display of healthiness of all mechanisms for rapid trouble shooting;

– Monitoring and historical trending of processparameters;

– Easy implementation of control logic.

To achieve these functional requirements, aPLC, RIO and network based automation sys-tem was envisaged with installation program-ming and HMI stations at strategic locationsand interfaced with existing shop equipmentand electrics.

The details of the various components of thesystem and work carried out are describedbelow in brief:

PLC & NetworkThe system configuration with PLC andNetworking Scheme is shown in Fig 2. Theautomation consists of the control and integra-tion of the various mechanisms of the coolingbeds and bar shear area of the mill using twoPLCs and six Remote I/O based units.

All the eleven nodes including two program-ming terminals and one HMI terminal are con-nected through a cold redundant communica-tion network of total length approximately1.2km.

The interconnection among all the nodes isby TCP/IP through multi mode Fibre-OpticCable and CAT6.

All required networking accessories incorpo-rated in the system are of industrial grade toensure the operation of the network is reliable.A cold standby of the network has also beeninstalled for quick changeover in case of dam-age to the network cable anywhere.

Each node has an adequate number of Inputand Output modules which are Digital and/oranalogue to interface all the required signalsfrom the field as needed for the application.

Connected to RM (O) BS1

Cold redundant comm. network

RM (Input)

Developmental

stn (PLC S/w)

Developmental

stn (PLC S/w)

Ethernet Switch Ethernet Switch

RM (Input)At OP desk of BS1

CR atbasement(CB -1)

CR atbasement(CB -2)

Near existing

panels

Communication cable (cold redundant)

Communication cable (single)

Near existing

panels

HMI Dev Stn

(Shift room/CP10)RM CP -

10)RM CP -

10)

PLC 1 (CB -1) PLC 2 (CB -2)

Op desk (CP -10)

At OP desk of BS2

Connected to RM (O) BS2

Remote IO for

cooling Bed-1

Cooling Bed-1

Cooling Bed-2

Programmer-1

Communitation network

Control room at cooling Bed-1

Control room at cooling Bed-2

150M

120M

100M

Bar shear

operator desk-2

Bar shear

operator desk-1

Romote IOmodule

Romote IOmodule

Ethernet switchElectrical shift roomProgrammer-2

Remote IO for

cooling Bed-2

Cooling bed

operator

desk

CP10

PLC-1

PLC-2

HMI

Panel for RM (O) (BS 1&2) + solenoid relays

50m

50m 50m

80m

30m 30m

80m

120m 120m

Fig 2 Main components of the communication network with multiple Nodes to help in future alterations to logic

Fig 1 Components of the PLC network based automation systemCP= Control Pulpit; RM = Remote; BS= Bar Shear; CB= Cooling Bed

durgapur structural_Layout 1 10/11/11 10:02 AM Page 1


Operator/Remote I/O DesksThe remote I/Os for the bar shear signals areplaced inside a new bar shear operator desk ateach cooling bed. These have reduced thebunch of signal cables by an Ethernet commu-nication cable (CAT 6 in this case) (Fig 3). Allthe solenoid activated field operations in thebar shear area such as gauge heads up/down,stopper raise/lower, hold down raise/lower,shear cut etc are locally terminated at a newlyinstalled Solenoid panel. This panel has twonetworking nodes connecting the nodes fromthe Remote I/O bar-shear operator desks. Thecommands to activate the solenoids are givenby the operators using switches and push but-tons on the bar shear operator desk.

A remote I/O based Operator desk is alsoplaced in the Control Pulpit. Here there are apair of interconnected networking nodes con-nected with their respective PLCs through opti-cal fibre cable (OFC). Various field signals andmultiple mode operation of the drives are con-trolled from this desk.

Field I/O InterfaceThe entire system required interfacing with alarge number of inputs and outputs using theexisting shop electrics. Very detailed designwork was carried out to formulate the completeI/O listing before commencement of otheractivities. An input signal for all the field con-trol devices has been taken to the system withproper isolation. The majority of digital inputshave been taken through the auxiliary contactsof the existing relays. Depending upon the loca-tion of the field signals, relay boards have beenprovided at various places and control of thedrives are interfaced with these relay boards.Signal interfacing work involved extensive con-duit, cable laying and termination.

HMI for monitoring statusTo address the absence of any online diagnos-tics tools and indications and the very long timetaken for fault finding; one HMI station is pro-vided in the Electrical control room for use todevelop graphics for the HMI screens for mon-itoring, when needed, some critical operation.

Software DevelopmentSoftware design and development involved aPLC application programme to display infor-mation in the HMIs, Auto control of variousdrives on the cooling beds and in the bar-sheararea and to providing appropriate interlocksbased on mill operation logics.

The programmes are developed in a modularmanner. Separate modules have been written forindividual control of the various operations ofthe drives such as ‘kick off ’, ‘push off ’, ‘shufflebar eccentric’, ‘shuffle bar lifting’, ‘Roller Tables’etc. The PLC software gives the status of variousequipment in the mill, which in turn is displayedat the HMI. In addition to the PLC applicationprogramme, HMI screens (One HMI screen isshown in Fig 4) were designed and softwaredeveloped for monitoring the process status.

Commissioning & TrialsCommissioning involved shutdown of the millat times while other parts did not. Detailed fielddesign and engineering was carried out inadvance and a detailed plan prepared to enablesmooth commissioning. Commissioning wascarried out in different phases. All jobs notrequiring shutdowns such as PLC configura-tion, network testing, HMI testing etc werecompleted in advance. Since testing the con-trols involved running the cooling beds and barshears in Auto mode as well as replacing oldinterlocks, the final change-over to the new sys-

Structural steels


tem was carried out in a phased manner replac-ing two to three control drives on the coolingbed and bar shears during weekly shutdowns.

Extensive trials were carried out off–line aswell as on-line during mill operation. Each andevery mechanism, where interlocks are used,required many trials so that the new systemruns trouble free and safely.

InstallationA comprehensive PLC based Automation sys-tem provides the instantaneous information at acentralised location so that easy diagnosis andrectification of faults can be performed. BeingPLC based enables easy and reliable implemen-tation of the control algorithm. The new controlscheme further established that a fibreoptic/Ethernet network-based system could besuccessfully implemented for critical controlareas as well as monitoring applications provid-ed the design is robust and all safety interlocksare considered.

The various featured incorporated in the sys-tem for monitoring and controlling the coolingbeds and bar shears drives have resulted in alowering of mill downtime and helped achievecentral supervision and control of the entirecooling beds and bar shears area.

This has resulted in instant faults diagnostics,troubleshooting, a reduction in mill downtimeand a 10% increase in output.

It is recommended that similar schemesshould be implemented in other areas of DSPwhere controls are either widely distributed orare relay logic based. The new system will havedistinct advantages over the old in terms of reli-ability, user friendliness and maintainability.The chances of errors will be reduced and anychange at a later date in operation logic will beeasy to implement through soft logic.

AcknowledgementsThe task force is highly indebted to the management of SAILfor providing this opportunity and continuous encourage-ment to the task force for carrying out project successfully.Special acknowledgments are due to all the people ofMerchant Mill, DSP for supporting the project and their tire-less efforts since concept to commissioning for maintainingquality and timely execution of the project. Task forceexpresses sincere thanks to all those who have directly orindirectly supported the project.

Bibliography

1. ‘Automated monitoring and diagnostics of metallurgical plants

and rolling mills’, Jorg Deckers, Olaf N Jepson, Siegfried Latzel’,

‘MPT International 5/2002’

2. Project Completion Report for RDCIS SAIL project No. 35:47:62,

implemented at Merchant Mill, BSP:

3. Project Completion Report for RDCIS SAIL project No. 59:68:34,

implemented at Merchant Mill, BSP:

4. White paper: Real Time Control on Ethernet

5. Gateways for Profibus DP published on www.prosoft-technolo-

gy.comFig 4 Example of HMI screen

Single communication cable (New bar shear desk)

Multiple multi core control cable (Old bar shear desk)

Fig 3 Comparison of old and new controlsystem

durgapur structural_Layout 1 10/7/11 9:40 AM Page 2

Special and stainless steel

Dry mechanical vacuum pumps in use forVOD and VD-OB processes

THE major target of the Vacuum OxygenDecarburisation (VOD) process for the pro-duction of stainless steel is to achieve a low C-content in presence of up to 30%Cr. Somesuper-ferritic steel grades require below100ppm for the sum of C+N. This requires theachievement of a low sulphur content.

The gas load of CO, CO2, Ar, N2, H2 and airleaks has to be handled by any vacuum pumpset in a safe and controlled manner. Thisincludes the abatement and removal of the veryheavy dust load inherent in the VOD process inwhich the ladle of steel to be decarburised anddegassed is placed in a tank which is sealed anda vacuum applied.

Dry mechanical vacuum pumps handle largeoff-gas mass flows that may be rich in CO, CO2or Ar. They fulfil the requirement of pressurecontrol in a rather elegant, economic and easy-to-handle way by using variable speed drives.

Most VOD plants operate at moderate blowrates to avoid undue Cr-losses, overheating,over-saturation of the melt surface by gas bub-bles and slag foaming as well as to reducesplashing generated by the oxygen jet combinedwith intensive Ar stirring.

There are several good solutions for gas cool-ing, dust abatement and pump set layouts onthe market using only dry running mechanicalpumps.

Market situationOver the past 50 years, about 80 steel degassingplants have used dry-running mechanical vacu-um pumps, and a steep increase in their use hasbeen seen since 2000 as well as a tendency totreat larger melt sizes, some of over 200t[1].About 60 of these plants are still operating,some for over 30 years. The plants are locatedin a number of regions including the formerSoviet Union (10 plants), German-speakingEurope (10 plants), Italy (9 plants), India (6plants) and Turkey (5 plants). Thus, close to70% are operating in Europe and Turkey withonly a few plants in China and north and southAmerica which indicates that this developmentis far from finished. This uneven geographicaldistribution of vacuum plants using mechanicalpumps is shown in Fig 1.

The advantages of such plants over steamejector systems and the reasons for their choicehave been explained by several authors[2-11].Beside the economic, environmental and vari-ous operational advantages it has been shownby a large number of tests in several plantsemploying both types of vacuum pumps thatdry running mechanical pumps offer betterresults in regards to final gas content[9-10].

More than a third of these plants also handleoxygen injection mainly for the selective decar-burisation of stainless steel in the VOD process.

There are good solutions available for degassing liquid steel using dry running pumps that have been industrially proven underextreme conditions of gas, dust and temperature load. Together with metallurgical modelling, off-gas analysis and off-gas flowcontrol, results can be obtained in a predictable way for the VOD process for stainless steel production and for the VD-OB and

RH-OB processes for low alloyed steel grades, ultra-low carbon, low carbon aluminium killed and interstitial free steels.By W Burgmann*, R Zemp** & M Godat**

Also there has been a tendency for theseplants to grow in charge size from around 10-50tfor castings and forging ingots to much largermelt sizes of 80-120t continuously cast for theproduction of stainless flat products.

There are a few more vacuum plantsequipped for vacuum degassing with oxygenblowing (VD-OB). However, they are not usedfor the selective decarburisation of high chromi-um bearing stainless steels but only for oxygenassisted decarburisation of low alloy grades.

Process targetsThe major target of the VOD is to remove Cwithout oxidizing the Cr. This is a real challengewhen aiming at less than 100ppm C in the finalproduct, since it is required to decarburisedown to <50ppm in the VOD – process, occa-sionally in the presence of up to 30%Cr.

A further challenge arises when simultane-ously a very low N content is aimed at. Somesuper-ferritic steel require <100ppm for thesum of C+N. This requires a start with a highC-content of >0.8% and to reach a final C con-tent of <20ppm after oxygen blowing andVacuum Carbon Decarburisation (VCD).

However, the low N content can only beobtained when dissolved oxygen and sulphur


*Consultant in Vacuum Metallurgy, Strasbourg, France **MTAG Marti-Technologie AG, Emmenbrücke, Switzerland

EU+CH+TUR 33

World 63A

fric

a 1

Middle+Far East

12

Ex-SU 10

Americas7

Fig 1 Geographical distribution of vacuumplants using dry-running mechanical vacuum pumps installed since 1980 for allprocesses (VD, VCD, VOD, RH) (CHSwitzerland TUR Turkey)

Year Customer Reaction Heat Suction capacity VOD Mainand country vessel size VD VOD - line products

0,67 hPa 100 hPat m3/h m3/h

Table 1 Degassing plants worldwide since1980 using mechanical vacuum pumps

1982 Sammi/Korea Vacuum ladle 35 85.000 15.000 R+Rg Forgings

1984 Punjab/India Vacuum ladle 15 28.000 12.000 R+Rg Long products

1984 IMIS/Mexico Converter 6 25.000 12.000 R+Rg Research

1986 Star Steel/India Ladle in tank 25 28.000 14.000 R+Rg Long products

1987 Kanakdhara/India Converter 8 25.000 12.000 R+Rg Castings

1988 M.G.Mittal/India Converter 9 25.000 12.000 R+Rg Castings

1990 Shen Jiang/China Converter 11 36.000 12.000 R+Rg Castings

1991 Dalong/China Converter 15 36.000 12.000 R+Rg Castings

1994 Upetrom/Romania Converter 11 39.000 12.000 R+Rg Castings

1995 Faur/Romania Converter 15 39.000 12.000 R+Rg Castings

1998 COST/Romania Ladle in tank 12 25.000 2.300 R+C Forgings

2006 Gonar/Poland Ladle in tank 25 66.000 15.500 R+S Forgings

2007 Mechel/Russia Ladle in tank 95 140.000 WRP Flat products

2007 Kamastal/Russia Ladle in tank 60 113.200 R+S Long products

2009 Dedini/Brazil Ladle in tank 35 86.000 9.270 R+S Castings

2009 VAGL/Austria Ladle in tank 50 80.000 14.000 R+S Castings

2009 Shyam/India Ladle in tank 30 28.300 R+S Forgings

2010 EMSS/Ukraine Ladle in tank 70 150.000 16.000 WRP Forgings

2010 Won Kang/Korea Ladle in tank 16 40.000 3.500 WRP Forgings

2010 Bhawani/India Ladle in tank 45 46.000 4.600 R+S Forgings

2010 Laxcon/India Ladle in tank 20 23.000 2.300 R+S Forgings

2010 Arvedi/Italy Ladle in tank 100 165.000 17.000 R+S Flat products

Project Outokumpu/Finland Ladle in tank 75 200.000 20.000 WRP Flat products

Project Ladle in tank 95 200.000 20.000 WRP Flat products

Project EMSS/Ukraine Ladle in tank 140 Forgings

Legend for VOD line: R – Roots, Rg – Gas cooled Roots, C – Claw pump, S – Screw, WRP – Water Ring Pump



contents are low. Thus careful deoxidation andslag management becomes indispensable.

The overall target of low C+N+S, high Cr-yield and long ladle lining life leads to thenecessity for very strong stirring with Ar. Thisshould always be >2.5% of the oxygen flow rateand may thus reach a specific Ar flow rate ashigh as 8 litres/min/tonne.

Details of some of the plants are summarisedin Table 1.

Some recent VOD plants have been built toperform a complete and controlled post-com-bustion of CO, metal vapours and dust particlesinside the reaction vessel.

The resulting gas load consisting of CO,CO2, Ar, N2, and H2 as well as any air leaks hasto be handled by the vacuum pump set in a safeand controlled manner. This includes the abate-ment and extraction of the very heavy dust loadthat is inherent in the VOD process.

Process featuresThe suction capacity for the high vacuum phaseof the VOD process is typically in the range of

900 - 1200m³/h per tonne. Higher suctioncapacities are only needed for reasons of pumpcapacity redundancy, rapid pump down orextreme pressure losses between pump andreaction vessel, or when there are plans for laterexpansion.

Most pump systems even with a rather lowsuction capacity in the VD phase have sufficientcapacity for the VOD oxygen blowing phaseprovided the oxygen blowing starts when thepressure is below 200hPa and the oxygen blowrate does not exceed 25m³/min.

Most VOD plants operate at moderate oxy-gen blow rates of 10 - 17m³/min and start blow-ing in a pressure range of 200 to 100hPa forthree essential reasons:– To avoid over-saturation of the melt surface

with CO-bubbles,– To reduce slag foaming,– To reduce splashing generated by the oxygen

jet together with intensive Ar stirring.

Higher oxygen blow rates also require a larg-er freeboard in the vessel. While 1m freeboard



Fig 2 Schematic vacuum plant with vacuum vessel, coarse dust catcher and various pumpset configurations A-B-C-D-E for the VOD-process using dry running mechanical pump setsand their respective suction capacities per module.

is observed in plants operating with an oxygenblow rate of 10m³/min, this value needs toincrease to 1.2 to 1.5m and even more in vacu-um ladles and converters when the oxygen blowrate goes up to >17m³/min with the accompa-nying Ar flow rate set at 2.5 to 5% of the oxy-gen flow rate.

The challenge for the pump system is to keepthe vacuum pressure during this phase suffi-ciently high and to keep the suction capacityconstant.

During the oxygen blowing phase the Cr/Cconcentration ratio prevailing at the oxygenimpact zone increases with falling C content. Bydecreasing the oxygen blow rate, the Ar/O2ratio at constant Ar flow is increased and bylowering the pressure the undesired Cr oxida-tion is restricted. Excessive Cr oxidation wouldotherwise require large amounts of reducingagents, which would then lead to an excessiveslag volume and render final degassing moredifficult.

The final oxygen blowing phase is thereforecharacterised by a reduced blow rate(<5m³/min) and the vacuum pressure in thevessel reduced to 20 to 10hPa[12-13]. The for-mation, but not the transport, of dust increasesin this phase.

The importance of reaching a very low finalpressure at the end of the VD phase and theadvantages offered in this respect by dry-run-ning mechanical vacuum pumps has recentlybeen shown by several authors[9-10] since lowergas content in the melt is obtained at lowerpressures.

VOD pump setDry-running mechanical vacuum pumps areexcellent at handling the large mass flows ofoff-gas, whether rich in CO if no post combus-tion takes place in the vessel, or rich in CO2 –in the case of controlled post-combustion – orrich in Ar, towards the end of strong stirringtreatments. The dry-running mechanical pumpset fulfils the requirement of pressure drop con-trol in a rather elegant, economic and easy-to-control way by using variable speed motordrives (VSD). They can reduce and keep con-stant the suction capacity to allow optimisedblowing of oxygen with respect to the ladle free-board and other restrictions such as slag foam-ing and splashing.

Sometimes operating at constant vessel pres-sure[10] rather than at a constant suction capac-ity during the main part of the oxygen blow isapplied. This practice is not purposeful and is indirect contradiction to the thermodynamic aimof promoting selective oxidation of carbon. Italso deprives the operator of the visible, naturalvariations in vessel pressure which signalprogress of decarburisation and its end point.

Most of the dry-running pumps in use forvacuum degassing applied to the VD and VCDprocesses can all be used for the oxidising vac-uum processes such as VOD or VD-OB tankdegassers. With controlled post-combustionwithin the vessel at pressures between 300 and100hPa – or below 100hPa without post-com-bustion – the risk of an explosion in the vesselis avoided.

The alternative of using water ring pumps(WRP) instead of dry-running pumps for theVOD oxygen blowing phase would limit the useof oxygen to a tank pressure >50hPa depend-ing upon the water temperature and climaticconditions. Further, the water must be freedfrom dissolved CO or the water circuit must beconfined and vented.

– A: 3-stage design with endless screw, pre-inlet cooled direct exhaust stage and mainpump with overflow-channel for VOD.

– B: 3- stage design with endless screw andwater cooled Roots pump motors.

– C: 3- stage design with endless screw andwater ring pump line for VOD.

– D: 4-stage design with endless screw, pre-inlet cooled direct exhaust stage and by-pass line for VOD.

– E: 4-stage design with endless screw, pre-inlet cooled direct exhaust stage and by-pass line for VOD. For large heat sizes andhigh oxygen blow rates. May be designed inan advantageous 5- stage layout.


Dust abatement and extractionAny mechanical pump set is only as good as itsgas cooling, gas drying, dust abatement anddust extraction system.

The VOD treatment generates 50-100g/m³ atSTP (5-10kg/t) of dust and a flow of hot off-gasaccording to the oxygen blow rate and thedegree of post-combustion in the vessel.

A water ring pump (WRP) does not solve theproblem of gas cooling and dust abatement.The off-gas temperature would be too high atthe WRP inlet.

In most layouts, the pump-house is at a dis-tance of 10 to 100m from the vacuum vessel.Thus the connecting pipe must be sized toallow for gas cooling, low pressure losses andrather high gas speeds in order to avoid clog-ging by dust deposits.

If a WRP pump was used, the full dust loadwould enter the pump making it a huge sludgegenerator that would need continuous water fil-tering and pressurising.

The dust contamination can be reduced bypassing the dust laden gas down an enlargedvertical pipe located in the first pipe bow closeto the vacuum vessel. The off-gas speed isslowed and the gas slightly cooled enabling thelarger dust particles to settle. Such devices arewell known for electric arc furnaces, RH-plantsand VOD-plants using steam ejectors as vacu-um pumps. This ‘dust catcher’ is an advantagealso when dry-running mechanical vacuumpumps are in use.

However, such dust catchers close to the ves-sel are not the final solution for sufficient gascooling and complete dust abatement. A fur-ther cooling of this dust-laden gas and a combi-nation of cyclone and bag filters are essential.Such an installation must also care for a lowpressure loss <0.1hPa, an on-load filter clean-ing, a continuous or batch-wise dust extractionduring the process and take into account thedifferent process steps and pressure levels ofthe VOD/VCD/VD - treatment.

The higher the degree of post-combustionwithin the vessel the greater is the challenge forgas cooling. But a deliberate high degree ofpost-combustion will also contribute to lessdanger of ignition of residual hot dust on thefilter bags and might lead to less skull forminginside the reaction vessel.

Any dust filter requires complete isolationfrom an oxidising atmosphere. Therefore a reli-able shut-off valve is necessary that can resiststhe hot and dust-laden process gas. There aregood solutions on the market.

Fig 2 shows the various possibilities of pumpset layouts offered by various plant suppliers.

All pump sets have in common the use ofendless screws as primary pumps and bi-lobeRoots-blowers for the subsequent stages. Whenpre-inlet cooled Roots pumps are used theypermit a direct exhaust to the atmosphere downto 200hPa and thus provide a very short pump-down time and the handling of a large amountof off-gas during oxygen blowing in the mediumpressure range from 150 to 50hPa. The down-side for this shortest pump-down time withthese pre-inlet cooled pumps are peaks of noiseand power demand.

In addition to the dry-pump configurationsshown in Fig 2 there are about a dozen modern

steel degassing and decarburising plants usingoil sealed (rotary vane) pumps as the primarystage of three-stage pump systems. These havehigh inner compression ratio than dry runningscrews. However, they are not the best solutionsince they have substantial maintenance anddisposal handicaps. The oil in contact with thesometimes humid off-gas, metal vapours andfine dust, in spite of gas filtering, must beexchanged weekly and may cause severe envi-ronmental damage.

Process controlBased on the experiences with several operat-ing VOD and VODC plants the essentialprocess parameters such as blowing and stirringrates to be used, temperature increase andyields of all involved chemical elements are welldocumented.

However, to control the process with the aimof achieving the target quality at the lowest pos-sible operating cost a metallurgical modelshould be used. Such a model optimises addi-tion of slag builders and reducing agents whileconsidering Cr losses to slag, temperature drop,lining wear, desulphurisation and the influenceon final degassing.

A parallel off-gas analysis is necessary to con-trol post-combustion. Together with the deter-mination of off-gas flow control, for instance bythe primary mechanical vacuum pumps, thebalance of carbon content can be continuouslymonitored (Patent pending).

Thanks to such a process model and the useof dry-running mechanical vacuum pumps thevarious process steps – main oxygen blow, over-blowing, boiling-off by VCD, slag reductionand final desulphurisation and degassing can becarried out in an uninterrupted manner withoutthe need for intermediate breaking the vacuumto take samples or temperature measurements.

RevampingAny vacuum plant that has been designed forthe degassing of Al-killed steels using the VDprocess can be used for the degassing of semi-killed or un-killed grades in the VCD processwith the purpose of obtaining low oxygen orlow carbon contents. A low S content can alsobe obtained during vacuum degassing if a pre-ceding ladle furnace treatment with good slagmanagement is provided. Thus it is possible toachieve Ultra Low Carbon (ULC) grades, lowcarbon Al-killed (LCAK) grades or interstitialfree (IF) grades in the process route LF-VCD-VD.

However, when the decarburisation requiresoxygen assistance according to the VD-OB orVCP-OB (RH-OB) process or the VODprocess is used for high chromium alloyed steelsan existing vacuum plant may be revampedincorporating the following measures:

– Oxygen lance on the vacuum vessel cover;– Vacuum-tight lock for central additions on

top of the vessel cover;– Increased ladle freeboard;– Improved splash protection and heat shield,

preferably by a combination of water cooledelements and a refractory centre piece;

– Increased Argon stirring to reach a specific flow rate of up to 8 litres/min/t;

– Dust catcher in the suction line close to the vacuum vessel;

– Cyclone that operates during the oxygen blowing phase;

– Increased off-gas cooling in the suction pipeclose to the vessel;

– Case wise by-pass suction pipe to avoid wind-milling of the pump stages that are not oper-ating during a prolonged oxygen blowing phase (40-70min);

– Off-gas analyser for at least CO, CO2 , H2 , O2 but preferably also for H2 O, N2 , Ar;

– Venting possibility of the vacuum vessel withnitrogen in case of emergency;

– Sufficient gas cooling by heat exchangers or pipes inside the pump set.

ConclusionDry-running mechanical vacuum pumps havedemonstrated their industrial viability for vacu-um degassing (VD,VCD,VCP) of heat sizes upto 230t[1] and for vacuum decarburisation(VOD) for heats up to 100t (VOD, VD-OB)with oxygen blow rates up to 20m³/min and Arstirring rates up to 8 litre/min/t.

The oxidising vacuum processes have to han-dle large gas flows, high gas temperatures andheavy dust loads. Gas cooling and effective dustabatement are therefore a must for any vacuumpump system.

Among the solutions for mechanical vacuumpumps only the water ring pumps used in theblowing phase do not give full satisfaction withrespect to operating at the lowest pressures,smooth transition from oxidising to reducingconditions and for dust removal.

There are good solutions available using onlydry running pumps that have been industriallyproven under extreme conditions of gas, dustand temperature load. Such layouts providesafe and reliable solutions.

Together with metallurgical modelling, off-gas analysis and off-gas flow control, the opera-tional results can be obtained in a predictableway with minimum work for the operator.

The same applies to the VD-OB and RH-OBprocesses in use for low alloyed steel grades,ultra-low carbon, low carbon aluminium killedand interstitial free grades.

References[1] www.vacuum-pumps-manufacturer.com[2] W Burgmann, MPT Intern 5 (2001), p 56-60[3] W Burgmann, MPT Intern 4 (2002), p 82-91[4] S Bruce, MPT Intern 6 (2002), p 44-46[5] V Cheetham, Millennium Steel (2005) p 95-98[6] W Burgmann, S Panza, Metallurgia Italiana 2

(2007), p 21-25[7] S Bruce, V Cheetham, 9th Europ Electr Steel

Conf Krakow / Poland (2008)[8] R Zemp, J Stahel, W Burgmann, Stahleisen 8

(2008), p 45-50[9] R Gottardi, A Partyka, S Miani, M Volpe,

AISTech Proc (2010) p 1243-1252[10] V A Ivanaeskiy, H Koblenzer, Danieli Seminar

Buttrio/Italy (2010) p 199-203[11] U Zöllig, T Dreifert, MPT Intern 3 (2011)

p 98-103[12] W Burgmann, Commissioning results 65 t VOD

at Isbergues / France (1984)[13] T Eichert, J Triplat, D Tembergen, MPT Intern 1

(2010) p 26-32



Contact

Wilhelm Burgmann, PhD

34, rue de Chambord, F 67000 Strasbourg, France

Tel +33 388 311 409 e-mail [email protected]


Applying statistical theory to bearing steel failure modes

FOR many years, inclusion analysis has been atthe forefront of investigative work to determinecastability issues and improve general productquality. In addition, speciality bearing steel fail-ure modes have been studied for many decadesand direct links to large non-deformable non-metallic inclusions in bearing steel have beenfound. One way to study the prevalence of largeinclusions in bearing steel is a statistical methodknown as Extreme Value (EV) analysis.

EV analysis is a theory that relies on theobservation of extremes and predicting furtherextremes. Recently, there has been a growingapplicability of EV theory to determining thelargest inclusion feasible in a volume of steel.When using a standard method such as theASTM Standard E 2283-03 for determiningEVs, the technique lends itself to be used as apreliminary test for bearing steel and comparingdifferent heats of steel. At the centre of successfor this method is the reliable and reproducibleability to produce the data needed in an unat-tended fashion. One technique that has showngreat promise is the use of automated ScanningElectron Microscopes integrated with EnergyDispersive X-ray Spectrometers (SEM/EDX).

Dynamic Beam Control A key technology for efficient inclusion analysisusing SEM/EDX systems is that of dynamicbeam control. The basic idea is to spend as lit-tle time as possible collecting pixels that are notessential to the problem trying to be resolved.With a skilled operator sitting at the controls,SEM/EDX systems do an incredible job ofexamining inclusions of interest. On the otherhand, for routine quality control analysis, whichrequires thousands or tens of thousands ofinclusions to be characterised, manual inspec-tions is too time consuming and inefficient.

One way to automate these inspectionprocesses is to use a frame-based analysis. Inthis mode of implementation, a conventionalscanning electron microscope (SEM) is usedvery much like a camera and automated via theenergy dispersive spectrometer; however, usingan SEM like a camera results in a fairly ineffi-cient analysis process. To accomplish this moreefficiently, a ‘smart’ beam control algorithm isemployed (Fig 1) wherein the beam is rapidlystepped across the specimen using a relativelycoarse raster that will pick up the features (ie,inclusions) of interest. At each point, the bright-ness of the backscatter signal is noted. Whenthe signal is low, ie dark, enough to indicate thatan inclusion is present, then the analyzer will go

A rapid method for collecting data oninclusion size and composition using anautomated scanning electron microscopeis described which enables Extreme Value(EV) analysis to be performed to quantifythe cleanliness of a steel.By T J Drake*

into a sizing algorithm at much higher resolu-tion. The final step in the sequence is to acquirean x-ray spectrum of the inclusion which takesapproximately one second per inclusion. Thus,features of interest can be characterised to arbi-trarily high precision while minimising the timespent in collecting uninteresting pixels. This isin contrast to the more conventional frame-based type of computerised analysis where acomplete frame of pixels is first measured at thefinest resolution required, and then analyzed byimage-processing software.

Since a SEM is a sequential-pixel device, andthe vast majority of pixels in a typical imageframe do not contain inclusions, dynamic beamcontrol results in dramatic improvements inmeasurement speed because it filters out themajority of the steel matrix.

Rapid collection of data is important forextreme value analysis, but perhaps moreimportant is turning that data into application-relevant information and knowledge. In theindustry, ASTM E 2283-03 dictates the use of astandard approach to characterising the size ofthe non-metallic inclusions. While variousapproaches exist, in the case of this study, theauthors have found that the square-root area isan effective parameter for EV studies. Based onback-scattered electrons, these SEM/EDX ana-lyzers are used to define the boundaries of theinclusions and consequently the area theyencompass. As a result, the analyzer uses theelectron beam much like a calliper to character-ize the area and determine what the largestinclusions are in a sample (Fig 2). In the event


*Dr Drake is Director of Market Development for ASPEX Corporation, USA

a stringer is detected, the full area of the inclu-sion is often determined based on the approxi-mate projected area of the stringer as measuredby the operator, once the stringer has been relo-cated. For each EV analysis, 25 – 30 samplesare collected from various slices of bars from asingle heat. Once cut into 25x25mm samples, asingle longitudinal face is polished to a final fin-ish with one- micron diamond slurry on anautomated polisher. Each sample is thenscanned to detect all inclusions above 1μm andcapture images for any inclusion larger than10μm maximum diameter. Each inclusion isalso characterised for elemental composition todetermine what type of inclusion is present.

Extreme Value AnalysisExtreme value analysis is one of several meth-ods which may be used to describe and com-pare the inclusion populations of steel samples.The initial use of extreme values occurring inpopulations to make statistical inferences aboutthat parent population was first identified byFisher and Tippett in 19281 and had most oftenbeen applied to environmental data.

The initial application of statistics of extremevalues (SEV) to the analysis of the inclusionpopulation in steel was by Murakami2 – 4 in theearly 1990s. Murakami’s approach, the detailsof which have been presented previously4,employs the Gumbel distribution5 to analyzethe data and has been employed by numeroussteel researchers. An example of a typical SEVplot comparing two different sets of steel sam-ples is provided in Figs 3 and 4, where the sam-ple set from steel A has larger oxide inclusionsthan the sample set from steel B.

An alternative variation of an extreme valueanalysis procedure is outlined in ASTM E2283.Some minor differences lie in the choice ofsample area, the number of samples to be eval-uated and the extrapolated area value. Perhapsthe most significant difference is in the param-eter choice used to define inclusion size. Thesquare root of inclusion area is employed inMurakami’s method, while maximum inclusionlength is called out in ASTM E2283.

Selection of the data regression method to beused for determining the SEV value at theextrapolated area is not always defined. Severalregression methods, eg, standard linear regres-sion, moment method and maximum likelihoodmethod, are outlined in ASTM E2283 and inseveral papers on SEV (see References). Insome cases, one method is recommended overothers, but the final choice is up to the end user.

Fig 2 SEM image of the largest detectedinclusion in a steel sample

Fig 1 ASPEXDynamic BeamControl for scanningsteel samples.Minimal time isspent on ‘empty’pixels by dynamical-ly analyzing thespecimen

Polished steelsample

Beam is coarselyrastered across

the field

Inclusion identi-fied and chords

drawn

Stagemove to

fields



ConclusionSEM evolution over the past two decades hasproduced robust automated tools that supportsteel mill applications. Innovations in this fieldare fuelled by a solution-driven approach inwhich the SEM is designed as an integrated sys-tem with application-specific reporting capabil-ities. For the steel industry, this integrated sys-tems approach has proven to reduce down-time, increase productivity, improve qualityand, ultimately, have a positive impact on prof-itability. The application of these SEM solutionsto rapidly correlate which not only sizes thelargest inclusions, but also their chemistry, is



Inclusion size

Steel A

Steel BInclusion area 1/2(μm)

Con

cent

rati

on (

#/m

m2 )

Cum

mul

ativ

e sa

mpl

e ar

ea

Fig 3 Typical SEV plot comparing two steelsfrom different sources. This metric indicatesthat Steel B is cleaner than Steel A

Fig 4 Typical histogram plot comparing the same two steels asshown in Fig 3. This metric also indicates that Steel B is cleanerthan Steel A

proving to be a powerful tool enabling steelproducers to ensure steel quality. Applyingthese new approaches to inclusion characteris-ing to provide cleanliness comparisons are pos-sible for bearing steels where the abilities ofSEMs continue to bridge the gap between datacollection and knowledge about steelmakingpractices.

1) R A Fisher and L H C Tippett, Proc Camb PhilSoc, 1928, 24, pp 180-1902) Y Murakami, Y Uemura and K Kawakami, TransJpn Soc Mech Engr, 1989, 55, pp 58-623) Y Murakami, Trans Jpn Soc Mech Engr, 1990, 56,

pp 1624) Y Murakami, Metal Fatigue: Effects of SamllDefects and Nonmetallic Inclusions, Yokendo Ltd,Tokyo, 19935) E J Gumbel, ‘Statistics of Extremes’, ColumbiaUniversity Press, New York, NY, 1958

Contact

ASPEX Corporation, 175 Sheffield Drive, Delmont,

PA 15626, USA

Tel +1 800 573 7736

e-mail [email protected].

Web www.aspexcrop.com

PLUS

PLUS

20%

20%

opics to be addressed:TTo

Explore

Examine projects,

Profit

xecutives Meet top e

Reasons to attend:

PP

xhibition opportunities contact:Sponsorship and e

Enquiries:

Use code STI50

xhibition opportunities contact:

.indiansteelconference.comwww

.indiansteelconference.com

or email: conferences@crugroup

el: +44 (0TTeGeneral enquiries:

or email: sandra.haines@crugroup

el: +44 (0)20 Sandra Haines TTe

Speaking opportunities contact:

y@crugroupor email: paul.terr

el: +44 (0)20 7903y TTeerraul TTeP

Media Partner

.comor email: conferences@crugroup

el: +44 (0)20 7903 2167

.comor email: sandra.haines@crugroup

el: +44 (0)20 7903 2410

Speaking opportunities contact:

.comy@crugroup

el: +44 (0)20 7903 2131

Media Partner



Vasa Museum replacing 5000 wrought iron boltsTHE Vasa Museum in Stockholm hasembarked on a project to replace 5000 wroughtiron bolts on the Swedish heritage vessel withbolts made of highly advanced stainless steelsnormally used within the demanding oil and gasindustry.

A Swedish national treasure, Vasa capsizedand sank as it prepared for its maiden voyage in1628, it was successfully raised from the bottomof the harbour in 1961 and carefully restored. Ithas since become a top visitor attraction inStockholm, attracting in excess of 1.1 millionvisitors a year from all around the world.

The existing iron bolts were installed for theirstrength and durability, but have since been dis-covered to be reacting with the atmosphere andconsequently causing chemical erosion, whichis damaging the historic woodwork of Vasa.Initial discussions between the Vasa Museumand Swedish special steel producer, Sandviktook place two years ago, leading to furtherinvestigations into the existingiron bolts and potentialreplacement materials. TheVasa Museum was keen totest different materials on asample of 200 boltschanged to test viability andsuitability. The final choicecame down to a decisionbetween carbon fibre and highalloyed stainless steels from Sandvik.

The research and development cooperationbetween the museum and Sandvik, which it isestimated will take more than five years to com-plete, will see the replacement of the majorityof iron bolts, installed in the 1960s.

“We decided to go with the high-alloyedstainless steels from Sandvik because theyproved to be the most suitable and versatile,and from our point of view the easiest to workwith,” explains Magnus Olofsson, Head of VasaUnit. “The carbon fibre option took longer toexchange the bolts, whereas there was a verygood exchange using the Sandvik material”.

The replacement of the bolts is a complexprocedure because the Vasa Museum has toremain open and active at all times, to continueto bring in visitors who provide crucial revenue,so important in the continued preservation ofthe vessel. During the process it is vital not tocause any undue movement in the ship thatcould compromise its structure. This makesbolt replacement a slow process.

Therefore, the detailed plan is to replacethree bolts in any one area at a time and an esti-mated maximum of six per day. Overall, the aimis to replace around 1000 bolts a year.

The bolts have to be long lasting for a mini-mum of 100 years, non corrosive, safe, strong,but also flexible enough to fit holes that arepotentially misshaped, in order to fit in with thelong term plan of preserving Vasa for another1000 years.

Each stainless steel bolt is made up of 7 or 8separate items, including tube, bar, nuts, wash-ers and springs and can vary in length, withsome up to 2 metres long. The materials usedare a super-duplex steel in addition to SandvikSAF 2707 HDO, an advanced hyper-duplexstainless steel developed by Sandvik.Replacement time varies, many of the holes areat difficult angles. In some cases the wood andthe bolt is damaged so this has to be cleaned

and repaired before the bolt can be fitted. Amechanical tool is supplied by Sandvik, whichhelps to carefully extract the corroded iron bolt.The tool is used to help install the new bolts.Sandvik and the Vasa Museum agreed that thefirst 1000 bolts should be installed followed bya period of monitoring crucial factors including,the bolt itself, the wood around the bolt and themovement of the bolt in its position. The resultsof this analysis can then be used to determinethe ongoing progress of the project and if anyadjustments are required.

Dr Marika Hedin, Vasa Museum Director,explains, “We have 10 full-time people engagedon a daily basis ensuring Vasa is being continu-


ally preserved. With a vessel of this age it is anessential, on-going requirement. It has been apleasure working so closely with the Sandvikpeople not least because the company’s exten-sive history.” Coincidentally, the announcementof the cooperation comes at the 50thAnniversary of when Vasa broke the surface inStockholm harbour in April 1961. ThisAnniversary will be celebrated from April andthroughout 2011. And next year, 2012, Sandvikwill celebrate its 150th Anniversary.

Abstracted from Stainless Steel Industry April 2011with permission.

5000 stainless bolts up to 2m long will replace the existing wrought iron boltsSource: Statens Maritima Museer Photo Karolina Kristensson

Each super-duplexstainless steel bolt ismade up of 7 or 8separate items

While replacing the bolts on the Vasa it is vital not to cause any undue movement in theship that could compromise its structure. Source: Statens Maritima Museer Photo Anneli Karlsson

Vasa capsized and sank as it prepared forits maiden voyage in 1628Source: Statens Maritima Museer Photo Bengt afGeijerstam

vasa_Layout 1 10/10/11 10:52 AM Page 1

Continuous casting

EVERY three years, the European ContinuousCasting Conference (ECCC) gathers plantbuilders, steelmakers, research centres andUniversities together. This year ECCC was heldin Germany, concurrent with the Metec TradeShow, and along with three other conferencesrelated to the steel industry (covering Coke &Ironmaking, Energy Efficiency and Modelling).The technical content was organised by theGerman Steel Institute VDEh and theSecretariat by Tema Technologie Marketing.Around 400 participated in ECCC.

Near net shape casting Belt Casting Technology BCT® by SMS Siemagwith Salzgitter and Clausthal TechnicalUniversity, is being developed industrially forthe first time for steel. The decision to go aheadwith commercialising this long - researched pro-gramme was taken in May 2010 and the firstproduction belt caster is being installed inSalzgitter Peine Steelworks where it should bein operation by 2012. The cast strip size will be15mm thick by 1000mm wide (with plans toextend to 1600mm) and cut to maximumlengths of 9m (Fig 1).

This challenging technology aims at castinghigh strength steel strip in high alloy grades dif-ficult to cast in a conventional curved caster.

The liquid steel – under a protective atmos-phere – is distributed onto an open horizontalbelt moving at casting speed. Side dams pre-vent spread of the liquid metal prior to solidifi-

This report summarises a sample of the130 papers, selected for presentation atthe 7th European Continuous CastingConference, chosen for highlighting newresults, break-throughs in the continuouscasting field or simply for their technicalcontribution to continuous casting.By Jeanne Choné*

cation and the strip is cooled from below. Theprimary cooling length is 11m, and the castingspeed 30m/min. To obtain uniform strip, thekey point seems to be the control of the shapeof the flow of metal out of the mould in termsof width and depth. An electromagnetic deviceguides the liquid as it spreads out on the belt.Belt material, cooling device and process moni-toring, are all part of the proprietary technologyof BCT (Plenary session 1 - 14:20).

The CSP® (Compact Strip Production) thinslab casting technology developed by SMSSiemag, and first commissioned in the 1980s,now presents extended possibilities. VerticalLiquid Bending machines (VLB) offer a highercapacity per line (up to 2Mt/y) than VerticalSolid Bending machines (VSB) which are limit-ed to 1.6Mt/y. VLB technology has taken expe-rience from VSB machines but has gone fur-ther; eg in the strand guide system, and air-mistcooling (Session 7 part 1 – 9:00).

ArcelorMittal at its CSP plant in Sestao,Spain studied the fluid flow in the mould fordifferent slab widths thanks to a mathematicaltool. They went on to select a new SEN design,to be industrially tested. This four port SENseems to give a more stable flow pattern, lowermeniscus velocity and a more homogeneoustemperature distribution (Fig 2) (Session 10 –13:40).

Danieli entered the field of thin slab castingwith their fTSC (flexible Thin Slab Caster tech-nology) enabling an extension of grades of steel


cast on such machines and also offering greaterproductivity. The technology was recentlyapplied at Posco Gwangyang works in SouthKorea where one of the few alternative forms ofthin slab caster – the ISP caster – had previous-ly operated. The paper provides operationalresults and technology key points (mould flowcontrol, lubrication, primary cooling, spraycooling, level control etc). Production on onestrand was stated as 1.8Mt/y at a casting speedof 8m/min (Session 7 part 1 9:40).

Mould lubrication powder entrapment hasbeen studied by water modelling by ShenyangUniversity China. Uncontrolled movements arethe main risks, arising from the submerged noz-zle design. (Session 7 part 2 –11:40).

Arvedi ESP (Endless Strip Production),developed by Arvedi in Cremona, Italy andengineered by Siemens VAI directly links thecaster with the rolling mill without any interme-diate buffer which is necessary in all other cast-ers. Rolling started industrially in AcciaieriaArvedi Cremona in June 2009. Output hasreached 1.2Mt/y at present but 1.8Mt/y is fore-seen within a few years. A funnel mould is used80mm in its maximum thickness and the cast-ing speed is over 6m/min. The in-line strip milldelivers a final coil thickness of 0.8mm to1.5mm. ESR’s main advantage claimed is ahuge cost reduction compared to conventionalstrip product, with 35% reduced cost whencompared with other thin slabs technologies(Fig 3) (Session 7 part 1 - 10:00).

*Choné Consulting, 18 avenue de Longchamp, F 92210 Saint Cloud Tel +33 1 4602 7935 web www.chone-consulting.com

A report on the 7th European ContinuousCasting Conference

Fig 1 Belt CastingTechnology is to becommercially trialed at Salzgitter Pein

Fig 3 Specific cash conversion cost of liquid steel to hot rolled coilfor ESP vs conventional and other thin slab casters

Fig 2 Influence of SEN design on temperature distribution in themiddle plane and at meniscus (W=1000mm, Vc=4.8m/min andimmersion=340mm) ArcelorMittal Sestao

Standard SEN

SEN A

Temperature at meniscus:

T°(°C)

T°(°C)

Averaged temperature in median plane:

SEN B

4 portsSEN

9,0€/t

16,5€/t

17,5€/t

1,8€/t44,9€/t

28,4€/t

37,0€/t

5,0€/t

6,8€/t

14,4€/t

2,2€/t

7,9€/t

8,3€/t

18,3€/t

2,4€/t

Personnel

Other

EnergiesMaterial

Conventional ESP Other

45

40

35

30

25

20

15

10

5

0



Continuous casting


The ESP technology employs: – AFM® funnel mould of KME Germany

AG&Co. According to KME, mould life is over several months without breakout (ses-sion 7 part 2 –11:00).

– The ABB electromagnetic brake EMBr to reduce waves in the meniscus and control themovement of the liquid.

– The K&E Technologies- RHI refractories submerged nozzle. The design of which is theresult of computer calculations and water model simulation (Session 7 part2 –11:20).

Tata Steel IJmuiden studied the lubricationof its thin slab casting DSP (Direct SheetPlant). The result is a choice of mild coolingtogether with an increased taper of the mouldto give less heat transfer at the meniscus buthigher along the remaining part of the mould(Session 8 –13:40).

The Tundish as a metallurgical toolThe influence of tundish slag on the cleanlinessof transient slabs produced at ladle changes hasbeen studied at Ternium Siderar in cooperationwith the Instituto Argentino de Siderurgia. Bytracing the slag, they were able to detect slagemulsification at ladle changes responsible for adeterioration in steel cleanliness in the transi-tion slabs, which became worst as casting speedincreased and also with increased number ofladles in the sequence. An argon barrier imping-ing on the sides of the metal stream was usedwhen casting high quality grades with some suc-cess in avoiding large non metallic inclusions(>30μm) (Session 2 – 16:00).

A set of casting devices in three locations;upstream, in the tundish and downstream, toprevent steel contamination with slag andrefractory wear products, was presented byVesuvius. These are the Turbostop™ impactpad, The MicroClean™ tundish Gas diffuser –a gas curtain set across the width of the tundishat its bottom, the Enhanced Ladle BottomYield ELBY™ to prevent a metal vortex andsubsequent ladle slag drainage, and the S-DADtundish nozzle to preventing tundish liningwear products entering the molten steel(Session 2 – 17:40).

Tundish refractoryArcelorMittal in Galati, Romania, has beenusing Dry Mass cold linings in the tundish sincethe first half of 2010 for its two slab casters.The product is supplied by Vesuvius-Tundex™.Hardening is obtained after curing one hour at360°, and no preheating before casting is neces-sary, offering subsequent savings. (Session14 –9:00).

Following the same basis, RHI recentlydeveloped a new ‘cold lining’ for the tundish.

The preparation consists in mixing the productwith a small amount of water, and setting it onthe tundish walls using a template and thenvibrating. It hardens after 30 minutes withoutheating. Until now, no reference for its use hasbeen cited. (Session 14 – 10:00).

The tundish wear lining is a potential sourceof non metallic inclusions. CSM CentroSviluppo Materiali, Italy, studied, the interac-tion between silica contained in the tundishrefractory and liquid carbon steel. Liquid steelreacts with silica at the lining interface to forma liquid slag, a potential source of ‘exogenous’non metallic inclusions in the liquid steel.Changes in steel composition may occuraccording to its initial composition and resi-dence time (Session 14 – 9:40).

Nozzle design/cloggingWhen casting round section blooms the sub-merged entry nozzle (SEN) – or shroud (SES)has been investigated using numerical andwater model methods. At the University ofScience and Technology Beijing China, variousnozzle design were modelled, the result is a rec-ommendation for a four port nozzle with out-lets in a tangential horizontal direction.According to the study, swirling at outletsdecreases the impingement depth of the steelflow and reduces the superheat in the upperpart of the mould. This shape is also reputed toinhibit mould level fluctuation of the metal(Session 10 – 14:20).

For slab casters, the aim is to design sub-merged nozzle outlets to produce a steady andsymmetric flow in the mould, with a flow pat-tern of two gentle double rolls without swirling,taking into account gas injection and castingparameters. To achieve the optimum design,the extensive use of numerical tools and watermodels is being jointly applied by refractorymanufacturers and steelmakers, and confirmedby plant measurements. RHI with Tata SteelIJmuiden, Krosaki Harima Corp with Tata SteelStrip Products UK, and Kobe Steel presentedtheir methods and optimum design (Fig 4)(Session 10). No apparent universal design hasemerged.

Dalarna University and KTH in Swedencarefully studied clogging in submerged graphi-tized alumina nozzles for stainless steel contain-ing rare earth elements. The graphitized alumi-na nozzle is coated by a ‘glaze’ to preventdecarburization during preheating. The studyshows that decarburization, whenever itappears, is detrimental in causing clogging. Theglaze is suspected to penetrate the nozzle insome parts during preheating. At such places, inused nozzles showing clogging, rare earth ele-ments are found under the accretions. (Session14 - 10:20).

Fig 4 Schematicillustration of theeven flow in themould Kobe Steel R&D

Fig 5 Comparison ofchill zone (shellgrowth) in mouldwithout optimizedheat extraction atcorners (left) withINVEX® mouldshowing regularshell growth (right)

Without FC mould

Disturbed meniscus

Calmer and hottermeniscus

Location of iron cores

Upper field

Lower field

Inclusions

Less penetrationdepth

VorticesThin powder

film

With FC mould

Fig 6 The FC Mould (right) uses two fieldcoils for electromagnetic flow control compared with a conventional slab castermould

Nozzle clogging in Ultra Low Carbon steel,according to Voest Alpine Stahl andMontanuniversitaet Leoben, increases with Tiand P content. These elements reduce the meltsurface tension. When Ti increases, deoxidationalumina particles are smaller and show in a thinsurface layer containing Ti at the steel contactregion responsible for a higher clogging tenden-cy. The influence of P is to enhance the Ti effect(Session 17).

ThyssenKrupp Steel in Duisburg, along withGeorg-August-Universität Göttingen, made anew approach to recognize the causes of clog-ging: the oxygen isotopes analysis. By analyzingoxygen isotopes in clogging deposits from sub-merged nozzles taken from different plantsover different periods, and comparing these topotential sources, the authors were able topoint out three sources of oxygen isotopes:Slide gate powder (reduction of chromite),deoxidation particles and oxygen from the air.

Mould lubricationConcast has developed a tubular copper mouldfor long products – blooms and billets – withintegrated cooling grooves and the cornerradius varying along the mould length to followthe product during shrinkage to maintain opti-mum heat extraction. This INVEX® mould hasadjustable, calculated corner radii. The caststeel is reputed to stay in contact with the watercooled mould and so prevent corner and offcorner cracks (Fig 5).

Experiences in CC machines for blooms (rail,tire cord) and billets (rebar) were mentioned.One advantage of such a mould is the castingspeed can be increased (Session 5 – 9:20).


Following the same basic rule of maximisingheat extraction along the mould – Siemens VAIMetals Technologies instrumented an experi-mental copper tube to improve the taper profileaccording to steel grade and operating condi-tions of the plant. The result is an ‘optimizedDiaMold’ for long product casters to achievehigh productivity (session 5 – 10:00).

Prosimet together with Feralpi Siderurgica inLonato Italy, investigated billet quality and per-formed trials on 140x140mm square section bil-lets to improve the heat exchange in the mouldand decrease subsurface defects (double skin,segregated half way cracks). The best lubricantfound is a mixture of 60% flux with 40% oil, inthe case of this CC machine which does not usea submerged nozzle (Session 8 – 13:20).

The University of Science and TechnologyBeijing, China, proposes to solve the unevenslab surface of peritectic steels by slightly mod-ifying the steel composition. They use ‘Thermo-calc’ to calculate the actual peritectic point andadjust the steel composition to change thesolidification mode so altering the relative pro-portion of δ ferrite and γ austenite subsequentto solidification to improve the uneven growthof the initial solidified shell. This is caused bythe δ γ transformation which results in acontraction and the formation of an air gapbetween the solidifying shell and the mould.(Session 8 – 15:40).

Tata Steel Projects and RD&T Teesside, UK,showed an improvement of the end face life ofCC moulds by applying a ceramic coating. This‘CASTCOAT’ can be set on slab or bloommoulds as well as on foot rolls. Applying the W-Co based coating is the proprietary knowledgeof Tata Steel and few details were given in thepresentation. With such a coating, life improve-ment is reputed from 2.5 to 10 times better andthe coating can be repaired if damaged (Session8 – 17:00).

The formation mechanism of Oscillationmarks (OM) has been carefully studied byMEFOS, Imperial College London and TataSteel The Netherlands.

According to their study on CC slabs:– OM initiate during the negative stripping

part of the cycle, whatever other casting parameters (frequency, casting speed) are used.

– OM are caused by variations in lubrication slag flow direction.

– Shell growth occurs mainly from the end of negative stripping and peaks at the middle of

Continuous casting


the positive strip time. The OM depth can then be predicted

according to changes in oscillation settings andcasting conditions.

Application of this has been made for shellformation in thin slab casting and should helpto achieve a smoother cast surface. (Session 8 –17:20).

Sumitomo Metal Industries, Kashima hasdeveloped a set of mould conditions to increasethe casting speed of hypo-peritectic steels.These are:

– The use of cuspidine-based mould powder, (CaO/SiO2=1.15; CaF2 = 25%) which is reputed to decrease heat transfer;

– The use of an electromagnetic brake EMBRin the mould;

– The SEN should deliver a double roll flow motion in the metal.

As a result it is possible to achieve a smootherslab surface along with an increase in castingspeed (session 12 – 10:40).

Secondary cooling The Secondary Cooling strategy may solvequality problems such as surface corner cracksfor micro alloyed and peritectic grades formedduring straightening according to a presenta-tion by ArcelorMittal (Session 3 – 16:40).

Ferritic stainless steels slabs (AISI 409L), sub-jected to bulging and side deformation, presenta more accurate shape by widening the second-ary cooling zone according to Posco’s TechnicalResearch Laboratory (Session 3 – 16:20).

Secondary cooling 3D calculationSiemens VAI has developed a 3D model ofcooling for slab casting. This model, named‘SIMETAL Dynacs 3D’ is said to account forlocal phase transformations taking place and forshrinkage. The corner situation is then welldescribed and solutions to treat ‘corner cooling’may follow (Session 12 – 10:20).

High pressure water spray coolingJFE Steel Corporation of Japan experimentedwith high pressure water cooling in the second-ary cooling zone of a slab caster and foundgreater efficiency than when using air-mist cool-ing. Properly set below the mould, and usingthe same amount of water, the casting speedwas increased by 15% according to the reportwithout any internal quality problems (Session15 -12:20).

Impact on qualityDragon Steel, a subsidiary of China Steel Corpin Taiwan (3Mt/y) is trying to move from bloomto billets for the production of low alloyed steelquality grades, using SMS Concast technology.The actual limitation to increasing the produc-tivity is the castability of the metal (Plenary ses-sion 1 – 14:00).

Posco implemented a soft reduction unit onits 8-strand 400x500mm bloom caster at itsPohang Works to decrease the centre segrega-tion in high carbon wire rod (over 0.8%C). Theamount of soft reduction is 20-30mm usingConvex-roll technology, which offers greaterefficiency and fewer risks than when using a flatroll profile. The Convex roll profile respects thecorners so reducing the formation of cornercracks (Session 5 – 11:20).

Electromagnetic stirring in the slab mould,prevents troublesome movements in the mouldliquid responsible for surface defects anduneven solidified shell. ABB, Danieli Rotelecand Nippon Steel have all develop such solu-tions for slab casting (Fig 6).

ABB presented results of its FC mould withBaosteel, Meishan works. The FC Mould usestwo static magnetic fields, an upper field at theslab meniscus level to control the meniscusmetal flow velocity and a second independentlycontrolled lower field in the lower part of themould to minimize the penetration depth of thesteel jets from the SEN (Session 4 – 16:40).

New & Revamped Machines New trends in slab casters revamps are tochange from bent to straight machines for qual-ity reasons and to built extra thick slab (250-400mm) casters to achieve the market quanti-ties required for heavy plates (Session 13 parts1 & 2).

For long product bloom casters, central seg-regation is of concern and machines are beingrevamped to meet the requirements of theautomotive market as well as to increase pro-duction.

Table 1 summarises recent caster projects.

Contact

The Proceedings of all four conferences are available in pdf format

on a single CD.

Price €100 including shipping but plus 19% German VAT.

Available from Congress Secretariat

TEMA Technologie Marketing AG

Theaterstrasse 74, 52062 Aachen, Germany

Tel +49 241 88970-43 Fax +49 241 88970 42

e-mail [email protected] web www.tema.de

Table 1 Recent caster projects

Siemens VAI ThyssenKrupp CSA New steelplant / 2010 Slab 5Mt/y Greenfield plant 2CC machines 250mmx800-2000mm

Danieli Various Upgrade in different plants worldwide Slab Participation to slab casters conversion from curved to vertical curved

in the decade in POSCO Gwangyang, TK Beekerwerth, ArcelorMittal Dunkerque and other projects

enhancement or modification

POSCO Gwangyang New machine/2010 Slab Slab 250-300mm vertical, bent heavy plates

POSCO Pohang New machine/2011 Slab 400 - 250mm vertical, bent. Pipe, heavy plates market

SMS Siemag Salzgitter New machine/commissioned 2010 Slab Slab 250/350mm bow type single strand. Micro alloyed,

heavy plates, pipe grades

Siemens VAI Acroni Republic Slovenia Revamping/2009 Slab Slab 250-250mm bow-type. carbon, stainless, special steels

Danieli ThyssenKrupp TKAST Terni New machine replacement/2009 Slab Single strand Slab caster 215mm Stainless steel 900kt/y stainless steel

Siemens VAI Shougang QinHuangDao China Bow type caster/2010 Slab Slab machine, Straight and curved on liquid 250-400mm for

alloyed medium carbon, pipe API, medium carbon plates.

Salzgitter Peiner Träger GmbH New production/2010 Combi Caster N°2. Beam blanks and slabs 250mm

SMS Saarstahl Revamping/2009 Bloom S3/5 strands 240² to 265x340mm Bloom carbon and alloyed qualities,

Mechanical soft reduction

Tata Steel Projects RINL Vizag SteelPlant India Revamping/2010? Bloom N°2 4 lines bloom casting machine

SMS Concast Sumitomo Metals Kokura New machine replacement /2009 Bloom Bloom Auto market

Plant maker Steelmaker Objective/year of start Type Remarks

Continuous casting

The influence of ceramic sprayed casterrolls on the internal quality of slab

TO obtain improved internal quality of contin-uously cast steel slabs the technique of sprayingthe caster rolls with a ceramic compound hasbeen developed to increase the thermo-mechanical rigidity of the slab subjected tothermo-mechanical stresses generated betweenadjacent sets of caster withdrawal rolls.

The idea behind this technique is to increasethe resistance to deformation (Ic) of the solidi-fying shell forming within the slab as it movesfrom mould to withdrawal rolls by optimizingthe uniformity of cooling of the slab betweeneach set of withdrawal rolls. This is achieved byminimising rapid fluctuations in the surfacetemperature of the slab, especially in the con-tact area between each roll and slab. A mathe-matical model to calculate thermal gradients,the development of the slab shell as it solidifies,the resistance of this solid shell to deformationand the cooling conditions has been derived.

The model predicts that the increase in thethickness δc of the ceramic coating or adecrease in its thermal conductivity κc is pro-portional to a decrease in the peak surface tem-perature in the roll contact area. The predica-tions also point out that improving the solidshell resistance depends on the optimum selec-tion of δc and κc which govern the fluctuationsin the cooling conditions of the slab and rolls.

The predications were also used to explainthe mechanisms and characterisation of therelationship between the ceramic coating andthe resistance of the slab shell with the thermo-mechanical rigidity of the steel slab.

The internal quality of continuously cast steelslabs is determined mainly by the intensity of theexternal and internal deformations taking placein the solid shell which first forms in the mouldand acts as a containment for the liquid steel asthe cast section is withdrawn from the mould1.

Beyond the mould, secondary cooling isachieved in a traditional spray chamber (Fig 1).

Deformation of the shell can be generated bythermo-mechanical stresses imposed on thesolidifying shell at various stages within the sec-ondary cooling zones. These stresses are associ-ated with unfavourable operating conditionsand with poor cooling patterns. This leads tothe broad face of the shell bulging in and out1,2.Such bulging is presumed to play a major role informing internal defects. These defects result inpoor quality in the final steel product ordecreases caster productivity due to the need toscrap the slab3-6.

This paper is concerned with improving thedesign of the roll spray section of the caster tominimize internal thermo-mechanical stressesand therefore improve the internal quality ofthe slabs cast.

A technique has been developed to improve the internal quality of continuously cast slabs by maximising the solid shell resistanceof the solidifying slab as it is withdrawn through the caster rolls. The aim is to optimize the thermal resistance of the caster rollsby spraying a thin layer of ceramic material coat on the roll surface. This ceramic layer has a significant effect on heat transferbetween slab and rolls but the result can be good or bad for slab internal quality depending on coating characteristics and casterwater spray cooling conditions. Also, the results show that the thermo-mechanical rigidity of the caster rolls is an essential tool toinvestigate the effectiveness of cooling in the caster and caster operating conditions which influence internal slab quality.By M O El-Bealy*

Numerous studies have been devoted tomathematical analysis of the high stresses gen-erated in coherent shells of continuously caststeel slabs in the secondary zones7,8. Thesestudies show that the resistance of the solidshell plays a major role in defining the level ofbulging and therefore the internal quality of theslab.

Miyazawa and Schwerdtfeger1 developed amodel to compute bulging based on the solidshell resistance concept. El-Bealy extended thismodel to study the effect of various coolingconditions9 on the formation of cracks halfwayalong the slab and the change in macrosegrega-tion10. He also studied the effect of differentcooling patterns7,9 and different dendritic solidphase distributions8 on the solid shell resistancein the secondary cooling zones.

Although the preceding models have beenextensively studied, the influence of homogene-ity of cooling between adjacent withdrawal rollshas received little attention. In the presentstudy, the mathematical model was extended toinclude the effect on the resistance of the solid-ifying shell to increasing the thermal resistanceor decreasing the heat removed from the slabsurface in the roll contact area.

Mathematical ModelsThe mathematical models have been developedfrom first principles and are based on the gen-eral framework for governing equations of heatflow, solidification, solid shell resistance andcooling conditions. Most of these equations arechosen for simplicity and could easily bechanged without introducing fundamentalchanges to the model. Only a few explanationsare provided here, and the reader is referred tothe original references for the details of themould, the assumptions, thermo-physical/mechanical properties of the steel alloy andnomenclature made in the derivation1,3,7,11-13.The model presentation is divided into fourparts:

A- Mathematical Modelling of HeatTransferA-1 Heat flow in slab: To determine the tem-perature distribution throughout the cross sec-tion of slab as indicated in Fig 2, the governingheat flow equation of the following form wasemployed11:

(Eq1)

(Eq2)


*Companies’ Chair of Materials Processing & Technology, ASU, Egypt, CTU, Germany, KTH, Sweden and MIT, USA. Egypt Branch, Ain Shams University, Cairo.

A-1-1 Initial & boundary conditions:Considering symmetry, only a two-dimensionaltransverse slice of the cast slab has been simu-lated as seen in Fig 2. The initial surface tem-perature (T ) when t=0, was taken as:

(Eq3)

For the surface boundary conditions, the sur-face slab heat flux can be computed from:

(Eq4)

On the slab surface, the heat flux balance canbe calculated from;

(Eq5)

A-2 Heat flow in work roll: The heat lost fromthe slab is gained by the caster roll in the rollgap, necessitating simultaneous solution of thegoverning equations. The same approach devel-oped by Sumi et al12 was used with the follow-ing assumptions13:

– the temperature change during roll contact was confined to a thin layer (δ), which is in acyclic steady state;

– the heat flow along the axial direction of rollsis ignored;

– heat conduction along the peripheral direc-tion (θ) was negligible compared with the bulk heat flow, because the Peclet number isrelatively high ~41000.

– the thermal conditions of the left and right rolls (in the vertical segments) are assumed tobe identical.Based on these assumptions, the governing

equation for temperature distribution in thecaster roll at complete contact with the slab sur-face can be simplified as:

(Eq6)

(Eq7)

where t* is the time taken for an elementalvolume of the roll to rotate through an angle measured from the reference point of the slabentry at roll contact area.

A-2-1 Initial & boundary conditions of workroll: The initial condition of the caster roll at theentry contact area is:

(Eq8)

φ

φ φ

φλ( )

–

–

z=υt

ρ ρ ρ ρ∇ ∇ ∇ ∇– –

θ =ωt

λ ρ


λ


The boundary conditions are as follows:

(Eq9a)

And at the surface

(Eq9b)The heat transfer coefficient (h) for each roll

cooling pattern was determined in the coolingconditions section.

B - Solidification ModelAs stated earlier, theoretical analyses havelinked the solidification behaviour to the solid-ification parameters. In this study, the solidfraction for different phases of the mushy zoneand the three phase peritectic reaction of a Fe-0.12%C steel alloy was computed by applyingthe approach developed previously7. The frac-tion of primary delta f determined by applyingthe following equation was employed until theperitectic temperature7.

(Eq10-a)

At the peritectic temperature and in the peri-tectic range, the following equation was used7:

(Eq10-b)

C - Solid Shell Resistance ModelThe position of the neutral axes and solid shellresistance (Ic) due to the heat transfer andsolidification phenomena1,7 can be calculatedby the same form of equations where, in thecase of the position of neutral axes, the equa-tion is:

(Eq11)

However, in the case of the solid shell resist-ance, the equation is:

(Eq12)

where (A), (m) and (n) in Equations 11 and 12are material parameters and can be determinedexperimentally by defining the uniaxial creeptest as illustrated in Ref1,3,7.

Continuous casting


To examine a macro-quality criterion of con-tinuously cast steel slab, a new concept calledmacro thermo-mechanical rigidity (Mac-TMR)has been proposed to reveal slab macro-defectssuch as bulging and related defects. This con-cept can be defined by computing the non-dimensional Mac-TMR number at certain dis-tance from the molten metal meniscus in themould as follows:

(Eq13)

Eq13 consists of two main parts where thefirst part addresses the thermo-mechanicalparameters and the second the thermo-materialparameters. The mechanical parametersinclude two parts: One for slab solid resistance(Ic) and roll diameter DR which is in the nomi-nator of the equation whereas in the dominator,roll length (l), the distance between a set ofcaster withdrawal rolls (WR) and ferro-statichead (Pz), all appear. In the thermo-mechanicalpart of Eq13, the slab geometry ratio is alsopresent. This ratio is the ratio between the slabsection modulus (Zs=I/x) and the slab width(Ws). The next part of Eq 13 contains the cast-ing speed (v) and the time the slab spendsbetween a set of caster withdrawal rolls (tR),and is located in the dominator of the equationof Eq 13. Also, (mk) is the exponent of solidphase (k)1,3,7.

D - Cooling ConditionsThe effect of various cooling conditions in themould and upper spray cooling zones on theNewtonian heat transfer coefficient profileespecially between adjacent withdrawal rollswas investigated. The simulated slab caster isbased on an actual industrial casting machine inuse at SSAB, Oxelösund, Sweden and the read-er is referred to the original references for thedetails of cooling and operating conditions.

Ladle

Tundish

Spraychamber

Ladle shroud

Middle slice

Slab

Roll

BTundish stopper rod

Submerged entry nozzleWater cooled copper mould

Support rollsWater sprays Torch cutter

Runout table

Straightener

Fig 1 A typicalcurved continuousslab castingmachine

Yx

I

Y

DR

Fig 2 Schematic of sprayed ceramic coating and slab grid ofcomputation

Due to the difficulties of measuring the surfacetemperature continuously in this region todetermine its thermal details, the sameapproaches proposed by El-Bealy et al9,14 formould and secondary cooling conditions wereapplied in the present study. In the upper sprayzone, an additional spray cycle9 was used tocool the slab surface.

The cooling conditions of this cycle can bedivided into three parts, each characterized bythe mechanisms of heat transfer. The threemechanisms corresponds to: conductive-con-vective roll contact region (rc), (Fig 3)9, fol-lowed by radiative-convective heat transfer inthe unsprayed, area (I), where there is no watercooling the slab directly, followed by (II) directspray cooling between the withdrawal rollswhere the spray impinges directly onto the slabsurface (ds) minus overlap. This is followed byanother unsprayed area (III) until completecontact with the next withdrawal roll set occursas shown in Fig 3.

Sometimes, the roll spray and direct spraynozzles generate areas of overlapping spraysub-regions between the unsprayed (ds & III)and direct sprayed regions where theNewtonian heat transfer coefficient (h) mayincrease slightly. Because of these heat transfermechanisms the

Newtonian heat transfer coefficient fluctu-ates rapidly between each set of caster with-drawal rolls.

Results & DiscussionTo examine the effect of different thicknessesand thermal conductivities of the sprayedceramic material on the Newtonian heat trans-fer coefficient (h), surface temperature (Tφ )and solid shell resistance (Ic) just for the middlebroad face slice shown in Fig 2, model simula-tions were run for a three phase peritectic steelalloy (Fe = 0.12%C). The results are sum-marised in Fig 4 (a-c) respectively.

Roll water nozzleRoll h

z

rc

ds

Slab

Roll water nozzle

Casting direction

Water nozzle

Fig 3 Schematic ofextra nozzle coolingcycle

λ

– λϖ

γ γ γγ

γ γγ γγ

Σ ∫

∫

– δ, –

–

–

– ––

– ––

{

) )(

}

� ��

δ δ

δ

–

Σ

( ( )( ))

δ

δc

-

-_

(

Effect of roll coating thickness cAs indicated in the study of simulating coolingconditions in the secondary cooling zones con-ducted earlier by Hibin and Brimacombe15 andmore recently by Hardin et al16, it is commonthat (h) fluctuates rapidly between one set ofwithdrawal rolls and the next in cycles based onthe cooling conditions. Fig 4 (a) shows thistrend where (h) fluctuates rapidly betweenadjacent roll sets. Plots are made for no coating,50μm and 150μm ceramic coatings. In the rollcontact region, for rolls without a ceramic coat-ing (h) increases rapidly to a maximum of840W/m2K where the rolls contact the slab,whereas in the case of rolls with a 50 and150μmm ceramic coating, the peak value of (h)decreases to 640 and 580W/m2K, respectively.This means that the maximum value of (h) inthe roll contact region, (see Fig 3), is propor-tional to the decrease in the ceramic coatingthickness.

This is followed by a rapid decrease in (h) inthe unsprayed region in the shadow of the rollto a low of 180W/m2K for different ceramiccoating thicknesses. As a result of overlappingbetween the roll spray and direct spray nozzlesa small sub-region forms in the unsprayedcooled regions on the both sides of directsprayed zone, (See Fig 3). In this sub-regionthe heat transfer coefficient (h) increases grad-ually. It again increases to a lower peak value of400W/m2K in the region where the water spraydirectly impinges on the slab between the rollsets. This is followed by a sudden deceasing inits value to 173W/m2K in another overlapping

Continuous casting


sprayed cooled sub-region. There is an observ-able difference in (h) between the first and sec-ond overlapping spray sub-regions. In the sec-ond sub-region, the value is very slightly higher(241W/m2K) than in the first overlapping spraysub-region (240W/m2K). This may be a positivesign showing that cooling is improving betweenadjacent sets of rolls further down the with-drawal segments.

The fluctuation in the surface temperature ofthe slab (Tφ) for uncoated, 50μm and 150μmmroll coatings is shown in Fig 4 (b). The resultsshow that maximum cooling on the slab surfaceappears at the roll contact region and the dropin the surface temperature is inversely propor-tional to the increasing in the ceramic coatingthickness. The surface temperature of the slab(Tφ) reaches a maximum value in the unsprayedregions between sets of withdrawal rolls.

Such a temperature profile is a positive signof improvement in cooling between adjacentwithdrawal roll sets.

Fig 4 (c) plots the resistance of the solidifyingshell (Ic) showing a continuous increase in itsstrength without fluctuations in value as the dis-tance from the meniscus of the metal in themould increases. The results show that (Ic)increases at different rates in the different cool-ing regions between a set of withdrawal rolls forthe different ceramic coating thicknesses. In theroll contact region, the rate of increase of shellstrength (Ic) is highest whereas it slows to aslightly lower rate in the overlapping spraycooled sub-regions. It is interesting to note thatthe rate of increase of (Ic) with distance from the

meniscus in the middle of direct spray cooling isapproximately zero for all coating thicknesses.Another interesting observation arises from test-ing these results where the total value of (Ic) at1m from the meniscus increases by 10% in thecase of a roll with a 50μm ceramic coating com-pared to a roll with no coating. However, thetotal value of (Ic) at 1m from the meniscusdecreases by 10% in the case of a 150μm ceram-ic coated roll compared with no ceramic coatingon the roll. This is due to the effect of the posi-tion of the neutral axes on the value of (Ic) wherethis position is controlled by temperature distri-butions and solidification phenomena asdescribed in equations [11] & [12]7.

Effect of thermal conductivity (κc)The data given in Figs 5 (a-c) demonstrate theinfluence of various thermal conductivities(κ c) of ceramic material on the simulatedNewtonian heat transfer coefficient (h), slabsurface temperature (Tφ ) and solid shell resist-ance (Ic) of the continuously cast steel slabs.

Fig 5(a) illustrates the comparisons of effectof the different shell resistance (Ic) on the heattransfer coefficient (h) for rolls coated withceramics of differing thermal conductivities.Both coatings show that (h) fluctuates rapidlyin the different cooling regions between a set ofrolls. The main observations are the value of (h)in the roll contact region is inversely propor-tional to increases in (κc) and (h) in the secondoverlapping spray cooling sub-region is lowerthan the previous one. This gives a negativeindictor highlighting poor cooling conditions

without

with+ 150μm

with+ 50um Low Medium

0

00.7 0.7

0.70.7

0.80.8

0.8 0.80.9 0.9

0.90.9

1 1

11

1.1 1.1

1.11.1

1220

1000

2000

3000

4000

5000

6000 2600

2500

2400

2300

2200

2100

2000

124012601280

1300

13201340 1390

138013701360

1290130013101320

13401350

1330

0.7 0.70.8 0.80.9 0.9Distance from meniscus, (m)

Distance from meniscus, (m)

Distance from meniscus, (m) Distance from meniscus, (m)



Hea

t tr

ansf

er C

oef,

(W

/m2 k

)

Hea

t tr

ansf

er C

oef,

(W

/m2 k

)

Surf

ace

tem

pera

ture

(°C

)

Surf

ace

tem

pera

ture

(°C

)

Solid

she

llre

sist

ance

(N

/mm

)1/m

Solid

she

llre

sist

ance

(N

/mm

)1/m

1 11.1 1.1

(a)

(b)

(c)

300

600

900650

500

350

200

50

(a)

(b)

(c)

Fig 5 Variations of (h) (T ) and (Ic) between adjacent withdrawal rollsets of different thermal conductivities of the ceramic coating

Fig 4 Variations of (h) (T ) and (Ic) for different ceramic coatingthicknesses

δ



Continuous casting


between a set of rolls where the slab surfacetemperature increases.

The model was next applied to examine theslab surface temperature (Tφ) between a set ofrolls as seen in Fig 5 (b). This reveals continu-ous reheating of the slab surface as predicted atsmall and fluctuating rates due to a largedecrease in the heat lost from the slab in the rollcontact area of ceramic coated rolls.

This is slightly more pronounced when thecoating has low thermal conductivity. Thisresult is detrimental and indicates that the cool-ing between sets of withdrawal rolls is insuffi-cient.

Fig 5 (c) shows computed (Ic) values underthe cooling and roll surface conditions used inFig 5 a & b. The predicted results point outthat there are steep changes in (Ic) betweenadjacent roll sets.

These steep fluctuations continue with dis-tance from the meniscus for different (κc) val-ues of the ceramic coating as shown in Fig 5(c). An interesting result comes from compar-ing (Ic) values for the first case examined, (seeFig 4c) applying this technique to the currentcases, (see Fig 5c) where (Ic) values drop by50% in the current cases. This is considered anindictor of lower internal quality of the contin-uously cast slabs for rolls of low and mediumthermal conductivity coatings.

Ceramic sprayed roll techniqueBefore proceeding further, it is appropriate toexplain briefly the thermal spray coatingmethod which it is proposed to use. The selec-tion of thermal spray method such as flamespray, electric arc spray and plasma arc spraydepends mainly on the type of application andon the economical considerations. In the pres-ent case, the standard flame spray method isadvised17.

Flame spraying includes low-velocity powdersprayed through the flame, rod flame, wireflame, while high-velocity processes includehigh velocity oxygen flame (HVOF) and thedetonation gun (d-gun). In the case of the cast-er roll, it is preferred to use low-velocity powderflame spraying. In this process, powdered feed-stock is aspirated into the oxyfuel flame, melt-ed and carried by the flame and air jets to theworkpice.

Particle speed is relatively low (<100m/s),and bond strength of the deposits is generallylower than when using the higher velocityprocesses. Porosity can be high and cohesivestrength is also generally lower. Spray applica-tion rates are usually in the order of 0.5 to 9kg/h(1 to 20 lb/h) for all but the lower melting pointmaterials which are sprayed at significantlyhigher rates. Substrate surface temperaturescan become high due to the flame impinge-ment.

Macro thermo-mechanical rigidityKnowledge of the contribution of the coolingconditions and the solid shell resistance (Ic) toMacro thermo-mechanical rigidity (Mac-TMR)of the slab is important in indicating how thedevelopment of the slab surface temperatureprofile can be controlled by adjustments to theflow rate from the water spray nozzles and thecharacteristics of the roll surface material.

Heat transfer of the slab is governed by directwater spray cooling, radiation, roll contact andby convection as the sprayed water drains awayand also by evaporation. These govern the totalheat extracted in each spray zone, as presentedin previous investigations9,18. In this study, the

without

medium

0.8

4.00E-04

3.00E-04

2.00E-04

1.00E-04

0.00E+00

Mac

-TM

R

0.9Distance from meniscus, (m)

1

lowwith+150μm

with+150μm

Fig 6 Variation of macro thermo-mechanicalrigidity of the slab with distance frommeniscus for various roll coatings

ceramic roll surface coating was included in theheat transfer parameters to improve the coolingand operating conditions between a set of with-drawal rolls.

To obtain a deep understanding of the tech-nique of producing a ceramic surfaced roll it isappropriate to analysis the mechanism of thecooling conditions between sets of adjacentrolls as well as its effect on the solid shell resist-ance and therefore, on Mac-TMR of the slab. Ithas been shown that the technique used to coatthe rolls has a significant effect on the coolingconditions in the roll contact area of the slaband unsprayed regions where slab is notsprayed with water during casting.

In the roll contact region, the maximum tem-perature at the slab surface generally falls pro-vided the roll surface material has thefavourable characteristics of high conductivityand a well laid coating. This is because thereduction in the heat flux between the roll andslab develops the strength of the solidifyingshell (Ic) significantly.

This decreases roll wear and the amount ofits elastic deflection which improves the inter-nal quality of the slabs cast. However, in regionswhere the slab is not sprayed by cooling waterthere are two observations of the effect of theceramic coating on the cooling conditions andtherefore, on (Ic): One condition is positive,improving (Ic), (see Fig 4 c), whereas the otherhas a negative effect where (Ic) drops and fluc-tuates rapidly under the changing coolingregions between adjacent sets of rolls, (see Fig5 c). This results from an unfavourable heattransfer coefficient (h) in the roll contact regionand the unsprayed slab region. The positive signimproves the internal quality of the slab whilethe negative condition contributes to poorinternal quality.

To analyse the macro thermo-mechanicalrigidity criterion (Mac-TMR) of the slab in thesecondary cooling zones, Equation [13] can beused. Eq [13] shows that Mac-TMR is propor-tional to the solid shell resistance (Ic) and thediameter of the roll, (DR) which appears in thenumerator of Eq [13] whereas it is inverselyproportional to the ferrostatic pressure, (P), thecube of the roll length (l), the casting speed (v),the time spent between a set of adjacent rolls(tR) and the type of steel (m). Fig 6 illustratesthe effect of these parameters on Mac-TMR atincreasing distances from the meniscus foruncoated rolls and rolls coated at thicknesses of50μm and 150μm with coatings of low andmedium heat conductivities. Quantitatively andqualitatively, there is a significant differencebetween the developments of Mac-TMR of theslab as the thickness of the ceramic coatingchanges and also as the thermal conductivity of

the coating changes from low to medium,depending on the cooling conditions. Whileslab rigidity (Mac-TMR) is highest for the thin-ner coating, it decreases when the coating haslow or medium thermal conductivity. Thisdivergence is due to unfavourable cooling con-ditions when the coatings have unfavourableconductivity. This agrees with the conclusionsof Grill et al19, and might explain why break-outs are found under poor cooling conditions inthe upper secondary cooling zone.

A further interesting observation arises fromexamination of these results. It is found that theslab may be subject to significant plastic defor-mation in the upper part of the caster, wherelow slab rigidity cannot be avoided, due to thelow Mac-TMR values of the slab there. Thismay result in serious external or internal defectsoccurring in the first stages of the secondarycooling zones such as a change in slab width15,interdendritic halfway cracks10 and centrelinesegregation16.

In conclusion, the thermo-mechanical rigidi-ty of the caster rolls is an essential tool to inves-tigate the effectiveness of cooling in the casterand caster operating conditions which influenceinternal slab quality.

AcknowledgementThe author is indebted to Companies’ Chair forMaterials Processing and Technology of Swedish IronMasters Association, Stockholm, Sweden, for finan-cial support of this investigation.

References1 K Miyazawa and K Schwerdtferger; Ironmaking& Steelmaking, 6, 68, 19792 E B Hawbolt, F Weinberg and J K Brimacombe;Metall Trans B, 10B, 229, 1979 3 J K Brimacombe and K Sorimachi; Metall TransB, 8B, 489, 19774 G Van Durnen, J K Brimacombe and FWeinberg; Ironmaking & Steelmaking, 2, 125, 19755 L Backer and G Gosselin; in Proceed OpenHearth Conf, Detroit, 53, 145, 19706 H Vom Ende and G Vogt; J Iron Steel Inst, 210,889, 19727 M El-Bealy; Can Metall Q, 36, 203, 19978 M El-Bealy; 80th Steelmaking Conf, ISSAIME,Chicago, IL, USA, 13, April 19979 M El-Bealy, N Leskinen and H Fredriksson;Ironmaking & Steelmaking, 22, 246, 199510 M El-Bealy; Scand J Metall, 24, Part I & II, 63 &106, 199511 D R Poirier, P J Nadapurkar and S Ganesan;Metall Trans B, 22B, pp 889, 199112 H Sumi, et al; Advanced Technology of plasticity,2, 1360, 1984 13 W C Chen, I V Samarasekera, A Kumar and E BHawbolt; Ironmaking & Steelmaking, 20, 113, 199314 M El-Bealy; 6th European Conference onContinuous Casting, Riccione – Italy, June 200815 J W Watson; (Slab Width Change Defect inContinuously Cast High Alloyed Steel Slabs(; Privatecommunications, ARMCO Steel, Middletown, Ohio,USA, 1995 16 P Sivession, CM Raihle and J Konttinen;Proceed Symposium on Advances in SolidificationProcesses, E MRS, Strasbourg, France, 1993 17 T M Thorpe; Thermal Spray Coatings, SurfaceEngineering, ASM Handbook, ASM International, 5,497, 199418 H A Weisinger, K L Schwaha and O Kriegner;2nd Process Technology Conf ISS-AIME, 2, 86, 1981 19 A Grill, K Sorimachi and J K Brimacombe;Metall Trans B, 7b, 177, 1976

Energy & environment

Energy saving and environmental protection: Tenova’s latest technologies

MAJOR steelmakers consider sustainability animportant component of their future develop-ment. The three pillars supporting sustainabili-ty are: economic, environmental and socialresponsibility.

The focus of this paper is on the environmen-tal side of sustainability and in particular on:Energy consumption and Greenhouse gases(GHG) emissions.

Steel production is energy intensive; it is thesecond industry after chemicals in terms ofenergy consumption (Fig 1). Energy constitutesa significant portion of the cost of steel produc-tion, ranging from 20% to 40% depending onthe process, local conditions, etc. Thus,improvements in energy efficiency result inreduced production costs and therebyimproved competitiveness.

The iron & steel industry has already gone along way in the direction of efficiency; sophisti-cated energy management systems ensure effi-cient use and recovery of energy throughout thewhole steelmaking process.

On the environmental side, CO2 emissionsintensity (tonne of CO2/t of crude steel) alsovary from plant to plant, and country to country.

As a whole, the iron & steel industry is a sig-nificant source of GHG emissions, accountingfor 4-5% of world carbon dioxide (CO2) emis-sions and 3% of GHG emissions1. It is thethird largest industrial source of GHG after thechemical and cement sector (Baumert, 2005).

Out of the sector’s estimated total emissionsof 2507Mt CO2-equivalent in 2006, 80% weredirect (on-site) emissions and 20% were indi-rect emissions from the generation of pur-chased electricity.

Over the 16 years 1990 – 2006, CO2 emissionsper tonne of crude steel decreased by 7%, froman average of 2.2tCO2/t of crude steel, to 2.0t.

The steel industry is not sparing its efforts to

limit its footprint and, on average, today CO2eqemissions have dropped to 1.9t of for everytonne of steel produced, according to the IEAEnergy Statistics.

The intensity of CO2 emissions vary fromplant to plant due to differences in the tech-nologies used, finished products, plant operat-ing efficiencies, plant maintenance, quality oriron ore and coal and the carbon intensity of theelectricity. The strongest factor affecting emis-sions intensity is the overall processing method.Two main steelmaking processes account for97% of the world steel production: the integrat-ed blast furnace-basic oxygen furnace (BF-BOF) route and the scrap/DRI-based electricarc furnace (EAF) route.

The BF-BOF route is more emission inten-sive than the scrap/DRI-EAF route, thoughestimates vary considerably (Fig 2). The highand low-end ranges indicate CO2-free and coal-based electricity generation, and account forcountry average differences.

International agreementsThe international effort to mitigate and adaptto climate change is coordinated and regulatedby the Kyoto Protocol (negotiated in 1997 andentered into force in February 2005) and theCopenhagen Conference (2009). The effortsestablished are not prescriptive and do not setout binding GHG emission targets.

In parallel to the Kyoto Protocol andCopenhagen Conference, Governments ofevery country have issued national primary poli-cies aiming at mitigating GHG emissions.

On average, the Kyoto Protocol andCopenhagen Conference’s target, to beachieved on a worldwide basis, is to reduceGHG gases by 15-20% by 2020 compared with1990 levels – the percent range depending onthe country.

In the past 30 years the steel industry has reduced its energy consumption per tonne of steel produced by 50%. This paper presents three of Tenova’s technologies which are achieving significant reduction in energy consumption and GHG emissions.By Gianluigi Nova*

In 2009, total global CO2 emissions increasedto 31.3bnt, almost 40% more than in 1990, thebase year of the Kyoto Protocol (Fig 3).

The assessment excludes CO2 emissionsfrom deforestation and logging, forest and peatfires, post-burn decay of remaining above-ground biomass, and from decomposition oforganic carbon in drained peat soils.

Collectively, the countries that signed theKyoto Protocol (Annex I) reduced CO2 andgreenhouse gas emissions in 2009 by 7% com-pared to 1990, the base year for the Protocol.Most of this decrease, though, has taken placedue to production cutbacks responding to thefinancial crisis. Greenhouse gas emissions couldrapidly increase toward pre-recession levels asindustrialized countries grow out of recession.

In the countries that did not sign the KyotoProtocol we have seen a growth in emissions.

Considering the above:– The worldwide economy will have to make a

major effort to just be able to get close to theambitious Kyoto Protocol and Copenhagen Conference target;

– The iron and steel industry will play an important role;

– Innovation will make a fundamental contri-bution.The most important innovations of Tenova’s

technologies in the field of energy efficiencyand CO2 emissions abatement follow:


*CEO Tenova. Based on Mr Nova’s presentation to InSteelCon 2011, Düsseldorf 27 June-1 July 2011

1 Unless specified otherwise, all CO2 and GHG emissions figures in this paper include both direct (on-site) emissions from fuel combustion and the use of coal and lime as feedstock and indirect emissions from

generation of the electricity and heat used in the steelmaking.

Chemicals Scrap - EAF

401000 million tonnes CO2

International transport – Developing countries

Other developing countries

China

Other economies in transition (EIT)

Russian Federation

Japan

Other OECD 1990 countries

USAEU15

Other large developing countries

30

20

10

0

1990 1995 2000 2005 2010

AdvancedBF-BOF

Present BF-BOF

DRI (naturalgas) - EAF

0%0 500 1,000

kgCO2 eg/t crude steel1,500 2,000

5% 10% 15% 20% 25%

Iron & steel

Pulp & paper

Non ferrousmetals

Non metallicminerals(cement included)

Fig 1 World industrial sector energy consumption by major energy-intensiveindustry. Source: IEA Data Services, World Energy Balances(2009), web site www.iea.org

Fig 2 CO2 intensity of crude steel by process(kgCO2eq/tHM)Source: IEA, 2007

Fig 3 Global CO2 emissions from fossil fueluse and cement production per region,1990-2009Source: Olivier and Peters, 2010 – www.pbl.nl

Industrialised countries (Annex I)



Direct Reduced IronTenova HYL direct reduced iron (DRI) tech-nology (marketed under the Energiron brand)is characterized by a significant environmentalcontribution in terms of CO2 abatement. TheHYL ZR DR process represents an advancedshaft furnace technology, based on zero reform-ing (reducing gases are generated ‘in-situ’, thecharge inside the shaft furnace acting as areformer for the feed gas cracking the con-stituents to H2 and CO). Fig 4 represents theprocess flow sheet.

A comparison between the ZR DR processand an integrated plant shows a reduction of55% in CO2 emissions if the CO2 – which has tobe removed from the process circuit before recy-cling the reducing gases – is sequestrated or sold,which is possible via the ZR DR process (Fig 5).

The selective CO2 removal, based on chemi-cal absorption (amines, hot carbonates solu-tions) which is inherent with the ZR DRprocess, becomes a real GHG abatement if theremoved CO2 is commercialised.

In fact, the capture of CO2 provides a lucra-tive by-product and many plants already takeadvantage of it. Ternium in Mexico for exam-ple, as well as the HYL plants in Indonesia andMalaysia, sell captured CO2 to gas companiesfor cleaning and use by local beverage indus-tries. Emirates Steel in Abu Dhabi sells cap-tured CO2 for use to boost oil extraction,instead of using natural gas.

A new development of the ZR DR process,recently patented and referred to as the‘Minimal CO2 Emission Scheme’ (Fig 6),assures the possibility to remove up to 80% oftotal carbon input as selective CO2. By the



incorporation of a Pressure-Swing AbsorptionPSA-type Physical Adsorption System, the car-bonaceous compounds are separated from therecycling gas (after CO2 absorption), feedingthem back to the reduction circuit and usingthe separated H2 as fuel instead of tail and/ornatural gas.

For example, using this new scheme for arecently proposed project for a 1.6Mt/y DRplant in Europe, only 19% of carbon emissionswould be non-selective CO2 vented into theatmosphere instead of the 30% in the conven-tional case without PSA.

The CO2 emission reduction which arises inthe ZR DR process can also be key to indirect-ly reducing emission in the traditional BF-BOFroute by charging pre-reduced DRI into the BF-BOF. For a 23% - 38% DRI charge, productionincreases by 20% - 28%, respectively and with23% lower CO2 emissions.

Energy efficiencySpecifically, the ZR DR scheme is the mostenergy efficient DR technology available; in factin terms of energy savings this technology hasbeen refined over the years to what is now thelowest consumption of energy-per-tonne ofDRI of any DR process on the market.

TG Heatrecuperetor Iron ore

Iron ore

Fuel(if required)

Naturalgas/COG

Selective(pure)CO2

PS

COCH4

Only forcold DRI

NG/COG

Non selective CO2 emissions: BF-BOF vs DR-EAF routes(location: 0.74kg CO2/kWh)

RGcompressor

DR shaft

DRI

EFSOP

iEAFiRecovery

DRI

Fuel

Oxygen

PGheater

Humidifier

NG

CO2 H2O

H2O

H2O

CG compressor

Carbon addition to EAF

Iron ore (production) + fluxes

HYL ZR DR OPTIONS

Non selective CO2 in flue gases

Electricity & O2 to DR plant

Power & O2 requirements in BOF/EAF

1,800

1,500

1,200

900

600

300

0

BF-B

OF

DR-

EAF

(CO

G)

-300

Left: Fig 6 MinimalCO2 EmissionScheme (~ 80%selective CO2removed)

Left: Fig 4 HYL ZRDR process flowsheet

Fig 5 (right)Comparison of CO2emissions by route

Below: Fig 7Consteel Evolution™scrap preheater

Yield 1.2%El energy15kWh/tonOxygen

5.9 Nm3/ton

Nat. gas1.6Nm3/ton

Charge C1.5Kg/ton

Power ontime

1.1 min

Savingsover

$2.00/ton

Electrodeconsumption

16%

Refractorywear 10%

Productivityimprovement

7%

Parameters directly impacted by EFSOP

Variables influenced by parameters directly controlled by EFSOP®

Electricity

Burners(O2,CH4)

Lance injection(O2,C)

Charge Cscrap(yield)

Right: Fig 8Operating resultsachieved usingEFSOP on-line off-gas analysis control(/t of good billet)

kg CO2/tLS

Oth

er

DR-

EAF

tech

nolo

gies

DR-

EAF

(NG

)

DR-

EAF

“Min

imal

C

O2

emis

sion

sche

me”

The overall energy efficiency of the process isoptimised by:– the higher operating pressure (6-8 barA),

which optimises power consumption;– the higher reduction temperature (above

1050°C), which increases the reduction process kinetics;

– ‘in-situ’ reforming inside the shaft furnace, which avoids an external reformer with its energy demands;

– various energy recovery units in the plant.

Therefore, the DRI product utilises most ofthe energy supplied to the process, with mini-mum energy losses to the environment. Theoverall energy efficiency of the ZR DR processis around 87%, compared with less than 75%for other DRI technologies. For natural gas-based plants, the requirements (including selec-tive CO2 removal and production of high met-alized and high-carbon DRI) are now only984GJ and 70kWh per tonne of DRI.

HYL DRI technology also allows the use ofCoke Oven Gas (COG) and Syn-Gas (gas fromcoal gasification). In both cases the basic ZRDR scheme can be used without modification.For example, considering that COG has about25% methane, while natural gas has +95%

PSAO2

CO2-freefluegases

hydrocarbons, the use of COG makes theprocess even easier. For coke oven gas-basedplants, ZR DR process consumption needs are1005GJ and 90kWh, including COG compres-sion while Syn-Gas has the lowest energydemands at 942GJ and 70-90kWh.

More importantly, the process provides evengreater energy savings for the electric steelmak-ing furnace, thanks to its inherent ability to pro-duce highly metalized DRI in excess of 94%metal of high carbon content in the form of ironcarbide. Furthermore, the product can be con-tinuously transported from the DR plant to theelectric arc furnace using the reliable HYLHytemp system for pneumatic hot transportand feeding to the EAF. This retains the inher-ent heat from the DR process of around 600°C,delivering the product already hot to the fur-nace through a port in the roof.

The combination of hot DRI and its high car-bon content, in excess of 3.5%, provides chemi-cal energy to the melting process, thus reducingpower-on-time from around 44 minutes for coldDRI to around 31 minutes, and reducing electri-cal energy requirements in the EAF from 530 toaround 380kWh/t liquid steel. The benefits pro-vided to steelmakers by hot charging a high-car-bon DRI represent millions of dollars in annualoperating cost savings by reduced energy costs,as well as increased productivity in the furnace.

Thanks to the above benefits, ZR DR tech-nology has had dramatic success in the past fiveyears. Since 2005, eight new plants have beenor are currently being built for a total newcapacity of 11.15Mt/y. Two additional projectsfor conversion of existing plants to the ZR DRprocess will add another 0.80Mt/y of incremen-tal capacity, to give an overall total of 12Mt/ywith this technology in just five years.

Among the most recent references EmiratesSteel Industry, located in Abu Dhabi, is one ofthe world’s largest projects to date with DRIproduction of more than 1.6Mt/y.

The technology has been developed to beable to build ZR DR modules of 2.5Mt/y in asingle unit; as in the case of those to be built atNucor’s new plant in Louisiana USA.

The benefits of this technology coupled witha modern EAF, provide an alternative to tradi-tional the BF-BOF route offering attractive sav-ings in capital expense, operating costs and alsosignificant environmental improvement.

Electric Arc FurnaceThe main R&D driver of Tenova is focused ondeveloping a more environmental friendly EAFwith lower energy consumption and less directand indirect GHG emissions.



Table 1 CO2emission related toa 1Mt/y steel plantwith top charge EAFequipped with various technologiesfrom Tenova

Left: Fig 9 iEAF arc furnace optimisation

Electroderegulation

Electric energyKTMultifunc.burner

KT Oxygenlance

KT Burnerinjector

Retro-action-actuator

Slag Steel

Scrap

Off gas

Furnace weightnovel sensors

HarmonicsV.J

Input-sensorOutput-software

Level 1

TDR-H

Level 2

EFSOPEAF

Off gas analysis

Che

mic

al e

nerg

y

Electric energyCombustion of natural gas(burners), charged coal, oil andelectrodes

Metallic charge oxidation(oxygen lancing)

Radiation,convectionand otherlosses

Electrical losses

Energy in liquid steel and slag

Furnace cooling water

Energy in off gas and dust

385

167

151

455

703

175

42

15

16

Tapping @ 1635°Cwith 115kg/tls of slag

Right: Fig 10 Energybalance in a tradi-tional top charge

EAF (kWh/t )

Tenova is working in many directions toachieve these targets:– Process optimisation based on off-gas real

time analysis (EFSOP®);– Dynamic process control including novel sen-

sors and process optimisation models (iEAF®);

– An efficient solution for off-gas heat recoveryto produce steam/electrical energy (iRECOVERY®);

– Continuous feeding and preheating system (Consteel®).

An EAF steel plant of 1Mt/y capacity topcharging 100% scrap (150t/h productivity)equipped with these Tenova technologies iscapable of cutting CO2 emissions by about65.5kt/y (Table 1).

The integration of these EAF technologieswith scrap preheating and continuous chargingin the latest Consteel Evolution™ is able toachieve overall CO2 reductions of 80kt/y ofCO2 (-15.4%).

Consteel evolutionConsteel is a well established proven technologywith 32 references already in operation since1989 and eight more under way. Tenova is con-tinuously working in improving its innovativesustainable technologies, the latest developmentbeing Consteel Evolution™ (Fig 7). This new sys-tem subdivides the scrap pre-heating tunnel intotwo sections: the first contains high-efficiencyburners (developed by Tenova LOI Italimpianti)while the second completes the combustion ofthe off-gas leaving the furnace. The two gas flowsmerge in an intermediate section, where they areextracted at high temperature.

With this innovative solution, CO2 emissionsrelated to the use of very high efficiency com-bustion systems, are more than balanced by thereduction in CO2 arising from using less electricenergy in the EAF compared with the tradition-al Consteel preheater which has no burners andrelies only on extracting heat from the EAF flue-

gas. The CO2 savings do depend on the methodof generating power (eg nuclear, hydro, coal orgas) and hence vary from country to country.

EFSOPOff-gas real time analysis has been, in the lastdecade, the new approach to optimise the ener-gy input in the EAF, thanks to the post-combus-tion control it enables (see Steel TimesInternational September 11 p17).

The successful story of more than 55 installa-tions worldwide demonstrates the reliabilityand effectiveness of the system in several oper-ative conditions.

The actual average results achieved per tonneof good billet are summarised in Fig 8.

iEAFiEAF® is the result of strong cooperationamong Tenova, Toronto University, CSMResearch Centre and Tenaris Dalmine. iEAF isan innovative dynamic process control systemfor real time management of arc furnace melt-ing, based on EFSOP, novel sensors and math-ematical on-line models.

The result obtained by iEAF is the holisticoptimisation of the melting phase and simultane-ously the achievement of both optimal tappingtemperature and carbon content (Fig 9).

The outcomes of the three installations oper-ating since 2010 show improvements whichroughly double that achieved by applyingEFSOP alone. The reference list will sooninclude a further four installations in Italy,Mexico and Canada.

This system is extremely versatile and has beenapplied to other energy intensive combustionprocesses such as the oxygen converter (BOF).For this application a new control package hasbeen developed under the iBOF® name, whichincludes slag slop control, end-point control andauto tapping to prevent slag carry over.

iRECOVERY®

Even in an extremely high efficient EAF pro-vided with all the above technologies a quarterof the energy is lost in the off gas. Fig 11 showsthe energy balance in a traditional top chargeEAF (in kWh/t).

Up to 30% of this can be recovered with theTenova iRecovery technology, a development ofthe former Evaporative Cooling System (ECS)applied for reheating furnaces. This has been

Tons of CO2 CO2

emissions %(direct & indirect)

per year

Traditional EAF 518000 0.0

with EFSOP® -7400 -1.4

with iEAF® -7400 -1.4

with iRecovery® -20700 -4.0

with Consteel® -30000 -5.8

Total reduction -65500 -12.6





proven on the 140t/h EAF ofGeorgsmarienhütte, Germany. Since 2009nearly 30% of the off-gas energy atGeorgsmarienhütte is recovered and turnedinto steam which is used for vacuum degassing,oxygen production and for heating purposes inwinter. The elimination of the cost of gas con-sumed by the boiler house is worth over €1M ayear. Tenova’s R&D activities are in anadvanced stage to increase the proportion ofenergy recovered from the off-gas and dust witha target of up to 70%.

An iRecovery waste gas duct works with pres-surized water at its boiling point which is ledthrough piping integral with the duct. The near-ly boiling water absorbs the energy from thewaste gas by evaporation. Steam and remainingwater are separated in a steam drum.

One of the enhancements of iRecovery is thecontinuous availability of steam from batchmode furnaces such as the EAF (See STIJul/Aug 2011 p 45).

Reheating furnaceIn past years Tenova LOI Italimpianti R&Defforts were directed to achieving a drasticreduction of NOx emissions and the significantresult of less than 60ppm at 3% O2 has beenachieved.

One of the most recent references for this arethe three 420t/h walking beams ReheatingFurnaces (RHF) for the new TKS mill inCalvert Alabama USA.

NOx emissions measured during perform-ance tests, conducted under the EPA method-ology, were 56ppm @ 3% O2, well below the

required legal limit of 71ppm @ 3% O2 estab-lished by ADEM (Alabama Department ofEnvironmental Management).

In parallel, recent R&D efforts have focussedon the reduction of energy consumption withthe design of a new type of regenerative andflameless burners with performances whichprovide two fundamental advantages: energysaving due to better thermal efficiency and evenlower NOx emissions.

The most modern high capacity slab reheatingfurnaces (420t/h) equipped with FullRegenerative Flameless Burners will have, on aEurope cost basis, an overall annual energy costof €47.6M of which €43.2M is the combustedfuel and €3.4M is electricity. In such a case, fuelconsumption can be reduced by10%-20% com-pared with a traditional furnace in the same oper-ating conditions. The amount depends on thefurnace configuration and operating conditions.

An example of a successful result of this typeof burner is the revamping of Tenaris Dalminemedium-pipe rotary hearth furnace. The maingoal of the revamp was to charge larger blooms(up to 5300mm) and to improve productivityby about 35%. At the same time a significantenergy saving in fuel consumption was achievedcorresponding to about 15% (See Steel TimesInternational May/June 2011 p 57).

The combustion system selected included theinstallation of 55 TRGX LOI Italimpianti FullRegenerative Flameless Burners with very lowNOx emissions well below the required legallimits.

Furthermore, nowadays the energy savingconcept is strongly related to the

utilization/recovery of low calorific value fuelssuch as Blast Furnace Gas (BFG) that is widelyavailable in the integral cycle steel plants.Tenova LOI Italimpianti is committed also inthis field developing new low calorific valueregenerative burners. In this case it is possibleto recover additional energy reducing at thesame time CO2 emissions.

In a 420t/h Rotary Hearth Furnace (RHF)fitted with low calorific value regenerativeburners a saving of €9.5M a year is achievablein fuel costs when fired with a mixture of 70%BF gas plus 30% natural gas and CO2 emisisonsare reduced by 63kt/y, compared with a conven-tional RHF of similar capacity.

ConclusionIn the past 30 years the steel industry hasreduced its energy consumption per tonne ofsteel produced by 50%. A similar reduction hasalso been achieved in the impact that the indus-try has on the environment. However, due to thisdramatic improvement in energy efficiency, thereis now only room for marginal further improve-ment on the basis of the existing technology.

This fits well with the R&D approach ofTenova which is oriented towards continuousimprovement of its technologies for achievingthe best performances in terms of energy effi-ciency and environmental sustainability.

Contact

Carlo Raggio, Director R&D, Tenova SpA

Via De Marini, 53 Genova Italy.

Tel +39 010 6054871 Fax +39 010 6054926

e-mail [email protected]

November 3 - 4, 2011Omni William Penn Hotel

Pittsburgh PA

www.electricsteelnow.com

Showcase your products and expertise to the coke, coal and steel community.

act Brian SantContcoal and steel communityand expertise to the cok

wcShoow

os atact Brian Sant.and steel communityy.

e,xpertise to the cokkeoductsour prcase yyo

omertcuseacand rt building nearto st

brian.sant7 7+1 20

s!omer

w clients andhing neeacelationshipsw rt building ne

[email protected] or11 9687 7

Hot strip mill

Automatic head-end cutting at Rourkela HSM

THE Hot Strip Mill (HSM) of Rourkela SteelPlant, India produces around 1.6Mt of hotrolled coils a year from around 101 thousandslabs rolled, each averaging 15.5t in weight, andwith a rolling rate of around 275t/h.

An automatic head-end cutting system acti-vates the crop shear located before the finishingstands to cut the head of the hot transfer ‘bar’(ie strip around 25-35mm thick) to present asquare face to the first finishing stand. This barwas rolled in the roughing stands and, atRourkela, then enters a coil box which buffersits passage through the mill between the rough-ing and finishing stands. As the bar exits the coilbox, the crop shear is activated while the bar isin motion. The automated system developedand implemented successfully at Rourkela SteelPlant HSM replaces a manual system whichpreviously required the bar to be stopped forthe cut, lowering mill productivity and yield.

The system consists of six Fibre Optic HotMetal Detectors (FOHMD), three encoders, adigital drive and PLC system. The FOHMDsare mounted below the roller table for precisesensing of the head end. One encoder has beeninstalled to measure the speed of the CradleRoll of the coil box to calculate the speed of thehot bar and two encoders are installed at thecrop shear, one for sensing the position of thecrop shear blade and the other to sense the cropshear motor speed. A digital drive regulationsystem has been installed for the crop shearmotor to achieve a faster response in its action.The control logic for automatic head-end cut-ting was developed in-house and programmedto a PLC.

The output from the encoders are processedin the PLC and scanned over a regular intervalof 10msec. The feedback generated is used tosynchronise the transfer bar speed with theshear blade speed. The proper synchronizationof crop shear motor speed with the strip speedis achieved and a ‘CUT’ command generatedby the PLC.

Prior to installing this system it was foundthat there were difficulties in cutting the head-end of the bar automatically to the requiredlength due to the unavailability of proper sens-ing and synchronization of the bar travel withthe shear. Hence, it was cut manually. Over

An automatic head-end crop system on the HSM of Rourkela Steel Plant, capable of cutting the head on the move, has replacedthe former manual system resulting in a reduction in crop size of 20% equating to 1985t/y of strip as well as improved millproductivity. By B N Ghosh*, I Banerjee*, S Singh*, R R Choudhary* ,K N Rao*, A Goswami*, D Sarkar**, A Gupta**,R Verma**, K Venkata Ramanna**, L K Mohapatra**

length cutting always occurred in this manualoperation, leading to extra material loss andthereby reducing the yield of the mill. Also itresulted in a reduction in crop shear blade life.

With the implementation of this new system,the head-end of all bars coming from the coilbox are sensed and cut to the desired lengthprecisely and automatically. The new system hasimproved the product quality, yield and millavailability. The system has helped in achievinga reduction in head-end crop length by 20%and the time taken for the head-end exiting thecoil box to head-end cutting to be reducedfrom 8 seconds manually to 4 seconds usingautomation. The head-end cutting system hasbeen in continuous operation since April 2011.

Conventional croppingIn a conventional hot strip mill, the position ofthe tail-end and head-end are detected by HotMetal Detectors mounted alongside the rollertable and the speed of the strip is sensed by atacho mounted on the first finishing stand (F1).The detection of the tail-end and head-end givethe instant of cut at both ends of the transferbar which determines the cut length and so thecoil weight after passing through the finishingstands. The cutting speed of the shear has tomatch the speed of the moving bar and thus theshear speed has to be synchronized with thismotion.

Such a conventional tail-end and head-endcutting system suffers from the following short-comings:

If sensing by the hot metal detector is incor-rect, the crop shear may not cut the ends of thetransfer bar. Therefore there will be severaltransfer bars which will be rolled in the finish-ing stand without cutting the head or tail. If thishappens, there is a risk of a cobble in the finish-ing train if the head chutes up. If the tail-endcrop is missed it is necessary to manually cut thefinal laps of the coil off with a gas-torch toremove the ‘fish-tail’ profile. No manual cutcan be made on the head as this would requireuncoiling the full length of coil.

If the sensing by the hot metal detector isnot precise, the cut length will vary and therebycause yield loss.

The actual strip speed is indirectly derived


*Authors are with RDCIS (Research & Development Centre for Iron & Steel), Steel Authority of India Ltd , Ranchi , India. **Authors are with Rourkela Steel Plant Rourkela, India

from the speed of the first finishing stand. Thisfluctuates due to the interstand looper opera-tion even though the input bar speed may notfluctuate.

The scope of the automation was to developa system for automatic head-end cutting whenthe hot bar was in motion. The layout of theHSM at Rourkela is shown in Fig 1.

A schematic of the head-end cutting systemis shown in Fig 2 and the head-end sensing sys-tem in Fig 3. A total of six HMDs in two rowsof three across the strip width are used to senseboth the head end and later the tail of the trav-elling bar. Using six HMDs provides optimumconditions to detect the irregular profile of thebar head and tail. In the case of malfunctioningof one or even two HMDs, the remaining sen-sors have been shown to be sufficient to pre-vent a head or tail crop from being missed.

The following steps have been followed toachieve the project objectives:

– Study of the dynamics of the crop shear;– System design for the automatic head-end

cutting of hot bar in motion;– Installation of FOHMDs with 3-axis adjust-

ment and purging air facility to keep the lens-es clean;

– Installation of three encoders, one to meas-ure the speed of the cradle roll, one to meas-ure the crop shear motor speed and one to monitor the crop shear blade shaft position;

– The introduction of a digital drive to improvethe response time of the crop shear;

– Development of control algorithms;– Interfacing of signals to the PLC;– Scaling of signals and converting into engi-

neering units;– Graphical presentation of process data;– Providing digital output to activate the shear;– Trial run and optimization of automatic head-

end cutting of the hot bar while in motion;– System stabilisation.

ImplementationThe installation and commissioning activitiesfor the head-end cutting system started inOctober 2010 and were carried out duringweekly shutdowns. Non-shutdown days wereused for preparatory work.

Fig 2 Schematic ofthe head-end

cutting system

Fig 1 Layout of Hot Strip Millat Rourkela Steel Plant,India

Walking beam reheatfurnaces 2x225t/hr

Descaler unit

Delaytable

Coil cropbox shear

Coilers

Cradle roll of coil box

Pinch roll

HMD

PLC

Crop shear

Scale washerpinch roll

F1 stand

Motor

MotorSpeed reference

Digital DC

drive

regulation

Power

stack

Cut command

Gear

Gear GearPulse tachofor positionfeedback

Pulse tacho for speedfeedback

Pulsetacho

Thicknessgauge

Synchronous motorRo: 3000kWx2Vo: 1000kWx2

R1 standDC Motor 3800kWx2 2470kWx2

R2 standDC Motor 6250kWx12470kWx2

F1YF63700kWx6

F1 F2 F3 F4 F5 F6R1

standR2

standR0N0stand



The six Fibre Optic Hot Metal Detectorswere installed below the roller table after thecoil box during the weekly shut down periods.The signals were fine tuned using the installedelectronics. Care was taken when laying thefibre optic cable to avoid damaging it as anydamage would result in a loss of signal.

An air purging system was installed to keepthe optics of the FOHMDs clean. The air purg-ing system is shown in Fig 4.

The adjustment of the FOHMDs waschecked by passing light through the lens anddown the fibre optic cable to the controllers.

The digital drive for the crop shear was firsttried out on a spare motor and after fine tuning,commissioned on the crop shear motor.

A 1200 PPR encoder was installed to meas-ure the speed of the coil box cradle roll in orderto calculate the speed of the hot bar. Two fur-ther encoders (1024 PPR) were installed on thecrop shear drive, one to sense the position ofthe shear blade and the other to sense the cropshear motor speed. The mounting of one suchencoder is illustrated in Fig 5.

Results The installed system has helped in achieving thefollowing benefits:

– Reduction in head-end crop length of 20% from the previous value equating to an annu-al saving of 1985t from 9925t of crop per year to 7940t.

– A 50% reduction in process time from 8 sec-onds to 4 seconds to cut the head, measuredfrom uncoiling the bar from the coil box to complete the head crop with the hot bar on the move.

The automatic head-end cut has now been incontinuous operation since April 2011.

A similar automated tail-end cutting systemhad already been implemented on the mill inNovember 2008. This uses the same FOHMDsbelow the roller table and now takes its speedreference from the coil box cradle roller,although in its original configuration it used thescale washer pinch roll which is still maintainedas a stand-by reference. (See Steel TimesInternational September Vol 34 2010 p 42-43).

The objective of the project was to augmentthe head-end cutting system in the HSM toachieve a reduction in the size of crop endsthereby increase yield and a reduction in theincidence of coil chute-up and resultant milldelays

The followings key points arise:• Precise Focusing: Hot Metal Detector

Hot strip mill


(HMD) is an important element for the oper-ation of the cutting system. For precise cut-ting of the head end, the diameter of the focused point of the HMD on the transfer bar should be around 5mm. To achieve this the distance between hot bar and the lens ofthe HMD located below the roller table is around 180mm. Thus, the HMD mounting arrangement has to be very close to the mov-ing bars.

• Complete Testing: In this project, fibre opticHMDs are installed below the roller table. Complete testing must be carried out beforeinstallation as once they are installed adjust-ment is difficult and requires a mill shut-down.

• Precise Reference: It has been established byexperiments that strip speed at the crop shearhas no direct relation with the speed meas-ured by the tacho on stand F1. In the new scheme, the strip speed is measured by a pulse tacho mounted in the coil box cradle roll. This provides a true representation of strip speed.

• Erection Planning: Proper planning has to becarried out in advance for mounting of criti-cal items. Those items, which require major shutdown/capital repair, need to be identi-fied during the design of the system and themain installation carried out during the mill’scapital shutdown.

The above learning points have been dis-cussed with the project taskforce so that thesecan be employed for continuous improvementin terms of system design and reduction in proj-ect execution time.

The new system is performing satisfactorilyfor head-end cutting. As reported in the litera-ture, hot strip mills abroad have improved yieldby using crop optimization system. With this inview, a new system may be developed for CropOptimization in the Hot Strip Mill of theRourkela Steel Plant.

AcknowledgementsThe authors are grateful to the collective ofOperation, Electrical & Mechanical department ofHot Strip Mill, and R&C Laboratory of RSP for theirhelp during installation and utilization of the system.The authors are also grateful to the management ofRSP and RDCIS for their continuous support, guid-ance, encouragement and all the necessary facilitiesprovided for smooth execution of this project. Theauthors also express their warm gratitude and sincerethanks to all those who have extended help directly orindirectly during various stages for successful imple-mentation of this project.

References[1] Proceedings of SPIE – Vol 2101 MeasurementTechnology and Intelligent Instruments. Sept 1993, pp 606-609 (Held in China).[2] Literature of Qualimatrix International,Measurement system for Hot Strip Mill[3] Delta Sensors-Vision system for crop optimization[4] Literature on Kelk Sensor for Rolling Mills

Contact:

B N Ghosh, Deputy General Manger & HOG, Power & Control

Group, Automation Division, R&D Centre for Iron & Steel, Steel

Authority of India Limited, Ranchi, Jhakhand, India.

Tel +91 65124 11149

e-mail [email protected]

Head end sensing by FOHMD (Fiber Optic Hot Metal Detector)

700m

m

770mm

HMDs

Fig 3 Head-end sensing by Fibre Optic HotMetal Detector

Fig 4 Air purging system for Fibre Optic HotMetal Detector

Fig 5 Encoder feed back for sensing speedof hot bar

PENN Stainless Products (USA) has intro-duced a new line of 330 plate and processedflat bar to its family of high-temperature prod-ucts. 330 plate and processed flat bar (Alloy330 UNS N08330) is ideally suited fordemanding, high-temperature, high-pressureapplications such as chemical and petrochemi-cal processing, thermal processing, ore process-ing, and power generation.

The 330 alloy provides superior resistance tocorrosion and heat, in even the most demand-ing, high-temperature environments. Alloy 330is extensively used where resistance to the com-bined effects of thermal cycling and carburiza-tion is necessary.

Available in thickness from 3/16” to 3/4”,(4.7 – 19.05mm) Penn Stainless Alloy 330 canbe custom fabricated to any shape or size

through water jet cutting or a number of otheravailable in-house processing methods.

Alloy 330 is an austenitic, nickel-chromium-iron-silicon alloy with excellent corrosion resist-ance provided by the high nickel content, aswell as its chromium and silicon content. In par-ticular, the material fends off chloride stresscorrosion cracking and sigma phase embrittle-ment, as well as oxidation, carburization andnitriding (up to 2200°F or 1204°C). Alloy 330also has a low coefficient of expansion, excel-lent ductility, and high strength.

Contact

Penn Stainless Products Inc, 190 Kelly Road, Quakertown, PA

18951 USA

Tel 1 800 222 6144 / 215 536 3053; Fax 215 536 3255

e-mail [email protected]; web www.330stainless.com

High-temp alloy 330 plate and flat bar


History

CARL Wilhelm Siemens (1823-1883) travelledfrom Germany to settle in England in 1843 andtook up citizenship in 1859. His younger broth-er Friedrich Siemens (1826-1904) joined him in1852 to help him in his efforts to improve thepuddling process by introducing the regenera-tive principle of fuel economy by preheating thecombustion air.

The first application of the Siemens regener-ative furnace was in 1861 in a glass works inBirmingham and met with great success. In1867, the Siemens brothers suggested in apatent that steel could be made by melting pigiron in such a furnace and removing carbon bythe addition of iron ore.

Around the same time, two French workers,Émile and Pierre Martin (father and son) wereexperimenting with steelmaking by melting pigiron in a reverberatory furnace and reducing thecarbon content by adding a suitable proportionof scrap metal. They adopted Siemens’ regener-ative system in 1863. The process became laterknown as the Siemens-Martin Process, andwhen adopted in North America was known asthe Open Hearth Process. This name probablyoriginated from the fact that the metal wasmelted on the bed of a furnace, open, asopposed to the closed or crucible process usedbefore. It had the advantage over the Bessemerprocess in that scrap could be melted, and highquality steel produced.

Wilhelm Siemens was an energy engineer notan iron master. Maintenance and control oftemperature when burning a solid fuel was dif-ficult and therefore he developed the gas pro-ducer system which involved gasification ofcoal. This enabled fuel to be alternately inject-ed in from either side of the furnace – unlikethe static location of a solid fuel such as coal orcoke. This cycling was a necessary requirementof a regenerative furnace. Siemens’ invention ofthe regenerative system not only economisedfuel consumption but through it, he was able toachieve a high temperature in the open hearthfurnace, one never before achieved, as a resultof the preheating of both the air and gaseousfuel before combustion.

In the open hearth process invented byWilhelm Siemens iron ore was added to the pigiron after melting to remove carbon. In con-trast, Pierre Martin used wrought iron scrapwith only enough pig iron to reach the requiredcarbon content in the finished steel.

Pierre Émile Martin (1824–1915) was born atBourges in Cher, graduated from the École desMines in Paris and became director of SireulForges owned by his father from 1854 to 1884.Fortuitously for Martin, the forge was locatednear a source of near pure silica from whichrefractory bricks could be made capable of with-standing the much higher temperatures of theregenerative furnace, refractory failure being aproblem which plagued Siemens in England.

The IndustrialistsAlfred Krupp (1812-1887) was born in Essen,Germany. He was the son of Friedrich Krupp(1787-1826) who had established a small steelfoundry in Essen in 1811. On his father’s deathin 1826 he had to leave school at the age of 14and take on the direction of the works. AlfredKrupp invested heavily in new technology tobecome a significant manufacturer of railwaymaterials and locomotives. He also invested inthe Bessemer process and acquired many minesin Germany and France. The company began to

make steel cannons in the 1840s. At the GreatExhibition of 1867 he exhibited a cannon madeentirely from cast steel that caused a sensationin the engineering world.

He became a major supplier of cannons forthe Russian, Turkish, and Prussian armies dur-ing the Crimean War (1853-1856) and theFranco-Prussian War (1870-1871). When hestarted managing the firm, it had five employ-ees; at his death, 20 000 people worked forKrupp, making it the world’s largest industrialenterprise.

Great financial expansion took place underthe management of his son Friedrich AlbertKrupp (1854-1902). During World War I,Krupp sold artillery to the Central Powers aswell as to the Entente, a policy which generatedhigh profits.

After the National Socialists came to powerin Germany in 1933, the Krupp works becamethe centre for German re-armament. In 1943,Alfried Krupp von Bohlen und Halbach (1907-1967), son of Gustav Krupp, took over man-agement. After Germany’s defeat, theNuremberg Military Tribunal tried Alfried as awar criminal for his company’s use of slavelabour. It sentenced him to 12 years imprison-ment and ordered him to sell 75% of his hold-ings. In 1953 he was released and resumed con-trol of the firm. In 1999 the Krupp Groupmerged with its largest competitor, ThyssenAG; the combined company — ThyssenKruppAG, became Germany’s fifth largest firm andone of the largest steel producers in the world.

Andrew Carnegie (1835–1919) was born inDunfermline, Scotland. At the age of 13 in1848 he emigrated with his family to the UnitedStates and settled in Allegheny, Pennsylvania.He went to work in a cotton mill then movedrapidly through a succession of jobs becomingSuperintendent of the Philadelphia Rail Roadat the age of 25, a task that saw him take thefirst troop train from the north to WashingtonDC which had been surrounded byConfederate troops when the Civil War brokeout on April 12 1861.

Following a spell of involvement in the oilbusiness and then helping to establish the

Keystone Bridge Company established to buildbridges in steel, he established a steel businessin 1865, with his friend Tom Miller – theCyclops Iron Company. This merged with arival forge supplying railway components thefollowing year to form the Union Iron Mills.Carnegie continued to concentrate on supply-ing steel for railroads and bridges. In 1866 hebecame involved with the Freedom Iron andSteel Company which installed Bessemer con-verters. The local ore was high in phosphorusmaking it unsuitable for this process but thediscovery of low phosphorus ores in the LakeSuperior region prompted him to set up a newworks near Pittsburgh in 1872. He employedAlexander Holley, a renowned expert inBessemer steelworks, to build the EdgarThomas Works (called after his old railroadboss, President of the PRR – a potential majorcustomer of the new works). ‘ET’ started pro-duction on August 22 1875 and the first rail ofBessemer steel was rolled a month later.

When Sydney Gilchrist Thomas overcamethe problem of treating high phosphorus iron inthe converter by adding lime – the ‘basic’process patented in England in 1877 –Carnegie was instrumental in getting theBessemer Association, which had been estab-lished by US steelmakers, to buy the US licenseto prevent its use by potential competitors totheir ‘acid’ process.

At age 65, Carnegie sold the company to thefinancier J P Morgan and devoted the rest ofhis life to his philanthropic activities and writ-ing, including his autobiography. Carnegie wasperhaps the first to state publicly that the richhave a moral obligation to give away their for-tunes. He created philanthropic and education-al organisations in the United States and inEurope to dispose of his wealth. One ofCarnegie’s lifelong interests was the establish-ment of free public libraries to make availableto everyone a means of self-education. He builtover 2500 libraries throughout the English-speaking world. �

Suggested readingsF. Habashi, Readings in Historical Metallurgy, Volume 1.Changing Technology in Extractive Metallurgy, MétallurgieExtractive Québec, Québec City, Canada 2006. Distributedby Laval University Bookstore Zone

By Fathi Habashi*


* Laval University, Quebec City, Canada

[email protected]

Right: Principal ofoperation of theSiemens Martin

furnace

Open Hearthfurnace viewed frompitside at RichardThomas & BaldwinLtd in Scunthorpe,UK circa 1950s

Pioneers of the Steel Industry:

Part 5. Open Hearth & Bessemer

Documents

NEWS SPECIAL & STAINLESS STEEL STRUCTURAL · Laiwu Steel produced 2.37Mt of iron and 3.33Mt of steel in the first half 2011. The steelmaker had earli-er set its annual steel production