HT-SPG

LARSEN & TOUBRO LIMITED HAZIRA WORKSHEATTREATMENTTRAINING MANUAL MAY-2001 (REV.-0)

This Manual is compiled by

Mr K S Rao (QA), Mr S P Ghiya (Inspection ) and Mr N M Bodalia (M FS)

Under the guidance of

Mr P D Lohidakshan (Weld Engg & Prod Engg )HEAT TREATMENT MANUAL

INDEX TOPIC PAGE NO. 1 . INTRODUCTION ON HEAT TREATMENT 4- 24 2 . FURNACE PARTS AND ATTACHMENTS 25- 37 3. STD. OPERATING PROCEDURES(HFS)38- 47 4 . STD. OPERATING PROCEDURES(PFS)48- 56 5 . STD. OPERATING PROCEDURES(MFS)57-69 6 . STANDARD PRACTICES FOR LSR70-74 7 . GOOD ENGINEERING PRACTICE 75-88 8 . CODE EXTRACT(REFERENCE ONLY) 89- 101 9 . ANNEXURES 102- 118

General Only qualified supervisors and operators including

LSR operators shall be authorised to operate furnace. A list of qualified personnel shall be prepared by QA

and published periodically. Thjs manual is prepared on the basis of experience

and feedback, taken from various personnel. This manual is for reference only.

HEAT TREATMENTWHAT IS HEAT TREATMENT ?WHY IS IT REQUIRED ?TYPES OF HEAT TREATMENTHEAT TREATMENT AT HZW

WHAT IS HEAT TREATMENTMATERIALS TREATED BY APPLICATION OF HEAT NORMALLY DONE IN SOLID STATEVARIOUS SOURCES OF HEAT PARAMETERS ARE HEATING RATE,SOAKING TEMP,SOAKING TIME,COOLING RATE AND COOLING MEDIA

WHY IS IT REQUIRED ?TO ENHANCE MATERIAL PROPERTIES / EASE IN FABRICATION BY CHANGINGStrength,Improve corrosion resistanceToughness/DuctilityHardness,Dimensional stability etcRemove diffusible hydrogen to avoid hydrogen crackingCARRIED OUT IN FABRICATION INDUSTRIES ,STEEL PLANTS, FOUNDRY, FORGING SHOPS etc..

MATERIALS HEAT TREATED

METALS & ALLOYS SINGLE PHASE MULTIPHASE ALLOYSSingle Phase : Copper Nickel Multiphase : Steels-LAS,QT METALS (Single phase ) Titanium,Al,Ni,Cu etc..

MATERIALS HEAT TREATEDCRITERIACOLD WORKED to NORMALAll materialsUNEQUILIBRIUM PHASES to EQUILIBRIUM:(Stabilise Microstructure & Phases)Stainless Steels ,Maraging SteelsSTRESSED to UNSTRESEDAll MaterialsCREATION OF UNEQUILIBRIUM CONDITIONSSteels

MATERIALS HEAT TREATEDMATERIALS CATEGORY

C-Mn , C-Mo , Cr-Mo , Ni -Steels, QTStainless Steels-Austanitic.MartensiticSteels enhanced by Heat Treatments Non Ferrous Materials; Titanium alloys, Aluminum alloys

TYPES OF HEAT TREATMENTNORMALIZINGANNEALINGSTRESS RELIEVING SOLUTION ANNEALING-Mainly SSHARDENINGTEMPERINGAGING

IRON CARBON DIAGRAM

Iron Carbon DiagramPortion related to Heat Treatment

NORMALIZING The steel is heated to 40 C above the upper critical temperature(910 c) followed by cooling in the still air.

Normalizing is done to achieve the following : To get Uniform structure and reduce chemical gradients To change Mechanical properties,UTS,YSHardness Impact properties To refine the grains

ANNEALING In this process, the steel is heated from 10 to 50C above the upper critical temperature(910c) and held for the desired length of time; followed by very slow cooling in the furnace

Annealing is done to achieve following :to soften the steel and improve ductilityto relieve internal stresses caused by previous treatment

SOLUTION ANNEALING In Stainless steels , it is heated to 1050C or above ,and held for the desired time; followed by quenching/blowing the air(cooling to room temperature within few minutes). Solution annealing is done on stainless steel and non ferrous alloys to achieve following:To soften the materialTo dissolve carbide precipitation formed at grain boundaries during manufacturing processTo improve Corrosion Resistance

AGING The Material is heated to a certain temperature, and held for the desired time; followed by normally for precipitation hardened alloys or cooling in air Aging is done on materials susceptible for aging characteristics : Maraging Steels Normally increase in strength To Improve Toughness/Ductile-brittle transition temp.

AGINGMaraging Steels M250Temperature : 485 C Normally 3 Hrs 15 mtsHeating Rate : 200 C per hr per inchCooling Rate : Cool in Air / Quench in water

STRESS RELIEVING The steel is heated to a temperature below or close to the lower critical point, followed by desired rate of cooling and there is no change in grain structure.Stress relieving is done to achieve following : To reduce Internal Stresses (residual Stresses)To soften the steel partially To improve ductile-brrittle transition temp. and equalize impact values

STRESS RELIEVINGC-Mn , C-Mo , Cr-Mo (< 2% Cr)C - Mn Steels , C - Mo Steels,Cr-Mo Steels SA 515Gr 70 , SA204GrA, SA387GR11CL1Temperature : 593 C MinNormally 600 - 640 C,650-690 C Time : 15 minutes minTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch

STRESS RELIEVINGCr-Mo SteelsCr - Mo Steels (Cr >2%)SA 335P22 ,SA335P5Temperature : 676 C MinNormally 680 - 700 C 2.25Cr 704 - 720 C 5 Cr Time : 15 mts minTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch

STRESS RELIEVINGNi -SteelsNickel Steels : 1,2,3% Ni SA 203 GrA ,DTemperature : 593 C MinNormally 600 - 640 C,650-690 C Time : 60 mts minTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch

STRESS RELIEVINGSteels enhanced by Heat Treatments Q&T Steels :9.5% Ni Steels , SA 517 Gr ETemperature : 538 C TypNormally < 600 C Time : Minimum 15 minutes to 2 HrTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch

FURNACE PARTS AND

THEIR ATTACHMENTS

LAYOUT OF A TYPICAL FURNACE (Electrical or Gas fired )

RECORDERP.I.D.

FURNACEJOBCOMPENSATING CABLETHERMOCOUPLECONTROLLING BURNER

THERMOCOUPLESPRINCIPLE OF A THERMOCOUPLE

THERMOCOUPLE MATERIALS

TYPES OF THERMOCOUPLES BEING USED IN HZW

PRINCIPLE OF THERMOCOUPLEThe basic principle of thermoelectric thermometry is that a thermocouple develops an emf which is a function of the difference in temperature of its measuring junction & reference junction. If the temperature of reference junction is known, the temperature of the measuring junction can be determined by measuring the emf generated in the circuit.

THERMOCOUPLE MATERIAL REQUIREMENT1. High coefficient of thermal emf.2. Continuously increasing relation of emf to temperature over a long range.3. Freedom from phase changes or other phenomenon giving rise to discontinuity in temperature emf relationships.4. Resistance to oxidation, corrosion and contamination.5. Homogeneity and reproducibility to fit an establish temperature & emf relationship.SPEED OF RESPONSE MAY BE IMPROVED AND RADIATION & CONDUCTION ERRORS MAY BE REDUCED BY THE USE OF SMALL DIAMETER THERMOCOUPLES.

TYPES OF THERMOCOUPLE BEING USED IN HZW K type : Material : Chromel + Alumel Nickel based ( 10 %Cr ) + ( 2 % Al ) Properties : Non-Magnetic + MagneticIn this type of thermocouple, the wires are joined at one end only to form a point-type temperature sensor. Instrumentation converts the millivolt signal to related temperature.

TYPES OF THERMOCOUPLE BEING USED IN HZW contd... K type : Dia : 2.5 mm 0. 7 mmInsulation Bare(ceramic)Refractory coatedAttachmentMechCapacitorUsability ReusableDisposableLocationPIT F/cexcept PIT F/cColor -Red & Yellow

recorderpidCompensating cableThermocouple wireWelded junctionCONSTRUCTION OF A K TYPE THERMOCOUPLEAccuracy : 0.75%Red ColorBlue ColorWhite ColorWhite/yellow+Ve-Ve-Ve+VeWhite ColorWhite/yellowBlue ColorRed Color

S TYPE THERMOCOUPLE S TYPE THERMOCOUPLE ARE THE STANDARD

THERMOCOUPLES.

IT IS USED FOR CALIBRATING K Type

THERMOCOUPLES.

MATERIAL OF CONSTRUCTION

90% PLATINUM + 10% RHODIUM PLATINUM

OXIDATION RESISTANCE , SO MORE LIFE .

Accuracy : 0.25 %

ISSUE METHODOLOGYFor DISPOSAL TYPE

Users will send their requirement of thermocouple

through Consumable slip ( mentioning HTR No ) to QA

QA shall issue the same .

QA shall issue identification sticker duly attached

Users shall ensure availability of identification sticker

on unused wire . See Annexure-12 for further details

COMPENSATING CABLECOMPENSATING CABLE IS DEFINED AS A PAIR OF WIRES HAVING SUCH EMF TEMPERATURE CHARACTERISTICS RELATED TO THE THERMOCOUPLE WITH WHICH THE WIRES ARE INTENDED TO BE USED, THAT WHEN PROPERLY CONNECTED TO THERMOCOUPLE THE EFFECTIVE REFERENCE JUNCTION IS IN EFFECT TRANSFERRED TO THE OTHER END OF THE WIRES.

MATERIAL ==> +ve COPPER ( white ) -ve COPPER NICKEL (blue ) for K TYPE .

See Annexure-9 (Annexure Page 1-4) for further details

P.I.D.PID = PROPORTIONAL INTEGRAL DERIVATIVE PID FUNCTIONS BOTH AS PROGRAMMER AND

CONTROLLER PID CONTROLLER CAN BE ZONE WISE PROGRAMME IS MADE IN SEGMENTS AS PER

DIFFERENT STAGES OF HEAT TREATMENT DIGITAL DISPLAY IS AVAILABLE FOR PROGRAMME

TEMPERATURE AND FURNACE TEMEPERATURE TYPICAL OR REPETITIVE HEAT TREATMENT CYCLE

CAN BE STORED IN PID(PROGRAMMER)

RECORDER

TYPES OF RECORDERPAPERLESS -- WITH COLOUR DISPLAY SCREEN ,HARD DISC AND FLOPPY DRIVE. NOT USED IN HZW.WITH PAPER -- CURRENTLY BEING USED IN HZW.

24 CHANNEL -- CURRENTLY BEING USED IN PFS( CHINO MAKE-- model no.I003

/Graph ET 001). 12 CHANNEL -- CURRENTLY BEING USED IN MFS1 AND HFS1

( CHINO MAKE -- model no. EH100 / Graph ET 201).

COMPENSATING CABLES ARE CONNECTED BEHIND THE RECORDER SCREEN IN CHANNELS.

X-AXIS IS FOR TEMPERATURE (RANGE = 0 TO 1200C)THE SCALE ON X-AXIS IS NON-LINEAR.

Y-AXIS IS FOR GRAPH SPEED.

VARIOUS SPEED OF GRAPHS ARE 12.5, 25, 50, 100 MM / HOURWE GENERALLY KEEP 25 MM / HOUR.

GRAPH PAPER GRAPH PAPERS ARE USED FOR PLOTTING THE

FURNACE TEMPERATURE VIA THERMOCOUPLE. THEY ARE FITTED ON THE RECORDER. GRAPH PAPER RECOMMENDED ON RECORDER ONLY

TO BE USED GRAPH PAPER FOR MFS1 AND HFS1 FURNACE

==> ET 201 CHINO MAKE, JAPAN GRAPH PAPER FOR PFS FURNACE ==> ET 001 CHINO MAKE, JAPAN THE LENGTH OF ONE BUNDLE OF GRAPH PAPER IS

GENERALLY 2000 MM. DOTTING TYPE RECORDER INK (CHINO MAKE, JAPAN)

IS USED IN RECORDER FOR PLOTTING OF GRAPH. USUALLY , 6 COLOURS ARE FILLED FOR PLOTTING. SEE ANNEXURE-10 FOR FURTHER DETAILS

STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE

HFS-I FURNACE SKETCH

1. PROJECT NO:2. SECTION NO :3. CHARGE NO :4. H. T. REQ. NO : BURNERHFS-I FURNACE SKETCH

STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE1.Receive the job as per HT request. 2.Receive heat treatment request duly approved bymetallurgy engineer. 3.Ensure that Insp. Clearance is available prior to loading for job.4.Load the supporting arrangement as per the attachedannexure -35.Ensure the spider arrangement as per attachedannexure - 56.Fix the thermocouples at locations shown in furnacecharge.7.Check the entire job as per check list (annex.-I).

STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE9.Move the bogie inside the furnace 10.Pass the thermocouples through ports andconnect it with compensating cables11.Set the program as per heat treatment request.Secure it and then run it in fast mode as check.Bring it back to the initial segment and hold.12.Insert heat treatment chart in recorder and adjustthe speed of the graph.13.Clear inspection of job and get the signature ofinspector on graph paper for firing the furnace.14.Check LPG level, pressure and temperature in thestorage tanks and note down in logbook.

STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE15. Switch on the power supply 16. Close the bogie door 17. Follow the procedure for startup of furnace in zone-I18.Start the blower from the field push button station provided 19.Give power supply to the ignition panel 20When the system healthy contact comes from the instrument panel, the lamp for the system healthy signal is on. This indicates that the combustion air pressure and gas pressure are within the specified limits21.Now the firing on the cycle can start.

STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE22. Open the pilot and main gas valves 23. Press start cycle button on doing so the cycle starts and purging start indicator lamp is on.24. After 3 minutes ( time adjusted through timer ) the purging is completed and ignition start lamp is ON At the same time the purging start lamp gets OFF. 25. After 10 seconds the ignition start lamp gets OFF By this time the pilot burner should have been fired and the pilot flame is established.26. Flame healthy signal LED gets on which is provided on the flame sensor relay. This can be viewed through the glass window provided in the ignition panel.

STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE

27.Due to certain length of pipe between the burner andsolenoid valves, which may contain air, the burnermay not light up in the first attempt. In that case,repeat the above mentioned procedure. 28.Once the main flame is established, the control ispassed on to the temperature controller.29.For startup of furnace in other zones, follow the samesteps no 16 to 27 mentioned above.30.After all zones are started, start recording time andtemperature from recorder every 30 minutes in thelogbook.31.Conduct spot checks for heat treatment every 4hoursand fill the spot check format.

STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE32.Monitor the heat treatment process and graph till the completion to ensure that it is as per programand heat treatment request.33.After heat treatment cycle is completed, shut offall LPG supply valves and let furnace run withblowers on for 15 minutes.34.Open the bogie door. Disconnect thermocouplesfrom compensating cable.35.Submit the graph and duly filled spot check formatsto inspection for approval of heat treatment.

36.Retrieve the thermocouples from the ports and thebogie out of the furnace.37.Allow the job to reach room temperature.38.Remove the thermocouples from the job carefullywithout damaging the junction of thermocouples andwithout making impression on parent material of job.39.Unload the job from the bogie and move the bogieinside the furnace.40.Close the furnace. Shut off the main power supply.STANDARD OPERATING PROCEDURE FOR HFS-1 FURNACE

STANDARD OPERATING PROCEDURE FOR PFS FURNACE

125T Bogie hearth furnace -- PFS

BURMERPFS FURNACE SKETCH

STANDARD OPERATING PROCEDURE FOR PFS FURNACE1.Receive the job as per HT request.2.Receive heat treatment request duly approved bymetallurgy engineer.3.Ensure that Insp. clearance is available prior toloading for job.4.Load the job on the bogie as per the heat treatmentfurnace request.5.Ensure the supporting arrangement as per theattached annexure-I.6.Ensure the spider arrangement as per annexure- II.7.Fix the thermocouples at locations shown in furnacecharge.

STANDARD OPERATING PROCEDURE FOR PFS FURNACE8.Check the entire job as per check list attached asannexure-III9.Move the bogie inside the furnace.10.Pass the thermocouples through ports andconnect it with compensating cables.11.Insert heat treatment chart in recorder and adjustthe speed of the graph.12.Clear inspection of job and get the signature of inspector on graph paper for firing the furnace.13.Check LPG level, pressure and temperature inthe storage tanks and note down in logbook.

STANDARD OPERATING PROCEDURE FOR PFS FURNACE14.Switch on the power supply.15.Close the bogie door.16.Switch on ID blower first and then the air blowerand maintain pressure at about 800mm WG by slowly opening the suction valve.17.Ensure that pressure of LPG from yard to inlet of pressure regulator is always less than 20psi (1.5kg/CM2).18.Open the inlet valve to the regulator and open the outlet valve.19.If pressure exceeds 1600 mm WG , isolate thepressure by lifting the handle of safety shut off valve.

STANDARD OPERATING PROCEDURE FOR PFS FURNACE20.Immediately start lighting the pilot burners and adjust the flame with the air valve . 21.Open the isolating valve for pressure gauge andadjust the pressure regulator by turning the screwprovided in the stem so that the pressure is maintained at about 1000mm WG.22.Light up alternate main burners and adjust the flame lengths uniformly.23.Lock the doors by pneumatic locking.24.After all zones start, record time and temperaturefrom recorder every 30 minutes in the logbook.

STANDARD OPERATING PROCEDURE FOR PFS FURNACE25.Conduct spot checks for heat treatment every 4 hours and fill the spot check format. Monitor the heat treatment process and graph per heattreatment request.26.After the heat treatment cycle is completed, shut off all LPG valves and let furnace run with blowers on for 15 minutes. 27.Open the bogie door. Disconnect thermocouples from compensating cables.28.Submit the graph and duly filled spot check formats to inspection for approval of heat treatment.

29.Retrieve the thermocouples from the ports and movethe bogie out of the furnace.30.Allow the job to reach room temperature.31.Remove the thermocouples from job carefully andwithout marking impression on parent material ofjob.32.Unload the job from bogie and move the bogie insidethe furnace.33.Close the furnace. Shut off the power supply.STANDARD OPERATING PROCEDURE FOR PFS FURNACE

STANDARD OPERATING PROCEDURE FOR PIT FURNACE IN MFS-I

PIT FURNACE SKETCH

STANDARD OPERATING PROCEDUREFOR PIT FURNACE 1.Receive heat treatment request duly authorizedby metallurgy engineer. 2.Receive the job for heat treatment withinspection clearance.3.Put the job either on support or on heattreatment fixture inside the furnace.4.Ensure that equal clearance is available on allsides between job and baffle.5.Ensure that the furnace is calibrated.6.Connect thermocouples with compensatingcable to PID.

7.Set the program in the programmer as per heattreatment request.8.Take a trial run of program to ensure the accuracy.9.Calibrate all 5 PIDs prior to starting the furnace.10.Insert the graph inside the recorder and take thesignature of inspector on the graph paper.11.Close the furnace door.12.Start the furnace by giving power supply ONSTANDARD OPERATING PROCEDUREFOR PIT FURNACE

13.Start recording the time and temperature in thelogbook every 30 minutes.14.Ensure that the cycle is functioning as per program. 15.After the heat treatment is over, open the furnacecover.16.If the job calls for water quenching, lift the job anddip it in quench tank.17.It the job calls for air cooling in still air, lift the joband put it outside on supports in open air. STANDARD OPERATING PROCEDUREFOR PIT FURNACE

18.It the job doesnt call for anything above, allow thejob to cool down in furnace.19.Keep the job outside after removing from furnace.20.Submit the heat treatment graph to inspection forapproval of heat treatment cycle.21.Close the furnace cover after the furnace is cooleddown to room temperature. STANDARD OPERATING PROCEDUREFOR PIT FURNACE

PROCEDURE FOR EMPTY FURNACE CALIBRATION Calibration of PIDS ( indicator & controller )1.Connect the millivolt source to the temperatureindicator or controller by a compensating cable.Care should be taken to clean the wires andterminals thoroughly before connections aremade.2.The millivolt output for various temperatureranging from 00C to 10000C in steps of 500C is fedto the indicator / controller.3.After the millivolt value / temperature readingdisplayed is steady, the reading ofindicator/controller shall be noted.

PROCEDURE FOR EMPTY FURNACE CALIBRATION Calibration of recorder 1.Connect the millivolt source to the recorder by acompensating cable. Care should be taken toclean the wires and terminals thoroughly beforethe connections are made.4.If the error in the indicated readings is more thanthe specified accuracy ( +/- 10C ), then correctionto be carried out for the indicator / controller andpoints 1 to 4 shall be repeated till the specifiedaccuracy is obtained is obtained.

PROCEDURE FOR EMPTY FURNACE CALIBRATION 2.The millivolt output for various temperatureranging from 400 C to 10000C is fed to therecorder and is allowed to plot on a graph.3.The graph thus obtained is reviewed for timeand temperature values. These values shouldmeet the accuracy requirements.4.If there is error in the values plotted on thegraph, then correction to be carried out for the recorder and points 1 to 4 shall be repeated till the specified accuracy isobtained.

PROCEDURE FOR EMPTY FURNACE CALIBRATION EQUIPMENT REQUIRED ACCURACY1. 20 Nos. big K-type thermocouples +/- 0.25%2. 10 Nos. small K-type thermocouples +/- 0.25%3. Millivolt source (wahl unit ) ( 1 micro volt at 1000 micro volts )4. Heat treatment fixture.5. Temperature indicators (PID) +/- 10C6. Recorder +/- on temperature scale. +/- minutes on time scale.

PIT FURNACE CALIBRATION PROCEDURE 1.Ensure that the PIDs are calibrated as mentioned above.2.Ensure that the recorder is calibrated as mentionedabove.3.Ensure that all the thermocouples used are calibrated.4.Ensure that the thermocouples are attached to the heattreatment fixture as shown in sketch-I.5.Place the heat treatment fixture inside the furnace withthermocouples in position. 6.Close the furnace lid. Start the furnace and the recorder.

7.Set the temperature of controller to 4000C.8.After reaching the set temperature, it is allowed to stabilize for half an hour.9.Measure and record the temperature indicated byeach of the 20 thermocouples. The temperature is tobe read through WAHL UNIT. 10.Three sets of readings are to be taken for eachthermocouples at an interval of 10 minutes.11.Also record the readings indicated by each of thethermocouples at an interval of 10 minutes.PIT FURNACE CALIBRATION PROCEDURE

PIT FURNACE CALIBRATION PROCEDURE12.The temperature is then raised in steps of 50 C up to10000C. ( I. e. 4000C, 4500C, .., 9500C, 10000C. ) Themeasured temperature is stabilized for 30 minutes.PID reading are also to be recorded along with this.13.The allowed temperature variation with respect to theset temperature is +/- 50C up to 8000C and +/- 100Cabove 8000C.14.This is allowed to plot on the graph and thus obtained for time and temperature values. 15.Calibration of furnace is valid for 1 year.

STANDARD OPERATING PRACTICES FOR LOCAL STRESS RELIEVING

LOCAL STRESS RELIEVINGWHY Local SR to be done only when furnace SR not feasible When only certain components to be PWHT

HOW Can be done by Electrical / Gas / diesel / Induction etc..

DETAILS ON ENSURING PWHT TEMP. IN WELDMENT AREA Soaking band(SB) = Widest weld width x+ t or 2 inches

whichever is less from edge of weld Heating band width (HB) Induction stress level Through thickness criteria SB + 4 rt where r = Inside radius, t = thickness Insulation band width (IB) Axial gradient HB + 4 rt

LSR -BAND WIDTHWeld width X + lesser of 1T or 2X tSoak bandInsulation bandHeating bandInside radius

LOCAL STRESS RELIEVING SET UP1.Provide multitonne roller on one end of vessel during LSR ofcircular seam when job is horizontal.2. If both ends are open during LSR, provide insulationfrom inside. If not possible , prevent airflow so thattemperature on inside surface do not drop down.3. Spider/prop shall be provided in such a way that upper portion of spider / prop is not welded with insidesurface to allow contraction/expansion of shell surface.4.Spider/prop shall be between 200- 500mm from heating zone.5.Temporary attachments, provided for holding insulation,shall be within soak band only.6. Minimum two thermocouples shall be provided frominside, when accessible.

LOCAL STRESS RELIEVINGNo Welding at top Multitonne roller LSR of C/SSB+HB+IBSpider orprop

GOOD ENGG. PRACTICES FOR FURNACE CHARGES& L S R

SUPPORTING ARRANGEMENTS1.Heat Treatment request shall be as per Annexure-7 and Annexure-8.2.Minimum distance between floor of the furnace and lower most part of the job shall be 300mm.3.The distance between burner flame and saddle support as well as furnace wall and job shall be 600mm.4.Minimum 90 degree saddle to be used, however 120 degree saddle is desirable.

600mm 900600mm SUPPORTING ARRANGEMENTS5.Saddle shall be arranged in such away that openend of the vessel is maximum 450mm from saddle support.6.Saddle shall be located as close to spiders (temporarily arranged to control deformation) as possible. burner 300mm(point no:2)

SUPPORTING ARRANGEMENTS7. Spiders shall be provided as per annexure-58 Saddle supports shall be selected as per annexure.-39. Spiders or vertical prop shall be provided at open ends, center and below man way/nozzles above 24 10. Avoid gap between saddle support and job surface

Zero gap Supporting arrangement SUPPORTING ARRANGEMENTS11. Locking/clamping of job, restricting the movement (axial/lateral) during heat treatment shall be avoided.12. All long nozzles projecting outside job surface shall be supported.

13. Checklist shall be prepared and attached with HT request before furnace is fired as per Ann-114. Spot check report shall be filled by supervisor as per Annexure-2 during job is being heat treated.15. Moonplate support and welding inside surface prior to release for Heat treatment as per Annexure-4 16. General idea about thermocouple locations and its attachments is as per Annexure-6SUPPORTING ARRANGEMENTS

GENERAL1.Blocking the flame of the burner is not desirable2.Burner shall have blue flame and not yellow3. Flame shall not directly impinge on job4. All burners shall be fired at a time5.Keep all job nozzles open during heat treatment6.Above 24 nozzles / manways shall be locatedtowards bottom

GENERALTemp. support Furnace floor Gasket machined surface7.Deoxidization agent shall be applied on all machined and gasket faces8.Gasket / machined face of loose assemblies shall not be touching any object.

THERMOCOUPLES1.All the thermocouples shall be tagged with aluminum sheet and identification hard punched on it. (For PIT furnace only)

2. Minimum two thermocouples to be attached for any charge.

3. Minimum 8 thermocouples to be used for a charge in HFS- I furnace if the job occupies all 8 zones 4. Maximum distance between two thermocouples for a sample job is as shown in annexure- 65. PTC shall have separate thermocouple THERMOCOUPLES

1. Use only TAU-90 capacitor Discharge Welding machine for thermocouple connection

2. Use WPS:999-154 R0 for attachment of thermocouple for cs/alloy steel material

3. Only trained person by welding engineering shall attach thermocouple

4. A list of qualified person shall be by Welding Eng. THERMOCOUPLES ATTACHMENTS

5. Clean surface prior to attachment.

6. Two wire of thermocouple shall be attached one after another. 7. Gap between two wire of a thermocouple shall be max. 3.0mm 8. Only calibrated thermocouple shall be used.

Calibration shall be by QA.

9. After PWHT, thermocouple area shall be ground and DP shall be carried out.

10. For further details see Annexure-11 & 13-(page 1&2) THERMOCOUPLES ATTACHMENTS

THERMOCOUPLES ATTACHMENT UNIT

495.bin

SPECIAL NOTEIF THE TEMPERATURE OF HEAT TREATMENT EXCEEEDS 650-DEGREE CENTIGRADE, THE MATERIAL AND SIZE OF SPIDERS AND SUPPORTS TO BE DECIDED BY PLANNING AND APPROVED BY DESIGN.

CODE EXTRACTS FURNACE PWHT L S R

REQUIREMENT OF HEAT TREATMENTAS PER ASME-SEC VIII Div.-1 SERVICE CONDITION (UW-2) MATERIAL (UG-85, UW-40,UCS-56,UAT-80,UHA-32,UNF-79) THICKNESS (UG-85, UW-40,UCS-56,UAT-80,UHA-32,UNF-79) LOW TEMERATURE

OPERATION (UCS-68) COLD WORKING (UG-79) CUSTOMER SPEC.

CODE EXTRACT FOR HEAT TREATMENT( 1 )The soak band shall contain the weld, heat affected zone and a portion of base metal adjacent to the weld being heat treated. The minimum width of this volume is the widest width of weld plus 1T or 2 inches, whichever is less, on each side or end of the weld. The term T is the nominal thickness.( 2 ) The operation of postweld heat treatment shall be performed either by heating the vessel as a whole in an enclosed furnace or heating the vessel in more than one heat in a furnace, provided the overlap of the heated sections of the vessel is at least 5 feet ( 1.5m). When this procedure is used, the portion outside of the furnace shall be shielded so that the temperature gradient is not harmful. The cross section where the vessel projects from the furnace shall not intersect a nozzle or other structural discontinuity.

CODE EXTRACT FOR HEAT TREATMENT( 3 )When the vessel is required to be postweld heat treated, and it is not practicable to postweld heat treat the completed vessel as a whole or in two or more heats; any circumferential joints not provisionally heat treated may be thereafter locally postweld heat treated by heating such joints by any appropriate means that will assure the required uniformity.( 4 ) While carrying out local postweld heat treatment, the soak band shall extend around the full circumference. The portion outside the soak band shall be protected so that the temperature gradient is not harmful.( 5 )Heating a circumferential band containing nozzles or other welded attachments in such a manner that the entire band shall be brought up uniformly to the required temperature and held for the specified time.

CODE EXTRACT FOR HEAT TREATMENT( 6 )Where more than one pressure vessel or more pressure vessel part are postweld heat treated in one furnace charge, thermocouples shall be placed on vessels at the bottom, center, and top of the charge or in other zones of possible temperature variation so that the temperature indicated shall be true temperature for all vessels or parts in those zones. ( 7 ) Postweld heat treatment, When required, shall be done before the hydrostatic test and after any welded repairs. A preliminary hydrostatic test to reveal leaks prior to PWHT is permissible.( 8 )For pressure vessels or parts of pressure vessels being post weld heat treated in a furnace charge, it is the greatest weld thickness in any vessel or vessel part which has not previously been postweld heat treated.

CODE EXTRACT FOR HEAT TREATMENT( 8 contd...)The nominal thickness is the total depth of the weld exclusive of any permitted weldreinforcement.For groove weld, the nominal thickness is the depth of the groove.For fillet welds, the nominal thickness is the throat dimension. If a fillet weld is used in conjunction of groove weld, the nominal thickness is the depth of the groove or the throat dimension, Whichever is greater. For stud welds, the nominal thickness shall be the diameter of the stud.

( 9 )For P1 material ( carbon steel), minimum holding temperature during postweld heat treatment shall be 1100 Deg. F ( 593 Deg.c).

CODE EXTRACT FOR HEAT TREATMENT

P. NO.

HOLDING TEMP.

NOM. THICKNESS

SOAKING PERIOD

1 ( CARBON STEEL) & 3 (LOW ALLOY STEEL)

1100 DEG. F(593 C)

UPTO 2

1 HR. PER INCH. , HOWEVER 15 MINUTES MINIMUM

OVER 2 TO 5

2 HOURS , PLUS 15 MIN. FOR EACH ADDITIONAL INCH ABOVE 2

OVER 5

2 HOURS , PLUS 15 MIN. FOR EACH ADDITIONAL INCH ABOVE 2

* POST WELD HEAT TREATMENT IS MANDATORY ON P-NO.3 GR. NO. 3 MATERIAL IN ALL THICKNESSES.

( 10 )Postweld heat treatment is mandatory in Following conditions :For welded joints over 1. 5 nominal thickness.For welded joints over 1.25 nom. Thickness through 1.5nom. Thickness, unless preheat is applied at a min. Temperature of 200F ( 94c )during welding.Vessels or parts of vessels constructed of base material with corrosion resistant integral or weld metal overlay cladding or applied corrosion resistant lining material shall be postweld heat treated when the base material is required to be postweld heat treated. In applying this rule, the determining thickness shall be the total thickness of base material.When the PWHT is a service requirement.


SERVICE CONDITION LETHAL SERVICE PWHT IS MANDATORY EXEMPTIONS ARE FEW


CODE EXTRACT FOR HEAT TREATMENT( 11 ) Postweld heat treatment is not mandatory for carbon steel jobs (P1 material ) in Following conditions (UG2):

If groove welds is not over in size or fillet weld with a throat thickness of or less used for attaching non pressure parts to pressure parts provided preheat to a minimum temperature of 200F is applied when the thickness of pressure Part exceeds 1.25. If studs are welded to pressure parts provided preheat to a minimum temperature of 200F is applied when the thickness of the pressure parts exceeds 1.25. for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining provided preheat to a minimum temperature of 200f is maintained during application of the first layer when the thickness of the pressure part exceeds 1.25.

CODE EXTRACT FOR HEAT TREATMENT The temperature of furnace shall not exceed 800F

( 4270C) at the time when the vessel or part is placed in it. Above 8000F( 4270C), the rate of heating shall not be more than 4000F Per hour (2000C/Hour) divided by the maximum metal thickness of the shell or head plate in inches, but in no case more than 4000F Per hour( 2220C Per hour ). During the heating period, There shall not be a greater variation in temperature throughout the portion of the vessel being heat treated than 2500F( 1390C) within any 15 feet ( 4.6m) interval of length.

CODE EXTRACT FOR HEAT TREATMENT During the holding period, there shall not be a greater difference than 1500f ( 830c) between the highest and the lowest temperature the portion of the vessel being heated During the heating & holding periods, the furnace atmosphere shall be so controlled as to avoid excessive oxidation of the surface of the vessel. The furnace shall be of such design as to prevent direct heat impingement of the flame on the vessel. Above 8000F ( 4270C), The rate of cooling shall not be more than 5000F Per hour (2780C/Hour) divided by the maximum metal thickness of the shell or head plate in inches, but in no case more than 5000F Per hour ( 2780C Per hour).

when it is impractical to postweld heat treat at the temperature specified in table mentioned in Sr.. No. 9, It is permissible to carry out the post weld heat treatments at lower temperatures for longer periods of time as shown in table below :CODE EXTRACT FOR HEAT TREATMENT

NOTES :

1. MINIMUM HOLDING TIME FOR 1 THICKNESS OR LESS ; ADD 15 MINUTES PER INCH OF THICKNESS FOR THICKNESS GREATER THAN 1.

2. THESE LOWER POSTWELD HEAT TREATMENT TEMPERATURES PERMITTED ONLY FOR P-NO.1 GROUP NO. 1 AND 2 MATERIALS.

346.bin

347.bin

348.bin

345.bin

Annexure-5

Sheet1

SELECTION OF SPIDERS AT OPEN ENDS FOR HEAT TREATMENT

SHELL THICKNESS

10000102030405060708090100

SHELL DIAMETER9500

9000

8500

8000

7500

7000ISMB 250

6500ISMB 250 BOX SECISMB 250

6000

5500

5000

4500

4000

3500ISMB 150

3000

2500

2000ISMB 125ISMB 150

1500

1000

500ISMB 125ISMB 150

102030405060708090100

SHELL THICKNESS

DATA FOR ABOVE CHANNELS:

DESIGNATIONWT/ MTR.(KG)WEB HTFLG WDFLG THKWEB THK

ISMB 12513125757.64.4

ISMB 15014.9150807.64.8

ISMB 25037.325012512.56.9

ISMC 25030.42508014.17.1

349.bin

HT REQUESTAnnexure-7

381.bin

HT CHARGEAnnexure-8

382.bin

Usage of compansating cableAnnexure-9page 1 of 4

Information on Graph Paper UsageAnnexure-10

Mechanical v/s capacitor discharge attachmentsAnnexure-11

Thermo. Couple Procurement ProcedureAnnexure-12

Thermo. Couple Attachment ProcedureAnnexure-13page 1 of 2

Thermo. Couple Attachment ProcedureAnnexure-13page 2 of 2

page of 108

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