A R C H I V E S o f

F O U N D R Y E N G I N E E R I N G

Published quarterly as the organ of the Foundry Commission of the Polish Academy of Sciences

ISSN (1897-3310)Volume 15

Issue 3/2015

85 – 90

18/3

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 1 5 , I s s u e 3 / 2 0 1 5 , 8 5 - 9 0 85

Structure and Usable Properties of Aluminum Continuous Ingots

T. Wróbel *, J. Szajnar, D. Bartocha, M. Stawarz

a Silesian University of Technology, Foundry Department, Towarowa 7, 44-100 Gliwice, PL *Corresponding author. E-mail address: tomasz.wrobel@polsl.pl

Received 20.05.2015; accepted in revised form 29.05.2015

Abstract In paper is presented results of studies concerning ingot of Al with a purity of 99.5% cast with use of stand of horizontal continuous casting. Mainly together with casting velocity was considered influence of electromagnetic stirrer, which was placed in continuous casting mould on refinement of ingots structure and theirs usability to plastic deformation. Effect of structure refinement and usability to plastic deformation obtained by influence of electromagnetic stirring was compared with refinement obtained by use of traditional inoculation, which consists in introducing of additives i.e. Ti and B to metal bath. On the basis of obtained results was affirmed that inoculation realized by electromagnetic stirring in range of continuous casting mould guarantees improvement in structure refinement and usability to rolling of pure Al continuous ingots. Keywords: Continuous casting, Aluminum, Structure, Inoculation, Electromagnetic stirring

1. Introduction The technology of continuous casting is applying usually in

production of ingots of Fe [1÷4], Al [5÷8] or Cu [9,10] alloys, with high yield and quality. The quality of continuous ingot in comparison with traditional gravity casting with use of ingot permanent mould concerns refinement and uniform of ingot structure, which results from solidification of metal in water cooled continuous casting mould.

Moreover the refinement of ingot structure can be increases by forced liquid metal movement in time of its solidification results from influence of electromagnetic stirring [1÷14]. The forced liquid metal movement guarantees limitation of unfavorable (mainly for plastic deformation of ingot) columnar macrograins from ingot primary structure at simultaneously increase amount of favorable equiaxed macrograins.

Other method of structure refinement is use of traditional inoculation consists in introducing into metal bath of specified substances, called inoculants. Inoculants increase grains density

as result of creation of new particles in consequence of braking of grains growth velocity, decrease of surface tension on interphase boundary of liquid – nucleus, decrease of angle of contact between the nucleus and the base and increase of density of bases to heterogeneous nucleation. The effectiveness of this type of inoculation depends significantly on crystallographic match between the base and the nucleus of inoculated metal. Therefore active bases to heterogeneous nucleation for aluminum are particles, which have high melting point i.e. titanium borides, titanium carbides, titanium nitrides, aluminum borides and aluminum titanide [11÷14]. But this effective method of inoculation in comparison with inoculation with use of electromagnetic field has three faults i.e. inoculants decrease the degree of purity and electrical conductivity of pure aluminum [11] and moreover are reason of point cracks formation during rolling of ingots [15].

Therefore the aim of studies was determined the influence of inoculation with use of electromagnetic field at defined casting velocity on structure refinement and usability to plastic deformation of continuous ingot φ30mm of Al with a purity of

86

99,5defocominocB to

2.

whicUnivmadwithcastrecorealimottime

defiveloof forwfromtempon 4cast

elecplacapplgene100

intromas

5%. Effect of ormation obtain

mpared with rculation, which o metal bath.

Range of On Fig. 1 viewch was constversity of Tec

de stand belongh a capacity of uing mould at

ooling, system oized method oion to forwardse and velocity fr

Fig. 1. View

In presented stned by combin

ocity from 100 tpresented me

wards/stop/forwm 30 to 80 mmperature of coo45÷55°C and teing mould was While in aim

ctromagnetic ficed in continulied rotating eerated by stirrHz. Moreover was oducing of addster alloy AlTi5

A

structure refinned by influencerefinement obconsists in intr

f studies w of the stand otructed in Fouhnology is preg to induction up to 60 kg of flow rate from

of continuous inf ingot movems, stop and/or bfrom 100 to 500

w of stand of hor

tudies was appnation of motioto 240 mm/min

ethod of ingowards/stop/etc.

m/min. In depoling water in cemperature of in

equaled 150÷3m of realizatio

ield (IEF) wauous casting melectromagneticrer supplied w

used traditionaditives i.e. Ti aB1 in amount 2

R C H I V E S o

nement and use of electromag

btained by usroducing of add

of horizontal coundry Departmesented. The m

furnace, whiccharge, water cm 0.1 to 10 ngot drawing a

ment defined byackwards perfo

0 mm/min set in

rizontal continu

lied method ofon to forwards n and stop in timot movement was obtained

pendence of usontinuous castingot after leavin300°C. n of inoculati

as used electromould (Fig. 2)c field with iwith current 8

al inoculation, and B to metal25 ppm Ti and 5

o f F O U N D R

sability to plasgnetic stirring wse of traditionditives i.e. Ti a

ontinuous castinment of Silesimain parts of th is also tundcooled continuol/min, system

and cutting, whiy combination

ormed in specifin control system

uous casting

f ingot movemein time of 1 s

me of 2 s. In resin combinati

average velocsed velocities ting mould was ng the continuo

ion with use omagnetic stir. In studies wnduction 60 mA at frequen

which consistsl bath in form 5 ppm B (IA).

R Y E N G I N

stic was nal and

ng, ian the

dish ous

of ich of

fied m.

ent s at sult ion city the set

ous

of rrer was mT ncy

s in of

Thingotson tra(PKR(PKKrepresLSKKreprescriteriincrearefinemetallwere etchedHNO3

F

E E R I N G V

Fig. 2. View ofcon

he degree of prs was representansverse sectio

R) and average aK). Moreover senting simulta

(width of cosented by area oion area of trianase of degree ement measurelographic studicarried out. And with use of 3 and 300 ml H2

Fig. 3. Graphic i

o l u m e 1 5 ,

f water cooled cntains electroma

rimary structurted by equiaxedn, average areaarea of macro-g

was applied aneous three paolumnar crystaof scalene trianngle tending to

of refinemenements in pures on transvers

nalyzed surfacesolution of: 50

2O.

interpretation o

I s s u e 3 / 2

continuous castagnetic stirrer

re refinement od crystals zonea of macro-gra

grain in columnrefinement c

arameters i.e. Pals zone). Congle (Fig. 3). Aa minimum co

nt. In aim ofre Al structurse section of coe for macroscop0 g Cu, 400 m

of refinement co

0 1 5 , 8 5 - 9 0

ting mould

f Al continuoue content (SKRain in this zonnar crystals zoncoefficient (RPKR, PKK andoefficient R i

According to thirresponds to th

f realization ore macroscopiontinuous ingotpic analysis waml HCl, 300 m

oefficient R

0

us R)

e e

R) d is is e

of c ts as ml

A R

cast the bflats330°with

3.

99.5withwithresurefin

of incontComcoluperccontzonedecrof us

inocstruccasezonecoluelectmovgrainoriencrys

coefavercontveloelect

C H I V E S o f

Usability to plain horizontal c

basis of results s in 6 roll pass°C by 1 h. In h rolls diameter

Fig. 4. Viewcon

Results oIn table 1 are p

5% continuous inh use of electromh use of Ti and ults of measurnement. On the basis of noculation by eltinuous casting p

mpared to initialumnar and equiacentage content otinuous ingot. Ine on transverse reasing of area ose of inoculationMoreover was a

culation by Ti acture of increasees simultaneous e on transverse sumnar macro-gtromagnetic stir

vement decreasen, but similarlntation of prim

stals zone. Summing on

fficient R was arage velocity of tinuous ingot. Hocity of ingot mtromagnetic stirr

f F O U N D R

astic deformaticontinuous casof cold rolling

s with intermedthese studies

r 550 mm (Fig.

w of cold rollinntinuous ingot t

f studies presented macrongots respectivemagnetic stirrinB additives. W

rements of pa

f obtained resultslectromagnetic sprocess refinemel state is presenaxed macro-graof equiaxed cryncrease in percensection of Al co

of macro-grains n by small amouaffirmed that in and B is presene of average veldecreases perce

section and incregrain. While rring with increes average area orly to the pre

mary structure o

the bases of affirmed generaf ingot movemenHowever sensitmovement can ring or mainly b

Y E N G I N E

on of Al with asting process w

of φ30 mm ingdiate annealing was used reve4).

ng process of φ3o 5 mm thick fl

ostructures of Aely in initial stateg and after trad

Whereas on Fig. arameters of

s was affirmed tstirring was obtaent of primary stnt decreasing ofains, however wstals zone on trantage content ofontinuous ingot in this zone was

unt of Ti and B. case of Al in innt negative infllocity of ingot mentage content ofeases average ar

in case of eased in averageof equiaxed and

evious cases, of ingot i.e. dec

analysis conceally negative infnt on primary sttivity of structube reduced usi

by addition of Ti

E R I N G V o

a purity of 99.5was determined gots to 5 mm thi

recrystallizingrsing rolling m

30 mm Al lat

Al with a purity e, after inoculati

ditional inoculati4÷7 are presenprimary structu

that in result of uained in horizontructure of pure Af area of particuwithout increase ansverse sectionf equiaxed crystwith simultaneos obtained in res

nitial state and afluence on primamovement. In thef equiaxed crystea of equiaxed a

inoculation e velocity of ingd columnar macoccurred negatcrease of equiax

erning refinemfluence of increatructure of pure ure on changes ng inoculation and B.

l u m e 1 5 , I

5% on ick

g in mill

y of tion tion nted ture

use ntal Al.

ular e in n of tals ous sult

fter ary

hese tals and by

got cro-tive xed

ment ase Al in by

Fig. percen(SKR

Fig. aver

Al co

Fig. avera

Al co

1

2

3

4

5

6

SKR

, %PK

R, m

m2

PKK

, mm

2

s s u e 3 / 2 0

5. Influence ofntage content o

R) of Al continu

6. Influence ofrage area of macontinuous ingot

7. Influence ofage area of mac

ontinuous ingot

SKR =

0

10

20

30

40

50

60

30 40

PKR = 0,R2

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

2,0

30 40

PKK =

0

1

2

3

4

5

6

30 40

1 5 , 8 5 - 9 0

f average velocif equiaxed crys

uous ingot in dimarked in T

f average velocicro-grain in equin different stat

Tab.1

f average velocicro-grain in coluin different stat

Tab. 1

= 0,02V2 - 2,89V + 12R2 = 0,88

SK

50 6

V, mm/min

,007V + 0,0062 = 0,99

PKR

50

V, mm/min

-6⋅10-4V2 + 0,08V - 1R2 = 0,96

50 6

V, mm/min

ity of ingot movstals zone on traifferent state of Tab. 1)

ity of ingot movuiaxed crystals

ate of inoculatio)

ity of ingot movumnar crystals

ate of inoculatio1)

22,08

R = 0,03V2 - 3,83V +R2 = 0,98

SKR = 0,0

60 70

n

= -4⋅10-4V2 + 0,06V R2 = 0,93

PKR = -1⋅10R

60 70

n

PKK = 2⋅1R

PKK = 8⋅11,10

60 70

n

87

vement (V) on ansverse section

f inoculation (as

vement (V) on zone (PKR) of

on (as marked in

vement (V) on zone (PKK) of

on (as marked in

+ 135,88

02V2 - 2,48V + 98,62R2 = 0,98

80

IEF+IAIEFIA

- 0,30

0-4V2 + 4⋅10-4V + 0,97R2 = 0,93

80

IEF+IAIEFIA

10-3V2 - 0,13V + 6,13R2 = 0,4727

10-4V2 - 0,08V + 4,65R2 = 0,64

80

IEF+IAIEFIA

7

n s

n

fn

2

7

3

5

88

TabMac

A

le 1. crostructures ofAverage velocit

movement V,

30

40

50

60

70

80

A

f continuous ingty of ingot mm/min

R C H I V E S o

gots of Al with In initialinoculat

o f F O U N D R

a purity of 99.5l state without tion (IEF+IA)

R Y E N G I N

5% After ielectro

E E R I N G V

inoculation withomagnetic stirrin

o l u m e 1 5 ,

h use of ng (IEF)

A

I s s u e 3 / 2

After inoculatioTi and B add

0 1 5 , 8 5 - 9 0

on with use of ditives (IA)

0

A R

Figrefin

contflatselecsurfflatsmovobtasmaThe founqualaddithe affirqual

F

R

C H I V E S o f

g. 8. Influence nement coeffici

of i

On the basis oftinuous ingots ts obtained ctromagnetic stifaces free froms was not affivement on theained from ingall delamination

greatest concnd in ingot caslity are characteition of Ti and edge into the frmed influence lity which is un

ig. 9. Example rolling from

R = -8

0

5

10

15

20

25

30

35

30 40

R

f F O U N D R

of average veloient (R) of Al cinoculation (as m

f results of studto rolling was afrom ingots irring. These f

m any cracking irmed influenceeir quality. Wots in initial stn which can pentration of th

st with average erized flats from

d B. There are pflat (Fig. 10). Mof average velo

nsatisfactory.

view of part of

m φ 30mm Al co by electromag

R

⋅10-4V2 + 0,13V - 1,63R2 = 0,97

50

V, mm/m

Y E N G I N E

ocity of ingot montinuous ingomarked in Tab.

dies concerningaffirmed that hig

cast with flats is characte(Fig. 8). Addi

e of average vWhile worse qu

tate. On flats eropagate into m

his type of survelocity 80mm

m ingots cast wpresent cracks

Moreover for thocity of ingot m

f flat thick 5 mmontinuous ingot gnetic stirring

R = -3⋅10-3V2 + 0,69VR2 = 0,62

R = 23

60 70

min

E R I N G V o

movement (V) ont in different sta1)

g evaluation of ghest quality ha

inoculation erized by smootionally for thevelocity of inguality have fledges are presematerial (Fig.rface defects wm/min. The wo

with inoculation progressing fro

hese flats was nmovement on th

m made by coldinoculated

V - 5,91

2⋅10-3V2 - 0,34V + 22,R2 = 0,56

80

IEF+IAIEFIA

l u m e 1 5 , I

n ate

Al ave by

oth ese got lats ent 9).

was orst

by om not

heir

d

Fig.r

Fig.

4. C B

formu1. In

costrco

2. Pustwin

,12

A

s s u e 3 / 2 0

10. Example vrolling from φ3

11. Example vrolling from φ

Conclusionased on conduc

ulated: noculation realiontinuous castructure refinemontinuous ingoture Al continuirring are chara

with initial statengots inoculated

1 5 , 8 5 - 9 0

view of part of f0 mm Al contin

view of part of fφ30 mm Al cont

by additions of

ns cted studies fol

ized by electroting mould ment and usabs. uous ingots inacterized by lare but simultaned by additions o

flat thick 5 mmnuous ingot in i

flat thick 5 mmtinuous ingot inf Ti and B

llowing conclu

omagnetic stirriguarantees imbility to rollin

noculated by rger refinemeneous smaller inof Ti and B.

89

m made by cold initial state

m made by cold noculated

sions have been

ing in range omprovement inng of pure A

electromagnetit in comparison

n comparison to

9

n

of n

Al

c n o

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 1 5 , I s s u e 3 / 2 0 1 5 , 8 5 - 9 0 90

3. Pure Al continuous ingots inoculated by electromagnetic stirring have larger usability to plastic deformation than ingots in initial state or inoculated by additions of Ti and B.

4. Increasing in average velocity of ingot movement negative influences on primary structure of pure Al continuous ingot. However sensitivity of structure on changes in velocity of ingot movement can be reduced using inoculation by electromagnetic stirring or mainly by addition of Ti and B.

Acknowledgements Project financed from means of Polish National Science Centre.

References [1] Adamczyk, J. (2004). Engineering of metallic materials.

Gliwice: Publishers of Silesian University of Technology. (in Polish).

[2] Zhou, S., Li, H., Rao, J., Ren, Z., Hang, J. & Yang, Z. (2007). Effect of electromagnetic stirring on solidification structure of austenitic stainless steel in horizontal continuous casting. China Foundry. 4(3), 198-201.

[3] Szajnar, J., Stawarz, M., Wróbel, T., Sebzda, W., Grzesik, B. & Stępień, M. (2010). Influence of continuous casting conditions on grey cast iron structure. Archives of Materials Science and Engineering. 42(1), 45-52.

[4] Szajnar, J., Stawarz, M., Wróbel, T. & Sebzda, W. (2010). Laboratory grey cast iron continuous casting line with electromagnetic forced convection support. Archives of Foundry Engineering. 10(3), 171-174.

[5] Lee, D., Kang, S., Cho, D. & Kim, K. (2006). Effects of casting speed on microstructure and segregation of electromagnetically stirred aluminum alloy in continuous casting process. Rare Metals. 25, 118-123.

[6] Beijiang, Z., Jianzhong, C. & Guimin, L. (2003). Effects of low-frequency electromagnetic field on microstructures and macrosegregation of continuous casting 7075 aluminum alloy. Materials Science & Engineering A. A355, 325-330.

[7] Li, Y., Zhang, X., Jia, F., Yao, S. & Jin, J. (2003). Technical parameters in electromagnetic continuous casting of aluminum alloy. Transactions of Nonferrous Metals Society of China. 13(2), 365-368.

[8] Wróbel, T., Szajnar, J., Bartocha, D. & Stawarz, M. (2013). The stand of horizontal continuous casting of Al and its alloys. Archives of Foundry Engineering. 13(3), 113-118.

[9] Yan, Z., Jin, W. & Li, T. (2012). Effect of rotating magnetic field (RMF) on segregation of solute elements in CuNi10Fe1Mn alloy hollow billet. Journal of Materials Engineering and Performance. 21(9), 1970-1977.

[10] Li, X., Guo, Z., Zhao, X., Wie, B., Chen, F. & Li, T. (2007). Continuous casting of copper tube billets under rotating electromagnetic field. Materials Science & Engineering A. 460-461, 648-651.

[11] Szajnar, J. & Wróbel, T. (2008). Influence of magnetic field and inoculation on size reduction in pure aluminium structure. International Journal of Materials and Product Technology. 33(3), 322-334.

[12] Wróbel, T. (2012). The influence of inoculation type on structure of pure aluminum. In 21st International Conference on Metallurgy and Materials METAL 2012 (pp. 1114-1120). Brno, Czech Republic.

[13] Wróbel ,T. (2013). Transformation of pure Al structure under the influence of electromagnetic field. Advanced Materials Research. 702, 159-164.

[14] Wróbel, T. & Szajnar, J. (2013). Modification of pure Al and AlSi2 alloy primary structure with use of electromagnetic stirring method. Archives of Metallurgy and Materials. 58(3), 941-944.

[15] Keles, O. & Dundar, M. (2007). Aluminum foil: its typical quality problems and their causes. Journal of Materials Processing Technology. 186(1-3), 125-137.