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: [email protected]
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.
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