43
INFLUENCE OF SB ON GAS CONTENT AND FLOWABILITY
OF ALLOY ALSI6CU4
Dušan Medlen
*I a No á
**Dana Bolib ucho á
***Dušan U gela
Uni e si y o Žilina
Depa men o Technological Enginee ing
Uni e zi ná 1, 010 26 Žilina, Slo akia
[email p o ec ed]
*Technical Uni e si y o Libe ec
Facul y o Mechanical Enginee ing
S uden ská 2, 461 17, Libe ec 1, Czech Republic
[email p o ec ed]
**Uni e si y o Žilina
Depa men o Technological Enginee ing
Uni e zi ná 1, 010 26 Žilina, Slo akia
[email p o ec ed]
***Uni e si y o Žilina
Depa men o Technological Enginee ing
Uni e zi ná 1, 010 26 Žilina, Slo akia
[email p o ec ed]
Abs ac
Cas aluminum-silicon alloys a e used in a numbe o au omo i e and indus ial weigh
sensi i e applica ions because o hei low weigh and e y good cas abili y. Modi ie s a e
usually added o mol en aluminum-silicon alloys o e ine he eu ec ic phase pa icle shape
and imp o e he mechanical p ope ies o he inal cas p oduc s and Al-Si alloys cas
p ope ies. In e ms o aluminum-silicon, his usually in ol es he addi ion o s on ium (S ),
sodium (Na) o an imony (Sb). The cas p ope ies luidi y and mould illing capaci y play a
key ole in he p oduc ion o hin-sec ion and geome ically complex cas pa s. The p esence
o apped gas o sh inkage po es in ce ain loca ions wi hin cas ings has been shown o
in luence a igue li e. In his pape he in luence o Sb on he gas con en and lowabili y o
AlSi6Cu4 has been esea ched.
In oduc ion
The excellen cas abili y and mechanical p ope ies o he AlSi6Cu4 alloy make i a popula
ound y alloy o au omo i e applica ions. [1] Nowadays ound y plan s a e o ced o educe
he wall hickness o cas pieces, o keep he na ow ole ance ex en (combus ion chambe ,
canal posi ion) and o minimize he su ace oughness (suc ion canal). The highe
equi emen s on cas pieces make he cons uc ion mo e ex ensi e and mo e complica ed. [2]
The cas p ope ies and mechanical p ope ies o he AlSi6Cu4 alloys can be imp o ed no
only h ough modi ying g ain e inemen bu also h ough applying hea ea men and o he
echnologies. In p ac ice, he mos common elemen s wi h he modi ying e ec a e s on ium,
sodium and an imony. Adding hese elemen s leads o a change in he shape o eu ec ic
silicon, esul ing in an inc ease o he mechanical and cas cha ac e is ics o he alloys. [1, 3]
44
Many expe imen s ha e been ca ied ou o s udy and explain he e ec o eu ec ic modi ie s
on hyd ogen, mic opo osi y and lowabili y. In gene al, i is obse ed ha modi ied cas ings
con ain mo e po osi y han unmodi ied ones. Howe e , he e is no consensus on he
mechanism. Some possible easons ha e been p oposed and s udied. In gene al, modi ie s can
inc ease he inclusion con en in he mel , dec ease hyd ogen solubili y in he solid me al,
change he solid-liquid in e ace mo phology, educe he su ace ension o he liquid me al
and inc ease he olume ic sh inkage. [1]
The AlSi6Cu4 cas ings mus mee he high equi emen s no only on he mechanical
p ope ies bu mus mee high equi emen s on p essu e igh ness as well. S on ium is now
widely used in p ac ice o he modi ica ion o he AlSi6Cu4 alloy. When modi ying he
AlSi6Cu4 alloys by s on ium, i was ound ou ha he alloy subjec ed o his ype o
modi ica ion has highe alues o he gas con en , leading o highe po osi y and hus
educing he p essu e igh ness. The aim o he expe imen al wo k was o in es iga e he
in luence o an imony on he gas con en o he aluminum alloy AlSi6Cu4. [4, 5]
1 Expe imen al p ocedu e
1.1 Mel ea men and cas ing p ocedu es
The Aluminum alloy AlSi6Cu4 was used as he expe imen al ma e ial. The chemical
composi ion o he alloy is lis ed in Tab. 1. The mel ing p ocess and he modi ica ion we e
ca ied ou in a g aphi e-chamo e mel ing c ucible in an esis ance o en. The g ain
e inemen p ocess using he e ining sal AlCuAB6 was ca ied ou while o e hea ing he
me al ba h o 730 °C ± 5 °C. The modi ica ion p ocess using an imony was ca ied ou unde
he same echnological condi ions.
The amoun o an imony chosen o each cas is lis ed in Tab. 2. This amoun was de e mined
and based on he mos widely used quan i ies shown in he li e a u e o Al-Si-Cu based
alloys.
Tab. 1 Chemical composi ion o he AlSi6Cu4 alloy
Elemen s Si Fe Cu Mn Mg Ni Zn Ti C
(w .%) 6,52 0,43 3,88 0,45 0,29 0,01 0,46 0,15 0,01
Tab. 2 Amoun o an imony o each cas o AlSi6Cu4 alloy used in he p esen wo k
Numbe o cas 1 2 3 4 5 6 7 8 9 10 11
Amoun o Sb (ppm) 0 100 300 500 800 1000 1500 2000 2500 3000 10000
1.2 Gas con en o he AlSi6Cu4 alloy
To imp o e he mechanical p ope ies o hese ma e ials, he common p ac ice is o e ine he
mic os uc u e o he cas ing, such as modi ica ion. I has been shown ha he de ec a ea and
dis ance om he ee su ace a e impo an ac o s ha de e mine he impac o de ec s on he
a igue li e o cas ings. A la ge le el o po osi y, which is loca ed in he cen e o he cas ing,
may no e ec he mechanical p ope ies o he a igue pe o mance. A smalle , isola ed po e
nea he su ace may ha e a signi ican impac . The designe s need o know how he cas pa
geome y and p ocess will impac he po osi y o ma ion. As such, i is impo an o de elop
a comp ehensi e model o p edic he size and loca ion o mic opo osi y in a cas ing as a
unc ion o he p ocess a iables. Mic opo osi y usually esul s om a ailu e o he
45
in e dend i ic eeding o o he exsolu ion o he dissol ed gas om he mel , o a
combina ion o he wo. [1]
To de ec he gas con en he Vacuum Densi y Tes e 3VT-LC, he acuum o ming and he
weighing-machine MK 2200LC we e used o he weigh iden i ica ion o he expe imen al
samples (Fig. 1). The weighing-machine e alua ed he densi y o he samples and also he
pe cen age, based on he ma hema ical and physical ela ionships and o mulas, and
de e mined he densi y index - DI. In each cas he e we e made wo samples whe e he i s
one was solidi ying in he ai and he second one was placed in a acuum o 7 minu es. The
c oss-sec ion cu s o he indi idual samples can be seen in Tab. 3.
F
ig. 1 Vacuum Densi y Tes e 3VT-LC and weighing-machine MK 2200LC
Tab. 3 C oss-sec ion cu s o AlSi6Cu4 modi ied by Sb
ai acuum ai acuum
Cas no. 1 (0 ppm Sb) Cas no. 2 (100 ppm Sb)
ai acuum ai acuum
Cas no. 3 (300 ppm) Cas no. 4 (500 ppm Sb)
4
4
6
The sa
m
conside
Fig. 2
s
g adua
e
Based
o
de e mi
he exp
e
ai
Cas n
o
ai
Cas no
ai
Cas no
m
ples o
A
ed as a b i
e
s
hows he
c
e
d amoun
s
o
n he co
m
ned amou
n
e
imen al s
a
o
. 5 (800 p
p
. 7 (1 500
p
. 9 (2 500
p
A
lSi6Cu4
m
e
o e ie
w
c
alcula ed
s
o an imo
n
m
pa ison
T
n
o he ga
s
a
mples.
acuum
p
m Sb)
acuum
p
pm Sb)
acuum
p
pm Sb)
ai
Cas n
o
m
odi ied b
y
w
o he po
o
alues o
h
n
y on he
b
T
ab. 3 and
s
con en
w
o
. 11 (10 0
0
y
an imony
o
si y o ma
h
e densi y i
b
asis o he
Fig. 2, i
w
as con i m
ai
Cas
n
ai
Cas
n
ai
Cas
n
acuu
m
0
0 ppm Sb)
solidi ied
ion and lo
c
ndex o h
e
ma hema
i
can be
n
ed by obse
n
o. 6 (1 00
0
n
o. 8 (2 00
0
n
o. 10 (3 0
0
m
in he ai
c
a ion.
e
AlSi6Cu
4
i
cal and ph
y
n
o ed ha
ing he c
acuu
m
0
ppm Sb)
acuu
m
0
ppm Sb)
acuu
m
0
0 ppm Sb)
in Tab. 3
,
4
alloy mo
d
y
sical ela
i
he ma he
m
oss-sec io
n
m
m
m
,
can be
d
i ied by
i
onships.
m
a ically
n
cu s o
47
The unmodi ied AlSi6Cu4 alloy showed DI = 11.11%, while by adding a Sb modi ie he e
we e ob ained signi ican changes, app ox. a 63 pe cen educ ion, in he gas con en
co esponding o 500 ppm Sb.
F
ig. 2 Densi y index o AlSi6Cu4 modi ied by Sb
1.3 Flowabili y o he AlSi6Cu4 alloy
The li e a u e su ey has shown ha he addi ion o s on ium (S ) dec eases he lowabili y o
he aluminium alloys. The au ho s ha e e ealed in hei wo ks ha he modi ica ion in a sand
o m educes he lowabili y o an AlSi alloy om 5 o 7%, while in a s eel mould he
educ ion is a li le bi smalle a ying be ween 2% o 3% [6, 7]. Molla d [8] has ound ou
ha he low p ope y o he aluminium alloys can be educed up o 8% due o S addi ion.
Ko e and Se ak [9, 10] ha e shown ha he lowe ing o he lowabili y h ough S addi ion is
no so high as h ough he modi ica ion wi h sodium. Acco ding o hem, he eason o he
s ong dec ease o he lowabili y o he AlSi alloys h ough he sodium (Na) addi ion migh
be due o i s e ec on he su ace ension o he AlSi alloys. The in luence o an imony (Sb)
on AlSi6Cu4 has no been in es iga ed.
In his subchap e he e ec o he an imony addi ion on he lowabili y o he AlSi6Cu4 alloy
has been in es iga ed. The amoun o an imony was a ied om 0 ppm up o 10 000 ppm
(Tab. 2). The p ocess pa ame e s such as he cas ing empe a u e 730°C and he pou ing
empe a u e 730°C we e held cons an du ing hese expe imen s. The accu acy o he cas ing
is limi ed by he ype o sand and he molding p ocess. In e ms o he lowabili y
expe imen s, sand molds we e used. The used molding sand consis ed o silica sand (SiO2)
85%, ben oni e (clay) 11%, and wa e 4%.
T adi ionally, he lowabili y is measu ed by using he spi al es . The lowabili y is
de e mined h ough he low leng h o an alloy in a spi al con ou . Fig. 3 shows he alues o
he low leng h (cm) o each spi al. The inal cas s (spi als) om each cas ing used o he
e alua ion o he low leng h a e shown in Tab. 4.
11,11
12,59
5,51
4,40
6,27
4,78
9,26
7,75 7,78
13,10
5,49
3,00
4,00
5,00
6,00
7,00
8,00
9,00
10,00
11,00
12,00
13,00
14,00
01234567891011
Densi y Index DI ( % )
Cas numbe

48
F
ig. 3 Flow leng h o AlSi6Cu4 modi ied by Sb
Tab. 4 Spi al es samples used o e alua ion o he low leng h o AlSi6Cu4
Cas no. 1
(0 ppm Sb)
Cas no. 2
(100 ppm Sb)
Cas no. 3
(300 ppm Sb)
Cas no. 4
(500 ppm Sb)
Cas no. 5
(800 ppm Sb)
Cas no. 6
(1 000 ppm Sb)
Cas no. 7
(1 500 ppm Sb)
Cas no. 8
(2 000 ppm Sb)
Cas no. 9
(2 500 ppm Sb)
Cas no. 10
(3 000 ppm Sb)
Cas no. 11
(10 000 ppm Sb)
53
60
67
62
69
80
72 72
75
77
63
50
55
60
65
70
75
80
85
01234567891011
Flow leng h (cm)
Cas numbe
49
Conclusion
In his wo k he in luence o an imony on he AlSi6Cu4 alloy on he gas con en and
lowabili y has been in es iga ed.
When modi ying he AlSi6Cu4 alloys by an imony, i was ound, ha he alloy subjec ed o
his ype o modi ica ion has lowe alues o he gas con en , leading o he lowe po osi y
ha has an e ec on he p essu e igh ness compa ing o modi ying he AlSi6Cu4 alloys by
s on ium. Based on he expe imen al esul s o he gas con en (Tab. 3 and 4), i can be
claimed ha he mos app op ia e amoun o an imony wi h he lowes DI= 4,04 % is 500 ppm
Sb. The gas con en o he es ed AlSi6Cu4 alloy sample, modi ied by 500 ppm Sb, dec eased
down o app ox. 37 % o he o iginal unmodi ied alloy (DI= 11,11%).
The spi al es expe imen s ha e shown ha he amoun o an imony in he aluminium mel
has an e ec on he low leng h. The inc ease in he amoun o an imony ex ends
signi ican ly he low leng h o he aluminium mel . Based on he expe imen al esul s, he
spi al es expe imen s (Tab. 5 and 6) can claim ha he mos app op ia e amoun o an imony
o he low leng h o AlSi6Cu4 is 1 000 ppm Sb. By addi ion o 1 000 ppm Sb he low
leng h inc eased o 51 % (80 cm) o he o iginal unmodi ied alloy (53 cm).
Combining he bes achie ed esul s o hese wo expe imen s we can ge 2 combina ions:
A. Choosing he bes achie ed esul in he gas con en expe imen s - 500 ppm Sb (dec eased
o 37%) - he low leng h inc eased o app ox. 14 % o he unmodi ied AlSi6Cu4.
B. Choosing he bes achie ed esul in he spi al es expe imen s – 1 000 ppm Sb (51 %
inc ease) - DI dec eased o app ox. 43 % o he unmodi ied AlSi6Cu4.
Acknowledgemen :
The au ho s wish o hank he Eu opean Regional De elopmen Fund o he ecei ed
inancial suppo o c ea e he p esen pape wi hin he execu ion o he p ojec called "The
Equipmen o he P oduc ion o he P o o ype Pa s by Cas ing on a Compu e -con olled
Base" wi h he ITMS code 26220220047.
50
Li e a u e
[1] CONLEY, J.G.; HUANG, J.; ASADA, J.; AKIBA, K..: Modeling he e ec s o cooling
a e, hyd ogen con en , g ain e ine and modi ie on mic opo osi y o ma ion in Al
A356 alloy. Ma e ials Science and Enginee ing A 285, 2000. 49-55
[2] BOUSKA, O.: The e ec o di e en cas ing pa ame e s on he ela ionship be ween
lowabili y, mould illing capaci y and cooling condi ions o al-si alloys. Me alu gija -
Jou nal o me allu gy, Se bia, 2008. 17-30
[3] MEDLEN, D.; BOLIBRUCHOVÁ, D.: Teo e ical s udies o AlSi6Cu4 alloys.
Technológ Vol. 2, 2010. 151-156
[4] GRZINCIC, M.: Manu ac u ing ends o engine blocks o au omobiles. Slé á ens í
Vol. 2-3, 2003. 74-80
[5] ROMANKIEWICZ, R.; ROMANKIEWICZ, F.: In luence o modi ica ion o silumin
AlSi6Cu4 on ac u e mo phology. Jou nal o machine manu ac u ing, ol. XLIX, 2009.
[6] BOLIBRUCHOVÁ, D.; TILLOVÁ, E.: Found y Alloys Al-Si, EDIS Žilina, 2005. 180
[7] SABATINO, M. D.; SHANKA, S.; APELIAN, D.; ARNBERG, L.: In luence o
empe a u e and alloying elemen s on luidi y o Al-Si alloys. Doc o al Thesis Fluidi y
o aluminium ound y alloys, T ondheim, 2005
[8] MOLLARD, F.R.; FLEMMINGS, M.C.; NYAMA E.F: Unde s anding aluminium
luidi y: he key o ad anced cas p oduc s. AFS T ans., 1987. ol. 95, p. 647-652
[9] KOTTE, R.: S on ium modi ica ion gi es c i ical mel con ol, Mode n Cas ing, 1985.
33-35
[10] SERAK, V.: Modi ikace sli iny AlSi10Mg sodikem a s onciem, Sbo nik Kon e ence
Aluminium, 2001
___________________________________________________________________________
Ing. Dušan Medlen, P o . Ing. I a No á, CSc., Doc. Ing. Dana Bolib ucho á, PhD.,
Ing. Dušan U gela
51
VLIV SB NA NAPLYNENÍ A ZABÍHAVOST SLITINY ALSI6CU4
Slé á enské Al-Si sli iny se použí ají řadě au omobilo ých a p ůmyslo ých aplikací
ná očných na nízké ího é účinky z dů odu jejich ela i ně malé mě né hmo nos i a elmi
dob é slé a elnos i. Modi iká o y se ob ykle přidá ají do oz a ených Al-Si p o zjemnění
a u čás ic eu ek ické áze a zlepšení mechanických las nos í inálních odli ků Al-Si sli in a
jejich slé á enské las nos i. P o sli iny Al-Si o o ob ykle zah nuje přidání s oncia (S ),
sodíku (Na), nebo an imonu (Sb). Od slé á enských las nos í jako eku os a schopnos
yplnění o my h aje klíčo ou oli p odukci enkos ěnných, geome icky složi ých odli ků.
Bylo p okázáno, že pří omnos zachyceného plynu a edy pó ů něk e ých mís ech odli ků,
má li na úna o ou ži o nos . V om o příspě ku byl zkoumán li Sb na naplynení a
zabíha os AlSi6Cu4.
DER EINFLUSS VON SB AUF DEN GASGEHALT UND
DIE FLIESSFÄHIGKEIT DER LEGIERUNG ALSI6CU4
Aluminium-Silizium-Legie ungen sind we den in de g oßen Anzahl in de Au omobil- und
Indus ieelek onik au g und ih es ge ingen Gewich s und ih e seh gu en Gießba kei
e wende . Modi ika o en sind we den no male weise im geschmolzenen Aluminium-
Silizium-Legie ungen zuge üg , um die Pa ikel o m on de eu ek ischen Phase zu e eine n
und die mechanischen Eigenscha en de s e igen Guss eile und de Al-Si-Legie ungen und
de en gegossenen Eigenscha en zu e besse n. Fü Aluminium-Silizium beinhandel hal e es
sich no male weise um die Zugabe on S on ium (S ), Na ium (Na) ode An imon (Sb). Von
den Gusseigenscha en spielen Fließ ähigkei und Fo m üllungs e mögen bei de P oduk ion
on Dünnschich - und geome isch komplexen Guss eilen eine Schlüssel olle. Die
Anwesenhei on au ge angenem Gas ode die Sch ump ung de Po en an bes imm en O en
im Guss üh zu eine Beein lussung des Lebensdaue . In diese A bei wu de de Ein luss
on Sb au den Gasgehal und Fließ ähigkei on AlSi6Cu4 un e such .
WPŁYW SB NA ZAWARTOŚĆ GAZU I LEJNOŚĆ STOPU ALSI6CU4
Odlewy s opu aluminiowo-k zemowego mają częs o zas osowanie w ozwiązaniach
p zemysłowych i mo o yzacyjnych w ażliwych na cięża , ponieważ są lekkie o az mają
ba dzo dob ą lejność. Mody ika o y dodaje się zazwyczaj do oz opionych s opów Al-Si w
celu złagodzenia ksz ał u cząs ek azy eu ek ycznej i pop awy właściwości mechanicznych
p oduk ów końcowych ze s opów aluminiowo-k zemowych (Al-Si). Ten s op zwykle
wymaga dodania s on u (S ), sodu (Na) lub an ymonu (Sb). Właściwości lejności i zdolności
napełniania o my odg ywają kluczową olę w p odukcji o m o cienkich ściankach i
geome ycznie skomplikowanych. S wie dzono, że obecność gazu, czyli pęche zyków w
niek ó ych miejscach odlewu wpływa na żywo ność i zw. "zmęczenie ma e iału". W
niniejszym a ykule badano wpływ an ymonu (Sb) na zawa ość gazu o az płynność
AlSi6Cu4.