casting geometry and process set up with focus on

«Çekinti Hatalarını Önlemede Parça Geometrisi ve Proses Dizaynının Önemi»

«Casting Geometry and Process Set Up With Focus on Shrinkage Defects»Frank Deibel

(Trakya Döküm)

1.Oturum: Döküm Sektöründe Rekabet Gücü1st Session: Competitiveness of Foundry Sector

Oturum Başkanı/Session Chairman: Memiş Sağıroğlu (Trakya Döküm Sanayi Tic. A.Ş.)

Oturumlarda yer alan sunumlar 3 Ekim 2016 Pazartesi tarihinde akademi web sayfasına (akademi.tudoksad.org.tr) yüklenecektir.

“your casting development partner’’

Iron Castings – ShrinkageA well known defect?

Influences of process, geometry and new part develpoment

2


AGENDA

•Defect appearance

•Cast Iron – Materials

•Casting geometry

•Moulding process – with friendly support of

•Conclusion


Appearance – Macro ShrinkageExternal shrinkage

• At last solidified and almost at upper located areas of themould. – As well at riser andingate areas.

• Defect surface rough dendritic.

• Funnel shaped and oftencontinuing insed the casting.

• Lack of material clearly visible.

Internal shrinkage

• Located at areas with huge wall thickness and / or wall thickness differences.

• Internal shrinkage has noconnection to the surface.

• Irregular shape and roughdendritic surface.

• Detection by non-destructive-testing.

Sink mark

• Located at outer areas andtransitions of sections.

• Frequent occurance with microshrinkage together.


AGENDA



•Casting geometry


•Conclusion


Simplified solidification ribbon

mould wall

End Startof cristallisation

bandwidth

Residual melt


Grey cast irons• Typical for volume deficite at grey

cast irons are the differences at specific voluminas of its structuralcomponents.

• In case of eutectic solidifcation, precipitatedgraphite is counteracting to shrinkage of theaustenite.

• This enables by a certain share of Carbon, good degree of nucleation and solidifcationconditions a „self feeding effect“.

• In case of huge share of eutectic precipitatedgraphite, this expansion can be more thanthe solidifcation contraction of the metallic phase – so total expansion will be possible.

Specific volumina [m³/g]

Ferrite 0,1271

Iron carbide 0,1303

Austenite (C saturated) 0,1360

Graphite 0,4475


Shri

nka

gevo

lum

e[c

m³]

Carbon saturation [Sc]

GJL - Influence of Carbon saturation to shrinkage volume

Macro / surface shrinkage

Micro shrinkage


Solidifcation – simplified representation

Temperature

Vo

lum

e

TS TL

1

2

Liquid contraction

Solidifcation contraction

Solid contraction

Balanced with gating andrisering

Balanced with contractionallowance

1

2


Temperature

Vo

lum

e

Grey iron [GJL]

Ductile iron [GJS]

Volume contraction vs. Temperature


Temperature

Vo

lum

e

Grey iron [GJL]

Volume contraction vs. Temperature

Liquid contraction

Volume expansion

Solidifcation contraction (mainly austenite contraction)

Solid contraction

Ductile iron [GJS]


Further aspects at GJS

Re

sid

ual

Mg

[%]

Modulus [cm]

• Inoculation is a further important parameterIts Efficiency is temperature dependend andtime limited.

• An almost eutectic composition, succesfulinoculations are leading to precipitation ofmany small nodules - short pouring times at low temperature as possible are supportingreduction / avoidance of shrinkage.

• Thermal analysis equipment is supportingprocess guidance.


0

10

20

30

40

50

60

70

0

5

10

15

20

25

30

35

No

du

lari

ty%

L_m

axµ

m |

gra

ph

itp

ort

. %

Microstructure by section

L_max Graphite portion Nodularity

Further aspects on ductile materials

Source of diagramm:Sintercast – Dr. Steve Dawson Source of information:

Giesserei 07/2007


AGENDA



•Casting geometry


•Conclusion


Casting oriented engineeringStep 1:

Design space at itsspecific

restrictions.

Step 6:

Production ofprototypes.


Evaluation of casting geometry


Development of risering

Version 1 Version 2 Version 4


Solidification

Version 5


AGENDA



•Casting geometry


•Conclusion


Animation moulding process


Sand shoot high speed slow motion

Shooting pressure 1bar Shooting pressure 2bar


Sand shoot simulation• Simulation software for

moulding line is currently underconstruction.

• Trials and investigations broughtup, that existing simulationsoftware need to be developedfurther.


AGENDA



•Casting geometry


•Conclusion


Conclusion

Casting orientednew part

devlopment

Metallurgyand

processguidance

Rigid mouldingprocess

Simultaneous engineeringand adjustments duringseveral optimization loopswill enable accurate castinggeometry.

Considering casting modul and itsrelevant areas towards- Base iron;- Mg-treatment;- Inoculation process.

Proper and sustainable mouldingand pouring process completesnew part development.


Thank you for your attention!Any question?

casting geometry and process set up with focus on

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