casting geometry and process set up with focus on
TRANSCRIPT
«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.
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Iron Castings – ShrinkageA well known defect?
Influences of process, geometry and new part develpoment
2
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AGENDA
•Defect appearance
•Cast Iron – Materials
•Casting geometry
•Moulding process – with friendly support of
•Conclusion
“your casting development partner’’
AGENDA
•Defect appearance
•Cast Iron – Materials
•Casting geometry
•Moulding process – with friendly support of
•Conclusion
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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.
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AGENDA
•Defect appearance
•Cast Iron – Materials
•Casting geometry
•Moulding process – with friendly support of
•Conclusion
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Simplified solidification ribbon
mould wall
End Startof cristallisation
bandwidth
Residual melt
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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
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Shri
nka
gevo
lum
e[c
m³]
Carbon saturation [Sc]
GJL - Influence of Carbon saturation to shrinkage volume
Macro / surface shrinkage
Micro shrinkage
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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
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Temperature
Vo
lum
e
Grey iron [GJL]
Ductile iron [GJS]
Volume contraction vs. Temperature
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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]
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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.
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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
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AGENDA
•Defect appearance
•Cast Iron – Materials
•Casting geometry
•Moulding process – with friendly support of
•Conclusion
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Casting oriented engineeringStep 1:
Design space at itsspecific
restrictions.
Step 6:
Production ofprototypes.
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AGENDA
•Defect appearance
•Cast Iron – Materials
•Casting geometry
•Moulding process – with friendly support of
•Conclusion
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Sand shoot high speed slow motion
Shooting pressure 1bar Shooting pressure 2bar
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Sand shoot simulation• Simulation software for
moulding line is currently underconstruction.
• Trials and investigations broughtup, that existing simulationsoftware need to be developedfurther.
“your casting development partner’’
AGENDA
•Defect appearance
•Cast Iron – Materials
•Casting geometry
•Moulding process – with friendly support of
•Conclusion
“your casting development partner’’
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.