numerical simulation to predict of the final shape of pm hip components
TRANSCRIPT
Numerical simulation to predict the final
shape of PM HIP components
IWM / IAPK Institute, RWTH Aachen University
Augustinerbach 4, 52062 Aachen Germany
Chung Van Nguyen
Email: [email protected]
Phone: +49 241 80 96291
Mobile: +49 176 82106600
2
Content
1 Introduction
2 Densification models
3 Implementation
4 Simulation results
5 Anisotropic shrinkage of PM-HIP components
3
Introduction
The powder HIP production processes
4
Courtesy of KEG GmbH
Anisotropic shrinkage
This problem leads to higher costs for post
processing and longer delivery time.
In order to improve technically and make it
cost efficient, NNS HIP parts must be
produced from the first shot with the
minimal geometrical allowances.
Thus, the main motivation is to create a
HIP simulation tool to replace the โtrial and
errorโ methodology.Courtesy of IWM
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Content
1 Introduction
2 Densification models
3 Implementation
4 Simulation results
5 Anisotropic shrinkage of PM-HIP components
6
Simulation approach
constitutive equations
ํ = ํ๐๐ + ํ๐๐๐๐ + ํ๐กโ
ํ๐๐๐๐ = ํ๐๐
+ ํ๐๐
Modified from Von Mises yield condition
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dํ๐๐๐
= dฮป๐f1๐ฯ๐๐
dฮป =
๐๐1๐๐๐๐
โ ๐ช๐๐๐๐๐๐ dํ๐๐
๐๐1๐๐๐๐
โ ๐ช๐๐๐๐๐๐ ๐๐1
๐๐๐๐+
๐๐1๐๐
โ ๐๐๐1๐๐๐๐
๐ฟ๐๐ โ๐๐1๐๐
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๐๐1๐๐๐๐
โ๐๐1๐๐๐๐
1 2
The plastic deformation calculation bases on the consistency condition, associated flow rule
and the mass conservation principle.
๐๐๐ =๐f1๐ฯ๐๐
๐๐1
๐๐=
๐โ๐๐โ1 ๐ฝ2โ1
3โ๐โ๐๐โ1 ๐ผ1
2
2๐๐๐1 1 2 โ โ โ ๐ โ ๐๐โ1 โ ๐0 โ ๐ โ ๐๐โ1)
๐๐1๐๐
= โ โ โ ๐๐ ,= โโ1 โ ๐๐
Constitutive equation:
plasticity model
๐1 ๐๐๐ , ๐, ๐ = ๐๐๐1 ๐) โ ๐1 ๐, ๐ โ ๐๐ฆ ๐ = 0 1
2
3
4
5
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ํ๐๐๐๐ = ํ๐๐ = ํ๐๐1 + ํ๐๐2
ํ๐๐๐๐ = ํ๐๐
๐๐2 = exp โ๐
๐ ๐)๐๐๐2
๐๐โ1 3๐ ๐
2๐๐๐ + ๐ ๐ ๐ผ1๐ฟ๐๐
ํ๐๐๐๐ = ํ๐๐
๐๐2 + ํ๐๐๐๐2
= ex p โ๐
๐ ๐)๐๐๐2
๐๐โ11 + ๐ โ
1
ex p ๐ํ๐๐๐๐
๐๐โ13๐ ๐
2๐๐๐ + ๐ ๐ ๐ผ1๐ฟ๐๐
Constitutive equation:
viscoplasticity model
1
2
3
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Content
1 Introduction
2 Densification models
3 Implementation
4 Simulation results
5 Anisotropic shrinkage of PM-HIP components
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Implementation in UMAT Subroutine
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Different material models
Table 1: Different constitutive equation used for HIP simulation
Modelโs name Characteristic
Plastic Elastoplastic ํ๐๐๐๐๐๐ = ํ๐๐
๐๐
Viscoplastic Elastoviscoplastic ํ๐๐๐๐๐๐ = ํ๐๐
๐๐2
Combined model No.1 Elasto-plasto-viscoplastic ํ๐๐๐๐๐๐ = ํ๐๐
๐๐+ ํ๐๐
๐๐ = ํ๐๐๐๐
+ ํ๐๐๐๐2
Combined model No.2 Elasto-plasto-viscoplastic ํ๐๐๐๐๐๐ = ํ๐๐
๐๐+ ํ๐๐
๐๐ = ํ๐๐๐๐
+ ํ๐๐๐๐1 + ํ๐๐
๐๐2
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Content
1 Introduction
2 Densification models
3 Implementation
4 Simulation results
5 Anisotropic shrinkage of PM-HIP components
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Simulation results of test capsules
Combined models give the best shape prediction with the error below 1,5%
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Content
1 Introduction
2 Densification models
3 Implementation
4 Simulation results
5 Anisotropic shrinkage of PM-HIP components
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Shape and size
Thickness, material properties
Number of weldlines, location
of welded joints
Inhomogeneous powder
distribution
Powder particle size, size
distribution can be different
Temperature, pressure
Temperature gradient
Capsule Powder prior to HIP HIP cycle
PM HIP Production process
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With a homogeneous initial powder distribution with an inhomogeneous initial powder distribution
Influence of capsule thickness
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Influence of initial
powder distribution
Relative density distribution was determined from experiment based on Image Analysis
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Influence of initial powder
distribution
Homogeneous initial powder distribution Powder distribution from experiment
Bending due to the influence of inhomogeneous powder distribution
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Influence of powder particle size
distribution
Table 5-4: Powder particle size fraction of three used powders
Fraction F1 F2 F3 F4 F5 F6
Micron >250 250-212 212-125 125-100 45-100 <45
Powder (P1) 17 16 15 10 28 14
Powder (P2) 17 16 15 10 28 0
Powder (P3) 50 0 20 5 10 15
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Influence of powder particle size
distribution
Influence of different powder distribution distribution
Final shape of capsules which used different powder fractions as shown in the previous slide
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Homogeneous
Powder dis.
Powder dis.
Taken from IA
Capsule No.1 Comparision of
the final shape
Influence of temperature
gradient
Bending due to the influence of temperature gradient
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Optimize capsuleโs shape and size
Thank you very much for your attention
Nguyen Van Chung
IAPK โ Institut fรผr Anwendungstechnik Pulvermetallurgie und Keramik
an der RWTH Aachen e.V.
Augustinerbach 4
52062 Aachen
www.iapk.rwth-aachen.de