full presentation - RWTH Aachen University

GTT-Technologies
GTT Technologies' ' 10th Annual Workshop, Herzogenrath,
Germany, June 4-6, 6, 2008
The need for thermochemical and
thermophysical property data in the
modelling of casting processes
(Christoph Honsel, Konrad Weiß)
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
0
Ch. Honsel 03.06.2008

RWP GmbH Tel.: 02471 123 0
Am Münsterwald 11 rwp@rwp-simtec.de
52159Roetgen www.rwp-simtec.de
- founded 1984 as spinn-off of the “Giesserei-Institutes der RWTH Aachen“
- Development and distribution of the FEM-program SIMTEC / WinCast
(mainly for calculation of solidification processes)
- Activities: Distribution of licenses, Support and training
consulting works
- Since 1997 Own Building in Roetgen, near Aachen
- Employees: 6 (in Roetgen)
Christoph Honsel: responsible for software development
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
1
Ch. Honsel 03.06.2008

Example:
Shimano disk brake
CAD FEM
temperature solidification time mechanical properties
GTT Workshop 04-06.06.2008
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2
Ch. Honsel 03.06.2008

idea
drawing
CAD
mesh generator
GTT Workshop 04-06.06.2008
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3
Ch. Honsel 03.06.2008

Definition of parallel
layers:
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

Calculation of section
planes:
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
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5
Ch. Honsel 03.06.2008

Enmeshment of a 2d
section with triangles:
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

Layer by layer :
3d enmeshment
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

idea
drawing
CAD
mesh generator
phys.
properties
initial
conditions
solidification
calculation
boundary
conditions
∂T
∂ ⎛ ∂T
⎞ ∂ ⎛ ∂T
⎞ ∂ ⎛ ∂T
⎞
ρc
p = ⎜λ
⎟ + ⎜λ
⎟ + ⎜λ
⎟ + Q&
∂t
∂x
⎝ ∂x
⎠ ∂y
⎝ ∂y
⎠ ∂z
⎝ ∂z
⎠
T = temperature
t = time
x,y,z
ρc
p
=
=
coordinates
density * spec. heat
λ
Q
=
=
conductivity
heat source/sink (latent heat)
& +
GTT Workshop 04-06.06.2008
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8
Ch. Honsel 03.06.2008

Calculation of
solidification
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
9
Ch. Honsel 03.06.2008

idea
drawing
CAD
mesh generator
phys.
properties
initial
conditions
solidification
calculation
boundary
conditions
interpretation
and
presentation
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
10
Ch. Honsel 03.06.2008

Interpretation:
3d isotherms
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
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11
Ch. Honsel 03.06.2008

interpretation:
local solidification time
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
12
Ch. Honsel 03.06.2008

idea
drawing
CAD
mesh generator
thermo-chemical
calculation
phys.
properties
initial
conditions
solidification
calculation
boundary
conditions
∂T
∂ ⎛ ∂T
⎞ ∂ ⎛ ∂T
⎞ ∂ ⎛ ∂T
⎞
ρc
p = ⎜λ
⎟ + ⎜λ
⎟ + ⎜λ
⎟ + Q&
∂t
∂x
⎝ ∂x
⎠ ∂y
⎝ ∂y
⎠ ∂z
⎝ ∂z
⎠
T = temperature
t = time
x,y,z
ρc
p
=
=
coordinates
density * spec. heat
λ
Q
=
=
conductivity
heat source/sink (latent heat)
& +
GTT Workshop 04-06.06.2008
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13
Ch. Honsel 03.06.2008

Geometry
standard wedge
Example:
standard wedge
Sensitivity analysis
Steels investigated
• 1.1201
• 1.6740
• AISI430
1248
2085
GTT Workshop 04-06.06.2008
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412
2544
• AISI304
2550 2710
• Microalloyed steel
• DP500
Sampling
points
14
Ch. Honsel 03.06.2008

Example:
standard wedge
Integration GE: the latent heat function, i.e. the fraction energy released
RO: the product of density and specific heat (ρ*Cp)
LA: the heat conductivity
Steel AISI304 at sampling point 2544
GTT Workshop 04-06.06.2008
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15
Ch. Honsel 03.06.2008

Example:
standard wedge
A Software/data link has been established between ChemApp and WinCast
- Calculated thermophysical properties are provided for use in WinCast
calculations.
- Calculation accuracy improved since four different latent heat release
(GE) and density*Cp (RO) modes can be computed.
ChemApp provides full phase equilibria, equilibria,
i.e. solid and liquid fractions,
phase names, phase composition, specific heat capacities or liquidus liquidus
and solidus temperatures.
The Scheil mode provides appropriate information for rapid cooling.
Interpolation between the results (Equilibrium and Scheil) Scheil)
permits
the influence of cooling velocity to be investigated in the WinCast WinCast
calculations.
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

Example:
standard wedge
Green curves: with new model
Note: no effect for sand casting
HPDC new solidification temperature interval 100% greater than actual.
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

interpretation:
local porosity
Example:
Shimano disk brake
Al:
hotspot = defect!
Cast Iron:
hotspot = defect ?
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

Cast Iron:
hotspot = defect ?
Example:
Shimano disk brake
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

Cast Iron:
hotspot = defect ?
Example:
Shimano disk brake
expansion depends on
• Components of alloy
• T,
• time
• …
GTT Workshop 04-06.06.2008
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[F. Krützner]
20
Ch. Honsel 03.06.2008

idea
drawing
Equilibrium of forces :
Fl = ∫ BklEki ( Biju j − ( ε i ) Θ ) dV
V
Bij = geometrical factors
Eij = Youngs modulus
ui = distortion vector
ε ) Θ = thermal expansion
( i
CAD
mesh generator
thermo-chemical
calculation
phys.
properties
initial
conditions
solidification
calculation
boundary
conditions
phys.
properties
initial
conditions
calculation of
stress and distortion
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
boundary
conditions
21
Ch. Honsel 03.06.2008

esidual stress and
ditortion
Aluminium A356:
no phase change after
solidification
e.g. steel:
Example:
Shimano disk brake
expansion due to a phase
change after solidification
GTT Workshop 04-06.06.2008
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22
Ch. Honsel 03.06.2008

e.g. steel:
Beispiel:
Shimano Fahrradbremse
expansion due to a phase
change after solidification
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
[T.Inoue et al., 1981]
23
Ch. Honsel 03.06.2008

idea
drawing
Equilibrium of forces :
Fl = ∫ BklEki ( Biju j − ( ε i ) Θ ) dV
V
Bij = geometrical factors
Eij = Youngs modulus
ui = distortion vector
ε ) Θ = thermal expansion
( i
CAD
mesh generator
thermo-chemical
calculation
phys.
properties
initial
conditions
solidification
calculation
boundary
conditions
thermo-chemical
calculation
phys.
properties
initial
conditions
calculation of
stress and distortion
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
boundary
conditions
24
Ch. Honsel 03.06.2008

Virtual product development
prototype
CAD-Construction
CAD Construction
• shape optimisation
Calculation of filling and
solidification
Calculation of
life cycle
Calculation of stress and
• cast process
distortion
• heat treatment
• machining
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
Calculation of load
stress
Calculation of mechanical
properties
25
Ch. Honsel 03.06.2008

idea
Interface
CAD
drawing
CAD
mesh generator
thermo-chemical
calculation
phys.
properties
temperature
initial
conditions
solidification
calculation
interpretation
and
presentation
stress
boundary
conditions
distortion
phys.
properties
thermo-chemical
calculation
phys.
properties
initial
conditions
calculation of
stress and distortion
GTT Workshop 04-06.06.2008
The full line of Finite Element Simulation www.rwp-simtec.de
boundary
conditions
Interface
FEM
26
Ch. Honsel 03.06.2008

Al-Si Al Si alloy
Mg alloy
DAS = f (t ( s)
Hall Petch: Petch
Yield strength = f (DAS)
Comparison between experiment and calculation
R p0,2
Rp0,2 =
p0,2 = (175 175 (175 ± 12) 12) MPa **
**
R p0,2
Rp0,2 =
p0,2 = (212 212 (212 ± 18) 18) MPa **
**
R p0,2
Rp0,2 =
p0,2 = 170 170MPa MPa *
*
R p0,2
Rp0,2 =
p0,2 = 220 220MPa MPa *
*
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008

One more example: example
austempered ductile iron (ADI)
Rapid cooling to Ta : γ → α + γHC ; Due to C enrichment Ms decreases
Before Bainite formation the process ceases.
GTT Workshop 04-06.06.2008
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Ch. Honsel 03.06.2008