2104国家增压技术论坛-Semi-solid moulding technology for making automotive turbocharge compressor

10 10 10
8 7 6 5 4 3 2 1 0
Viscosity (Pas)
10 10 10 10 10 10 10 10
3890.5γ
-1 -1.1
288403.2γ 2454.7γ 467.7γ
-6
-0.84 -0.95
45185.6γ 1659.6γ
10
-5
-1 -2
Aluminium melt Graphite tube
Piston Process
Graphite crucible
Die Casting
Lowcost
Good control flexibility
Suitable for a variety of alloy
17
1
4
2
5
3
6
Rheo-casting slug
SSM provides a new way for low-cost and high quality products.
SSM has inherently better durability than cast product and has lower costs than MFS. Rheo-castings can get the similar mechanical properties as thixocastings. But the cost is much lower .
2
3
Horizontal Section
319S aluminum alloy Al-6%Si-3%Cu-0.3%Mg modified by Sr
Vertical section
4
100
90 80
Fraction liquid (%)
70
60 50
40 30
A356 A357 2014 6082 7075 7010
Liquid Fraction：about 50%
8
Compressor wheel Tooling Real-time controlled Buhler die casting machine
Tooling is made up of 14 petals that fit into a carrier ring
25
MIM process
Microstructure
Homogeneous microstructure. Fine grains. Casting defects free
Mechanical properties
Alloy Cast In713c Rupture Rm(MPa) 850 Yield Rp0.2(MPa) 740 Elongation(%) 8
10
Semisolid metal flow behavior:(non-Newtonian)
When the shear rate is high, the solidifying dendrites are broken and the fluidity is increasing (the viscosity is decreasing).
Sintered MIM713c
HIPped MIM713c
1082
1375
916
959
12
25
26
GRINM leads developing MIM turbine wheels together with the University of Science and Technology Beijing, Beijing Institute for Materials and WeiFu Technologies Ltd. Key know-hows on die design, injection, vacuum sintering and HIP etc have been gained. Turbine wheels with density more than 99.5% have been achieved.
1
Introduction to the compressor wheel Material selection for the SSM process Thixo-casing process
2
3
34 5 6
Rheo-casting process Concluding Remarks Future works
10 8 6 4 2 0
Casting 354.0
Casting C355
SSM Thixo-casting 319s
Forging 2618
15
Elongation (%)
319s SSM compressor wheel
Casting compressor wheel
The fatigue life of compressor wheels provided by different methods
18
Filling ability
Microstructure
(a)
Silicon Particles
Rheo-casting
a
Thixo-casting
(c)
19
20
SSM has been successfully applied to manufacture very complex geometry turbocharger compressor wheels and now in production.
was improved on the basis of Power Law model.
Power Law Cut-off model
a 0 K if
n
0
a 0 K 0 if
n
0
Viscosity decreasing phenomenon in filling process
Turbine wheels manufactured by Metal Injection Moulding (MIM)
A turbine wheel works under the conditions of high temperature, corrosive environment, cyclic speed and resonance frequency of blade
Compressor wheel
Biscuit
Overflow and vent
Runner
9
Front view
Left view
Filling direction of the semi-solid slurry
Material tracing video（Simulation） The red part of the slug will fill into the compressor wheel cavity.
Tensile properties (Holset Spec) of casting vs forging vs SSM materials
160
Density corrected stress (MPa / g/mm )
3
140 120 100 80 60 40 20 0
UTS YS Elongation
21
Cost
MFS
Thixocasting
SSM
201 alloy
Ideal
Cast
SSM
Rhrocasting
Durability
22
Report in 2015
Turbine wheels manufactured by Metal Injection Moulding (MIM)
23
Future works to be reported in 2015
319s DSC test Heating Cooling
7075
A357
7010
Rheoprocessing, Thixomolding
Thixoforming
A356 2014
20 10
0 450 500 550 600 650 6082
Thixoforging
700பைடு நூலகம்
Temperature (° C)
-1.25 -1.38
-2
10
10
-4
10
-3
10
10
-1
10
0
10
1
10
2
10
3
10
4
Shear rate (1/s)
11
Nowadays, viscosity modelling for semi-solid alloy slurry usually use the Power Law model, the Carreau model, the Cross model and the Bingham Model etc. In our work，we use the Power Law Cut-Off model （PLCO）which
12
Simulation results
13
Partial filling experiment
Casting C355, 354.0
Thixo-casting 319s
MFS 2618
3D X-ray CT test of the Thixo-casting compressor wheel
14
The working performance of Thixo-casting and traditional casting compressor wheel