Aiming at die casting thick-walled ADC automobile clutch gear

P-Cu modification on hypereutectic Al-Si alloy suitable for die casting was conducted.Die casting scheme for clutch gear was designed and simulated

meanwhile

vacuum die casting and local pressurization technology were developed.The results show that with 0.1% P addition

ADC14 exhibits good modification effects with 6 h modification time

where primary Si phase in the alloy reaches 20

4

0 μm with uniform distribution

and the depth of Si particle depletion zone on surface of the castings is in the range of 0.18

0

.20 mm.At a given injecting parameters

the mechanical vacuum valve is superior to zig-zag valve in vacuum effects

and the rejected rate with gas hole is decreased by 10%.Shrinkage porosity（hole） at thick-wall of the gear can be effectively eliminated by optimized local pressurization

and the quality of the gear is improved

qualification rate of mass-production is more than 95%.