高强耐磨过共晶铝合金离合器齿轮的压铸技术

Die Casting Technology of Hypereutectic Al-Si Alloy Clutch Gear with High Strength and Wear Resistance

针对压铸成形的ADC14汽车离合器齿轮厚壁部件,研究了适于压铸的过共晶Al-Si合金的P-Cu变质处理工艺。设计并模拟了齿轮的压铸工艺方案,开发了真空压铸及局部加压技术。结果表明,当P的加入量为0.1%时,ADC14的变质效果好,变质时间可达6h。铸件中初生Si尺寸为20～40μm,分布均匀;铸件表面的Si贫乏区深度在0.18～0.20mm范围内。在相同压射参数下,采用机械式真空阀比搓衣板式排气阀的真空效果好,铸件的气孔缺陷废品率下降10%以上。优化后的局部加压技术消除了厚壁部位的缩松缺陷,提高了铸件内部质量。批量生产合格率达95%以上。

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 20~40 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%.