过共晶铝合金汽缸体的挤压铸造

研究了过共晶铝合金挤压铸造性质和形成特点,探索了适合过共晶铝合金汽缸体的熔炼变质工艺、挤压铸造工艺,以及化学成分对金相组织、力学性能的影响。结果表明,用较高的挤压压力,辅助局部增压技术,以及采用合理的模具结构,改善排气系统,汽缸体铸件经机械加工浸渗后,能顺利通过1.38MPa卤素气体检漏试验,并且具有很强的抗磨、抗腐蚀性能,满足了汽车空调压缩机使用要求。适量的Zn元素存在,有利于细化B390合金显微组织,减少汽缸体铸件热裂倾向。合适的有机硅白涂料能有效解决汽缸体铸件表面腐蚀问题。

Squeeze casting for hyper-eutectic Al-alloy compressor housing

The behavior and forming characteristic of squeeze casting hyper-eutectic Al-alloy were studied. The modification and squeeze casting process of hyper-eutectic Al-alloy compressor housing and the effect of chemical composition on microstructure and mechanical properties were analyzed. It was found that, with higher squeeze pressure, local boosting pressure technique and proper die structure, the compressor housing can be capable of passing a 1.38 MPa halogen gas test with no leakage after machined and dipped. The part had strong wear and corrosion resistance, which could meet the requirements of automobile air-conditioner compressor. The proper zinc content could modify the microstructure of B390 alloy and reduce the check cracks of compressor housing casting. The proper silicon-bonded white coating could solve the surface corrosion problem of compressor housing casting.