本文通过一系列的实验,对发动机活塞的常用材料——ZL3合金由于熔炼中操作不慎造成晶粒粗化的因素及其规律进行了研究。並探索了细化这种已粗化晶粒的工艺措施,而这种工艺措施在较长时间的生产实践中已被证明是有效的。在金属晶粒理论的阐述方面,除“遗传性粗化”外,还提出了“传染性粗化”的概念。 This article through a series of experiments, the common material of the engine piston - ZL3 alloy due to inadvertently caused by the melting operation of coarse grains of the factors and their laws were studied. And explored the process of refinement of such coarse grains, which has proven to be effective in a longer period of production practice. In the elaboration of the theory of metal grains, in addition to “genetic coarsening”, but also put forward the concept of “contagious coarsening.”