一种高铬铸铁磨球的亚临界处理

主要研究了高铬铸铁磨球采用亚临界处理工艺时的组织转变和性能变化 ,用X衍射、扫描电镜、磁性法和硬度测定法分析了它的硬化机制。研究表明 ,在亚临界处理过程中 ,铸铁基体组织中的残余奥氏体会析出二次碳化物并在冷却过程中转变为马氏体 ,出现二次硬化现象 ,使其硬度上升。在适当的处理温度和处理时间下 ,能得到最高的硬度 ,即用亚临界处理的磨球能达到常规热处理的性能 ,从而大大降低生产成本。

THE STUDY OF SUB-CRITICAL TREATMENT FOR THE GRINDING BALLS OF HIGH CHROMIUM CAST IRON

The microstructure transformation and property change of the high chromium cast iron (HCCI) grinding balls subjected to sub-critical treatment was studied.The hardening mechanism was analyzed by using X-ray diffraction, SEM, magnetism method and harness test. The results showed that during sub-critical treatment process,the retained austenite in the matrix precipitated secondary carbide and transformed into martensite in cooling process, the alloy showed secondary hardening and its hardness increased. Through proper treatment temperature and time, the HCCl grinding balls would get the optimal hardness and property which was attained normally by traditional heat treatment, and the production cost reduced.