20Cr2Ni4A钢奥氏体晶粒长大规律与高温渗碳工艺

Austenitic grain growth law and high temperature carburizing process of 20Cr2Ni4A steel

对20Cr2Ni4A钢高温奥氏体晶粒长大规律进行了研究,获得了其奥氏体晶粒长大动力学模型,并在此基础上进行了高温渗碳工艺试验。结果表明,对于经高温渗碳处理后晶粒粗大的20Cr2Ni4A钢,多次回火可以改善表层有效硬化层区域组织,也会在一定程度上提高心部的综合力学性能,渗碳结束后强制快冷至650℃短时保温可以显著细化奥氏体晶粒,并大幅提高其综合力学性能。

Austenitic grain growth of 20Cr2Ni4 A steel was researched,and the austenitic grain growth model was obtained,and the high temperature carburization process was carried out. The results indicate that the coarse grain and surface effective case microstructure of the20 Cr2 Ni4 A steel specimen resulted from high temperature carburizing can be refined with multiple tempering,and the comprehensive mechanical properties in the core can be improved. That forced quick cooling to 650 ℃ and holding for a short time after carburization can refine the grains markedly and improve the comprehensive mechanical properties greatly.