奥氏体氮碳共渗层淬火时效与残余奥氏体分解的研究之二

Further Study of Quench-Aging of Austenitic Nitrocarburizing Layer and Dissolation of Retained Austenite

本文对奥氏体氟碳共渗后化合物层的淬火时效及残余奥氏体分解过程作了进一步的研究。结果表明,普通碳钢氟碳共渗后经时效处理,使其表面硬度达到HV1200以上。用光镜和扫描电镜对奥氏体淬火层在回火过程中的转变进行了观察,发现残余奥氏体的分解首先在奥氏体淬火层与化合物交界的界面上形核,残余奥氏体分解的核心很多,而核心的长大则很缓慢,分解产物十分细小,与常见的贝氏体形貌有很大差别,此外还观察到回火马氏体针叶增宽的现象。

This paper deals with further the quench-aging of compouned layer and the dissolution of retained austenite after austenitic nitrocarbuzing. It was shown that the surface hardness of nitrocarbuzing layer after aging is higher than HV1200 for common carbon steel. By scanning electron microscopy and optical microscopy,the change of austenitic quench-layer in the course of tempering was observed.It was found that the nuclecation occur on the boundary between austenitic quench-layer and compound while retained austenitic was resolved,there are many these nuclei,and its growth rate is very slow.So that the dissolution products was very fine,its morphology was different for common bainite.It was also observed that the tempered martensitic laths or plates was widen.