18CrNiMo7-6钢的热处理工艺研究

Study on Heat Treatment Process of 18CrNiMo7-6 Steel

本文对18CrNiMo7-6渗碳钢进行了不同热处理工艺试验,预备热处理采用调质、正回火工艺,渗碳后采用一次淬火、二次淬火工艺进行对比。采用金相法检验预备热处理后的金相组织、渗碳后的心部组织,和碳化物级别、马氏体、残余奥氏体、内氧化的评级等;同时对预备热处理后材料的力学性能进行了检验。结果表明:采用调质预备热处理、渗碳后二次淬火工艺的18CrNiMo7-6渗碳钢的渗碳层性能指标最好,适用于高参数齿轮渗碳淬火。

In this paper,the different heat treatment process test for 18 CrNiMo7-6 carburizing steel was carried out,quenching and tempering,normalizing and tempering process were adopted as the pre-heat treatment.The primary quenching and the secondary quenching process after carburizing were compared.The carburizing structure with different process was inspected by metallographic method,including microstructure after pre-treatment,core microstructure after carburizing and the carbide grade,martenite and residual austenite grade,inner oxidation grade etc.were evaluated,and the mechanical properties of materials after pre-heat treatment were also tested.The result showed that the best properties index in carburizing layer of 18 CrNiMo7-6 carburizing steel was obtained under the pre-treatment process of quenching and tempering and secondary quenching after carburizing,and this process should be suitable for the quenching of the high parameter gears.