阀压板热处理工艺的分析与改进

Analysis and Improve on Heat Treatment Process for Valve Plate

碳氮共渗温度低,减小了共渗过程的畸变量。因为碳氮共渗过程中氮渗入渗层,使得淬火后马氏体的比容较大,阀压板经碳氮共渗和淬火后马氏体转变引起的畸变量较大。碳氮共渗降低了Ms点,淬火后渗层组织中残余奥氏体增多,影响压溃试验值。通过采用渗碳、淬火工艺后减小了畸变量,提高了压溃试验值。有效地满足了技术指标要求并获得了良好的重复性和再现性。

The amount of distortion is decreased due to lower temperature of carbonitriding. Because the specific volume of martensite is larger after quenching due to absorbing nitrogen during carbonitriding process,the amount of distortion is large after valve plate carbonitrided and quenched. The martensite starting temperature Ms is fallen by carbonitriding,so retained austenite in carbonitriding case is increased after carbonitriding of parts,to influence the crushing test value. After adopting carburizing and quenching process,the amount of distortion is decreased and the crushing test value is increased. The technical requirements are fulfilled efficiently and repeatability & reproducibility of heat treating process is achieved.