3.5NiCrMoV钢的离子渗氮

Ion-nitriding of 3.5NiCrMoV Steel

对含0.25%C、1.62%Cr.3.75%Ni.0.33%Mo和0.09%V(质量分数)的3.5NiCrMoV钢进行了正火、调质处理和离子渗氮。离子渗氮工艺为:①普通工艺520℃×7 h;②490℃×20 min+540℃×20min冷却至490℃重复7次的循环工艺。渗氮后检测了渗层的深度和表面硬度。试验结果表明:普通离子渗氮的3.5NiCrMoV钢的渗层深度为0.22~0.23 mm,而循环离子渗氮的3.5NiCrMoV钢的渗层深度为0.27~0.28mm;循环离子渗氮的3.5NiGrMoV钢的表面硬度略高于普通离子渗氮的3.5NiCrMoV钢。

3.5NiCrMoVsteel containing 0.25%C,1.62%Cr,3.75%Ni,0.33%Mo,and 0.09%V(by mass)was ion-nitided after being normalized and quenched and tempered.The ion-nitriding processes were as follows:①common practice consisting of soaking at 520℃ Cfor 7 h;and②cyclic practice consisting of soaking at 490℃ for 20 min at.first and then at 540℃ for 20 min followed by cooling to 490℃ which was repeated seven times.The case depth and surface hardness of the steel were detected after ion-nitriding.The results showed that the 3.5 NiCrMoV steel developed case depth of 0.22 to 0.23 mm after the common oin-nitriding and case depth of 0.27 to 0.28 mm after the cyelic ion.-nitriding,and the cyelically ion-nitrided 3.5NiCrMoV steel possessed slightly higher surface hardness than the commonly ion-nitrided one.