不锈钢低温盐浴表面氮化技术发展与现状

不锈钢具有良好的耐蚀性、韧性和可加工性，但其硬度低、耐磨性差，严重制约了其在有磨损腐蚀要求环境体系中的应用.为了提高不锈钢的抗磨损性能，通过低温活性盐浴表面处理技术提高其耐磨性的同时不降低其耐蚀性，使得其在具有磨损的腐蚀介质环境中能够提高其抗磨损性能而不被腐蚀，可延长其使用寿命.本文系统地介绍了低温活性盐浴表面氮化处理技术的发展、原理及应用和处理后表面氮化层的特点、组织和表面性能.低温活性盐浴表面处理后，表层活性N原子扩散在奥氏体间隙中形成过饱和固溶体的S-相，产生特殊的位错-应力FCC结构，使得奥氏体晶格发生严重变形，不但提高了其腐蚀性，同时大大提高了其硬度，使得不锈钢硬度能够达到1 000 HV0.1，其抗磨损性能亦得到了显著提高.
Stainless steel possesses excellent corrosion resistance, toughness and machinability. However low hardness, and poor wear resistance largely restrict its industrial applications in the wear or corrosion environments. In order to improve the wear resistance of stainless steel, this work introduces a low-temperature active salt bath surface treatment technology without reducing its corrosion resistance, which can enable the enhancement of the wear resistance in the corrosive environment, and thus extend its service life. This article mainly introduces the progress, principle and applications of low-temperature active salt bath surface nitriding technology and the characteristics, microstructure and mechanical property of nitriding layer. It is shown that the surface active N atoms diffuse into the austenite lattice gap to form the supersaturated solid solution, S-phase and to emerge a special dislocation-stress FCC structure, causing the serious deformation of the austenite lattice. After such a treatment, the corrosive property dramatically enhances, and the hardness increase up to 1 000 HV. Meanwile, wear resistance significantly improves.