采用高温渗氮在奥氏体/铁素体双相不锈钢表面形成了奥氏体高氮层。试验结果表明,渗氮层氮含量可达1.0%,与原材料相比氮含量增加了2倍。原始双相组织已经转变为奥氏体,渗氮层深度达到2 mm以上。采用合理优化的高温渗氮工艺,可在提高不锈钢强度、硬度的同时,其伸长率、断面收缩率仍然保持较高的水平。高温渗氮工艺制备高氮无镍不锈钢的最佳工艺参数为:加热温度1200℃、氮气压力0.3 MPa、保温时间24 h。 High temperature nitriding is used to form a high-nitrogen austenite layer on the austenitic / ferritic duplex stainless steel surface. The experimental results show that the nitrogen content of nitrided layer can reach 1.0%, and the nitrogen content increases two times compared with the raw material. The original duplex structure has been transformed into austenite, nitrided layer depth of 2 mm or more. Reasonably optimized high-temperature nitriding process can improve the strength and hardness of stainless steel, while its elongation and reduction of area still maintain a high level. High temperature nitriding process for the preparation of high nitrogen nickel-free stainless steel optimum process parameters: heating temperature 1200 ℃, nitrogen pressure 0.3 MPa, holding time 24 h.