高温渗氮工艺对高氮无镍不锈钢组织及力学性能的影响

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。

Effects of high temperature nitriding on microstructure and mechanical properties of high nitrogen nickel-free stainless steel

High temperature nitriding is an effective method to generate high nitrogen austenite layer on surface of austenite/ferrite duplex stainless steels.The results show that the nitrogen content reaches above 1.0%,which increased 2 times compared with that of the original material.The single austenite stainless steel can be obtained,the nitrided layer depth approximately above 2 mm.The tensile strength of the nitrided specimen is higher than that of the original specimen,while the elongation and reduction of area are not obviously reduced,still keep in a high level.The best process parameters of high temperature nitriding are heating temperature 1200 ℃,nitrogen pressure 0.3 MPa and holding time 24 h.