双相不锈钢表面奥氏体高氮层的制备技术

高温渗氮是在奥氏体/铁素体双相不锈钢表面形成奥氏体高氮层的一种有效方法.为了获得氮含量高、组织均匀且适合于后续加工的表面高氮不锈钢层，必须确定合理的高温渗氮工艺.通过优化高温渗氮工艺参数，研究了双相不锈钢高温渗氮过程中加热温度、保温时间、氮气压力等对渗氮效果的影响.结果表明，通过高温高压渗氮可使不锈钢表面形成高氮氮化层，可使双相不锈钢通过渗氮发生表面奥氏体转变，获得组织梯度变化的多相复合不锈钢材料.

Fabrication technology of high nitrogen austenite layer on surface of duplex stainless steel

High temperature nitriding is an effective method to generate high nitrogen austenite layer on surface of austenite/ferrite duplex stainless steels.In order to obtain the thicker austenite layer with both high content of nitrogen and homogenous microstructure on surface of the duplex stainless steels,it is necessary to develop an appropriate high temperature nitriding technology.The influence of such factors as the heating temperature,holding time and nitrogen pressure on the nitriding effect for a austenite/ferrite duplex stainless steel was investigated through optimizing technological parameters for the high temperature nitriding.The result indicates that the high nitrogen layer with the greater thickness can form on the surface of the stainless steel using the developed high temperature nitriding technique.The austenitic transformation occurs on the surface of the duplex stainless steel during high temperature nitriding,and thus a multi-phase stainless steel with microstructural gradient can be obtained.