高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0．83表面机械纳米化及其热稳定性研究

Study on Surface Mechanical Nanocrystallization and Thermal Stability of 0Cr21Mn17Mo2Nb N0.83 High Nitrogen Austenitic Stainless Steel

对高氮奥氏体不锈钢0Cr21Mn17Mo2Nb N0.83进行表面机械压磨处理,重点研究经360 min表面机械压磨后,高氮奥氏体不锈钢表面纳米层的组织结构和在不同加热温度、保温时间条件下,该纳米表面层的热稳定性。结果表明:高氮奥氏体不锈钢0Cr21Mn17Mo2Nb N0.83经360 min表面机械压磨处理后,表面晶粒尺寸达到纳米级别,表面层的硬度较芯部基体增加一倍以上,且由芯部基体到表面的晶粒逐渐细化;机械压磨以及随后的热处理均未造成高氮奥氏体不锈钢表面层单一奥氏体结构的改变,表明该种材料具有良好的结构稳定性;加热温度对高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0.83表面纳米层及过渡层的组织稳定性起决定作用,而保温时间对其影响不大。

In this paper, the high nitrogen austenitic stainless steel 0Cr21Mnl 7Mo2NbN0.83 had been treated by surface mechanical grinding mefhod. The microstructure of nanostructured surface layer and its thermal stability under the condition of different heating temperature and holding time had been mainly investigated. The results show that after mechanical attrition ＆ grinding treatment for 360 minutes, the surface grain size of high nitrogen austenitic stainless steel OCr21Mnl7Mo2NbNO.83 is reduced to nanometer scale, and the hardness of surface nanolayer is increased more than two times. From the steel matrix to the surface layer, the grain size shows gradient distributio：a. Because mechanical attrition ＆ grinding treatment and subsequent heat treatment have not induce changes ir the structure of the surface layer, 0Cr21Mnl 7Mo2NbN0.83 high nitrogen austenitic stainless steel has good structure stability, which keeps the single austenite. Heating temperature plays a decisive role on the structure transf3rmation ofnanometer surface layer and transition layer, while the holding time has little influence on it.