高氮低镍奥氏体不锈钢的力学性能及析出相

Mechanical properties and precipitates of high nitrogen and low nickel austenitic stainless steel

通过对高氮低镍奥氏体不锈钢(0Cr25Ni2Mn17Mo1NbN)进行1100℃固溶处理,水冷,利用万能拉伸试验机测试其力学性能并和316L奥氏体不锈钢进行对比。将高氮低镍奥氏体不锈钢在不同温度(700、750、800℃)时效2 h,利用光学显微镜和洛氏硬度计,观察不同温度下时效2 h试验钢的析出状况和试验钢的硬度,利用扫描电镜、透射电镜来观察和分析试验钢800℃析出物的形貌及种类。试验结果表明,高氮低镍奥氏体不锈钢在1100℃固溶处理后有良好的力学性能,高氮低镍奥氏体不锈钢在800℃大量析出相为σ相,其次是Cr2N,伴有少量Cr23C6析出,还有微量Nb(C,N)析出。析出相形态有胞状、短棒状和片状布满整个基体。试验钢时效后的硬度值要比时效前(固溶态)的硬度值高,且试样随时效温度升高其硬度值呈现上升趋势。

Mechanical properties of a high-nitrogen low-nickel austenitic stainless steel(0 Cr25 Ni2 Mn17 Mo1 NbN)solution treated at 1100℃then water-cooled were tested using a universal tensile tester and compared with 316 L austenitic stainless steel.At the same time,the highnitrogen low-nickel austenitic stainless steel was aged at different temperatures(700℃,750℃,800℃)for 2 h,and the precipitation condition of the experimental steel and the hardness of the steel at different aging temperatures were investigated by optical microscopy and Rockwell hardness tester.Scanning electron microscopy and transmission electron microscopy were used to observe and analyze the morphology and types of precipitates of the steel aged at 800℃.Experimental results show that the high-nitrogen low-nickel austenitic stainless steel possesses good mechanical properties after solution treatment at 1100℃.High-nitrogen low-nickel austenitic stainless steel has a large amount of precipitated phase at 800℃asσphase,followed by Cr2 N with a small amount of Cr23 C6 precipitated,and there is a trace of Nb(C,N)precipitation.The morphology of precipitated phase is cellular,short rod and flake,covering the whole matrix.The hardness of the test steel after aging is higher than that before aging(solid solution state),and the hardness of the sample increases with the increase of aging temperature.