摘要
对退火态高氮不锈轴承钢进行真空高压气淬并深冷后在不同温度下回火空冷处理,采用光学显微镜、X射线衍射仪、场发射环境扫描电镜、场发射透射电镜、洛氏硬度计和万能材料试验机,研究并分析了不同回火温度对高氮不锈轴承钢显微组织与力学性能的影响。结果表明:当回火温度由180℃升高到550℃时,硬度、抗拉强度及屈服强度呈现先下降后上升再迅速下降的变化趋势;试验钢降碳增氮,组织中没有粗大的共晶碳化物存在。当回火温度为500℃时,基体组织为回火索氏体,碳化物M23C6和氮化物Cr2N细小弥散均匀分布于基体上;在500℃回火时出现了二次硬化,强度和硬度达到峰值,这与碳氮化物弥散强化有关。采用1050℃真空气淬60 min+深冷处理(-100℃×2 h)+500℃空冷2 h回火工艺可以获得良好的综合力学性能。
Annealed high nitrogen stainless bearing steel was subjected to high pressure gas quenching and cryogenic treatment and then tempered at different temperatures and air cooled.The effect of different tempering temperature on microstructure and mechanical properties of the high nitrogen stainless bearing steel was studied by means of optical microscope,X-Ray diffractometer(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM),Rockwell hardness tester and universal material testing machine.The results show that with the tempering temperature increasing from 180℃to 550℃,the hardness,tensile strength and yield strength display a trend of increasing after the first falling and then rapidly decreasing.There are no coarse eutectic carbides observed in the structure due to reducing carbon content and increasing nitrogen content in the composition of the tested steel.When the tempering temperature is 500℃,the matrix structure is tempered sorbite,and the carbides M23C6 and nitride Cr2 N are dispersed uniformly and finely.The secondary hardening occurs at500℃,and the strength and hardness reach the peak state,which is related to the strengthening of carbonitride dispersion.Good comprehensive mechanical properties can be obtained by 1050℃high pressure gas quenching for 60 min+cryogenic treatment(-100℃×2 h)+500℃×2 h air cooling tempering.
作者
石成朋
刘平
张柯
李伟
杨旗
郝庆国
Shi Chengpeng;Liu Ping;Zhang Ke;Li Wei;Yang Qi;Hao Qingguo(School of Materials Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Key Laboratory of Engineering Materials Application and Evaluation,Shanghai Research Institute of Materials,Shanghai 200437,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2020年第11期157-163,共7页
Heat Treatment of Metals
关键词
高氮不锈轴承钢
回火温度
碳化物
氮化物
力学性能
high nitrogen stainless bearing steel
tempering temperature
carbide
nitride
mechanical properties
