摘要
采用金相显微镜、扫描电镜、洛氏硬度计、冲击试验,观察和分析了7Cr17MoV马氏体不锈钢在990~1110℃淬火+180~220℃回火的组织和性能变化。结果表明:淬火组织为残留奥氏体和碳化物分布于马氏体基体上。随淬火温度的升高,残留奥氏体含量和马氏体过饱和度增加,针状马氏体组织变粗,1080℃淬火硬度升高到最大值62.5HRC。冲击试验结果表明:随回火温度逐渐升高,试样硬度有部分下降,但韧性显著提高,200~220℃时韧性最佳,达到19 J/cm^2。综合硬度和韧性考虑,最佳热处理工艺为1080℃淬火+200~220℃回火。盐雾试验表明:1080℃淬火+200℃回火后腐蚀率小于4%,符合使用要求。
Microstructure and properties changes of 7Cr 17MoV martensitic stainless steel quenched at 990-1110℃ and tempered at 180-220℃ were investigated by means of OM, SEM,hardness and impact tests. The experimental results show that the microstructure of the quenched steel is retained austenite and carbides scatter on martensite basement. As the quenching temperature increasing, the amount of retained austenite and supersaturation degree of martensite increase and the acicular martensite is coarsened. The maximum hardness value of 62.5 HRC is obtained for the steel quenched at 1080 ℃. The impact test results indicate that： as the tempering temperature increasing gradually, hardness decreases but impact toughness of the steel increases significantly. The maximum impact toughness value of 19 J/cm2 is obtained for the steel tempered at 200 ℃ -220 ℃. 1080℃ quenching ＆ 200 ℃ ~220 ℃ tempering is the best heat treatment process in consideration of hardness and impact toughness. The NSS test results indicate that the corrosion rate is less than 4% after quenching at 1080 ℃＆ tempering at 200 ℃, which can meet the requirements of manufacture and application.
出处
《热加工工艺》
CSCD
北大核心
2015年第24期192-196,共5页
Hot Working Technology
基金
四川省油气田材料重室开放基金资助项目(x151514kcl13)
大学生课外开放实验项目(KSZ14123)
