7Cr17Mo马氏体不锈钢组织和冲击韧性  

Microstructure and impact toughness of 7Cr17Mo martensitic stainless steel

作　　者：宋自力[1] 杜晓东[1] 陈翌庆[1] 王家庆[2] 叶诚[1] 李连颖[1] 

机构地区：[1]合肥工业大学材料科学与工程学院,安徽合肥230009 [2]安徽省电力科学研究院材料所,安徽合肥230009

出　　处：《材料热处理学报》2011年第5期95-99,共5页Transactions of Materials and Heat Treatment

基　　金：广东省教育部产学研结合项目(2009A090100045);科技部创新基金(09C26213404170);安徽省教育厅自然科学重点项目(KJ2009A094)

摘　　要：采用光学显微镜(OM)、扫描电子显微镜(SEM)、洛氏硬度计、冲击试验机等观察和分析了7Cr17Mo马氏体不锈钢在980～1110℃不同温度淬火下的组织特征和性能变化。结果表明,淬火组织为残留奥氏体和碳化物分布于隐针马氏体基体上,碳化物以(Fe,Cr)23C6为主。随着淬火温度的升高,残留奥氏体含量增加,马氏体过饱和度增加,针状马氏体组织变粗,1060℃时硬度升高到最大值59 HRC。冲击试验结果表明在980～1080℃淬火时,随淬火温度升高,冲击韧性提高,1080℃时冲击韧性最好,其后下降。SEM断口形貌表明室温下冲击断裂方式为微孔聚集型断裂。Microstructure and properties of 7Cr17Mo martensitic stainless steel quenched at 980-1110 ℃ were investigated by means of optical microscopy（OM）,scanning electron microscopy（SEM）,hardness and impact tests.The experimental results demonstrate that the microstructure of the quenched steel consists of retained austenite,carbides and acicular martensite.The carbides are identified to be mainly（Fe,Cr）23C6.As the quenching temperature increases,the amount of retained austenite and supersaturation degree of martensite increase and the martensite is coarsened.The maximum hardness value of 59 HRC is obtained for the steel quenched at 1060 ℃.The impact test results indicate that impact toughness of the steel increases first to the maximum value at 1080 ℃ and then decreases when the quenching temperature increases from 980 ℃ to 1080 ℃.The impact fracture occurs in the manner of microvoid coalescence at room temperature according to the SEM fracture surface observation.

关 键 词：马氏体不锈钢 淬火温度 显微组织 冲击韧性 

分 类 号：TG156.31[金属学及工艺—热处理]