回火温度对不同淬火处理0.6C超级贝氏体钢组织及性能的影响  

Effect of tempering temperature on microstructure and properties of 0.6C super bainitic steel quenched by different methods

作　　者：孙林 洪振军 胡坤 苏震 徐新乐 金阳 董达善[4] Sun Lin;Hong Zhenjun;Hu Kun;Su Zhen;Xu Xinle;Jin Yang;Dong Dashan(China North Advanced Technology Generalization Institute,Beijing 100089,China;School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Inner Mongolia First Machinery Group Co.,Ltd.,Baotou Inner Monglia 014030,China;Logistics Engineering College,Shanghai Maritime University,Shanghai 201306,China)

机构地区：[1]中国兵器工业新技术推广研究所,北京100089 [2]上海交通大学材料科学与工程学院,上海200240 [3]内蒙古第一机械集团有限公司,内蒙古包头014030 [4]上海海事大学物流工程学院,上海201306

出　　处：《金属热处理》2020年第10期54-59,共6页Heat Treatment of Metals

基　　金：国防基础科研计划(JCKY2017208B003)。

摘　　要：分析了不同回火温度下等温盐浴和淬火-配分-回火(Q-P-T)工艺处理0.6C超级贝氏体钢的微观组织和力学性能。结果表明:经230℃×10 h+320℃×7 h两步法等温淬火处理后,试样在360~500℃温度区间出现明显的第二类回火脆性,而Q-P-T试样回火脆性温度区间为450~470℃,经Q-P-T工艺处理后,回火脆性温度区间明显变窄,试样力学性能全面提高。利用SEM、TEM、XRD等手段对显微组织进行表征,揭示了Q-P-T试样优于等温处理的两个主要因素:经Q-P-T工艺处理后,微观组织更为细化,随着亚晶界的增多,组织稳定性进一步增强,碳化物晶界偏聚受到阻碍,难以连接成网状,故经Q-P-T工艺处理后试样第二类回火脆性区间极大缩小;经Q-P-T工艺处理后薄膜状残留奥氏体含量增大,奥氏体更为稳定,有利于减弱第二类回火脆性的影响。Microstructure and mechanical properties of the 0.6C super bainitic steel were analyzed after isothermal salt bath quenching and quenching-partitioning-tempering(Q-P-T)respectively and then tempering at different temperatures.The results indicate that the reversible temper brittleness appears in the temperature range of 360-500℃after treated by two-step austempering at 230℃×10 h and 320℃×7 h,while the tempering brittleness temperature range of Q-P-T specimen is 450-470℃.Respectively,after Q-P-T process,the tempering brittleness temperature range is obviously narrowed and the mechanical properties of the specimen are improved.The microstructural characterization by SEM,TEM and XRD reveals two main factors resulting in the mechanical properties of the Q-P-T specimen superior to those of the isothermal treatments:after the Q-P-T treatment,the microstructure is more refined,and with the increase of subgrain boundaries,the stability of the microstructure is further enhanced,and the carbide segregation to the grain boundaries is hindered,so it is difficult to connect into a network.Therefore,after the Q-P-T treatment,the reversible temper brittleness temperature range is greatly reduced;after the Q-P-T treatment,the film-like retained austenite increases in the content and is more stable,which is beneficial to weaken the influence of reversible temper brittleness.

关 键 词：超级贝氏体钢 Q-P-T工艺 第二类回火脆性 碳化物偏聚 薄膜状残留奥氏体 

分 类 号：TG146.2[一般工业技术—材料科学与工程]