25CrMoA钢奥氏体冷却转变参数的确定  

Determination of Austenite Cooling Transformation Parameters of 25CrMoA Steel

作　　者：宋佳 张银凤 刘晓军 于善伟 丁志敏[1] SONG Jia;ZHANG Yinfeng;LIU Xiaojun;YU Shanwei;DING Zhimin(School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,China;Department of Technology Development,CRRC Dalian Co.,Ltd,Dalian 116022,China;Dalian City Product Quality Inspection Institute,Dalian 116021,China)

机构地区：[1]大连交通大学材料科学与工程学院,辽宁大连116028 [2]中车大连机车车辆有限公司工艺技术部,辽宁大连116022 [3]大连市产品质量检测研究院,辽宁大连116021

出　　处：《大连交通大学学报》2018年第2期89-93,共5页Journal of Dalian Jiaotong University

摘　　要：采用热膨胀法、末端淬火法与金相和硬度分析等试验手段对25Cr Mo A钢加热转变临界点和880℃奥氏体化后的连续冷却转变参数进行了确定.结果表明:25Cr Mo A钢加热转变的临界点Ac1和Ac3分别为758℃和841℃.经880℃奥氏体化的25Cr Mo A钢冷却后获得马氏体和贝氏体组织的临界冷却速度分别为127℃/s和44℃/s,而在冷却速度低于43℃/s时,将有铁素体和珠光体组织同时出现.相应地,880℃淬火时25Cr Mo A钢钢棒1/2半径处获得马氏体+贝氏体的临界直径约为48 mm.The critical transition points of 25CrMoA steel in the heating process and the continuous cooling transformation characteristics of 25CrMoA steel austenite cooled from 880℃to room temperature are studied by thermal expansion method,end quenching method,metallographic analysis and hardness analysis methods.The results show that 25CrMoA steel critical transition points Ac 1 and Ac 3 are 758℃and 841℃respectively in the heating process.The critical cooling rates of obtaining martensite and bainite microstructure after austenitizing 25CrMoA steel heated at 880℃are 127℃/s and 44℃/s respectively.However,the ferrite and pearlite microstructures will appear when the cooling rate is lower than 43℃/s.Accordingly,the critical cooling diameter of the 25CrMoA steel bar 1/2 radius getting martensite+bainite when quenched at 880℃is about 48 mm.

关 键 词：25CrMoA钢 末端淬火 临界冷却速度 

分 类 号：TG142.1[一般工业技术—材料科学与工程]