深冷处理对核电级低碳钢微观组织及性能的影响  

Effect of cryogenic treatment on microstructure and properties of nuclear grade low carbon steel

作　　者：徐科 胡明磊 张维 胡斌 李冬升[2] 刘仁才 Xu Ke;Hu Minglei;Zhang Wei;Hu Bin;Li Dongsheng;Liu Rencai(CNNC Nuclear Power Operation Management Co.,Ltd.,Haiyan Zhejiang 314300,China;School of Materials Science and Engineering,Jiangsu University,Zhenjiang Jiangsu 212013,China)

机构地区：[1]中核核电运行管理有限公司,浙江海盐314300 [2]江苏大学材料科学与工程学院,江苏镇江212013

出　　处：《金属热处理》2025年第1期81-87,共7页Heat Treatment of Metals

摘　　要：为研究深冷处理对核电级低碳钢材料力学性能及组织演变的影响,利用显微硬度计、X射线衍射仪、扫描电镜及透射电镜等对经不同热处理工艺后20钢的力学性能及显微组织进行了表征。结果表明,回火处理促进部分残留奥氏体转变为马氏体以及碳原子的析出导致马氏体细化,使得硬度从淬火态的468.5 HV0.1提高至回火态的480.3 HV0.1;深冷处理促进试验钢中残留奥氏体转变为细小的板条状马氏体,同时,深冷处理引起试验钢中的马氏体产生晶格畸变,使得组织内应力和位错等缺陷增多,进而促进马氏体中碳原子的析出,导致析出强化作用增强,致使试验钢经淬火-深冷-回火处理的硬度提高至495.3 HV0.1。In order to study the effect of cryogenic treatment on mechanical properties and microstructure evolution of nuclear grade mild steel,the mechanical properties and microstructure of 20 steel after different heat treatments were characterized by means of microhardness tester,XRD,SEM and TEM.The results show that the tempering treatment promotes the transformation of partial retained austenite into martensite and the precipitation of carbon atoms leading to martensite refinement,resulting in an increase in hardness from 468.5 HV0.1 of the quenched steel to 480.3 HV0.1 of the tempered steel.The cryogenic treatment promotes the transformation of the retained austenite into fine lath martensite in the tested steel,and at the same time,the cryogenic treatment causes lattice distortion in the martensite,which leads to the increase of stresses and defects such as dislocations in the microstructure,which in turn promotes the precipitation of carbon atoms in the martensite,leading to the enhancement of precipitation strengthening,resulting in the increase of hardness of the tested steel to 495.3 HV0.1 after quenching-cryogenic-tempering treatment.

关 键 词：低碳钢 深冷处理 显微硬度 板条状马氏体 残留奥氏体 

分 类 号：TG161[金属学及工艺—热处理]