回火温度对两相区淬火态40CrNiMo钢组织和力学性能的影响  

Effect of Tempering Temperature on Microstructure and Mechanical Properties of Intercritical Quenched 40CrNiMo Steel

作　　者：何晓波[1] 魏宏宇 张可 于萌 白玉静 HE Xiaobo;WEI Hongyu;ZHANG Ke;YU Meng;BAI Yujing(Technology Center,Anyang Iron&Steel Group Co.,Ltd.,Anyang 455004,China;School of Metallurgical Engineering,Anhui University of Technology,Ma'anshan 243032,China)

机构地区：[1]安阳钢铁集团有限责任公司技术中心,安阳455004 [2]安徽工业大学冶金工程学院,马鞍山243032

出　　处：《机械工程材料》2025年第3期49-54,共6页Materials For Mechanical Engineering

基　　金：河南省博士后科研启动项目(202103098);安徽省高等学校科学研究项目(2023AH051090)。

摘　　要：采用740℃两相区淬火工艺对40CrNiMo钢进行油淬,然后在不同温度(570,600,630℃)下进行回火处理,研究了回火温度对试验钢组织和力学性能的影响,并与850℃完全淬火再回火处理钢进行对比。结果表明:两相区淬火再回火后试验钢的组织均由回火索氏体、铁素体及渗碳体组成,随回火温度的升高,颗粒状渗碳体加速析出并聚集长大,α铁素体再结晶程度增大,试验钢硬度由203 HV降低至194 HV,且低于完全淬火再回火的试验钢。两相区淬火再回火处理时,回火温度的变化未对试验钢的低温冲击韧性产生显著影响,−20℃冲击吸收能量变化幅度在4~5 J,且−20℃冲击吸收能量高于完全淬火再回火的试验钢;不同回火温度下的冲击断口呈明显的韧性断裂特征,韧窝尺寸和数量变化不大。在试验参数范围内,试验钢两相区淬火再回火的最佳回火温度为630℃,回火后的−20℃冲击吸收能量为33 J,满足工程应用要求,同时具有较高的硬度(194 HV)。40CrNiMo steel was treated by oil intercritical quenching at 740℃,and then was tempered at different temperatures(570,600,630℃).The effects of tempering temperature on the microstructure and mechanical properties of the test steel were investigated and compared with those of the steel treated by fully quenching at 850℃and tempering.The results show that after intercritical quenching and tempering,the microstructure of the test steel consisted of tempered sorbite,ferrite and cementite.With the increase of tempering temperature,the granular cementite precipitated rapidly and aggregated to grow up,the recrystallization degree ofαferrite increased,and the hardness of the test steel decreased from 203 HV to 194 HV and was lower than that of the fully quenched and tempered test steel.Under intercritical quenching and tempering,the change of tempering temperature had no significant effect on the lowtemperature impact toughness of the test steel,and the variation range of the impact absorption energy at−20℃was 4‒5 J.The impact absorption energy at−20℃of the intercritical quenched and tempered test steel was higher than that of the fully quenched and tempered test steel.The impact fracture at different tempering temperatures showed obvious ductile fracture characteristics,and the size and number of dimples did not change much.Within the range of test parameters,The optimal tempering temperature for the intercritical quenching and tempering treatment of the test steel was 630℃;at this time,the−20℃impact absorption energy of the test steel was 33 J,which met the engineering application requirements,and the steel also had a relatively high hardness(194 HV).

关 键 词：40CRNIMO钢 两相区淬火 回火温度 显微组织 冲击韧性 

分 类 号：TG156[金属学及工艺—热处理]