直接淬火对590 MPa含铜HSLA钢组织演变及力学性能的影响  

Effect of direct quenching on microstructure evolution and mechanical properties of a 590 MPa Cu-bearing HSLA steel

作　　者：王惟一 潘应君[1] 周乃鹏 柴锋[2] 罗小兵[2] Wang Weiyi;Pan Yingjun;Zhou Naipeng;Chai Feng;Luo Xiaobing(Faculty of Materials and Metallurgy,Wuhan University of Science and Technology,Wuhan Hubei 430000,China;Research Institute of Structural Steels,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China)

机构地区：[1]武汉科技大学材料与冶金学院,湖北武汉430000 [2]钢铁研究总院有限公司工程用钢研究院,北京100081

出　　处：《金属热处理》2025年第3期118-124,共7页Heat Treatment of Metals

摘　　要：对比离线淬火(Q)工艺,研究了直接淬火(DQ)工艺对590 MPa含铜HSLA钢组织演变及力学性能的影响。对经两种工艺处理后的试样,借助光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)分析其微观组织,通过拉伸试验、冲击试验测试了其抗拉强度、屈服强度和低温韧性。结果表明,DQ工艺保留了控制轧制获得的大位错密度和细小晶粒,DQ试验钢的显微组织呈现压扁拉长的状态,Q试验钢的显微组织则为等轴晶粒,DQ试验钢的有效晶粒尺寸较Q试验钢更小,但强度和低温韧性差别不大。后续回火过程中产生了富Cu相和碳化物的析出,利用位错、细晶、沉淀等增强作用提高材料的屈服强度,并利用细晶强化弥补了位错密度增加、压扁状组织等因素造成的韧性下降。经直接淬火+680℃回火后试验钢综合性能最佳,其屈服强度较离线淬火+680℃回火(QT680)试验钢提高159 MPa,达到805 MPa,-84℃冲击吸收能量达到了248 J。Compared with the off-line quenching(Q)process,the effect of direct quenching(DQ)on the microstructure evolution and mechanical properties of a 590 MPa Cu-bearing HSLA steel was studied.The microstructure of the specimens was analyzed by OM,SEM,EBSD and TEM.The strength and toughness were tested by tensile test and impact test.The results show that the DQ process retains the large dislocation density and fine grains obtained through controlled rolling.The microstructure of the DQ tested steel exhibits a flattened and elongated state,while the microstructure of the Q tested steel consists of equiaxed grains.The effective grain size of the DQ tested steel is smaller than that of the Q tested steel,but there is little difference in strength and low-temperature toughness.In the subsequent tempering process,Cu-rich phase and carbide precipitation are produced,and the yield strength of the tested steel is improved by the enhancement of dislocation,fine grain and precipitation,while the reduction of toughness caused by the increase of dislocation density and the flattened structure is made up by fine grain strengthening.After direct quenching+680℃tempering,the tested steel has the best comprehensive properties,and the yield strength is 805 MPa which is 159 MPa higher than that of off-line quenching+680℃tempering and the impact absorbed energy at-84℃is 248 J.

关 键 词：含铜HSLA钢 直接淬火 屈服强度 低温韧性 

分 类 号：TG156.3[金属学及工艺—热处理]