摘要
使用扫描电镜(SEM)、电子背散射衍射(EBSD)、X射线衍射(XRD)、热膨胀仪等手段表征贝/马复相42CrMo钢并测试其力学性能,研究了在低于M_(s)点的不同温度等温淬火对42CrMo钢贝/马复相的微观组织和力学性能的影响。结果表明,在250℃、280℃和310℃等温淬火后42CrMo钢的显微组织均由贝氏体和马氏体复相组成。随着等温淬火温度的提高贝氏体相变速率随之提高,其体积分数从18%提高到63%,冲击断口由脆性解理断裂向混合式断裂转变,冲击韧性显著提高。250#和280#的贝/马复相组织的尺寸较小,而310#的贝氏体和马氏体板条都发生粗化,抗拉强度降低。280#总晶界的长度分别为250#和310#的1.65倍和2.43倍。晶界密度的显著提高使280#的屈服强度最高。在280℃等温淬火保温1.5 h后,42CrMo钢的屈服强度和抗拉强度分别达到1399 MPa和1708 MPa,延伸率和冲击吸收功分别为12.3%和51.6 J。与310#和250#相比,280#的综合力学性能更优。
The effect of isothermal quenching temperatures below M_(s) point on the microstructure and mechanical properties of bainite/martensite multi-phase 42CrMo steel was studied by scanning elec-tron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray diffraction(XRD),thermal expansion analyzer and mechanical property tester.The results show that the microstructure of 42CrMo steel is composed of bainite and martensite phase after isothermal quenching at 250 ℃,280 ℃ and 310 ℃,cor-respondingly,the quenched 42CrMo steels were named as 250#,280#and 310#steel respectively.With the increasing isothermal quenching temperature,the phase transformation rate of bainite is enhanced,and bainite volume fraction increases from 18%to 63%.The mode of impact fracture transforms from brit-tle cleavage fracture to mixed fracture,while the impact toughness is significantly improved.The bainite/martensite multi-phase microstructure of 250#and 280#steels is fine.However,bainite and martensite laths of 310#coarsens,and large-sized martensite block appears,so that its tensile strength decreases.The total grain boundary length of 280#is 1.65 times that of 250#,and 2.43 times that of 310#respective-ly.The significantly increased grain boundary density makes 280#possess the highest yield strength.Af-ter being isothermally hold at 280 ℃ for 1.5 h then quenched,the yield strength and tensile strength of 42CrMo steel reach 1399 MPa and 1708 MPa,respectively,and the elongation and impact absorption en-ergy are 12.3%and 51.6 J,respectively.Compared with 310#and 250#,the 280#steel has better overall mechanical properties.
作者
江腾
李星
刘汉强
崔珊
刘宏亮
刘军
栾义坤
姜周华
JIANG Teng;LI Xing;LIU Hanqiang;CUI Shan;LIU Hongliang;LIU Jun;LUAN Yikun;JIANG Zhouhua(School of Metallurgy,Northeastern University,Shenyang 110819,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Benxi Iron and Steel Group Co.,Ltd.Technical Center,Benxi 117000,China)
出处
《材料研究学报》
北大核心
2025年第11期837-844,共8页
Chinese Journal of Materials Research
基金
国家自然科学基金(52404354)。
关键词
金属材料
等温淬火
微观组织
力学性能
贝氏体
metallic materials
isothermal quenching
microstructure
mechanical properties
bainite
