φ135 mm 48MnV钢曲轴磨削裂纹分析  

Analysis on grinding crack of φ135 mm 48MnV steel crankshaft

作　　者：王强[1] 赵四新[1] 余大江[1] 高加强[1] WANG Qiang;ZHAO Sixin;YU Dajiang;GAO Jiaqiang(Research Institute,Baoshan Iron and Steel Co.,Ltd.,Shanghai 201999,China)

机构地区：[1]宝山钢铁股份有限公司中央研究院,上海201999

出　　处：《物理测试》2024年第6期23-28,共6页Physics Examination and Testing

摘　　要：经过表面感应淬火和回火的φ135 mm规格48MnV钢曲轴连杆颈,在磨削探伤阶段发现表面存在龟甲状裂纹。利用体视显微镜、金相显微镜、能谱仪和硬度计等对φ135 mm规格48MnV曲轴连杆颈表面裂纹进行分析,确定连杆颈裂纹为磨削裂纹。裂纹仅存在于淬硬层表层,深度约340~510μm;淬硬层表层硬度最低,随后淬硬层硬度先升高,后趋于平缓,再缓慢降低至连杆颈基体硬度。由淬硬层到连杆颈基体的显微组织为:淬火马氏体+残留奥氏体→回火屈氏体+回火马氏体→回火马氏体→铁素体+珠光体。During the grinding and inspection stage,some surface-initiated turtle-back cracks were observed on the connecting rod neck of φ135 mm 48MnV steel crankshaft after surface induction hardening and tempering.These surface cracks were analyzed by optical microscope,scanning electron microscopy equipped with an energy dispersive spectrometer,and microhardness tester.The results indicated that the observed cracks were grinding cracks.The cracks only existed on the surface layer of the hardened layer,with a depth of about 340-510μm.The surface layer of the hardened layer had the lowest hardness.Then it firstly increased and then leveled off,and gradually decreased to the hardness of connecting rod journal substrate.The microstructure of the connecting rod journal from the hardened layer to the substrate was:quenched martensite+residual austenite→tempered martensite+tempered troostite→tempered martensite→ferrite+pearlite.

关 键 词：48MnV 曲轴 磨削裂纹 淬硬层 

分 类 号：TG580.6[金属学及工艺—金属切削加工及机床] TG115