20CrMoH合金钢减速器伞齿轮轴断裂失效分析  

Fracture failure analysis of 20CrMoH alloy steel reducer bevel gear shaft

作　　者：李兵 徐飞越 张鹏 邢俊峰 唐正群 Li Bing;Xu Feiyue;Zhang Peng;Xing junfeng;Tang Zhengqun(School of Materials Science and Engineering,Hubei University of Automobile Technology,Shiyan Hubei 442002,China;Avita Technology(Chongqing)Co.,Ltd.,Chongqing 401120,China;Dongfeng Automotive Fasteners Co.,Ltd.,Shiyan Hubei 442002,China)

机构地区：[1]湖北汽车工业学院材料科学与工程学院,湖北十堰442002 [2]阿维塔科技(重庆)有限公司,重庆401120 [3]东风汽车紧固件有限公司,湖北十堰442002

出　　处：《金属热处理》2025年第1期292-298,共7页Heat Treatment of Metals

基　　金：湖北省科技重大专项(2022AAA001);湖北省重点研发计划(2021BAB019)。

摘　　要：针对20CrMoH合金钢减速器伞齿轮轴在安装拧紧过程中发生断裂的问题,结合光学显微镜、显微硬度计、扫描电镜等检测手段,对其断裂试样宏观形貌、微观组织、硬度等进行检测与分析,查明断裂原因。结果表明,20CrMoH钢伞齿轮轴的裂纹起源于螺纹起止槽加工不良处,多点起源断裂,源区磨损严重,随后在弯曲剪切应力作用下,裂纹沿渗碳过渡层二次起源后断裂,断口形貌呈现出沿晶形貌特征。零件的化学成分和硬度基本满足要求,零件心部的硬度出现较大散差。总的来说,零件表现为大应力过载断裂特征,这是由于不良加工刀痕及材料的状态造成应力集中,导致断裂,后续建议排查拧紧时的受力状态和改善热处理工艺条件,从而降低感应退火层深,缩小热影响区范围。In response to the problem of fracture of 20CrMoH alloy steel reducer bevel gear shaft during installation and tightening,the macroscopic morphology,microstructure,and hardness of the fracture specimen were tested and analyzed using optical microscopy,microhardness tester,scanning electron microscopy,and other detection methods to identify the cause of the fracture.The results show that the cracks in the 20CrMoH steel bevel gear shaft originate from poor machining of the thread start stop groove,with multiple points of fracture and severe wear in the source area.Subsequently,under the action of bending shear stress,the cracks propagate along the carburized transition layer and fracture,with the fracture morphology showing intergranular features.The chemical composition and hardness of the parts basically meet the requirements,but there is a significant variation in hardness at the core of the parts.Overall,the parts exhibit characteristics of high stress overload fracture,which is caused by stress concentration due to poor machining tool marks and material conditions,leading to the fracture.It is recommended to investigate the stress state during tightening and improve the heat treatment process conditions to reduce the depth of the induction annealing layer and narrow down the heat affected zone.

关 键 词：20CrMoH合金钢 伞齿轮轴断裂失效 微观组织 断口形貌 

分 类 号：TG142.41[一般工业技术—材料科学与工程]