数控仿形铣床传动齿轮断裂分析  

Fracture Analysis on Drive Gear of CNC Profiling Machine

作　　者：于强[1] 汪广宇 郭磊[2] 

机构地区：[1]四川理工学院理学院,四川自贡643000 [2]四川理工学院材料与化学工程学院,四川自贡643000

出　　处：《热加工工艺》2015年第18期237-239,242,共4页Hot Working Technology

基　　金：材料腐蚀与防护四川省重点实验室开放基金(2012CL08);四川理工学院教改基金(JG-1502)

摘　　要：采用轴与齿轮联体设计制造经高频调质热处理的40CrNi传动齿轮在服役期间发生了提前失效开裂。采用金相显微镜分析显微组织,扫描电镜观察断口,显微硬度计测量硬度。结果表明:齿轮心部显微组织为块状铁素体+片层珠光体+少量粒状珠光体。40CrNi传动齿轮提前失效开裂的原因是调质处理加热温度低,冷却速度慢,齿轮未淬透;机加工引起了疲劳裂纹的萌生,疲劳源是由粗糙机加工引起的应力集中而形成;热处理工艺未能使力学性能达到良好的抗冲击性、抗疲劳性要求,最终导致疲劳断裂。The drive gear with shaft of 40 CrNi steel treated by high-frequency quenching and high temperature tempering generated early failure crack during the service. The microstructure,fracture morphology and hardness test of fracture gear tooth was observed by metallographic microscope,SEM and Vickers hardness test,respectively. The results show that： the core part microstructure of gear tooth consists of massive ferrite,lamellae pearlite and a small amount of granular pearlite. The reasons for the early crack is that quenching heating temperature is low,cooling speed is slow,and the gear is not enough to be hardened. The rough machining causes the fatigue crack initiation,and the cutter mark of machining becomes surface fatigue crack fountain. The good impact resistance and fatigue resistance cannot be gotten by heat treatment process,and then the fatigue crack appears.

关 键 词：齿轮 断裂 显微组织 40Cr Ni钢 

分 类 号：TG156.5[金属学及工艺—热处理]