曲轴终锻下模失效机理分析  

Failure mechanism analysis of a final forging lower die for crankshaft

作　　者：夏玉峰[1] 郑晓凯[1] 杨显红[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400044

出　　处：《金属热处理》2013年第11期127-130,共4页Heat Treatment of Metals

基　　金：中央高校基本科研业务费科研专项资金(CDJZR12110045)

摘　　要：通过扫描电镜、能谱分析、显微硬度测试,分析了一种曲轴终锻下模的失效形式。模具采用双金属堆焊修复,锻打一定次数后模具停止使用。结果表明,表层由于受热应力与机械应力影响,出现疲劳裂纹,合金元素含量减少并重新分布;受回火效应影响,表面强度、硬度降低;氧化层的脱落,加剧了磨损,并沿坯料流动方向形成犁沟;侧面受润滑剂迪塞尔效应作用,出现点蚀及剥落;模口部位圆角半径小,应力集中系数大,容易磨钝。Failure mechanism of a final forging lower die for crankshaft was analyzed by macro-observation, SEM and EDS analysis and micro-hardness test. The die was repaired by hardfacing dual-metal and failed after a number of strokes. The result show that surface layer of the die suffers severe thermal and mechanical stress, fatigue cracks appear and alloying elements decrease and redistribute. Tempering effect leads to the surface layer＇s strength and hardness decrease. Oxidation layer＇s peeling aggravates wear and leads to furrow along the flow direction. With lubricant＇s diesel effect, pitting and peeling appear on the lateral surface. Due to small round radius and bigger stress concentration on it, the die orifice is easily to be worn.

关 键 词：热锻 失效分析 疲劳裂纹 磨损 

分 类 号：TG315.2[金属学及工艺—金属压力加工]