曲轴毛坯冷校直过程中失效的原因分析  

Failure cause analysis of crankshaft blank in cold straightening process

作　　者：丛建臣 于晓东[2] 马明珠[2] 吴永臣[2] 张华东 Cong Jianchen;Yu Xiaodong;Ma Mingzhu;Wu Yongchen;Zhang Huadong(School of Mechanical Engineering,Shandong University of Science and Technology,Zibo Shandong 255049,China;Tianrun Crankshaft Co.,Ltd.,Weihai Shandong 264413,China)

机构地区：[1]山东理工大学机械工程学院,山东淄博255049 [2]天润曲轴股份有限公司,山东威海264413

出　　处：《金属热处理》2020年第7期224-227,共4页Heat Treatment of Metals

摘　　要：45钢曲轴毛坯在采用冷校直消除锻造后微小变形的过程中出现断裂。使用直读光谱仪、布氏硬度计、光学显微镜、拉伸试验机、扫描电镜等设备对断裂毛坯进行化学成分、力学性能、微观组织、断口形貌特征等分析。结果表明:断口附近基体组织晶粒粗大,出现魏氏组织;力学性能显示出较低的塑性和冲击韧性,可以判断毛坯组织过热。这是导致锻坯脆性断裂的直接原因。通过调整锻造过程中感应加热参数、锻后控冷工艺、正火工艺,过热组织得以消除。A 45 steel crankshaft blank fractured in the cold straightening process to eliminate the slight deformation after forging.The spectrometer,Brinell hardness tester,metallographic microscope,tensile testing machine,scanning electron microscope and so forth were used to analyze the chemical composition,mechanical properties,microstructure,and fracture morphology characteristics of the fractured blank.The results show that the matrix structure near the fracture is coarse,and the Widmannstatten microstructure appears;the mechanical properties such as plasticity and impact toughness are low,which indicates the microstructure is overheated.This is the direct cause of brittle fracture of the forged billet.By adjusting the induction heating parameters in pre-forging process,the post-forging controlled cooling process and the normalizing process,the overheating structure is eliminated.

关 键 词：失效分析 过热 正火 晶粒度 锻造毛坯 

分 类 号：TG115.21[金属学及工艺—物理冶金]