Fracture analysis of chilled cast iron camshaft  

作　　者：Li Ping Li Fengjun Cai Anke Wei Bokang 

机构地区：[1]School of Material Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China [2]China Yituo Group Co., Ltd., Luoyang 471004, Henan, China [3]School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China

出　　处：《China Foundry》2009年第2期104-108,共5页中国铸造（英文版）

基　　金：supported financially by the postdoctoral foundation from Yituo Group Co.,Ltd.,China;the doctoral foundation from Henan Polytechnic University,Henan,China.

摘　　要：The fracture of a camshaft made of chilled cast iron, installed in a home-made Fukang car, happened only after running over a distance of 6,200 km. The fractured camshaft was received to conduct a series of failure analyses using visual inspection, SEM observation of fracture section, microstructure analysis, chemical composition analysis and hardness examination and so on, while those of CKD camshaft made by Citroen Company in France was also simultaneously analyzed to compare the difference between them. The results showed that the fracture of the camshaft mainly results from white section in macrostructure and Ledeburite in microstructure; the crack in the fractured camshaft should be recognized to initiate at the boundary of coarser needle-like carbide and matrix, and then propagate through the transverse section. At the same tide, the casting defects such as dendritic shrinkage, accumulated inclusion and initiated crack and abnormal external force might stimulate the fracture of camshaft as well. Based on failure analysis, some measures have been employed, and as a result, the fracture of home-made camshafts has been effectively prevented.The fracture of a camshaft made of chilled cast iron,installed in a home-made Fukang car,happened only after running over a distance of 6,200 km.The fractured camshaft was received to conduct a series of failure analyses using visual inspection,SEM observation of fracture section,microstructure analysis,chemical composition analysis and hardness examination and so on,while those of CKD camshaft made by Citroēn Company in France was also simultaneously analyzed to compare the difference between them.The results showed that the fracture of the camshaft mainly results from white section in macrostructure and Ledeburite in microstructure;the crack in the fractured camshaft should be recognized to initiate at the boundary of coarser needle-like carbide and matrix,and then propagate through the transverse section.At the same time,the casting defects such as dendritic shrinkage,accumulated inclusion and initiated crack and abnormal external force might stimulate the fracture of camshaft as well.Based on failure analysis,some measures have been employed,and as a result,the fracture of home-made camshafts has been effectively prevented.

关 键 词：CAMSHAFT CAR chilled cast iron FRACTURE LEDEBURITE 

分 类 号：TG333.17[金属学及工艺—金属压力加工] U464.134.1[机械工程—车辆工程]