气缸盖裂纹失效分析及改进研究  

Analysis and Improvement Research on Cylinder Head Crack Failure

作　　者：刘刚 郑智锋 郝贤 高敏 Liu Gang;Zheng Zhifeng;Hao Xian

机构地区：[1]山西柴油机工业有限责任公司舰船动力研究所

出　　处：《工程机械》2024年第10期142-147,I0023,I0024,共8页Construction Machinery and Equipment

摘　　要：某柴油机气缸盖出现裂纹故障,裂纹呈曲折扩展并贯穿端部。在裂纹产生区和其他区域进行了金相检查,并用显微镜和扫描电子显微镜(SEM)对取自断裂端的样品进行了微观结构观察。同时,通过有限元分析确定了气缸盖失效部分的载荷状态。结果表明,温度最高和热力耦合下应力最大点均不在裂纹位置,表明温度和过载不是导致缸盖失效的主要原因。而该裂纹始裂部位处于铸件壁厚突变区域,裂源位于水孔内腔工件结构拐角处,并沿拐角分布。裂纹扩展走势曲折,呈沿晶开裂,断面上存在较严重氧化色,裂源附近存在枝晶及夹渣,这些裂纹特征均属于铸造热裂纹。表明该裂纹是由于铸造过程的热裂纹而引起。The cylinder head of a diesel engine showed a crack fault,with the crack extending zigzag and penetrating through the end.Metallo graphic examination was conducted in the crack area and other areas,and microstructur al observations were made on samples taken from the fractured end by using a microscope and a scanning electron microscope(SEM).Meanwhile,the load state of the failed part of the cylinder head was determined through finite element analysis.The results show that the points of maximum stress under the highest temperature and the thermodynamic coupling are not at the crack location,indicat ing that temperature and overload are not the main causes for cylinder head failure.The crack initiation site is in the area of sudden change in casting wall thickness,and the crack source is located at the corner of the workpiece structure in the water hole cavity and distributed along the corner.The crack extends zigzag and shows intergranular cracking,with a serious oxidation color on the cross section and dendrites and slag inclu sions near the crack source,and these crack characteristics belong to hot cracks in casting,indicating that the crack is caused by the hot crack during the casting process.

关 键 词：气缸盖裂纹 金相分析 有限元分析 铸造热裂纹 

分 类 号：TK428[动力工程及工程热物理—动力机械及工程]