【作者】 龙香丽； 岑举； 杨维沛； 王涛； 于笋；

【Author】 LONG Xiang-li;CEN Ju;YANG Wei-pei;WANG Tao;YU Sun;Yuchai Machinery Co.,Ltd.;

【机构】 广西玉柴机器股份有限公司；

【摘要】 对某型船用失效活塞进行裂纹分布和断口特征观察、化学成分分析、金相检验及硬度检测,分析了裂纹产生的原因。结果表明:用支撑销钉安放可溶盐芯时方法不当,内冷油道中出现小凸台,在热负荷和机械负荷的共同作用下产生裂纹,并扩展至燃烧室。高温、高压燃气串入内冷油道,引发内冷油道与环槽之间裂纹的产生,造成环岸崩缺,最终致使活塞失效。在失效原因分析的基础上,提出了改进建议。更多还原

【Abstract】 In order to find out the failure cause of the marine diesel engine piston,macro observation for cracks and fracture,chemical composition analysis,metallographic examination and hardness testing were carried out.The results showed that the soluble salt core fixed method by pin was improper,because it would create small convex platform in the internal-cooled oil passage,and cracks would appear under the influence of the heat load and mechanical load,and would spread to the combustion chamber.The gas of high temperature and high pressure would enter into the internal-cooled oil passage,causing the cracks between the internal-cooled oil passage and piston ring groove,thus the piston ring bank would collapse and lead to failure eventually.Based on the cause analysis,some improvements were suggested.更多还原