针对船用柴油机拉缸故障，利用直读光谱仪、光学显微镜、扫描电子显微镜、能谱仪等对活塞裙以及缸套断口的宏观和微观形貌特征、化学成分、金相组织和力学性能等进行分析。结果表明：活塞裙的薄壁孔存在疏松缺陷，这些缺陷引起活塞裙疲劳开裂，使得活塞裙与缸套配套间隙减小，活塞裙与缸套产生黏着磨损，最终发生拉缸故障。

Aiming at the cylinder pulling failure of marine diesel engine, the macroscopic and microscopic morphology characteristics, chemical composition, metallographic structure and mechanical properties of the fracture of piston skirt and cylinder liner were analyzed by direct reading spectrometer, optical microscope, scanning electron microscope and energy spectrometer. The results show that there were loose defects in the thin-walled hole of the piston skirt. These defects caused the fatigue cracking of the piston skirt, which reduced the matching gap between the piston skirt and the cylinder liner. The piston skirt and the cylinder liner were adhesively worn, and finally the cylinder pulling fault occurd.