镍磷复合镀缸套穴蚀原因分析

Analysis of Cavitation Erosion of Nickel Phosphorus Composite Plated Cylinder Liner

某发动机的镍磷复合镀层缸套,在使用一段时间后,发生了失效,在水道部位和环带上出现不同程度的穴蚀现象。采用宏观观察、缸套及镀层的化学成分分析、硬度分析、金相分析、扫描电镜分析和能谱分析,结合发动机的工作原理等分析方法对该缸套失效原因进行了分析。结果表明:发动机工作时由于活塞的上下运动,导致缸套的振动,在缸套和冷却液之间形成负压,产生气泡,气泡爆裂冲蚀镀层,镀层冲蚀掉后,在缸套石墨裸露的地方沿着石墨冲蚀缸套造成的。建议规范发动机中活塞与缸套的结合间隙来减少震动,减少缸套外壁石墨裸露率,确保镀层的均匀无缺陷,同时规范冷却液的使用。

The nickel phosphorus composite coating cylinder liner of a certain engine has occurred in different degrees of cavitation erosion in the cylinder liner and the ring area after a period of use. The failure causes of the cylinder liner were analyzed by macroscopic observation, chemical composition analysis, hardness analysis, metallographic analysis, scanning electron microscope analysis and energy spectrum analysis, and the working principle of the engine. The results show that the vibration of the cylinder liner is caused by the engine working, and the negative pressure is formed between the cylinder liner and the coolant, and the bubbles are produced, and the blowout of the cheongsam is caused by the erosion and erosion of the coating and the cylinder sleeve. It is recommended to standardize the processing technology of the engine and the exposed rate of graphite on the outer wall of the cylinder liner and ensure the uniformity of the coating,at the same time,regulate the use of coolant..