发动机气缸体泄漏原因分析

摘要

The engine block leaked during testing in South China Sea. Appearance observation of gas channel and fracture surface, energy spectrum analysis, microstructure inspection, and hardness testing were performed. The results show that the cracks of block are stress corrosion cracks. The highly-concentrated chloride ion on surface of gas channel, and the high sensitivity to stress corrosion caused the stress corrosion cracking of the engine block. The stress corrosion failure of the block can be prevented by carefully cleaning to reduce the remained chloride ion as well as improving the material state or changing material to lower the sensitivity to stress corrosion.%发动机气缸体在南海试验时发生泄漏故障。对气缸体气道表面形貌、裂纹形态及裂纹断口进行了宏微观观察、能谱成分分析，对气缸体的金相组织及硬度进行了检查。结果表明：气缸体的裂纹性质为应力腐蚀开裂；由于气道表面残留高浓度的Cl-以及材料具有较高的应力腐蚀敏感性，使得气缸体在残余应力作用下发生应力腐蚀开裂。要预防气缸体发生应力腐蚀失效，可采取加强清洗以减少Cl-的残留、改善材质状态或更换材料以降低其应力腐蚀敏感性等措施。