某石油炼厂板式空冷器板片在较短时间内发生严重的开裂。根据该厂提供的失效件, 采用电子探针、金相显微镜、扫描电镜和电子能谱仪等对开裂板片的成分、金相、断口宏观及微观形貌和腐蚀产物进行了分析。结果表明,板式空冷器最外层板片开裂为应力腐蚀开裂, 次外层板片开裂为腐蚀疲劳所致。

Serious cracking of some plate air cooler sheets occurred in short time when operated in a refinery. The chamical composition, metallography, macro-morphology and micro-morphology of the fractured parts and corrosion products on cracked sheets were analyzed by electron probe microscopic analyzer (EPMA), metallurgic microscopy, scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS). The results showed that the cracking in outer layer of plate air coolers was attributed to stress corrosion cracking (SCC), and the cracking in inner layer was attributed to corrosion fatigue.