波纹不锈钢换热板腐蚀开裂失效分析

FAILURE ANALYSIS FOR CORROSION CRACKING OF A HEAT-EXCHANGER OF STAINLESS STEEL

对失效开裂的波纹不锈钢板进行了外观检查,用电子显微镜观察了开裂断口和裂纹断口的形貌与特征;能谱分析得到了断口腐蚀产物和不锈钢板上沉积物的元素组成与含量;红外光谱分析结果表明使用在波纹不锈钢板端之间的三元乙丙橡胶密封垫片用粘合剂为氯丁橡胶,分析推断氯离子来源于氯丁橡胶的高温分解.综合分析结果表明,波纹不锈钢换热板失效开裂是由氯离子导致的应力腐蚀开裂所致;以穿晶型开裂为主,同时也存在沿晶型开裂.

The appearance of the failed heat - exchanger of stainless steel was examined by naked eye, the morphology and feature of the fracture of the failed heat - exchanger of stainless steel were obtained by SEM, the element content of the corrosion product on the fracture and the scales on the stainless steel were also analyzed. The IR result indicted that the rubber seal gasket was made of polychloroprene, which can be decomposed to produce Cl^- at high temperature. The overall analysis result showed that stress corrosion cracking was induced by Cl^-, the cracks were trans - granular mainly but there were also inter- granular cracks.