金属缠绕垫片外圈腐蚀-疲劳断裂失效分析  

Corrosion-fatigue Fracture Analysis of Metal-wound Gasket Outer Ring

作　　者：任方田 REN Fang-tian(Wanhua Chemical(Ningbo)Co.Ltd.,Ningbo 315800,China)

机构地区：[1]万华化学(宁波)有限公司,浙江宁波315800

出　　处：《石油化工设备》2025年第1期75-80,共6页Petro-Chemical Equipment

摘　　要：某沿海化工管道系统中法兰接头出现泄漏。对导致泄漏的金属缠绕垫片外圈断裂部位进行了形貌、金相、化学成分等检验检测分析,探讨了垫片外圈断裂的机理。结果表明,垫片外圈与法兰螺栓之间产生的强烈挤压导致垫片被挤压出凹坑并承受较大的周向应力,加之受垫片材料304不锈钢未进行固溶处理又在沿海大气环境中服役的影响,导致其沿晶应力腐蚀开裂敏感性增强,在挤压凹坑萌生沿晶应力腐蚀裂纹,最终在振动环境中发生了疲劳裂纹扩展。因此,垫片外圈断裂是沿海大气环境中高应力水平下力腐蚀开裂和疲劳共同作用的结果,根据失效原因给出了预防建议。A flange joint leaked in a coastal chemical pipeline system.The fractured part of the outer ring of the metal spiral wound gasket that caused the leak was examined and analyzed in terms of morphology,metallography,and chemical composition,and the fracture mechanism of the outer ring of the gasket was discussed.The results show that the strong extrusion between the gasket outer ring and the flange bolts caused the gasket to be squeezed out of a pit and subjected to high circumferential stress.In addition,the gasket material,304 stainless steel,had not been solution-treated and had been exposed to the coastal atmospheric environment,which increased its susceptibility to intergranular stress corrosion cracking Intergranular stress corrosion cracks started in the extrusion pits and fatigue cracks eventually propagated in the vibration environment.Therefore,the fracture of the outer ring ofthe seal was the result of the combined effects of stress corrosion cracking and fatigue in the high-stress coastal atmospheric environment,and prevention suggestions were proposed based on the failure causes.

关 键 词：管道 法兰 接头 垫片 断裂 机理 

分 类 号：TQ050.7[化学工程]