316L不锈钢波纹管泄漏原因分析

316L不锈钢波纹管在装配使用一个月后发生泄漏。采用体视显微镜、扫描电子显微镜、光学显微镜和化学分析仪,对失效波纹管进行了断口宏微观观察、金相组织检查和化学成分分析。结果表明：裂纹起始于波纹管内壁波峰处,其周围存在大量腐蚀产物,主要以穿晶裂纹为主,沿圆周方向穿透管壁而形成泄漏点。分析认为,波纹管失效性质为典型的应力腐蚀,失效原因为高温下波纹管内壁在海水强腐蚀性环境和较大拉应力共同作用下产生应力腐蚀开裂所致。

Analysis on Leakage of 316L Stainless Steel Bellows

A 316L stainless steel bellows leaked after serving for one month. Macro and micro observation on the fracture sur-face, inspection of the metallurgical structure and chemical analysis were carried out with a stereo microscope, a scanning electren microscope（ SEM）, an optical microscope（OM） and a chemical analyzer. The results show that the cracks initiated from the wave crest of the inner wall and there were a great deal of corrosive products near the cracks. Most of the cracks were transgranular cracks, and the cracks penetrated through the bellows along the circumferential direction, ultimately causing the leakage. It was concluded that the cracks were caused by typical stress corrosion. Under the co-effect of high temperature, corrosive environment of the seawater, and greater tensile stress, cracks came into being at the inner wall of the bellows.