通过断口、能谱、化学成分及ANSYS应力分析等,对某气化炉连接短节法兰进行了失效分析。分析结果表明:焊缝处组织恶化,晶粒粗大,在湿的H_2S环境下发生沿晶应力腐蚀,形成初始裂纹源。而超温导致较大的温差应力,引起焊缝处及螺钉连接处支撑板与法兰变形不协调,使失效部位应力急剧上升,是裂纹扩展的主要原因。 Through the fracture, energy spectrum, chemical composition and stress analysis of ANSYS, the failure analysis of a gasifier to connect the short flange was carried out. The results show that the microstructure of the weld is deteriorated and the grains are coarse. Under the environment of wet H 2 S, intergranular stress corrosion occurs and the source of the initial crack is formed. The overtemperature caused by large temperature stress, causing the weld and screw connections at the plate and the flange deformation is not coordinated, so that the failure of parts of the sharp rise in stress is the main reason for crack growth.