锅炉锅筒的给水管座与锅筒在焊接和消除应力热处理后经探伤检查发现沿焊缝有环向裂纹,并扩展至给水管座的内壁形成纵向裂纹。采用化学成分分析、宏观和微观检验以及力学性能分析等方法对给水管座的裂纹产生原因进行了分析。结果表明: 由于焊接工艺规范控制不当,未及时进行消氢处理，焊件的碳当量提高具有明显的淬硬倾向，焊接结构和较大的焊件厚度引起拘束应力等综合作用产生了延迟裂纹。

Feed-water pipe saddle and boiler cylinder after finished welding and stress-relieved heat treatment was found circular crack by detection with drum welding,and expend to internal surface of feed-water pipe saddle and make lengthways crack. Through chemical composition analysis,macroscopic tests,metallographic tests and mechanical property test,the cracking analysis of feed-water pipe saddle was conducted. The result showed that the crack of feed-water pipe saddle was a delayed crack,because welding procedure code didn’t control well,carbon equivalent of welding components have obvious quench trend and welding didn’t avoiding hydrogen treatment,welding structure and larger thickness of welding components occured constrain stress etc.