炼油制氢装置换热器出口管线开裂原因分析

Analysis on Causes of Cracking of Heat Exchanger Export Pipeline in a Refining Hydrogen Plant

E5103换热器出口管线靠近阀门大小头短节处焊缝产生泄漏,采用化学成分分析、金相检查等方法对泄露原因进行了分析。发现该管道短节两端焊缝均有裂纹存在,裂纹起始于管道内壁焊缝熔合线处,管道材料组织正常,管道内壁熔合区裂纹是由交变载荷引起的,通过疲劳扩展最终穿透外壁引起介质泄漏。

As leakage occurred pipeline, the causes of 1 at the welding line of transition pipe near the valve of E5103 eakage were analyzed with methods of chemical analysis check. During the failure analysis, cracks were found on both ends of the welds of the began from the inner wall of the weld line fusion zone, and the pipe material and the heat exchanger export and metallographical transition pipe, which weld line organization were normal. The cracks in the inner pipe weld line fusion zone were caused by alternating load, which finally penetrated the outer wall through fatigue extension, and thus caused medium leakage.