二甲苯管线弯头表面裂纹失效分析

Failure Analysis of Surface Crack of Elbow Pipe Elbow

采用化学成分分析、硬度测定、金相分析、SEM观察和能谱分析等手段,对二甲苯管线弯头表面裂纹产生的原因进行了分析,并结合管线的损伤模式和检验情况,提出了管线安全运行措施。结果表明:弯头内外表面裂纹为管坯皮下气泡热推成型所致,属于制造缺陷;高温硫化物腐蚀和冲蚀是管线的主要损伤模式;打磨去除弯头外表面裂纹,控制二甲苯物料中的硫含量,严格工艺操作,能够保障管线的安全运行。

The chemical composition analysis,hardness measurement,metallographic analysis,SEM observation and energy spectrum analysis were used to analyze the causes of surface cracks in the elbow pipeline elbow.Combined with the damage mode and inspection of pipelines,Pipeline safe operation measures.The results show that the internal and external surface cracks of the elbow are caused by the hot pressing of the bubble under the tube blank,which is a manufacturing defect.The high temperature sulfide corrosion and erosion are the main damage modes of the pipeline;the grinding removes the external surface crack of the elbow and controls the xylene material.The sulfur content,strict process operation,can ensure the safe operation of the pipeline