摘要
文章通过对制氢装置中变气管道使用的操作条件、工艺介质进行分析;对异径管道裂纹进行宏观观察、渗透检测;对管道母材进行了硬度测试、金相观察、化学成分分析;对裂纹断口进行宏观、微观检查。发现管道上裂纹由内壁起源,呈弧形向外壁扩展,断口平齐未见明显的塑性变形和腐蚀结垢特征,且裂纹几乎穿透整个壁厚;管道小头端母材中有大量的滑移线,显微组织为奥氏体加形变诱导马氏体组织,具有典型的冷作硬化特征,还有少量孪晶;管道母材硬度值不符合奥氏体不锈钢硬度值不大于190 HB的规定,且管道大头、小头端外壁硬度差别较大。由此得出异径管道成型后未进行最终固溶处理是导致开裂的最根本原因,并对此类不锈钢管件在使用中如何防止开裂提出了相应的防护措施。
The analysis of the operating conditions of shift gas pipe and process medium in hydrogen generation plant,the macroscopic observation,penetration testing for cracks on reduced pipe,the hardness testing,metallographic observation,analysis of chemical compositions for base material of pipe and macroscopic and microscopic examinations have found out that： the cracks on the pipes originated from internal wall and propagated to the external wall in curve form.The fracture is flush and there is no apparent plastic deformation and corrosion.The cracks almost penetrate the entire thickness of pipes.The base material of reduced end of pipe has a large number of slip line with typical cold-work characteristics,whose microstructure is Austenitic plus Martensitic structure.The hardness of base material does not meet the specification requirement of hardness of austenitic stainless steel which is no greater than 190 HB.There is a great difference between hardness of larger pipe end and smaller pipe end.The analysis concludes that no final solid-solution treatment after forming is the basic cause for cracking.The protective measures for preventing cracking of this type of stainless steel pipe in operation are proposed.
出处
《石油化工腐蚀与防护》
CAS
2012年第2期56-60,共5页
Corrosion & Protection In Petrochemical Industry
关键词
中变气
固溶处理
敏化
应力腐蚀
开裂
shift gas
solid-solution treatment
stress corrosion
cracking
