冶金复合三通失效分析

Analysis on Failure of Metallurgical Composite Tee

针对迪那气田干线冶金复合三通的穿孔泄漏问题,从复合层的厚度、穿孔发生的位置、焊缝处的硬度、金相组织等方面进行分析,得出结论:三通穿孔的原因是由于厂家的制造工艺不完善,导致复合三通环焊缝周向内衬层严重不均,致使焊接时在内衬层焊趾处产生点状或线状缺陷并发生穿孔,管道内气体从该处进入并接触碳钢基管壁,导致基管冲蚀刺漏。经分析认为,采用该工艺制作的同批次三通可能存在同样问题。对在用的同批次三通进行检测,发现有一个三通在同样位置存在同样问题。对存在问题的三通进行更换,避免了穿孔泄漏事件的发生,提高了装置的本质安全,保证了气田的平稳运行。该研究对气田干线冶金复合三通失效问题的分析及处理有参考意义。

In Dina gas field, piercing leakage occurred to a metallurgical composite tee of main line. The cladding layer thickness, the position of corrosion, weld hardness, microstructure, and production process were analyzed. It concludes that the cause of the tee perforation is due to imperfect manufacturing process, which causes uneven cladding layer thickness of the tee girth weld and results in weld problem and perforation of cladding layer. The gas erosion of the base carbon steel causes pipe leakage through the dot or line perforation. According to analysis, it is believed that the same problem may exist in the same batch of metallurgical composite tee produced by this process. It is found through detection that same issues exist at the same position in the same batch of tee in service. It is necessary to replace the tee with such issue and avoid the occurrence of the same perforated leakage, improve the essential safety of the device, and ensure the smooth operation of the gas field. This study provides reference for the analysis and treatment of the metallurgical composite tee failure in gas-field main line.