热切割对X80M钢管环焊接头组织及性能的影响

Influence of Thermal Cutting on Microstructure and Performance of X80M Pipe Girth Welding Joint

针对油气长输管道焊接施工中的连头焊接,分析了热切割对X80M钢管母材的影响。采用焊条电弧焊根焊+自保护药芯焊丝填充、盖面焊接工艺对热切割坡口进行焊接,并对焊后的环焊接头进行了力学性能测试及组织分析。结果表明,热切割会恶化X80M钢管母材组织,导致近坡口处硬度增高;由于焊接过程的"二次热作用",消除了热切割对母材组织的影响,近坡口处组织得到改善,环焊接头性能满足要求。在X80M管道的现场连头焊接作业中,可以采用热切割方式进行坡口加工。

For the tie-in welding in welding construction of oil and gas pipeline, the influence of thermal cutting on X80M pipe base metal was analyzed.The process of electrode arc root welding with self-shield flux cored wire filling and coveting welding was carried out for the thermal cutting groove. The mechanical properties and microstructure of the girth welding joint were tested and analyzed. The results show that the thermal cutting deteriorates the microstructure of X80M pipe and increases the hardness near the groove. Due to the effect of second heating process during welding, the influence of thermal cutting on base metal is eliminated, the microstructure near the groove improves, and the mechanical properties of girth welding joint meet the requirements. At the scene of X80M pipeline connecting head welding, groove machining can adopt the method of thermal cutting.