厚壁双相不锈钢焊管的焊接方法和相平衡控制

Welding Method and Phase Balance Control for Thick Wall Duplex Stainless Steel Pipe

双相不锈钢焊管在海洋油气及工程中应用正在日渐增多,为适应耐海洋油气腐蚀要求,钢种也在增加并向经济型延伸,壁厚已增至12~40 mm。通过对厚壁双相不锈钢焊管的焊接方法、焊接参数以及焊缝力学性能的讨论,指出壁厚8 mm以上的双相不锈钢焊管只能采用多道多层焊,GTAW/PAW或者GTAW/PAW＋SAW多道焊都是实用选择,为减少填充焊层次数目,宜采用不对称U形或双角度坡口设计;为了确保焊缝金属相平衡和耐腐蚀性,单道焊缝的热输入及层间温度应有更严格控制;填充金属选择则应考虑供货状态。

The application of duplex stainless steel pipe in marine oil gas and engineering is increasing gradually. In order to meet the requirements of marine oil gas corrosion, the steel grades are added and extended to the economic type, the wall thickness has been increased to 12~40 mm. Through discussion of welding method, parameters and weld mechanical performance for thick wall duplex stainless steel pipes, it pointed out that for the wall thickness more than 8 mm of duplex stainless steel welded pipe can only adopt multi-channel multi-layer welding, GTAW/PAW or GTAW/PAW＋SAW multiple welding are all practicable method. In order to reduce the filling welding layer number, it should use asymmetric U-shaped or double angle groove design.However, in order to ensure phase balance and corrosion resistance of the weld metal, the heat input of single weld and interlayer temperature should be strictly controlled, and the selection of filler metal should consider its supply status.