输水用螺旋缝双金属复合管焊接工艺研究

Study on Welding Process of Helical Weld Bimetallic Composite Pipe for Water Conveyance

针对螺旋焊管作为基管时,双金属复合管机械复合难度大、焊缝组织难控制等问题,开发了一种螺旋缝冶金双金属复合管的焊接工艺。通过对双金属复合管常用焊接方法的对比分析,确定了埋弧焊的焊接方式,并根据埋弧焊高稀释率的特点,对过渡层、不锈钢层和碳钢层的焊接材料进行了试验研究。结果显示,选用高Cr焊丝(w(Cr)≥40%)完成不锈钢层及过渡层的焊接,选用与不锈钢层成分相当的焊丝完成碳钢层焊接,可有效降低焊缝硬度,得到以奥氏体为主的焊缝组织。研究结果表明,采用冶金双金属复合板试制的螺旋缝双金属复合管各项性能均符合相关标准要求,且焊缝具有优异的强度和塑性。

Aiming at the problems of difficult mechanical compounding and difficult control of weld microstructure of bimetallic composite pipe when helical welded pipe is used as base pipe,a welding process of helical welded metallurgical bimetallic composite pipe is developed.Through the comparative analysis of common welding methods of bimetallic composite pipe,the welding mode of submerged arc welding is determined.According to the characteristics of high dilution rate of submerged arc welding,the welding materials of transition layer,stainless steel layer and carbon steel layer are experimentally studied.The results show that selecting high Cr welding wire(w(Cr)≥40%)to complete the welding of stainless steel layer and transition layer and selecting welding wire with the same composition as stainless steel layer to complete the welding of carbon steel layer can effectively reduce the weld hardness and obtain the weld structure dominated by austenite.The trial production of helical welded composite pipe was carried out with metallurgical bimetallic composite plate.The results show that the properties of bimetallic composite pipe meet the requirements of relevant standards,and the weld has excellent strength and plasticity.