中俄天然气管道工程全自动不等壁厚焊接工艺研究

Fully automatic unequal wall thickness welding technology for Sino-Russian Natural Gas Pipeline Project

大口径不等壁厚连头焊接时,由于壁厚不同,易导致根焊高度不同;采用焊条电弧焊或RMD根焊时,厚壁侧极易产生咬边或未熔合;因焊接停留时间控制不当出现埋藏性气孔缺陷;内焊道也会与厚壁侧内壁母材产生夹角,形成假未熔合现象.针对上述问题开展了中俄天然气管道工程全自动不等壁厚焊接工艺研究,确定了不等壁厚的焊接工艺;根据接头设计型式,选取了适合的焊接方法及各层焊接工艺参数,探索了根焊和外焊接的技术操作特点,并通过预定参数进行大量的焊接试验,焊接出合格焊口.

When welding large diameter pipes with unequal wall thickness,it is easy to lead to different root welding height due to different wall thickness.When arc welding with welding rod or RMD root welding is used,the thicker wall side is easy to cause undercut or unfusion.Due to improper control of welding residence time,buried blowhole defects occur.The inner weld will also have an angle with the inner wall base metal of the thicker wall side,resulting in false unfusion phenomenon.In view of the above problems,the automatic unequal wall thickness welding technology for Sino-Russian natural gas pipeline project is studied,and the welding process for different wall thickness is determined.According to the joint design type,the suitable welding method and corresponding welding process parameters are selected,the operation characteristics of root welding and layers welding technology are explored,and a large number of welding tests are carried out through predetermining parameters.The qualified welding joint is achieved.