Manufacturing method for 2205 dual-phase steel thin-wall welded pipe

The invention discloses a manufacturing method for a 2205 dual-phase steel thin-wall welded pipe. The manufacturing method comprises the following steps that firstly, a 2205 dual-phase steel plate with the thickness smaller than or equal to 3 mm is formed to be in a tubular shape; and secondly, an ER 2209 welding wire is used as a filling material, a pulse tungsten inert gas (TIG) welding method with no groove and a narrow gap is adopted for welding areas to be welded of the tubular 2205 dual-phase steel plate formed in the step 1 with automatic wire filling, and the 2205 dual-phase steel thin-wall welded pipe is obtained. According to the manufacturing method for the 2205 dual-phase steel thin-wall welded pipe, the pulse TIG welding method with no groove and the narrow gap is adopted, and the automatic wire filling weld is adopted with the ER 2209 welding wire as the filling material; groove processing is not needed in the welding process, no preheating is needed before the welding, no thermal treatment is needed after the welding and the whole welding is one-layer welding; on the premise of ensuring reliable quality of welding seams, welding efficiency is increased, and the quality of the welding seams are reliable; various properties of the welding seams can satisfy the standard and meet the operating requirement; a process reference is provided for mass production of thin-wall 2205 dual-phase steel.