There is no difference between Targon-arc welding and Targon-arc welding in the process of backing. Targon-arc welding is suitable for thin-walled small pipe diameter (generally DN50 and below, wall thickness of 4mm), and the purpose is to ensure the quality of weld root and good appearance imaging.

When the pipe diameter is larger and the wall thickness is thicker, the argon arc welding shall be used for the bottom manual welding of the cover surface. The purpose of the manual welding of the cover surface is that the pipe diameter is larger and the manual welding can ensure the appearance quality, and the work efficiency is higher than that of the argon arc welding, and the cost is lower than that of the argon arc welding.

High quality welded joints can be obtained by using argon arc welding technology.Argon arc welding backing welding process in the boiler water wall, superheater, economizer, such as welding, the joint quality is good, the X-ray detector, level of weld are Ⅱ magnitude.

(1) good quality

As long as the selection of appropriate welding wire, welding process parameters and good gas protection can make the root get good permeability, and the permeability is uniform, the surface is smooth and neat.There is no general welding rod arc welding is easy to produce welding nodule, not penetration, sag, pores and slag and other defects.

(2) high efficiency

In the first layer of pipe welding, manual argon arc welding is continuous arc welding.Arc welding is broken arc welding, so manual argon arc welding can improve the efficiency of 2~4 times.Because argon arc welding does not produce welding slag, it is not necessary to clean up the slag and repair the welding pass, so the speed is increased faster.In the second layer of arc welding cover surface, smooth and neat argon arc welding bottom is very conducive to arc welding cover surface, can ensure good fusion between layers, especially in the welding of small diameter pipe, the efficiency is more significant.

(3) easy to master

The welding of the root seam of manual arc welding must be performed by experienced welders with high technical level.Using manual argon arc welding, general workers engaged in welding work after a short time of practice, basically all can master.

(4) the deformation is small

In argon arc welding, the heat affected zone is much smaller, so the welding joint deformation is small, and the residual stress is also small.