Rectangular pipe welding according to process requirements need groove butt welding, stitching reserved space. The design of welded joints is relatively weak link in welding engineering. Groove weld forms of internal quality control and manufacturing quality of welded structures has a very important role.

Process requirements is the first layer of weld penetration must ensure good back forming, welding current, arc voltage, wire feed speed and welding speed adjustment based on device type, square and rectangular tube to reduce welding distortion, welding production principles taken from the middle to both sides of segmented layered symmetrical skip welding, welding deformation generated straight weld smaller than conducive to disperse and release stress, avoid complex stress in welding.

Narrow straight swing welding plastic deformation zone formed during welding occurs only once, and because of the continuous weaving welding heat input capacity, heated area, large plastic deformation zone is caused by compression, thus greatly shrink after welding deformation.

When hierarchical segmentation skip welding, very small section of each layer, the heat required is small, and each layer is divided into several segments skip welding, soldering each section are basically re-create a temperature field on a cold plate every time the emergence of a narrow zone of plastic deformation, and thus the average width of the plastic deformation zone smaller than the corresponding layered straight welding, longitudinal shrinkage is small, compared to the straight-through continuous welding deformation swing once filled with even smaller.