Order to reduce welding deformation, according to the following principles rectangular butt welding welding sequence: take from the middle to both sides of the symmetry STAGED stitch welding, galvanized pipe parameters, welding deformation small welding than straight, is conducive to stress dispersion and release, to avoid stress in complex weldment. Straight swing welding, the narrower plastic deformation zone formed by welding start appear only once, but due to the continuous weaving welding, heat input capacity, heated area, large plastic deformation area is caused by compression, thus shrinkage after welding is Big. STAGED jump when welding galvanized pipe factory, each layer very small cross-section, the required heat is small, and each layer is divided into several segments stitch welding, galvanized pipe, every weld section basically On a cold steel re-establish a temperature field, every plastic deformation zone a narrow, thus the average width (ie transverse shrinkage of size) plastic deformation than the corresponding small weld layered straight, longitudinal shrinkage is small, Compared to continuous once-through swing welding deformation to fill even smaller. Standard Classification of square tube production according to the production standard score: GB square tube, the standard square tube, inch pipe, American standard tube, square tube European standard, non-standard square tube. Sectional shape by cross-sectional shape of square tube classify classification: (1) simple section square tube - square pipe, rectangular square tube (2) complex section square tube - flower-shaped square tube, opening shaped pipe, corrugated pipe, shaped square tube square tube surface treatment classified according to sub-surface treatment: hot dip galvanized pipe, galvanized pipe, oiled square tube, square tube pickling use classification RHS By Application - decorative square tube, square machine tools pipes, industrial machinery square pipe, chemical pipe, square steel pipe, shipbuilding pipe, automobile pipe, steel beams with square tube, square tube for special purposes by the wall thickness of the pipe wall thickness classification classification - - Ultra thick-walled square tube, thick-walled pipes and thin-walled square tube galvanized tubes offer, Chun steel (certified), galvanized pipe provided by the Tianjin Steel Co., Ltd. Chun Branch. Chun Branch Tianjin Iron and Steel Co. (www.tjsjkgt.com) is Jinghai County of Tianjin, steel leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Chun Branch pipe in leadership with the staff warmly welcome all inquiries negotiations to create Chun steel better future.