The joint formed by the
lsaw steel pipe when joining the two connected bodies is called a weld bead. Both sides of the weld are subjected to welding heat during welding, and changes in structure and properties occur. This area is called the heat affected zone. Due to the welding material of the workpiece material and the welding current of the straight seam steel pipe during welding, overheating, embrittlement, hardening or softening may occur in the weld and heat affected zone after welding, which also deteriorates the weldment performance and deteriorates the weldability. This requires adjustment of the welding conditions, pre-heating of the weldment interface before welding, welding heat preservation and post-weld heat treatment can improve the weld quality of the weldment.
Straight-slit steel pipe is a process in which two or two kinds of materials of the same kind or different materials are integrated by atomic or molecular bonding and diffusion, and the method for causing the bonding and diffusion of atoms and molecules is heated or pressurized. Or heat and pressurize at the same time.
In addition, the welding foot has a local rapid heating and cooling process, and the welding zone cannot be freely expanded and contracted due to the restraint of the surrounding workpiece body, and the welding stress and deformation are generated in the weldment after cooling. Important products need to eliminate welding stress after welding and correct welding deformation.
The cross-sectional shape of the butt joint weld of the straight seam steel pipe is determined by the thickness of the welded body before welding and the groove type of the two joints. When welding a thick steel plate, grooves of various shapes are opened at the joint edges for penetration to facilitate feeding of the welding rod or the welding wire. The groove type has a single-sided welded groove and a double-sided welded groove. When selecting the groove type, in addition to ensuring the penetration, it is also necessary to consider the convenience of welding, less filler metal, small welding deformation of the straight seam steel pipe and low processing cost of the groove.
