Air-cooled tube plate welded joints for the butt joints, pass the ball required to pass the experiment, the root of penetration, no cracks and unfused defects, and the joint strength should be greater than or equal to the strength of the base metal. In the air-coolers industry design, manufacturing process, heat exchange tubes and tube plate welding quality determines the quality of air-cooled cooler and life.

At present, my company's heat exchange tubes and tube plate connection methods are mainly welded and welded together with two, its essence, all belong to the fillet welding structure, although increased inflation and strength inflation, still can not guarantee the elimination of pipe and tube plate There is a gap between the air cooler so that the use of this type of structure prone to gap corrosion, overheating and other issues. Coupled with the expansion of the deformation there is a large residual stress, easy to produce stress corrosion, and when used in high temperature environments, due to creep of the material expansion of residual stress relaxation, causing joints loose or fall off caused by leakage. The internal hole welding structure is butt structure, which solves the pipe and tube plate joint stress corrosion cracking has the obvious superiority, greatly extend the life of the equipment, improve the quality, work stability, the use of reliable, but in the air cooler industry, within the Hole welding structure is still a blank. The reasons for the quality of the joint to meet the standard requirements are as follows: the first pass self-melting and the arc heat concentrated, the shape of the tungsten rod shaved into a cone angle of 30 ° to 50 ° can increase Welding penetration, the arc will weld the root of the joint well, to ensure full penetration joints; fill wire with the second time to increase the thickness of the weld; two times to fully meet the joint strength of weld thickness requirements.