Tubulation welding method of stainless steel outer composite tube

The invention discloses a tubulation welding method of a stainless steel outer composite tube. The lower portion of the gap of tube blanks formed by bending a stainless steel composite plate is directly welded in an argon tungsten-arc welding mode, basic layer carbon steel of the stainless steel composite plate is welded and then automatically forms a downwards concave welding joint, after the welding joint is forcedly cooled with water, capping welding is directly carried out on the welding joint in a gas metal arc welding mode until the surplus height of the welding joint is 1-1.50 mm, then water is sprayed for cooling, and tubulation welding of the stainless steel outer composite tube is finished. The tubulation welding method is simpler than an existing method, the stainless steel outer composite tube does not need to be grooved, forming is realized one time, and as the protective atmosphere is gas, good corrosion resistance is realized, and the cost is lower compared with other welding methods. The tubulation welding method of the stainless steel outer composite tube guarantees that the strength of the welding joint of the stainless steel outer composite tube is higher than that of parent metal, and also guarantees that the welding joint of the stainless steel composites has good anti-corrosion performance.