Method for welding cut surface butt joint formed by thin welding base materials

The invention relates to a method for a welding cut surface joint formed by assembling cut surface ports, in particular to a method for welding a cut surface butt joint formed by thin welding base materials in nuclear power engineering, and aims to solve the problems that the machining period of tubes and welding period are relatively long, the welding cost is high, and part of the materials are not completely welded in the prior art. According to the method, the thickness of each welding base material is less than or equal to 6.0mm. The method comprises the following steps of: selecting protective gas and a tungsten electrode; assembling craters; overlapping an ultrasonic electrical signal on pulse welding current to generate a stable ultrasonic- tungsten inert gas (TIG) combined weld electric arc by taking ultrasonic waves and TIG combined electric arc welding machine as a welding power supply of automatic welding equipment, and performing backing welding on the surface butt joints without feeding wires; pe