Plasma and TIG welding method for ultrahigh-strength steel cylindrical part

The invention discloses a plasma and TIG welding method for an ultrahigh-strength steel cylindrical part, and belongs to the field of ultrahigh-strength steel welding. The method comprises the steps that firstly, an assembly clearance L1 and an assembly unfitness of butt joint L2 are determined; secondly, welding grooves are designed, specifically, by means of the combination mode that single-side V-shaped grooves and non-groove parts on the back surface of a welding seam are alternately arranged, the single-side grooves on the back surface guarantee the strength and thickness of the positioning welding seam, the non-groove parts on the back surface guarantee the effective action range of a positioning area, and the thickness and the total length of positioning welding spots are reduced; and finally, through accurate welding track control and welding parameter adjustment, rapid adaptation of welding parameters of a circular seam closed-loop connection area is achieved, and the quality problems of incomplete p