Large caliber aluminium alloy pipeline non-pad tungsten electrode argon arc single face welding and double face shaping method

Abstract

The invention discloses a method for large-calibre aluminium-alloy pipeline no-liner tungsten electrode argon arc one-side welding both-side formation, comprising the following steps of: assembling of groove angle and clearance, grinding of tungsten electrode, cleaning before welding, adjusting welding process parameters, tack welding, and welding of a bottom coating, a filling layer and a covering layer. The pipe is horizontally fixed and the position is marked by hour; the welding sequence is left half-ring and right half-ring; each half-ring comprises overhead welding, vertical position welding and downhand welding; the welding is started at a position where L is equal to 5-10mm close to six of the overhead welding; the vertical position welding is then carried out; finally, the front half-ring is ended at 12 of the downhand welding; before the rear half-ring starts welding, the connection is grinded as a slope; the welding seam formed by the connection and the front half-ring welding position is overlapped by 3-5mm; the welding of the rear half-ring is started from 6 of the overhead welding and ended at 12 of the downhand welding through the vertical position welding; the welding is carried out by a continuous feeding method. The surface of the welding seam of the method has no pores or cracks, is completely welded and beautiful, and has good internal and external forming; by the non-destructive testing, the first-time qualification rate achieves 100%, the welding seam achieves the class-1 quality, the construction procedures are reduced, and the construction cost is reduced.

Description

technical field [0001] The invention relates to a welding method for metal materials, in particular to a tungsten argon arc welding method for large-diameter aluminum alloy pipes. Background technique [0002] Welding of aluminum alloy pipes is one of the key technologies in petrochemical oxygen production, nitrogen production, and ammonia engineering and large-scale utility boiler installation engineering in thermal power plants. There are two traditional welding methods. One is to add a liner inside the large-diameter aluminum alloy pipe. Depending on the size of the pipe, the liner is divided into 3 to 4 equal parts. A U-shaped groove is opened in the center of the liner. Then the liner is knocked out and taken out, and when the high-altitude long-distance pipeline assembly welding is installed, the liner cannot be taken out. The second is not to take out the liner, the center of the liner is not slotted, and it is placed inside the pipe as a whole. When the pipes are al...

AI Technical Summary

Problems solved by technology

The above two traditional methods only reduce the difficulty of welding. Although the front side of the groove becomes a weld, the weld cannot be formed due to the existence of the back liner, and because the margin of the liner is not welded with the pipe as a whole, the resulting The interlayer affects the service life of the pipe, wastes material and increases fluid resistance

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