Large-thickness aluminum alloy flange plate welding method

Abstract

The invention provides a large-thickness aluminum alloy flange plate welding method. For welding of a large-thickness 2219 aluminum alloy flange plate, the welding process method of direct-current helium arc TIG welding bottoming and variable-polarity tungsten electrode argon arc swing filling and capping is adopted, 4-6 layers of traditional tungsten electrode argon arc welding are changed into three layers, and the welding efficiency is improved; and meanwhile, welding heat input and welding deformation of the flange plate are effectively reduced, and the welding quality and geometric dimensional accuracy of the flange plate are guaranteed. Direct-current helium arc bottoming welding is used, welding wires are not added, the production cost can be saved, the high anode power density and the electric arc shrinkage effect of helium arcs are utilized, a low-defect and high-quality welding connector can be welded, welding leakage shoveling is not needed for the back, three-pass welding residual stress and welding deformation are small, and the welding quality is good.

Description

Technical field [0001] The present invention belongs to the field of welding manufacturing, and specifically, a large thickness large diameter aluminum alloy flange is used for the bottom of the ellipsoid, which is welded by DC helium arc TIG solder bottom + variable polar tungsten argon arc welding and cover. Process and method. Background technique [0002] The flange on the bottom ellipsoid surface is a closed weld structure because the flange is a combined product after forging, and its own rigidity is large, and the weld site is contrast after assembling the welding flange on the bottom of the box. Large, stress concentration and stress peak levels are high. Further, since the manual welding flange cannot complete the large diameter aluminum alloy flange to block the weld, a large number of welded joints is formed after multiple arcing and arc, resulting in a concentrated weakening area and risk zone in the weld stress. Make the end of the ellipsoidial box, it is prone to cr...

AI Technical Summary

Problems solved by technology

[0004] With the increase of the structural thickness of aerospace products, conventional variable polarity argon tungsten arc welding can no longer meet the technological requirements of products in welding and manufacturing.

Because the free arc contraction ability of variable polarity argon tungsten arc welding is poor, the energy density of the arc on the anode is low, and the penetration ability of the arc is weak, which makes the weld depth shallow and the welding efficiency low; for 15mm thick ellipse The welding of the bottom of the ball box and the flange must adopt the welding process of variable polarity tungsten argon arc welding. At least 4-6 layers of multi-layer and multi-pass welding on one side are required to ensure that the weld seam is filled and there is no obvious undercut. defect

And variable polarity tungsten argon arc welding is often due to factors such as poor arc stiffness and weak penetration ability during the welding process of large-thickness flanges, which makes the heat input redundant during the flange welding process on the bottom of the ellipsoidal box, resulting in weld seams The tissue is overheated and overburned, and finally the tensile strength and elongation of the flange weld will decrease; and the multi-layer and multi-pass welding of the large-thickness aluminum alloy flange will cause large residual stress and welding deformation at the weld position. Seriously affects the geometric shape and size of the bottom of the ellipsoidal box, increasing the risk of cracking during the hydraulic test and its service

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