The causes and preventive measures of local deformation in aluminum profile welding
Aluminum alloy welding refers to the welding process of aluminum alloy materials. Aluminum alloy has high strength and light weight. The main welding processes include manual TIG welding (non melting inert gas shielded welding), automatic TIG welding, and MIG welding (melting inert gas shielded welding), including the base material, welding wire, shielding gas, and welding equipment. The causes and preventive measures of local deformation in aluminum profile welding.
（1） Cause of occurrence
(1) The rigidity of the processed parts is small or uneven, and the shrinkage and deformation after welding are inconsistent.
(2) The uneven arrangement of welding seams in the processed parts leads to uneven shrinkage, and areas with more welding seams experience significant shrinkage and deformation.
(3) Improper operation by processing personnel, lack of symmetrical layering, segmentation, and intermittent welding, inconsistent welding current, speed, and direction, resulting in inconsistent deformation of processed parts.
(4) Excessive biting during welding can cause welding stress concentration and excessive deformation.
(5) Uneven welding placement causes deformation when stress concentration is released.
（2） Preventive measures
(1) During design, efforts should be made to ensure that the stiffness of each part of the workpiece and the welding seams are evenly arranged, and symmetrical welding seams should be set to reduce crossing and dense welding seams.
(2) Develop a reasonable welding sequence to reduce deformation. If welding the main weld seam first and then the secondary weld seam, welding the symmetric weld seam first and then the asymmetric weld seam, welding the weld seam with large shrinkage first and then the weld seam with small shrinkage, welding the butt weld seam first and then the fillet weld seam.
(3) For workpieces with large welding seams, segmented, layered, and intermittent welding is adopted, and the current, speed, and direction are controlled to be consistent.
(4) When manually welding longer welds, the intermittent welding method should be used in sections, with welding from the middle of the workpiece to both ends. During welding, personnel should be symmetrically dispersed to avoid deformation caused by heat concentration.
(5) Large workpieces with asymmetric shapes should be assembled and welded after correcting the deformation of small components to reduce overall deformation.
(6) When welding workpieces, they should be frequently flipped to offset each other’s deformation.
(7) For components that are prone to angular deformation after welding, pre deformation treatment should be carried out before welding, such as V-shaped groove docking of steel plates. Before welding, the interface should be appropriately raised to make it flat after welding.
(8) By increasing the rigidity of the workpiece through external welding reinforcement to limit welding deformation, the position of the reinforcement should be set on the opposite side of the shrinkage stress.
（3） Handling method
For deformed workpieces, if the deformation is not significant, flame correction can be used. If the deformation is significant, use the method of baking while using a jack to correct it.
