Welding deformation of sheet metal weldments is a common problem in the welding process, and controlling welding deformation is crucial to ensure product quality.
Welding parameters, including welding current, arc voltage, welding speed, etc., have a direct impact on welding deformation. By accurately controlling these parameters, welding deformation can be minimized while meeting welding quality. For example, using a smaller welding current and arc voltage, as well as an appropriate welding speed, can reduce welding heat input, thereby reducing deformation.
Different welding methods also produce different amounts of deformation. For sheet metal weldments, the appropriate welding method should be selected according to material thickness, structural characteristics and welding requirements. For example, laser welding has the advantages of high energy density, low heat input and small deformation, and is suitable for thin plate welding. MIG/MAG welding is suitable for welding medium and thick plates.
The use of shielding gas can effectively prevent the weld from being oxidized at high temperature, control the weld formation, thereby improving the weld quality and reducing deformation caused by excessive welding. At the same time, the shielding gas can also take away part of the heat of the welding position in time, further reducing the amount of deformation.
A reasonable welding sequence can balance the stress distribution during welding and reduce deformation. For complex sheet metal weldments, a reasonable welding sequence should be formulated according to factors such as product shape and weld bead direction.
Timely removal of heat generated during welding is an effective way to reduce welding deformation. Common cooling methods include copper heat transfer, water heat transfer, gas heat transfer, etc. For large sheet metal weldments, copper cooling plates or water cooling systems can be used to speed up the cooling speed.
Fixing the weldment with a fixture can form a positioning constraint to restrain the deformation during welding. The design and use of the fixture should be reasonably planned according to the structural characteristics and deformation trend of the weldment.
By pre-analyzing the welding deformation direction and deformation amount and taking reverse pre-deformation measures, the welding deformation and pre-deformation amount can be offset after welding, thereby achieving the purpose of controlling welding deformation. This method requires the use of CAE analysis or actual welding deformation analysis to determine the pre-deformation amount.
Controlling the welding deformation of sheet metal weldments requires starting from multiple aspects, including welding parameter control, welding method selection, shielding gas control, welding sequence optimization, cooling method selection, fixture use, and pre-deformation control.
