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Most welding deformations occur due to asymmetrical heat generation during welding, which leads to uneven expansion. The following are several methods for preventing welding deformation, provided for reference: 1. Reduce the cross-sectional area of the weld; while ensuring that a complete weld free from excessive defects is obtained, use smaller groove dimensions (angle and gap) as much as possible. 2. Use a welding method with low heat input. For example: CO2 gas shielded welding. 3. For thick plate welding, multi-pass welding should be used instead of single-pass welding whenever possible. 4. Where the design requirements are met, intermittent welding can be used for the welding of longitudinal and transverse stiffening ribs. 5. When welding on both sides is required, a symmetric groove on both sides should be used, and a welding sequence that is symmetrical with respect to the component’s central axis should be adopted for multi-layer welding. 6. When the thickness of the T-joint plate is large, a groove-type fillet weld is used. 7. The pre-weld reverse deformation method is used to control the angular deformation after welding. 8. Use rigid fixtures to control post-weld deformation. 9. Use the reserved length method of components to compensate for the longitudinal contraction deformation of welds. For example: 0.5~0.7 millimeters can be reserved per meter for H-shaped longitudinal welds. 10. Twisting of long members. It mainly relies on improving the flatness of the sheets and the precision of component assembly to ensure accurate groove angles and gaps. The direction or alignment of the arc is accurate, so that the angular deformation of the weld and the longitudinal deformations of the flanges and webs are in line with the length direction of the component. 11. When assembling components with many welds or installing structures, a reasonable welding sequence must be adopted. 12. When welding thin plates, the underwater welding method is used. That is, the molten pool is surrounded by a shielding gas in water, and the gas removes all the water from the surrounding area to ensure proper welding. With this method, the metal surrounding the solidification pool is promptly cooled by water, thereby keeping the degree of deformation to a minimum (a circulating cooling fluid is applied on the side opposite to the welding area to remove the heat generated during welding). 13. Multi-segment symmetric welding, that is, weld one segment, pause for a while, then weld on the opposite side and pause again.