13 Key Points to Preventing Welding Deformation

Due to the asymmetric heat generated during welding, the majority of welding deformations occur, resulting in uneven expansion. Here are several methods to prevent welding deformation for reference:

1. Reduce the cross-sectional area of the weld seam, and use smaller groove sizes (angles and gaps) as much as possible while obtaining a complete and defect free weld seam.  
2. Adopt welding methods with lower heat input. For example, CO2 gas shielded welding.  
3. For thick plate welding, multi-layer welding should be used instead of single-layer welding as much as possible.  
4. Under the condition of meeting the design requirements, intermittent welding method can be used for the welding of longitudinal and transverse reinforcement ribs.  
5. When both sides can be welded, a double-sided symmetrical groove should be used, and in multi-layer welding, a welding sequence that is symmetrical to the center and axis of the component should be used.  
6. When the thickness of the T-shaped joint plate is large, a sloping angle butt weld is used.  
7. Use pre weld anti deformation method to control post weld corner deformation.  
8. Use rigid fixture fixation method to control post weld deformation.  
9. Use the reserved length method of components to compensate for longitudinal shrinkage deformation of welds. For example, the H-shaped longitudinal weld seam can reserve 0.5-0.7 millimeters per meter.  
10. Distortion of long components. Mainly relying on improving the flatness of the board and the assembly accuracy of the components, to ensure accurate groove angles and gaps. The direction or alignment of the arc should be accurate to ensure that the angle deformation of the weld and the longitudinal deformation values of the flange and web plate are consistent with the length direction of the component.  
11. Reasonable welding sequence should be adopted when assembling or installing components with a large number of welds.  
12. When welding thin plates, the underwater welding method is used. Surrounding the molten pool with protective gas in water and completely eliminating nearby water with gas to ensure normal welding. By using this method, the metal around the solid melt pool is cooled by water in a timely manner, while controlling the deformation to a very small extent (adding circulating coolant on the opposite side of the welding side to remove the heat generated during welding).  
13. Multi section symmetrical welding, that is, welding one section and stopping for a while, then welding on the opposite side and stopping for a while.