How to prevent welding deformation of large structural parts?

In the welding process of large structural parts, deformation is a relatively easy problem. In order to prevent welding deformation, what should be paid attention to in process measures?
1. Select the appropriate welding sequence. For welded structures with many components, the components shall be welded and corrected respectively, and then assembled and welded as a whole. In this way, the deformation is less than that of assembling as a whole first and then welding.
2. Select reasonable welding sequence. In order to prevent welding deformation, strip welding method, back welding method and symmetrical welding method shall be adopted in the welding sequence.
3. Inverse deformation method. It is to give the weldment a deformation opposite to the deformation direction after welding, and the deformation of the workpiece before welding is just offset after welding.
4. Select reasonable welding methods and specifications. The energy density and heat input of various welding methods are different. For thin plate welding, the welding method with high energy density shall be selected.
5. Rigid fixation method. This method is useful to reduce welding deformation.