The methods for preventing and reducing welding deformation must consider welding process design and overcoming changes in cold and hot cycles during welding. Shrinkage cannot be eliminated, but it can be controlled. There are several ways to reduce shrinkage deformation.
1. Do not weld excessively
The more metal is filled at the welding point, the greater the deformation force will be generated. Correctly setting the size of the weld seam not only results in smaller welding deformation, but also saves welding materials and time. The amount of welding metal used to fill the weld seam should be minimized, and the weld seam should be flat or slightly convex. Excessive welding metal will not increase strength. Instead, it will increase the contraction force and increase welding deformation.

3. Reduce weld beads
Using coarse welding wire and fewer welding passes reduces deformation compared to using fine welding wire and multiple welding passes. The cumulative shrinkage caused by each weld bead during multiple welding increases the total shrinkage of the weld seam. From the figure, it can be seen that the welding process with fewer passes and thicker electrodes has better results than the welding process with more passes and thinner electrodes.
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Attention: The use of coarse welding wire, few pass welding or fine welding wire, and multi pass welding process depends on the material. Generally, materials such as low-carbon steel and 16Mn are suitable for coarse welding wire and few pass welding, while materials such as stainless steel and high carbon steel are suitable for fine welding wire and multi pass welding

Another commonly used method for balancing shrinkage force is to place the same welded workpiece relative to each other and clamp it tightly. Pre bending can also be done by placing the wedge in the appropriate position on the workpiece before clamping.
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Special heavy-duty welding workpieces can generate the required balance force due to their own rigidity or the mutual position of the parts. If these balance forces are not generated, other methods need to be used to balance the contraction force of the welding material in order to achieve mutual cancellation. Balance force can be other contraction forces, mechanical constraints formed by fixtures, constraints formed by the sequence of component assembly and welding, and constraints formed by gravity.