Influence of Welding Sequence and Welding Deformation of Thin Steel Plate

Analysis of welding deformation

Welding is to connect two workpieces by heat, but heat will cause welding thermal deformation of workpieces. When the workpiece is heated unevenly, the stress is greater than the yield point of the material, and the workpiece will expand and deform, resulting in residual stress and residual deformation after cooling.

Welding deformation control

Using continuous spot welding instead of continuous welding can prevent and reduce the harm caused by welding deformation. In addition, the common methods are reverse deformation method. Using assembly and welding sequence to control deformation is also a good method, which is beneficial for maintenance personnel to improve efficiency and reduce labor intensity.

Influence of welding sequence

After the test, with the same machine, operator, welding method, the same batch of thin steel plate with the same specification as the object, continuous spot welding, short time interval test, compare the deformation degree of plate after welding under different welding sequence.

Summary and analysis

Continuous spot welding can control welding heat accumulation, control in a small range, reduce thermal deformation.

Segmented welding is better than non segmented welding in controlling the overall deformation of sheet steel, especially in the longitudinal direction. In the constrained transverse direction, with the increase of the weld length, the longitudinal curl of the thin steel plate limits the transverse deformation. The welded workpiece will have greater stress and long-term continuous deformation. The welding deformation of the segmented steel plate is small. When the segmented steel plate is segmented, a cooling time is obtained and the deformation is small, which is better than that of the non segmented steel plate.

From the effect of segmented welding, welding from the middle to both ends is better than welding from both ends to the middle. When the two ends of the steel plate are welded to the middle, the heat in the middle is continuously accumulated, causing serious deformation in the middle. Sequential welding makes the heat increase rapidly along the welding direction and keep cooling. The same is true for welding from the middle to both ends. The heat dissipation effect of the steel plate is good, and the deformation is small. Therefore, the welding of the thin steel plate should be carried out from the middle to both ends by continuous spot welding.