In the production process of steel structure, welding process is generally used at the joint, and under the effect of welding stress, the welding structure has various forms of deformation. < br style = "list style type: none;" / > 1. Causes of welding deformation: < br style = "list style type: none;" / > welding stress and deformation are caused by local and uneven heating of weldments during welding. When welding, the weld and the metal in the heating zone near the weld expand. Because the cold metal around prevents the expansion, compressive stress and plastic shrinkage deformation occur in the welding area, resulting in different degrees of longitudinal and longitudinal shrinkage. Due to the shrinkage in these two directions, various deformations of the welded structure are caused. < br style = "list style type: none;" / > 2. Factors influencing welding structure deformation: < br style = "list style type: none;" / > the influence of welding method in several common welding methods of building steel structure, except electroslag welding, submerged arc welding has large heat input, and in other conditions such as weld area, the shrinkage deformation is large. The heat input of manual arc welding is in the middle, and the shrinkage deformation is smaller than that of submerged arc welding. CO2 gas shielded welding has small heat input and small shrinkage deformation response. The higher the preheating temperature and interlaminar temperature of the workpiece, the higher the preheating temperature and interlaminar temperature are, equivalent to the increase of heat input, which slows down the cooling rate and increases the shrinkage deformation. < br style = "list style type: none;" / > the influence of weld position on deformation, because the weld position is asymmetric in the structure, the asymmetry of weld position will cause various deformation.