The reasons for the deformation in the processing of steel structure are as follows:
(1) The deformation that occurs in the processing of complex steel structures, mainly hot deformation, cold deformation, or interrelated components, cannot be assembled into one.
(2) Thermal deformation is often caused by improper welding process; cold deformation is caused by the large volume and poor rigidity; related components cannot be assembled into one, which is related to inaccurate scribe line, wrong assembly sequence or deformation.
(1) Fixture fixing method: clamp the combined weldment with a very rigid fixture, control the deformation with a forced force, and then perform welding. This method is called the fixture fixing method.
The expansion force and contraction force generated in the weldment during welding are limited by the force of the fixture, which can significantly reduce the deformation. However, this method has large internal stress in the weldment, and this method is not suitable for components that require small internal stress in the weldment.
(2) Anti-deformation method: Before welding, the component should be judged according to the condition of the metal member to be welded. When cooling after welding, the direction of deformation and the amount of shrinkage will bend or obliquely weld the weldment in the opposite direction in advance. After welding, due to its shrinkage and deformation, it will just return to the predetermined shape position. The purpose of preventing welding deformation and reducing welding stress can be achieved.
(3) Adopt positioning control method: Before welding, the component uses many welding points to locate the welding part or all around, and it can also press heavy objects on both sides of the welding seam. This method is called the positioning control method.
(4) Welding sequence method: Correctly arranging welding sequence is an effective method to prevent welding deformation. The rule of welding deformation is that the deformation caused by the first weld is the largest. The amount of deformation caused by each weld cannot generally cancel each other. The final deformation direction is the same as the deformation caused by the first weld.