For the deformation of the grid steel structure, it is a problem that each construction unit is worried, because the grid engineering belongs to artificially welded the steel component combination one by one. Affects the quality, installation progress and structural carrying capacity of the entire project. There are many reasons for welding deformation, so strictly controlling during the welding process
The uneven temperature of the
steel structure of the grid of the grid of the grid of the grid of the grid of the grid can cause uneven expansion and shrinkage of the welded parts after heating, and the welding stress is produced, which eventually causes deformation. Common welding deformations are: 1) vertical contraction and deformation; 2) horizontal contraction and deformation; 3) angle deformation; 4) bending deformed; 5) twisting; 6) wave deformation.
Measures for welding deformation control measures for mesh steel structure:
1) Reduce the cross -section area of the weld. Under the premise of deep and non -exceeded defect welding, as small as possible (angle and gap) as much as possible.
2) For the yield strength below 345MPA, the steel with poor stiffness adopts a smaller thermal input, the steel structure of the grid of the grid is not preheated or reduced the preheating, and the inter -layer temperature is preferred; Such as CO2 gas protection welding.
3) Thick plate welding uses multi -layer welding instead of single -layer welding.
4) In the case of meeting the steel structure design requirements of the grid, the welding of vertical enhanced ribs and horizontal enhanced ribs can be used.
5) When both sides of the grid of the grid can be welded, the double -faced ramp should be adopted, and the sequence of welding sequence of symmetrical welding in the component and the axis is used during multi -layer welding.
6) When the t -shaped joint board is thick, the weld is connected to the open slopes.
7) Use the pre -welding anti -deformation method to control the corner deformation after welding.
8) Using a rigid fixture fixation method to control the steel structure of the grid to deform after welding.
9) Use the component reserved length method to compensate for the vertical contraction and deformation of the weld.
10) The distortion of the long component of the grid steel structure, mainly rely on improving the flatness of the board and the accuracy of the assembly assembly, so that the angle and gap of the slopes are accurate. The vertical deformation value of the plate is consistent with the length of the component.
11) When welding or structural installation of the component group with many welds, the steel structure of the grid should adopt a reasonable welding order.
12) Try to minimize the number and size of the welds in the design of the steel structure of the grid, and arrange the welds reasonably. In addition to avoiding the dense welds, the position of the weld should be as close as possible to the neutral axis of the component and so that the welded seams should be The layout is very symmetrical to the neutral and the axis in the component.
For different steel grids of different steels, different welding methods and welding sequences need to be adopted. Therefore, before construction, you should do full homework to reduce the generation and deformation of stress.
