In the construction of the Guangzhou Steel Structure Project, welding deformation directly affects the installation of steel components and steel structures and their use functions. And due to the additional bending moments, secondary stresses, etc. generated during the bearing, which indirectly affect the performance of the steel structure project, so the control of welding deformation is very important. According to the causes and influencing factors of the welding deformation that were previously shared by Xiao Bian, the following misuses of controlling deformation can be taken:
1. Reduce the cross-sectional area of ​​the weld: In the premise of obtaining a good and non-overdetermined weld seam, use as small a groove size (angle and clearance) as possible.
2. For steels with a yield strength of 345 MPa or less, use less heat input for steels that are not hardenable, and do not preheat or reduce preheating and interlayer temperatures as much as possible: use a smaller heat input method, such as CO2 gas. Protection welding.
3 thick plate welding as much as possible using multi-layer welding instead of single-layer welding.
4. In case of meeting the design requirements, the welding of longitudinal stiffeners and transverse stiffeners can be interrupted welding.
5. When both sides are capable of welding operation, a double-sided symmetrical groove should be adopted, and in the multilayer welding, the welding sequence with the axis of the member and the axial symmetry should be used.
6. When the T-joint plate thickness is large, a beveled corner butt weld is used.
7. Use post-weld anti-deformation method to control the post-weld angular deformation
8. Using rigid fixtures to control post-weld deformation
9. The longitudinal length shrinkage of the weld seam is compensated by the component-prepared length method. For example, the longitudinal weld length of H-shaped steel can be set to 0.5mm-0.7mm per meter, and the length of each pair of transverse ribs can be set to 0.5mm. The reserved perimeter method is used. Compensate the longitudinal and lateral shrinkage deformation of the welds of the cylindrical pipe members. If the plate thickness is greater than 10mm, 2.0mm circumference is reserved for each longitudinal and circumferential weld.
10. For the distortion of long components, mainly by improving the plate flatness and component assembly accuracy, so that the groove angle and gap is accurate, the arc is pointed or centered accurately, so that the weld angle deformation and longitudinal deformation of the wing and web Along the length of the member.
11. The design should minimize the number and size of welds. In addition to avoiding weld density, the weld should be arranged properly. The position of the weld should be as close as possible to the neutral axis of the component, and the layout and components of the weld should be made. The symmetry of the neutral axis.
12. A reasonable order of welding should be adopted when assembling a large number of welded joints or when installing a steel structure.