Optimizing welding sequence of TIG cross-joint of Invar steel using residual stresses and deformations

In this paper, a number of welding sequences were designed by numerical simulation to study the welding deformation of Invar steel cross-splicing joint during diagonal welding and adjacent angle welding, and the optimal welding deformation control process was obtained. Results show that segmental welding can control effectively welding deformation. Material on both sides of the weld was under tensile stresses and became compressed along the thickness direction during welding. When segmented welding is studied, irrespective of the welding sequence used in the upper and lower half welds, it is found that it had strong effect on welding deformation control of the joint. When the welding sequence of the upper and lower half welds is opposite, the welding deformation is minimum. When welding a series of welds in an inwards direction from the outside to the inside for large cross-splicing structures, the joint welding deformation is symmetrical, which has the best control effect on the overall joint deformation, but the deformation at the four corners of the large cross-splicing structure is still significant.