Abstract: In order to get the optimizing scheme of T type joint’s welding sequence, the effect of welding sequence on welding residual stress field of T joint is simulated from the view of multibead welding, subsection welding and multilayer welding on the basis of ensuring reasonable welding heat source and estab-lishing the finite model. For the multibead welding, the residual tensile stress appears in the weld and nearby while the maximum value appears in the weld. Moreover, the method of the different welding direction between adjacent beads during the multibead welding makes the residual tensile stress peak value minimum. The subsection welding in which the prior welding section is the two end section and the latter welding section is the middle section not only can increase the low stress region of weld, but also can effectively decrease welding residual stress of the prior welding section. Moreover, the decreasing effect of subsection welding is related to the welding direction of the latter welding section and the distance between one point of the prior welding section and the end of the latter section. In the multilayer welding process, the method of symmetry welding gets the minimum residual tensile stress.

Key words: Stress field, Subsection welding, T joint, Welding sequence