CONTROL OF WELDING RESIDUAL STRESS AND DEFORMATION FOR THE ROD SUPPORT OF A CRANE

The counter jib and rod support are the main stress-bearing parts of crane due to large load. But the long weld seams of their joints produce great residual stress and deformation affecting the welding strength. In order to reduce the residual stress and the deformation simultaneously, an optimal welding procedure was proposed considering the effective length of welding seam. Firstly, a theoretic model of welding seam was built as T-joint of Q355 steel. The accuracy of model was verified by the welding experiments. By numerical simulation, the appropriate welding process parameters were obtained. Four welding procedures were designed to investigate the influence of the welding sequence. Results show that the welding sequence has a great influence on residual stress and deformation of the long welding seam. The welding quality can be improved by segmented welding and simultaneous welding. The optimized welding procedure of long welding seam can reduce the residual stress by 8.04 % and the maximum deformation by 74.1 % considering welding sequence. Therefore, it is recommended in the actual welding process of crane.