The welding of 7 200 KW electric locomotive body bolster pillow-waist barrel changes from manual welding to IGM welding manipulator welding,based on the structure and technology analysis,the welding technology using IGM welding manipulator is developed and implemented. The results show that by controlling the size of workpiece assembly,adjusting the welding parameters and the number of welding layers,and improving the programming of welding manipulator, the IGM welding manipulator with rich argon gas shielded welding not only can completely meet the design requirements of the structure to ensure the quality,but also greatly improve the welding efficiency.