The box variable shell welding process should pay attention to the requirements of the workpiece according to the drawings placed in the exact location, measurement of qualified first spot welding and then welding, if necessary, with the help of tire clamps; try to use the flat welding, if the other position welding, should be adjusted to weld the current, so that it is less than the flat welding current by 10%; weld is longer or the structure of the assembly, should be fixed and then welded in segments to avoid deformation; welded box variable to knock the flux skin, clean up the weld tumor, the tools. To remove the flux skin, clean up the welding tumor, welding slag, to ensure that the weld is smooth and clean; box variable shell grounding device should be welded around, should not hurt the connection threads, molding should be in accordance with the requirements of the drawings and standards, the shape of the corresponding adjustments