According to the traditional welding process, when stainless steel pipe mouth or closed container is welded by one side welding and double side forming welding, because the root weld bead is easy to oxidize and burn, it generally needs to be filled with inert gas protection in the pipeline or container. This welding process is complex, the effect is not good, the cost is high, and sometimes the operate difficultly. These problems can be overcome by argon arc welding process of back self-shielded welding wire (rod) of COREWEL.