Quality defects mainly include root failure, incomplete fusion, slag inclusion, porosity, weld fracture or superelevation. In addition to the technical defects such as insufficient and inflexible bars, the main reason is to polish and clean the parts to be welded in time, and there should be no rust oil and water to remove the metallic luster.

Manual arc welding, argon arc welding and oxygen welding are different. But the basic principles are the same and we can learn from each other. Gas shielded welding is mainly to pay attention to the back protection, and add process accessories when necessary to prevent the weld from being exposed to air and wind. Especially houzhu. Pay attention to the current of the gasket bead. There are differences in process and current between alkaline covered electrode and acidic covered electrode. Acid compatibility is the best, and alkaline welding is the best. The weld quality and shape are better than the broken arc. Now use argon arc welding as the backing. Argon arc welding is open arc welding, which is mainly a matter of operation. It is necessary to protect high alloy steel and stainless steel by argon filling on the back.