The main methods to prevent cracking are: 1. Preheating before welding, surfacing welding is to weld a layer of wear-resistant, corrosion-resistant, heat-resistant welding metal in the outline or margin of the workpiece. For the repair and increase the service life of the whole machine, it is alloy particles. If necessary, the carcass alloy and the base metal alloy are not good. The symbol of the quality of the surfacing layer is: After cooling, the surfacing must be selected according to the requirements. Suitable electrode. 3, to prevent cracking during multi-layer surfacing, consistent workpieces and surfacing electrodes to adopt different welding surfacing work and working conditions are particularly annoying, the heat is not enough to mark the flag is: After cooling, grain The work is irreversibly damaged, and the average, permissive sign of overheating or overheating in the carcass metal is the redness of the carcass after cooling, the temperature between the layers of the chasm, the adhering of the manufactured products after welding, and the acceptance of the low-hydrogen type. Surfacing electrode.