The Copper and copper alloy clad steel plate has the following characteristics: the clad copper is single-phase α organization ‚ During welding heating ‚ Copper is easily heated and grows to form coarse single-phase α Organization; When the temperature exceeds 300 ℃ ‚ The oxidation ability of copper is significantly enhanced ‚ Oxidation to form Cu2O ‚ Forming low melting point eutectic with Cu; At high temperature ‚ Cu can be mixed with impurity elements (such as Pb) in the base metal or welding wire ‚ Bi ‚ S, etc.) form eutectic with low melting point ‚ During welding cooling ‚ Low-melting eutectic aggregates a lot of grain boundaries ‚ Weakening the intergranular strength; Copper has good thermal conductivity ‚ Large linear expansion coefficient ‚ Fast cooling rate of weld during welding cooling ‚ Welding stress is large. Therefore, due to the existence of eutectic with low melting point in high temperature zone during welding ‚ Hot cracks are easily formed under welding stress.