Select and strictly control welding process parameters of the galvanized steel sheet. The evaluation of spot welding quality of galvanized steel sheet refers to the strength and corrosion resistance of a single weld joint, and more importantly, the qualified rate of the weld joint under the condition of mass production. In actual production, there are many factors affecting welding quality, such as network voltage fluctuation, shunt, electrode wear, assembly quality and so on. Since the range of welding parameters of galvanized steel plate is small, it needs to be strictly controlled and adjusted when the plate thickness changes. Reasonable electrode material, shape and size shall be adopted, and the electrode shall be repaired or replaced in time. Good cooling of the electrode is very important to ensure the welding quality. Multi pulse or * +, - Current method to weld galvanized steel plate. One is to increase the preheating and post heating current, and the other is to increase the ramp up and ramp down current. Lane et al. Studied the effect of changing current by photographing the formation process of nugget with high-speed photography. They believe that:
1) (galvanized steel sheet）the change of current can promote the formation of nugget;
2)（galvanized steel sheet)The change of current before welding is conducive to the uniform formation of nugget;! "The current change after welding helps to restrict nugget and prevent spatter;
3) (galvanized steel sheet)the current after welding and before welding can combine the advantages of both. This current change has been used in the welding production of galvanized steel sheet.
