Compound cleaning method for hot dip steel member

The composite cleaning process for hot plated steel part includes pouring the composite cleaning liquid into ultrasonic cleaning tank for filling 2/3 of the tank, selecting the ultrasonic generator power in the power density of 50-100 W/L in the cleaning liquid, setting the workpiece to be cleaned inside the composite cleaning liquid at 25-50 deg.c, and ultrasonic cleaning for 3-20 sec. The composite cleaning liquid consists of 30 % concentration hydrochloric acid solution 7-20 wt%, additive 5-10 wt% and water the rest. The additive consists of surfactant comprising OP-10, 6501 and peregal in the weight ratio of 1 to 1 to 1.5 and water, and has concentration of 12-20 wt%. The present invention can complete the surface cleaning of hot plated steel part in one step, and has the advantages of simple process, low cost, stable quality, less pollution and being suitable for industrial production.