Process on the tandem mill, use the cold rolled or galvanized (electro-galvanized or hot dip galvanized) steel as base metal, pretreat the surface, paint one layer or multi-layer paint with the method of roller coating or spray coating, then bake and cool down. It is also called prepainted steel, widely used for construction, household appliances, transportation, packaging, machining, indoor decoration, medical equipment, automobile industry, etc.