One of the primary functions of phosphated steel plates is to ensure the firm adhesion of the primer when the topcoat is sprayed. During the phosphating process, a phosphating film forms on the surface of the steel plate. This film enhances the adhesion between the primer and the steel plate, laying a solid foundation for subsequent painting processes. As a result, the paint film is less prone to peeling, thereby improving the quality and durability of the entire coating system and better meeting the needs of topcoat customers.