Pretreatment method for electrodeposition coating in electrodeposition coating line

摘要

PROBLEM TO BE SOLVED: To remove surface oxides, slags, weld fume and the like generated on the surface of an object to be coated in an electrodeposition coating line with respect to an object to be coated having a welded portion or an object to be coated with a high-strength steel plate. It is an object of the present invention to provide a pretreatment method for electrodeposition coating in an electrodeposition coating line capable of removing an object. SOLUTION: This is a pretreatment method before an electrodeposition coating step (5) of forming an electrodeposition coating film on the surface of an object to be coated in each step flowing through an electrodeposition coating line, and at least a degreasing step (a degreasing step). In the pretreatment method including the pretreatment step line (B) in which 1), the surface adjustment step (3), and the chemical conversion film treatment step (4) are sequentially performed, the pretreatment step line (B) is the degreasing step (1). It is a pretreatment step line (A) including a coating inhibitor removing step (2) to be chemically treated between the surface adjusting step (3) and the surface adjusting step (3). [Selection diagram] Fig. 1