Antirust overlay film forming method of PC steel strand

The objective of present invention is to provide an antirust overlay film forming method of PC (prestressed concrete) steel strand of steel material subject to tension of prestressed concrete construction method used for architectural and constructional structure, which will not damage the flexibility and adhesive strength to the concrete of the PC steel strand, can protect the surface from damage, and forms thick double overlay film easily. The antirust overlay film forming method of PC steel strand comprises the following steps: forming a plating overlay film on the outer peripheral surface of the raw wire, performing wire drawing treatment on the raw wire formed with plating overlay film to form the raw wire for the, twisting a plurality of the raw wire for the strand together to form the PC steel strand comprising a core wire and side wires, temporarily untwisting the PC steel strand and performing shot blasting on the core wire and the side wires, forming resin overlay films on the outer peripheral surface of the shot blasted core wire and side wires, and once again twisting the wires together after the resin overlay is cooled down.