PRODUCTION OF RUST PREVENTIVE COATED PC STRAND

PURPOSE:To bring respective single wires into contact with each other and to prevent the generation of elongation, exclusive of deformation of the single wires themselves at the time of pulling by using the wires which are previously coated with rust preventives on the outer peripheries of the internal core wires and inner layer wires and forming these wires into twisted wires, then subjecting the wire to a bluing treatment. CONSTITUTION:The twisted wire A1 in the state of coating the core wire 6 and the inner layer wires 23 with the rust preventive by each of the single strands is formed in stranding-up. This wire is inserted into a bluing furnace 11 where the rust preventive material 15 is melted by the bluing heat and is displaced by the force in the tangent direction of the respective single strands so that the respective single strands are made into a straightforward state or the state approximate thereto. The spaces among the respective single strands in the twisted wire A1 are filled with the displaced rust preventive material 15, by which internal gaps 14 are filled. A rust preventive coating layer 20 is then formed on the outer periphery of the twisted wire A2, by which the circumferences of the respective single strands are subjected to the perfect rust preventive treatment and the perfect bluing treatment as well.