PC-STEEL STRANDED WIRE AND RUST-PROOF DOUBLE-COATING FILM BINDING STRUCTURE FORMATION PROCESSING METHOD FOR USE IN SUCH PC-STEEL STRANDED WIRE

摘要

PPROBLEM TO BE SOLVED: To form a thick coating layer over the surface layer (external surface) of a PC-steel stranded wire without damaging the flexibility thereof as well as a bonding strength when bonded to concrete, so as to improve tensile fatigue characteristic and avoid exposure of under-materials due to damaged coating layer. PSOLUTION: The subject method of this invention comprises the following steps A to C. Step A is a pre-treatment for carrying out an under-material adjustment by unbinding the returning side-wire of the PC-steel stranded wire 1 from its core-wire. Step B is a primary coating treatment for loosely stranding a side-wire with respect to the core-wire, and then applying synthetic resin powder as a coating material to the whole surface layer except a spirally ditched portion formed due to stranding, thus forming a resin coating layer only on the surface layer. Step C is a secondary coating treatment for unbinding the side-wire of the PC-steel stranded wire 1 from the core-wire thereof, applying, by way of core-wire adjustment means, the synthetic resin powder coating material to the periphery of the unbound core-wire as well as side-wire, thereby separately forming resin coating layers producing double coating in certain portions of the side-wire. A final step is to strand the side-wire with respect to the core-wire to return the side-wire to its original position, thereby ensuring that the doubly coated portion appears on the surface layer of the PC-steel stranded wire. PCOPYRIGHT: (C)2005,JPO&NCIPI