MANUFACTURING METHOD OF CORRUGATED STEEL PIPE WITH COATING POLY URETHAN AND MANUFACTURING METHOD THEREOF

摘要

A method for manufacturing a corrugated steel pipe coated with polyurethane is provided to increase corrosion resistance, wear resistance, and strength of the pipe and to extend the life time of products by applying high-strength polyurethane on the corrugated steel pipe. A method for manufacturing a corrugated steel pipe(10) coated with polyurethane comprises the steps of: installing plural rolls wound with an original sheet(11), on a loading unit(20) and sending the original sheet to the upper and lower ends of a loading rack body(30); making a curved plate by forming gullies by pressing the original sheet supplied to the lower end of the loading rack body, by plural press rolls(31); forming a bent surface(14) by bending both sides of the curved plate in different directions and bending both sides of the original sheet supplied to the upper end of the loading rack body, in the same direction of the curved plate; forming a pipe by laminating the curved plate and a flat plate while the flat plate is positioned inside and spirally winding the laminated plates by a molding unit(40) receiving the curved plate and the flat plate, and producing a pipe body by winding the bent surfaces while the bent surface wound for the next time includes the bent surface wound in advance, and bringing two bent surfaces into contact with the surface of the corrugated steel pipe by pressing two bent surfaces by a press roll(41); and forming an equal coating layer to improve durability of the corrugated steel pipe, by coating the pipe in order according to each nozzle by positioning supply pipes having plural nozzles at the longitudinal inner and outer sides of the corrugated steel pipe.