| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a polyolefin resin coated steel pipe excellent in surface appearance capable of preventing the occurrence of unevenness in the resin surface after cooling even in a case that the high temperature preheating of the steel pipe required by a powder primer excellent in corrosionproof properties is performed. SOLUTION: In the manufacturing method of the polyolefin resin coated steel pipe by coating the surface of a steel pipe with a molten sheetlike polyolefin resin while spirally winding the sheetlike polyolefin resin around the surface of the steel pipe, in a cooling precess after resin coating, the resin surface is cooled by laminar water to be wholly coated with a continuous water film to be cooled to a temperature below the melting point of the resin and, even after the resin surface is cooled by laminar water, it is continuously cooled without raising the temperature of the resin surface to its melting point or above. By this method, the polyolefin resin coated steel pipe excellent in surface appearance is manufactured. COPYRIGHT: (C)2006,JPO&NCIPI |
