| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a steel tube having double corrosion-resisting metallic coating layers in a simple process by forming an intermediate resin layer and a surface coating layer of the corrosion-resisting metallic plate on the surface of the steel tube. SOLUTION: While rotating the steel tube 3 in the direction of the arrow A, the steel tube is moved in the direction of the arrow B at a prescribed speed, a belt-like corrosion-resisting metallic plate 1 is delivered from a coil 5 and plural block materials 2 are joined the upper surface of the plate with a joining device 6. The corrosion- resisting metallic plate 1 on which the block materials 2 are joined at prescribed intervals is wound around into a spiral shape abutting the block materials 2 on the surface of the steel tube 3. At this time, while imparting a constant tightly-winding force to the corrosion-resisting metallic plate 1 with a press roll 7 and pinch rolls 8, the metallic plate is wound around. Simultaneously, mutual edges of the metallic plates 1 are overlapped and the edge parts are welded with a welding machine 9. A resin is poured into the clearance which is formed with the block materials 2. Next, a plastic filler is filled into the clearance between the steel tube 3 and the metallic plate 1 at both ends of the steel tube 3. The resin is forced into through a pouring port on the side of the corrosion-resisting metallic plate. |
