| 摘要 |
PURPOSE: A steel pipe and a manufacturing method thereof are provided to minimize the discharge of harmful materials in a coating process since a steel pipe is coated with polyurea coating material. CONSTITUTION: A manufacturing method of steel pipes comprises following steps. A steel pipe is fixed on the inner side of a sunk hole(H) of the ground by a spacer. The height of a jetting unit(300) is maintained above the top of the steel pipe through the operation of a movable member. When the raw material of the urea coating material is stored in first and second hoppers of the jetting unit, the rotary motor(130) of a rotating unit(100) is operated. The steel pipe is rotated by the rotating unit, a pressure cylinder(400) is extend and contracted. The urea coating material of the first and second hoppers are successively sprayed on the surface of the steel pipe, so a urea coating layer is formed. The inner surface of the steel pipe is coated with the urea coating material through an injection nozzle. The steel pipe coated with the urea coating material is drawn out.
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