| 摘要 |
The present invention relates to a method and an apparatus for manufacturing a spiral-type rib steel pipe wherein a spiral-type rib steel pipe is wound in a spiral shape and then cut to be formed. The method for manufacturing a spiral-type rib steel pipe comprises: a coating steel sheet preparation step of arranging a coating steel sheet having a coating layer on an uncoiler; a rib initial formation step of forming the coating steel sheet, unwound by the uncoiler, to have preliminarily molded ribs deepened by a rib initial molding unit of a forming unit; a rib intermediate formation step of making a coating-type bending steel sheet, located between the preliminarily molded ribs, with a curvature of a corner decreased by a rib intermediate molding unit; a rib post-formation step of forming a coating-type rib flat steel sheet having a complete rib as the coating-type flat steel sheet is pressed by the corner rib post-molding unit; a lock seam formation step of forming a lock seam as edges on both sides of the coating-type rib flat steel sheet are pressed by a lock seam formation unit; a pipe manufacturing step of making the coating-type rib flat steel sheet with the lock seam having been formed into the spiral-type rib pipe by a pipe manufacturing unit; and a steel pipe cutting step of cutting the manufactured spiral-type rib steel pipe by a cutting unit. Therefore, reverse friction on the surface of the coating steel sheet is prevented by making rotation speeds and rotation amounts of the rolls, comprising the forming units, constant. Consequently, the coating layer can be prevented from being damaged by reverse friction. |
