Abstract: A method for manufacturing an electric resistance steel pipe having a good toughness at a welded portion is provided, the method being capable of stably manufacturing an electric resistance welded steel pipe having a desirable toughness at a welded portion although a steel strip serving as a base material has a dimensional variation. Groove shapes and are applied to edges and of an open pipe, an edge shape monitor continuously captures images of the edges and immediately before electric resistance welding, and the captured images are input to an arithmetic processing unit for image processing.

Abstract: A method for manufacturing an electric resistance steel pipe having a good toughness at a welded portion is provided, the method being capable of stably manufacturing an electric resistance welded steel pipe having a desirable toughness at a welded portion although a steel strip serving as a base material has a dimensional variation. Groove shapes and are applied to edges and of an open pipe, an edge shape monitor continuously captures images of the edges and immediately before electric resistance welding, and the captured images are input to an arithmetic processing unit for image processing.

Abstract: The present invention relates to a production method for a hot rolled strip in a hot rolling line. An object of the present invention is to ensure stable running of a hot rolled strip on a hot runout table, and to prevent excessive displacement of the hot rolled strip above a pass line, and, for example, a head folding defect and a tail folding defect resulting from the displacement. In the method of the present invention, a fluid jet is squirted above a hot rolled strip conveyed by a hot runout table so as to pass over the hot rolled strip running without touching a surface of the hot rolled strip running on a pass line (a strip-conveying surface of the hot runout table). A strip portion displaced upward from the pass line beyond a predetermined level collides with the fluid jet, and the displacement of the strip portion is thereby corrected.

Abstract: The present invention relates to a production method for a hot rolled strip in a hot rolling line. An object of the present invention is to ensure stable running of a hot rolled strip on a hot runout table, and to prevent excessive displacement of the hot rolled strip above a pass line, and, for example, a head folding defect and a tail folding defect resulting from the displacement. In the method of the present invention, a fluid jet is squirted above a hot rolled strip conveyed by a hot runout table so as to pass over the hot rolled strip running without touching a surface of the hot rolled strip running on a pass line (a strip-conveying surface of the hot runout table). A strip portion displaced upward from the pass line beyond a predetermined level collides with the fluid jet, and the displacement of the strip portion is thereby corrected.