Abstract: A plant information display method for displaying elements related to a plant in a tree view of hierarchical representation comprises the steps of a tree view display step of displaying plural tree view representations based on different viewpoints side by side and a relation display step of graphically displaying a relation between elements separately contained in the plural tree view representations, which are displayed in the tree view display step. In this method, plural tree view representations based on different viewpoints are displayed side by side and a relation between elements, which are separately contained in the plural tree view representations displayed side by side, is graphically displayed.

Abstract: The present invention is an improvement of such methods as the Stiefel-Mannesman piercing, and the Mannesmann piercing methods with a pair of driven rolls which impart a screw movement to the work piece, and has the roll axis inclined to the centerline of mill. Instead of a conventional pair of driven disc rolls or shoes, one driven disc roll and one shoe or one guide roll are used in the invention to form the rolling pass together with the driven rolls, and the centerline of pass is greatly off set from the centerline of mill toward the one shoe or guide roll. The operating efficiency and quality of tubular products are simultaneously enhanced.