APPARATUS FOR MANUFACTURING WELDED STEEL PIPE AND METHOD OF OPERATING THEREOF.

摘要

An apparatus composed of, successively arranged from upstream to downstream of a roll forming process, an edge bend roll for restraining by rolling a pipe material at a part ranging from an edge portion to a boundary portion with a side portion of the pipe material to bend it; a first center bend roll for restraining by rolling the side portion of the pipe material to bend it; second to fourth center bend rolls for restraining by rolling a boundary portion between the side portion and a bottom portion of the pipe material to the bottom portion of the pipe material and applying side pressure to the pipe material from opposite sides to bend the boundary portion to the bottom portion of the pipe material; a plurality of cage rolls disposed on both sides of these rolls; and first and second fin pass rolls for further forming the pipe material by rolling. Driving means are provided to at least the edge bend roll, the first center bend roll and the first and second fin pass rolls, and furthermore, all of the upper rolls of the first to fourth center bend rolls are set in a housing, and all of the lower roll stands of the first to fourth center bend rolls or all of the lower roll stands of the second to fourth center bend rolls are set on a common subbase plate.