METHOD AND INSTALLATION FOR PRODUCING FORGE-WELDED PIPE

摘要

PURPOSE:To form adequately a pipe without generating rupture in the joint part of skelps by welding and joining the preceding skelp and the succeeding skelp in such a way that the joint line has the angle of inclination satisfying the specific equation. CONSTITUTION:Welding and joining of a preceding skelp and a succeeding skelp by a flash butt welding machine are accomplished under specific conditions in a process for producing continuously a forge-welded pipe. More specifically, the end parts of the skelps S1 and S2 to be joined are diagonally formed by a crop shear and both ends are joined in such a way that the joint line A thereof forms an angle of inclination theta. The angle theta is so determined as to satisfy the condition W.alpha.tantheta>=l where W is designated as the width of the skelp, (l) as the inter-stand distance of a stretch reducer and alpha as the elongation of the pipe body up to the position on the outlet side of the central stand or (the number of the stands used/2)th stand in the stand group to be used with the stretch reducer.