VERFAHREN UND VORRICHTUNG ZUR HERSTELLUNG VON MIT QUERRIPPEN VERSEHENEN ROHREN

摘要

A method and apparatus of forming ribbed pipes, after an initial pipe restressing in which bending of the rib of the plane perpendicular to the rolled pipe axis takes place, and straightening of the rib thenafter. Then on duplex metal pipes, the outside pipe is additionally compressed to the core pipe.