Prodn. of corrugated metal pipes - with use of an expandable mandrel and external, axially displaceable disk-shaped jaws

摘要

The method concerns production of corrugated metal pipes out of initially smooth cylindrical pipes which are first preformed by means of a radially expandable wavy mandrel and external jaws provided with a corresponding wavy surface. A radially expandable mandrel (13) with an outside diameter corresponding to the inside diameter of the corrugation of such a preformed pipe, while disk-shaped jaws (15) are inserted from outside into the wave bottoms (9). The jaw disks are subsequently pressed against one another, thus axially folding the wavy form of the pipe into corrugations. Also claimed are a tool for implementation of the method, and a resultant corrugated pipe.