Mechanical expander for spiral welded steel pipe - where radial expanding tools possess spiral grooves matching the weld

摘要

Mechanical expander, for the stepwise radial widening of steel pipe, uses a tool head consisting of a tapered polygon. On each flat on the periphery of the polygon is a segment supported by a hollow beam joined to a cylinder contg. a piston. The piston rod drives the segments radially outwards. The segments contain =1 spiral groove corresp. with the spiral weld in the pipe; and =1 second groove at 90 degrees to the first groove. The steel pipe is aligned on a conveyor feeding the pipe stepwise over the head. Several spiral grooves are pref. provided on the segments, and the steel pipe can pref. be rotated by the conveyor during its forward feed, esp. using sets of rollers on the conveyor track. Pipes possessing a spiral welded seam can be expanded radially.