Making an elongated product

Abstract

An elongated product is formed such that first a core is formed, the outer surface of the core being made of plastic. Thereafter, a tubular metal layer is extruded such that the layer is seamless. When the metal layer is extruded, a clearance is allowed between the metal layer and the core. After the metal layer has cooled, the diameter of the metal layer is reduced such that the metal layer contacts the plastic core. Thereafter, the metal is annealed such that the flexibility of the metal layer increases.

Description

Background technique [0001] The present invention relates to a method of manufacturing an elongated product comprising forming a core with a plastic outer surface, extruding a seamless metal layer onto the core (allowing a gap between the metal layer and the core), cooling the metal layer and reduce the diameter of the metal layer to make contact with the plastic surface of the core. [0002] The invention also relates to a plant for the manufacture of elongated products, said plant comprising a plastic extruder for extruding a core, a metal extruder for extruding a seamless metal layer on the outside of the core (the The inner diameter of the metal layer is larger than the outer diameter of the core so that the metal layer does not contact the core) and reducing means for reducing the diameter of the metal layer so that it contacts the plastic core. [0003] The invention also relates to an elongated product comprising a core having a plastic outer surface and a seamless tub...

AI Technical Summary

Problems solved by technology

The technical solution is quite complex

Also, it is very difficult to ensure the adhesion between the core and metal cladding

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