Patent ID: 8365568
Filing Date: 2013-02-05
Classification: B21C,B29C

Abstract:
1. A method of manufacturing a seamless multilayer composite pipe comprising: a) providing a seamless metal pipe formed by extrusion with at least one continuous layer covering its inner surface by co-extruding adhesive material and material for the at least one continuous layer onto the inner surface of the seamless metal pipe; and b) passing the seamless metal pipe covered with the at least one continuous layer through a unit to reduce the diameter of the seamless metal pipe by cold working, wherein in step a) the seamless metal pipe is provided with at least one continuous layer covering its inner surface by the further steps of: a1) adjusting a distance d between a hot-extrusion die and a co-extrusion head in the direction of extrusion of the seamless metal pipe; a2) feeding metal material to the hot-extrusion die; a3) feeding the adhesive material through a channel and feeding the material for the continuous layer through a channel to the co-extrusion head; a4) extruding the metal material through the hot-extrusion die and cooling the hot seamless metal pipe through its external surface; and a5) co-extruding the adhesive material and the material for the continuous layer through the co-extrusion head onto the inner surface of the cooled seamless metal pipe, simultaneously to extruding the seamless metal pipe.