Continuous process for the production of very long precision tubes and installation for carrying out the process

摘要

A novel method and a novel apparatus for continuously forming a very long tube with precise internal and external dimensions from a metal tube blank by reducing the internal diameter of the blank to that of an internal mandrel on which the blank is telescoped, preferable by cold forming the blank onto the mandrel and immediately thereafter, drawing of the tube while it is still on the mandrel to its final external dimension; with no annealing taking place between the two steps.