Fremgangsmåde til fremstilling af en fyldt, sømløs rørtråd

1,177,993. Making welding wires; drawing. ELEKTRODENFABRIK OERLIKON BUHRLE A.G. 21 Nov., 1967 [23 Nov., 1966], No. 53025/67. Headings B3A and B3P. A tubular wire, particularly a welding wire, filled with a compressed pulverous material is formed by tightly winding a seamless or welded tube on to a core, which is shaken on a shaker table 13 whilst a predetermined quantity of pulverous material is introduced into the open end of the tube, after which the tube is drawn through at least one die to further consolidate the filling powder by reducing the tube external diameter without modifying the wall thickness and is then further drawn to reduce the external diameter and wall thickness of the tube, the compacted pulverous material precluding reduction of the tubes internal diameter. In an embodiment a 50 m. length iron tube is internally shot-blasted, degreased, annealed and drawn through a die on to the drum. After the tube has been filled from a container 19 with the filler material comprising deoxidizing and alloying substances, slag formers and iron, it is drawn through two dies, passed through a chemical cleaning bath and finally electroplated with copper. The tube may be annealed between drawing operations and may be coated with a corrosion inhibiting layer.