Improvement in the trefilacao profiles filled or hollow improvement in trefilacao profiles filled or hollow

摘要

1376116 Extruding CEFILAC 26 Jan 1973 [16 March 1972] 4163/73 Heading B3P In a hot extrusion process the starting billet is coated with a layer of powdered metal and a layer of amorphous material before heating and extrusion to seal the surface of the billet against contamination. Each coating may be applied separately or simultaneously to the lateral external surface of the billet, the end surfaces and to the interior surface of the billet if it is hollow. The powdered metal may be copper applied by a spray gun. The amorphous material is applied by dipping, spraying or painting and comprises enamel or one or more vitreous salts or citreous oxides or mixtures thereof. A thin layer of molydenum disulphide may be used as a lubricant. The billet is a titanium, zirconium or their alloys.