GB818817A - Improvements relating to the manufacture of composite metal products - Google Patents

Abstract

818,817. Making composite sheet, bar, strip and wire; casting composite ingots. WIGGIN & CO. Ltd., H. Aug. 16, 1957 [Aug. 28, 1956], No. 26290/56. Classes 83 (1) and 83 (2). In a method of making a composite metal product, e.g. sheet, strip, bar or wire, a cladding- metal is cast and allowed to stand long enough for a layer to solidify around the whole wall of the mould, the molten metal within this layer is then poured out and the cavity filled, while the cladding-layer is still plastic, by casting in a core metal, the resultant ingot being then shaped, prior to extrusion into sheet or other shape. A nickel-chromium stainless-steel is cast into a cylindrical cast-iron mould and allowed to stand for ten minutes before returning the metal which has not solidified to the furnace or ladle. Molten-iron or mild-steel is then immediately cast into the cavity defined by the layer of chilled cladding-metal. The ingot, after being fed with iron, is cropped and turned when cold to clean it and shape it to fit an extrusion container, from which it is extruded to sheet, strip, wire or bar. The coremetal may be exposed at the top of the ingot or may be totally clad by casting additional cladding-metal after completion of the core. Other cladding-metals used on an iron or mildsteel core are nickel-copper alloys, nickelchromium or nickel-chromium cobalt alloys, nickel and tool-steel. Further, a nickel-cladding may be used on a nickel-chromium-alloy core. Sheet products may be subsequently reduced by rolling, bar may be rolled to form strip, and wire may be reduced by drawing. Clad-sheet or strip may be formed into a tube, the longitudinal weld being made wholly in the cladding-metal.