GB386359A - Improvements in or relating to the manufacture of cemented carbide discs - Google Patents

Abstract

386,359. Alloys ; tools ; electric furnaces. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London. -(Assignees of Taylor, G. F. ; 115, Balltown Road, Niskayuna, New York, U.S.A.) Sept. 7, 1931, No. 25083. Convention date, Sept. 8, 1930. [Class 82 (i).] Thin cemented carbide discs for use as glass cutters, saws, &c., which consist of a sintered mixture of a carbide such as tungsten carbide and a binding medium such as iron, nickel, cobalt, &c., are made by placing a layer of the mixture of carbide and binder between two discs of carbonaceous material in an electrically nonconducting mould, heating the mixture momentarily to its sintering temperature, and simultaneously applying pressure, utilizing the apparatus and operating conditions described in Specification 385,629. The mould comprises a hard glass tube 18 in the ends of which are inserted plungers 19, 20 having central holes 21, 22 which accommodate a removable or temporary plug or rod 23. Graphite discs 24 having a central opening and layers 25 of the powdered material to be sintered are inserted alternately on the lower plunger. The plungers are positioned between extensions 8, 101 provided with adjustable sleeves 26, 27. A tube comprising the carbide, binding metal, and starch paste may be squirted, and after removing the paste by firing in hydrogen equal lengths may be cut and separated with paper to form the layers 25. The carbide discs may also be reinforced by the introduction into the powdered material, prior to heating and pressing, of small molybdenum wires, for example C- or O-shaped wires. Diamond dust may be added to the powdered materials as described in Specification 349,732, [Group XXIII], the discs preferably being also reinforced by wires. Carbide discs with no central aperture can be produced by omitting the plug 23 and employing solid plungers and solid graphite discs 24. Specifications 213,524, 288,521, 289,477, [all in Class 82 (i), Metals, Extracting &c.], and 351,189, [Group XXIII], also are referred to.