GB331121A - An improved process for manufacturing tools of homogeneous alloys of great hardness - Google Patents

Abstract

331,121. Brewer, G., (Krupp Akt.-Ges., F.). July 25, 1929. Compound forms; lathe tools.-Tools of great hardness, such as turning tools, are made by melting a mixture of metals of high melting point, such as chromium, molybdenum, titanium, tungsten, uranium or vanadium, and metalloids such as carbon, boron or silicon, with or without other metals such as iron, cobalt or nickel, then cooling to produce a finely grained texture, then finely powdering, then pressing to form the tool and subsequently or simultaneously sintering by external heat or resistance heating at a temperature which does not destroy the fine texture, e.g. 1500‹ to 1900‹ C. 400 grms. of powdered tungsten may be mixed with 40 grms. of titanium carbide and melted electrically in a carbon crucible having carbon terminals, in a hydrogen atmosphere. The melt is poured into a watercooled copper mould and is then powdered and shaped in swages under a pressure of 4000 kgs. per sq. cm. The shaped bodies are sintered for 12 minutes at a temperature of 1750‹ C. in hydrogen below atmospheric-pressure, cooled down to 1500‹ C. in 40 seconds and then allowed to cool to room temperature in 45 minutes. The additional metals or the metalloids may be introduced into the mixture during melting after pouring from the crucible. The pressing operation may include the formation of holes or recesses in the tool. The bodies may be immediately subjected to a further heat treatment between 1000‹ C. and 2000‹ C. to improve the texture and may also be subjected to mechanical treatment such as forging, rolling, pressing, &c. at 2000‹ C. The alloy may contain tungsten with less than 3 per cent of carbon. Specifications 157,747, 157,749. 294,086, [all in Class 83 (iii), Metals, Cutting], and 310,885, [Class 82 (i), Metals, Extracting &c.], are referred to.