A new or improved gas carburising process

摘要

564,345. Gaseous mixtures. BIRMING HAM ELECTRIC FURNACES, Ltd., and HANCOCK, P. F. July 3, 1940, No. 11182. [Class 55 (ii)] [Also in Group II] In a gas-carburizing process the charge is heated in a furnace in an atmosphere containing producer gas produced by passing air over heated charcoal, and containing not more than 10 per cent of hydrogen to which is admixed 2-20 per cent of butane, propane, or methane. The gaseous mixture may comprise 20-2.5 per cent of butane and 80-97.5 per cent producer gas. The charge may be heated in the gaseous mixture above until a high surface carbon content is obtained and then heated in an atmosphere of charcoal producer gas only so that the surface content is reduced and diffusion of some of the carbon therein towards the core has taken place. -The producer gas may com-r prise 26-34 per cent of carbon monoxide 0-4 of carbon dioxide, 2-7 of hydrogen and the balance nitrogen. Reference has been directed by the Comptroller to Specifications 480,103 and 512,944.