GB565946A - Improvements in or relating to the decarburization of austenitic manganese cast ironalloys - Google Patents

Abstract

565,946. Furnaces. BIRMINGHAM ELECTRIC FURNACES, Ltd., ROBIETTE, A. G. E., and HANCOCK, P. F. Feb. 27, 1942, No. 2568. [Class 51 (ii)] [Also in Group II] Austenitic manganese cast iron alloys are decarburized in a furnace by an agent which is relatively non-oxidizing to the manganiferous austenite, but is decarburizing to the carbon content. The decarburizing agent may be gaseous and containing one or more of hydrogen, water vapour and carbon dioxide, carbon monoxide being also present when carbon dioxide is used and in sufficient proportion to prevent the oxidation of the austenitic or in solid or liquid form, e.g. molten barium chloride with or without barium oxide, or a mixture of sodium chloride and manganese dioxide. The treatment is carried out at a temperature between 700‹ C. and the temperature of incipient fusion of the alloys. The treatment of castings of an alloy containing 9-25 per cent of manganese, 2-6 of carbon up to 2 of silicon and not more than 0.15 of phosphorus is referred to. Part of the manganese may be replaced by nickel and/or copper to such an extent that the alloy may contain up to a total of 24 per cent of nickel and copper, the manganese content being not less than 5 per cent. Other elements, such as chromium, molybdenum, titanium, tungsten and vanadium, may be present in individual amounts of up to 5 per cent. but not exceeding 12 per cent in all. If the castings are of relatively thick section, the castings may be recarburized as described in Specification 565,887, [Group II], so as to average out the carbon content at the surface. Specifications 314,439, [Class 72], 539,461 and 564,252, [both in Group II], are also referred to.