Improvements in or relating to hard cemented carbide materials

摘要

Hard carbides of metals such as titanium, molybdenum, tungsten, &c. containing free carbon are formed by heating mixtures containing the finely divided oxides of the metals and an excess of carbon in a graphite cylinder, plugged at both ends, in a hydrogen furnace. Mixed carbides containing free carbon may be prepared by reducing, or oxidizing, double salts or mixed salts of the metals to produce alloys or oxides which are subsequently carburized.ALSO:A process for making hard cemented carbide material includes forming a hard carbide containing free carbon, mixing the carbide with a metal or metals of the group iron, cobalt, and nickel, and a metal capable of forming a hard carbide, or an oxide of such a metal, and sintering the mixture to decarbonize it in respect of free carbon. Hard carbides containing free carbon are formed by carburizing metals or their oxides. Mixed carbides may be formed by reducing or oxidizing mixed salt crystals or double salts to form alloys or oxides which are subsequently carburized. The metal added for decarbonizing may be the same as or different from the metal of the carbide to which it is added. The mixture may be hot pressed, or cold pressed and sintered twice at different temperatures.