Regulation and determination of the phase composition of tungsten hard metals

Conclusions The two-frequency magnetic method can be employed for detecting the presence of additional phases (free carbon and the ₁-phase) in tungsten hard metals. The degree of carburization of tungsten hard metals and hence the presence and amount of free carbon and the ₁-phase can be regulated with sufficient accuracy for practical purposes by adding graphite or tungsten powder to electrocorundum packing material and varying the rate of hydrogen flow. Control over this process may be exercised by the magnetic method. The carbon content of tungsten hard metals grows when the concentration of graphite in packing material is raised, the concentration of tungsten in packing material is lowered, and the rate of hydrogen flow is decreased. The hard metals can thus change in structure from three-phase WC + Co + ₁ to two-phase WC + Co and then to three-phase WC + Co + C alloys.Translated from Poroshkovaya Metallurgiya, No. 4(220), pp. 46–50, April, 1981.