The theoretical carbon content of tungsten carbide is 6.128% (atomic 50%). When the carbon content of tungsten carbide is greater than the theoretical carbon content, free carbon (WC+C) appears in the tungsten carbide.
The presence of free carbon will carbonize the surrounding area during sintering. The growth of tungsten grains results in uneven grains of cemented carbide; tungsten carbide generally requires high combined carbon (≥6.07%) free carbon (≤0.05%), and total carbon is determined by the production process and scope of use of cemented carbide.
