Equilibrium solubility products of molybdenum carbide and tungsten carbide in iron

Solubility products for molybdenum carbide and tungsten carbide are absent from the literature despite their importance in secondary hardening steels and in microalloyed steels. Equilibrium solubility products were calculated for MoC, Mo2C, WC and W2C in ferrite and austenite. Molybdenum and tungsten carbides exhibit greater solubility than traditional microalloy carbides in iron and their predicted solution behavior is similar to that of other Group VI transition metal carbides. The calculated solubility products are consistent with precipitation behavior during secondary hardening in steels.