Carbide- and nitride-forming elements, such as titanium, vanadium, and niobium, play important roles in the metallurgy of many modern steel products. These elements readily precipitate as stable carbides/nitrides during processing, even when present at relatively small levels. The precipitation of these alloy carbides/nitrides provides a means for controlling strength or hardness, grain size, the level of solute carbon, and other factors that affect properties and performance. Precipitation in austenite during hot deformation has received considerable attention and ''solubility products'' for many compounds have been published and used as alloy/processing development tools. The technologically important alloy nitrides generally exhibit relatively low austenite solubility. Alloy nitride solubilities in ferrite are even lower and, for practical purposes, can often be considered zero. In contrast, some alloy carbides exhibit substantial solubility in ferrite. However, thermochemical or solubility data on carbide/ferrite equilibria are sparse and, as a result, few experimental ferrite solubility relationships are available. A method is described herein for obtaining such a relationship from a known or assumed austenite solubility product using information on the activity coefficients of the solutes of interest. Solubility relationships for titanium-, vanadium-, and niobium-carbide in ferrite are then derived from published austenite solubility products and available thermodynamic informationmore » on binary Fe-Ti, Fe-V, and Fe-Nb solid-solutions.« less