There are many kinds of metallic carbides that exist in pure forms or as precipitates in a variety of alloy systems, but the focus here is on alloys of iron. Most steels destined for long-term mechanical stability at elevated temperatures contain a variety of solutes designed to precipitate substitutionally alloyed phases. Titanium carbide is therefore defined to be chemically active because when bonded to steel, it stimulates ferrite formation from austenite, by locally decarburising the austenite. The binary carbides all have a metallic character, are paramagnetic and melt at very high melting temperatures. It is quite common therefore for titanium or niobium carbides to precipitate in liquid steel prior to its solidification. Laves phase also precipitates in tempered martensite of the type common in creep-resistant power plant steels, where a myriad of other precipitates usually precede the formation of Laves particles.