This compilation opens with a section discussing the key interactions required to successfully friction stir weld carbon steels. Friction stir welding is a relatively recent development, predominantly technologically established using aluminum, where the lower melting point of the material greatly aided the process. Next, corrosion models of carbon steel in aqueous solution are reviewed under atmospheric and oxygen depleted environments by focusing on the cathodic reaction and the corrosion film formed on carbon steel as a function of pH and anions. In conclusion, the temperature relation of interlamellar spacing of pearlite with supercooling in carbon steels, based on a previously theoretically foundation, has been determined by the pearlite and bainite phase volumes in alloy steels from the degree of supercooling.