Engineering steels are among the steels for mechanical construction and are characterized by a carbon content generally above 0.25%, and can be alloyed or unalloyed. Heat-treatable steels are used to fabricate parts that require a combination of strength and tenacity, with relatively uniform values throughout the cross section or down to a certain depth. These properties are obtained through heat treatments such as quenching and tempering, which constitute the process known as beneficiation.