All metals fall into one of two categories: ferrous or nonferrous. A metal is considered nonferrous if it contains less iron than any other metal.
Cast iron, steel, and the various steel alloys are ferrous metals. Meanwhile, tin, zinc, silver, gold and many other metals utilized primarily for metal plating or as alloying elements are considered nonferrous. Many metals used in the fabrication of parts, such as aluminum, magnesium, titanium, nickel, copper and tin alloys, are also classified as nonferrous.