Ferrous metals mainly refers to iron, manganese, chromium and their alloys, such as steel, pig iron, ferroalloy, iron and so on. Having a metallic luster, good electrical conductivity, thermal conductivity and mechanical properties, and the material having a positive temperature coefficient of resistance. Metal is a big family, there are 86 kinds of metal in the world right now. Usually people put metal into two categories, ferrous and non-ferrous metals, which are based on the color and nature of the metal features to classification. Metal black metal than is called non-ferrous metals.

Ferrous metals are industrial collectively iron, chromium and manganese. It also includes three metal alloys, especially steel and ferrous metal alloy steel. The opposite of black metal nonferrous metals. In fact pure iron and manganese is a silvery white, silver and chromium. Since the steel surface is usually covered with a layer of black iron oxide, and manganese and chromium alloy steel is mainly used in smelting black. So will be "misclassified" as black metal.

Classification black metal has its meaning, because these three metals are the main raw material for steel smelting, and steel occupies an extremely important position in the national economy, is also an important indicator to measure the strength of a country. Ferrous metal production accounts for about 95 percent of the world's metal production.