1. Black metal refers to iron and its alloys. Such as steel, pig iron alloys, cast iron, etc. Both steel and pig iron are alloys based on iron and mainly supplemented with carbon, collectively referred to as iron carbon alloys. Pig iron refers to the product made by smelting iron ore into a blast furnace, mainly used for steelmaking and manufacturing castings. Casting pig iron is melted in a molten iron furnace to obtain cast iron (liquid), which is then cast into castings. This type of cast iron is called cast iron. Ferroalloy is an alloy composed of iron, silicon, manganese, chromium, titanium, and other elements. Ferroalloy is one of the raw materials for steelmaking and is used as a deoxidizer and alloying element additive in steelmaking. 2. Put pig iron for steelmaking into a steelmaking furnace and melt it according to a certain process to obtain steel. Steel products include steel ingots, continuous casting billets, and various steel castings directly cast. Generally speaking, steel refers to steel that is rolled into various types of steel. Steel belongs to ferrous metals, but steel is not entirely equal to ferrous metals. 3. Non ferrous metals, also known as non-ferrous metals, refer to metals and alloys other than ferrous metals, such as copper, tin, lead, zinc, aluminum, as well as brass, bronze, aluminum alloys, and bearing alloys. In addition, chromium, nickel, manganese, molybdenum, cobalt, vanadium, tungsten, titanium, and other metals are also used in industry. These metals are mainly used as alloy additives to improve the properties of metals. Tungsten, titanium, molybdenum, and other metals are mostly used to produce hard alloys for cutting tools. The above non-ferrous metals are all referred to as industrial metals, in addition to precious metals such as platinum, gold, silver, and rare metals, including radioactive uranium, radium, etc.