Steelmaking is the process for producing
steel from
iron ore and
scrap. In steelmaking, impurities such as
nitrogen,
silicon,
phosphorus, sulfur and excess
carbon are removed from the
raw iron, and alloying elements such as
manganese,
nickel,
chromium and
vanadium are added to produce different grades of steel. Limiting dissolved gases such as
nitrogen and
oxygen, and entrained impurities (termed "inclusions") in the steel is also important to ensure the quality of the products cast from the liquid steel. Steelmaking has existed for millennia, but it was not
commercialized until the 19th century. The ancient
craft process of steelmaking was the
crucible process. In the 1850s and 1860s, the
Bessemer process and the
Siemens-Martin process turned steelmaking into a
heavy industry. Today there are two major commercial processes for making steel, namely
basic oxygen steelmaking, which has liquid pig-iron from the blast furnace and scrap steel as the main feed materials, and
electric arc furnace (EAF) steelmaking, which uses scrap steel or
direct reduced iron (DRI) as the main feed materials. Oxygen steelmaking is fuelled predominantly by the exothermic nature of the reactions inside the vessel where as in EAF steelmaking, electrical energy is used to melt the solid scrap and/or DRI materials. In recent times, EAF steelmaking technology has evolved closer to oxygen steelmaking as more chemical energy is introduced into the process.