Steel Making Shop Facilities

Steel Making Shop Facilities

Steelmaking is the process of producing steel from iron ore and/or scrap.

Two major commercial processes are used. Basic oxygen steelmaking uses liquid pig-iron from a blast furnace and scrap steel as the main feed materials. Electric arc furnace (EAF) steelmaking uses scrap steel or direct reduced iron (DRI). Oxygen steel making has become more popular over time.

Basic Oxygen Steelmaking (BOS) involves melting carbon-rich pig iron and converting it into steel. Blowing oxygen through molten pig iron oxidizes some of the carbon into CO−

 and CO2, turning the iron into steel. Refractories (materials resistant to decomposition under high temperatures) - calcium oxide and magnesium oxide - line the smelting vessel to withstand the heat, corrosive molten metal, and slag. Chemistry is controlled to remove impurities such as silicon and phosphorus.

Electric Arc Furnaces make steel from the scrap or direct reduced iron (DRI). A "heat" (batch) of iron is loaded into the Furnace, sometimes with a "hot heel" (molten steel from a previous heat). Gas burners may assist with the melting. As in BOS, fluxes are added to protect the vessel lining and help impurity removal. The furnaces are typically 100 ton-capacity that produce steel every 40 to 50 minutes. This process allows larger alloy additions than the basic oxygen method.

The next step commonly uses Ladles. Ladle operations include de-oxidation (or "killing"), vacuum degassing, alloy addition, inclusion removal, inclusion chemistry modification, de-sulfurization, and homogenization. It is common to perform Ladle operations in gas-stirred ladles with electric arc heating in the furnace lid. Tight control of ladle metallurgy produces high grades of steel with narrow tolerances.