Steelmaking
 

The actual steelmaking process begins at Gary Works, Great Lakes Works, Granite City Works, Mon Valley Work's Edgar Thomson Plant outside Pittsburgh and Fairfield Works near Birmingham, Ala. At these locations, the iron ore and coke are combined with limestone in the 12 blast furnaces the company operates domestically. The molten iron that emerges is sent on to basic oxygen furnaces where steel scrap is added and carbon and other impurities are removed by the injection of oxygen during what is called a basic oxygen process or BOP. After leaving the "BOP shop," the steel is further refined before being poured into continuous casters, which form the slabs from which all flat steel products are made. With 19.4 million tons of annual domestic steelmaking capability, U. S. Steel sells a variety of steel sheet, tubular and tin products, as well as coke and taconite pellets.

Finishing   U. S. Steel's finishing plants, located at Gary Works, Granite City Works, Fairfield Works, Great Lakes Works, Midwest Plant in Portage, Ind., Mon Valley Works' Irvin Plant just outside Pittsburgh and its Fairless plant near Philadelphia, Pa., East Chicago Tin in Indiana, and Lorain Pipe Mills in Lorain, Ohio, customize products to the exacting standards our customers demand. Pickling, for instance, is the process in which sheet steel and tin coils are cleaned in a bath of hydrochloric acid. Cold reduction, or cold rolling, improves the steel's surface and desirable metallurgical properties while reducing its thickness from 55-90 percent in just minutes.  Annealing, or heat-treating, restores important physical properties, such as malleability, that are lost in the rolling process. And during electrolytic coating, a thin covering of a positively charged alloy is deposited over negatively charged steel. Zinc-coated or galvanized sheets are also produced with a hot-tip coating process. Iron Ore Mining and Processing   United States Steel Corporation is an integrated steelmaker: we make steel by processing iron ore and other raw materials in blast furnaces rather than by melting scrap metal, as mini-mills do. This allows us to produce high-quality, high-strength, lightweight and formable steel: steel with unique properties that are virtually impossible to produce using other processes. U. S. Steel itself supplies two of the raw materials used in the steelmaking process: iron ore and coke. Iron ore, the chief component of steel, is mined and processed by our Minnesota Ore Operations at two facilities: Minntac in Mt. Iron and Keewatin Taconite in Keewatin, both on Minnesota's Mesabi iron range. After being extracted from the ground, the iron ore, or taconite, is crushed into a fine powder and separated from impurities with the use of magnets. The concentrated powder is then agglomerated into marble-sized pellets that are later fed into blast furnaces. Coke Production   United States Steel Corporation is an integrated steelmaker: we make steel by processing iron ore and other raw materials in blast furnaces rather than by melting scrap metal, as mini-mills do. This allows us to produce high-quality, high-strength, lightweight and formable steel: steel with unique properties that are virtually impossible to produce using other processes. U. S. Steel itself supplies two of the raw materials used in the steelmaking process: iron ore and coke. Coke, an almost pure form of carbon, is produced from coal. At Gary Coke Plant in Gary, Ind., Clairton Works outside Pittsburgh, Pa., and Granite City Coke Plant not far from St. Louis, Mo., the pulverized coal is baked to produce coke for the steelmaking process.