Iron and steel industry in the United States

In 2014, the Iron and steel industry in the United States was the world’s third-largest producer of raw steel (after China and Japan), and the sixth-largest producer of pig iron. The industry produced 29 million metric tons of pig iron and 88 million tons of steel. Most iron and steel in the United States is now made from iron and steel scrap, rather than iron ore. The United States is a major importer of iron and steel, and iron and steel products.

Employment as of 2014 was 149,000 people employed in iron and steel mills, and 69,000 in foundries. The value of iron and steel produced in 2014 was $113 billion.

As of 2015, major steel-makers in the United States included: AK Steel, Carpenter Technology, Commercial Metals Company, and Nucor, Steel Dynamics, and U.S. Steel.

There are two main types of steel mills. The traditional large integrated steel mill, which reduces metallic iron from ore (iron oxide) and makes it into pig iron and steel, has been steadily declining in importance for decades in the US. The second type, the mini-mill, or specialty steel mill, which produces new steel products by melting steel scrap, now produces the majority of steel in the US.

In 2014, there were 11 operating integrated steel mills in the United States, down from 13 in 2000. Integrated mills produced 31% of the steel produced in the US.

In an integrated steel mill, iron ore is reduced to metallic iron. In the US, this is done in blast furnaces. The direct-reduction method of producing iron from ore has not been used in the US since 2012. Some of the iron from the blast furnaces is converted to steel; today this is done in basic oxygen furnaces. Iron ore, coke, and flux are fed into the blast furnace and heated. The coke reduces the iron oxide in the ore to metallic iron, and the molten mass separates into slag and iron. Some of the iron from the blast furnace is cooled, and marketed as pig iron; the rest flows into basic oxygen furnaces, where it is converted into steel. Iron and steel scrap may be added to both the blast furnace and the basic iron furnace.

US Steel operates a number of integrated steel mills, including the Gary Works in Gary, Indiana. They also operate the Edgar Thomson Works, which is the iron- and steel-making unit of the Mon Valley Works, which includes three other related plants. The Company operates the Great Lakes Works, and Granite City Works.

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