ABSTRACT
Iron produced in the blast furnace is converted into the following commercial products by a refining step: steel; wrought iron; cast irons and pure iron. Steel falls approximately between cast iron and wrought iron. Wrought iron was known since antiquity and was the major ferrous material produced until the 19th century; it is produced in limited amounts. Wrought iron is practically pure iron—low in carbon, sulfur, manganese, and phosphorus—but contains an appreciable amount of slag in mechanical admixture. Cast iron is a series of iron-carbon alloys containing more than 1.5% C, together with silicon, sulfur, manganese, and phosphorus which are impurities from the raw material and not alloying elements. Steelmaking involves the removal of the impurities in pig iron. Steel from open hearth has much less oxygen and nitrogen content than steel from converters using air since it is difficult to control the end point during blowing in the converters.
