History of the steel industry (1850–1970)

The history of the modern steel industry began in the late 1850s, but since then, steel has been basic to the world's industrial economy. This article is intended only to address the business, economic and social dimensions of the industry, since the bulk production of steel began as a result of Henry Bessemer's development of the Bessemer converter in 1857. Previously steel was very expensive to produce and only used in small expensive items such as knives, swords and armour.

Steel is an alloy composed of between 0.2% and 2.0% carbon, and the balance of iron. From prehistory through the creation of the blast furnace, iron was produced from iron ore as wrought iron, 100% Fe, and the process of making steel involved adding carbon to the iron, usually via serendipity in the forge or via the cementation process. The introduction of the blast furnace reversed the problem. A blast furnace produces pig iron, which is an alloy of approximately 90% iron and 10% carbon. If the process of steelmaking begins with pig iron instead of wrought iron, the challenge is to remove a sufficient amount of carbon to get it to the 0.2 to 2 percent for steel.

Before about 1860 steel was an expensive product, made in small quantities and used mostly for swords, tools and cutlery; all large metal structures were made of wrought or cast iron. Steelmaking was centered in Sheffield, Britain, which supplied the European and the American markets. The introduction of cheap steel was due to the Bessemer and the open hearth processes, two technological advances made in England. In the Bessemer process, molten pig iron is converted to steel by blowing air through it after it was removed from the furnace. The air blast burned the carbon and silicon out of the pig iron, releasing heat and causing the temperature of the molten metal to rise. Henry Bessemer demonstrated the process in 1856 and had a successful operation going by 1864. By 1870 Bessemer steel was widely used for ship plate. By the 1850s, the speed, weight, and quantity of railway traffic was limited by the strength of the wrought iron rails in use. The solution was to turn to steel rails, which the Bessemer process made competitive in price. Experience quickly proved steel had much greater strength and durability and could handle the increasingly heavy and faster engines and cars.

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