<P> 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 . </P> <P> 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, 99.82% - 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 . </P>

What most directly led to an increase in steel production in the late 1800s