Steel

Steel is a generic name for a large group of iron alloys that include the plain carbon and alloy steels... Although any iron-carbon alloy containing less than about 2% carbon can be considered a steel, ....AISA syandard carbon steels embrace a range of carbon contents from 0.06% maximum to about 1%...

All carbon steels contain minor amounts of manganese, silicon, sulfur, phosphorus, and sometimes other elements. At all carbon levels the mechanical properties of carbon steel can be varied to a useful degree by heat treatments that alter its microstructure. Above about 0.25% carbon steel can be hardened by heat treatment...

Alloy steels are steels with enhanced properties attributable to the presence of one or more special elements or of larger proportions of manganese or silicon than are present ordinarily in carbon steel.

(from "Iron alloys" in McGraw-Hill Encyclopedia of Science and Technology vol 9 p 448-449 [1997])

At the start of the Civil War, the surviving national small-arms factory, the Springfield Armory, got its files, most of its steel, and all its gun iron from England... the new tariff of 1861, which substantially raised duties on imported steel, proved a more powerful stimulus than military self-sufficiency in getting Americans to break their dependence on Sheffield steelmakers.

To make steel an artisan first had to get the right amount of carbon in his iron. A steelmaker could start with pig iron and remove all the silicon and most of the carbon, or he could begin with wrought iron and add the desired amount of carbon...

(from Robert B. Gordon American Iron 1607-1900 [Johns Hopkins Press 1996, p 173]
TN704 .N5 G67 1996)