Steel is an iron alloy containing 0.5 to 1.5 percent carbon. It is more useful than simple iron due to its increased strength. Stainless steel contains 10 to 30 percent chromium in addition to carbon, and it is resistant to rust.
The addition of molybdenum further increases the strength and decreases the weight of steel. Steel is produced by melting iron and limestone in a furnace, at temperatures around 1,600 degrees Fahrenheit. Its density depends on the alloy constituents and varies between 7.75 and 8.05 grams per cubic centimeter. The historical discovery of iron and steel manufacturing processes played an important role in the development of human civilization.