Steel, one of the most important metals of our modern world, comes from naturally-occurring minerals such as iron ore. This strong, useful metal is employed in everything from serving spoons to skyscrapers.
Iron ore that occurs naturally in the earth's crust must be transformed in order to produce one of the several useful metals derived from it, including cast iron, wrought iron and steel.
The addition of a small amount of carbon, another element, to iron helps lend steel its strength.
Steel often contains elements other than iron and carbon: manganese, phosphorus, sulfur, silicon, nickel and chromium. Sometimes the elements are added intentionally. At other times, they occur naturally.
At a steel plant, a heat source melts iron ore in a furnace at temperatures exceeding 1,540 degrees Celsius (2,800 degrees Fahrenheit). Molten iron is then processed to create steel.
According to the U.S. Geological Survey, iron and steel are, on average, the least expensive metals available. Of all the tons of metal produced in the world each year, 95 percent is iron and steel.