The material we call steel is in fact an alloy, a mixture of different metals. The element iron (symbol Fe) makes up a large percentage of all steels, generally composing more than 75 percent of the mix by percent of total mass. Steel is made from iron, and in the process, some element percentages are reduced in the alloy composition (such as carbon and silicon), and other elements (such as chromium, nickel, and tungsten) are added, depending on the type of steel needed.
This type of steel is inexpensive and contains less than 0.25 percent carbon, with about 99 percent of the material deriving from iron. Construction I-beams are made of this steel.
This steel contains 0.60 to 0.99 percent carbon (C), with close to 99 percent iron.
Stainless N Steel
This alloy can be used to make flatware and cutlery, among other things, and often has a composition of 0.18 percent carbon, 18 percent chromium, and 8 percent nickel, with about 74 percent iron.
Hi-Speed Tool Steel
This steel is generally 0.7 percent carbon, 4 percent chromium, 10 percent tungsten, and 1 percent molybdenum, with about 84 percent iron. It is used to make drill bits and saw blades (alloy of Fe, C, Cr, W, and Mo).
Silicon (Electrical) Steel
This steel is used in motors and generators and has a composition of about 0.6 to 5 percent silicon (Si), with one specific steel made of 0.4 percent carbon, 2 percent silicon, and 97.6 percent iron.