Steel

• Steel is an alloy of iron, with carbon being the primary alloying element.
• 0.02% <= Carbon Content <= 2.06% (by weight)
• Steel
• Alloyed
• Low: some of all alloying elements < 5%
• High 
• Unalloyed: Cu < 0.4%, Cr < 0.3%, Mo < 0.08%, Ni < 0.3%
• Alloyed Steel: Steel + Some Alloying Elements like Manganese, Nickel, Chromium, Molybdenum, Boron, Titanium, Vanadium, Niobium = Modified Characteristics
• Stainless Steel: Alloyed steel w/ Cr => 10.5% (i.e. high alloyed)

• Steel specified by purpose of use and mechanical properties (unalloyed)

• Steel specified by chemical composition (unalloyed)

• Steel specified by chemical composition (low alloyed)

• Steel specified by chemical composition (high alloyed)