• Steel can be clasified depending on its alloy.steel balls image by Igor Shootov from Fotolia.com
  
  Steel is a general name given to the metal made from combining carbon and iron. However, steels come in a wide variety of alloys, or combinations of other materials with the steel. These alloys can be generally broken down into three families depending on their uses: high carbon and simple steel, stainless steel and tool steel.
  
  

High Carbon and Simple Steel

• High carbon and simple steels are are basically mixtures of only carbon and iron. Though other trace elements are present in these steels their presence is due to byproducts in the smelting process and not specifically added to produce a desired property. These steels are given a 10XX code by the American Iron and Steel Institute that determines their carbon content where the XX digit determines the percentage of carbon in the steel. High carbon steel can be strengthened through tempering and is used as a structural material.
  
  

Stainless Steel

• Stainless steel is, in the most general terms, steel with a higher percentage of chromium added to the steel, which helps it resist rusting and corrosion. Stainless steel typically contain less the 30 percent chromium and the amount of chromium content is generally proportional to the corrosion resistance but usually at the cost of other properties such as hardness or toughness. There are a number of different nomenclatures for stainless steel though the Society of Automotive Engineers grade stainless steels in series from 100 to 600 depending on the corrosion resistance and harden-ability.
  
  

Tool Steel

• Tool steels are generally steels with particular elements added to increase certain properties. These steel use letters to classify the properties of the steel. For instance, O-series steels are oil hardened, A-series steels harden in air and W-series steels harden in water. Other series include the D-series which is able to be worked cold and the S-series with has improved shock resistance. There are also custom and patented steels with their own nomenclature given by the foundry.