Simple Carbon Series Steels

The earliest forms of steel were iron with small amounts of carbon added to increase the strength and toughness of the iron. With time additional elements were found to change the properties of iron when added to the mix: chrome, nickle, molybdenum, vanadium, and others.

The simple carbon steels are identified by the format: 10xx(x). The 10 (number 10) indicates that the steel only has carbon added, no other alloys. The 2 or 3 digits that follow the 10 indicate how much carbon has been added. 1018 steel has had 0.18% carbon added. 1084 has had 0.84% carbon added. 10125 has had 1.25% carbon added. In each case the steel has become harder and stronger.

The amount of carbon defines the 3 major groupings of carbon steel: low-carbon steel is from 0.05% to 0.35%; medium-carbon steel is from 0.35% to 0.5% carbon; high-carbon steel contains over 0.5% carbon.

The amount of carbon added is often referred to as "points" of carbon. 0.18% carbon is often refered to be 18 points of carbon. A "point" is equal to 1/100% of carbon.

In addition to the carbon, there will be small amounts of other elements in the steel: manganese, silicon, phosphorus and sulfur, but those are considered to be impurities in the steel, they have not been added as part of the manufacturing process, as the carbon has.

When heat treating simple carbon steel, one can quench the steel in water or even brine (very salty water). Simple carbon steel can take the shock of such an aggressive quench, where other steels which have more complex alloy mixes would not be able to stand up to such rapid cooling.

-- AlbinDrzewianowski - 15 Apr 2009