Carbon steel (containing <1.7% C in an iron matrix) are used as low-cost, large volume construction materials in chemical, petrochemical, and power plants, as well as in process vessels, tubing, and other load supporting structures. Widely used in springs, bearings, rods, and wires, carbon steel is also consumed in large amounts as automotive and ship body and part materials. Sometimes it is used as very cheap alternative to cutting tool materials.
Low alloy steels (containing <10% C, Mn, Cr, Ni, Mo, B, V, and Si combined), have better strength and hardness than carbon steels – and even stainless steels if temperature is well under 400º C. Low alloy steels are used as construction materials in chemical, petrochemical, and power plants, as well as in process pressure vessels, tubing, and load supporting structures. They are also used as automotive and low cost aerospace part materials and low cost cutting tools.
One special class of low alloy steels is the chrome-moly (Cr/Mo Steels) steels. These steels contain up from 1-9% Cr and 0.5- 1% Mo. Having good creep resistance and high temperature characteristics, these alloys have found great success in the petrochemical and power generation industry applications. Typical products for these industries include boilers, heaters, heat exchangers, reactors, and hydrocrackers.