20CrNiMo formerly U.S. Steel AISI, SAE standard steel No. 8720. Performance and 20CrNi hardenability steel similar. Although Ni content of the steel half 20CrNi steel, but because of a small amount of Mo elements, the upper curve of isothermal transformation of austenite to the right; compounded by an appropriate increase in Mn content, resulting in the steel hardenability is still very good, the intensity is higher than 20CrNi steel. Commonly used in the manufacture of small and medium cars, tractor engine and transmission in gear; 12CrNi3 steel manufacturing requirements can also replace higher-performance core part of carburizing, cyanide parts, such as oil drilling and metallurgical open pit with the cone bit claws and teeth cone body. 20CrNiMo due to the presence of molybdenum in addition to a very good overall performance but also the ability of certain outside temperature. For the manufacture of turbine rotor gear the entire cross section of the internal combustion engine valve rod forgings.