30CrMo This steel has high strength and toughness and hardenability of high, in the oil critical quenching through diameter of 15 ~ 70mm; thermal strength of steel is also good, below 500 DEG C has enough high temperature strength, but 550 DEG C when the strength was significantly decreased; when the alloy elements in the lower welding is quite good, but when connecting the upper limit in the welding medium, and in front of the welding preheating to more than 175 DEG C; steel can be good machinability. When the cold deformation plastic medium; heat treatment in 300 ~ 350 DEG C with first class temper brittleness; tendency to the formation of white spots.
  This steel is usually used in quenched and tempered state, when the carbon content is the lower limit of the steel is also used for requirements of carbon steel core strength is higher. In the medium-sized machinery manufacturing industry is mainly used in the manufacture of big cross section in high tempering parts, such as shaft force under the working conditions, as well as by the steering wheel spindle, high load the bolt, stud bolt, gear and so on; used in the manufacture of welding parts in the chemical industry, welding structure and high pressure conduit in working medium containing nitrogen and hydrogen temperature not exceeding 250 DEG C sheet and tube structure; in steam turbine, boiler manufacturing fasteners made below 450 DEG 500 DEG C for work. By the flange and nut pressure, especially suitable for the manufacture of 300 atmospheric pressure, pipe below 400 DEG C work.