Standard: GB / T 3077-1999
Main Features
The carbon steel is quenched and tempered steel, strength, wear resistance and hardenability were relatively high, the critical quenching in oil diameter 10 ~ 25mm, the critical quenching diameter in water of 22 ~ 45. After quenched with good mechanical properties, machinability is still good; but when overheating heat sensitivity and tendency to temper brittleness, water quenching easy to crack, white spot sensitive, and cold welding of plastic deformation and low defects.

Application examples
The steel generally used in the quenched state can also be used in the normalizing condition, suitable for manufacture of high stress and wear conditions in the work of the parts. When the workpiece diameter is less than 60mm, the performance and 40Cr steel quite. Tractors and general machinery in the automotive manufacturing, for the manufacture of universal joint shaft, axles, connecting rod cap, friction plate, worm gears, gear shafts, axle tram and steam locomotive, carriage shafts, heavy duty racks, and cold-drawn state bolts and nuts, etc.