What is the quenching and heat treatment process of 40Cr steel?

40Cr steel is the standard steel grade of GB in China, and 40Cr steel is one of the most widely used steels in mechanical manufacturing industry. After quenching and tempering, it has good comprehensive mechanical properties, good low temperature impact toughness and low notch sensitivity. The hardenability of steel is good. It can be quenched to 28 ~ 60mm in water quenching and to 15 ~ 40mm in oil quenching.

In addition to quenching and tempering, 40Cr steel is also suitable for cyaniding and high frequency quenching. When the hardness is 174-229hb, the relative machinability is 60%. The steel is suitable for making medium-sized plastic mould.

After quenching and tempering at medium temperature, 40Cr steel is used to manufacture parts which can bear high load, impact and work at medium speed, such as gear, spindle, oil pump rotor, slide block, sleeve ring, etc.

After quenching and tempering at low temperature, 40Cr steel can be used to manufacture parts with heavy load, low impact, wear resistance and body thickness less than 25 mm, such as worm, spindle, shaft, sleeve ring, etc.

After quenching and tempering and high frequency surface quenching, 40Cr steel is used to manufacture parts with high surface hardness and wear resistance without great impact, such as gears, sleeves, shafts, spindles, crankshafts, pins, connecting rods, screws, nuts, intake valves, etc.