40Cr steel is the standard steel grade of Chinese GB, and 40Cr steel is one of the most widely used steels in the manufacturing industry. After quenching and tempering treatment, it has good comprehensive mechanical properties, good low temperature impact toughness and low notch sensitivity. The steel has good hardenability. It can be hardened to Ф28-60mm when water quenching, and Ф15-40mm when oil quenching.
In addition to the treatment, the steel is also suitable for cyanidation and quenching. The performance of the quenching treatment is good.
40Cr steel is better than 45 steel. 45 steel is mostly used in the quenched and tempered state. According to the process requirements and tempering temperature, it is often adjusted to use within the range of 2 to 34HRC. It is a common structural material with a wide range of uses. 40Cr steel is mostly used for important engineering structures. Tempering hardness varies according to tempering temperature. The 45 steel supplied by hot rolling requires ≤29HBW, while 40Cr only requires annealing or high temperature tempering, and the hardness in the supply state is ≤207HBW. The hardness in the hot rolled state is higher, mostly between 20 and 260HBW. Higher than this value often causes cutting difficulties. or shear crack