45Mn2 and 45# steel, which better?

Which steel is better, 45Mn2 steel or 45# steel?

45Mn2 steel is based on the addition of manganese element to 45# steel. After quenching and tempering at high temperature, 45Mn2 steel can obtain good matching of high strength and good toughness. That is to say, it has good comprehensive mechanical properties. 45Mn2 steel is often used to manufacture shafts, connecting rods, fasteners and so on products that bear large loads.

The price of 45Mn2 steel is higher than that of 45# steel, and the properties of 45Mn2 steel after heat treatment are better. It can be used as parts under high stress and wear conditions, such as universal joint shaft, axle, connecting rod cap, friction disc, etc. The properties of 45Mn2 steel after heat treatment are better than 45# steel and worse than 40Cr steel.