What is 45# steel?

What is 45# steel?
45# steel is a kind of carbon structural steel, which belongs to a kind of medium carbon steel. Its chemical composition contains about 0.42-0.50% carbon, 0.50-0.80% silicon, 0.17-0.37% manganese, 0.035% phosphorus, 0.035% sulfur, and a small amount of chromium, nickel, copper and other elements. 45# steel has high strength and hardness and is suitable for the manufacture of some mechanical parts with high requirements, such as shafts, gears, bolts, etc. Its heat treatment process can improve its hardness and strength through quenching and tempering, making it have good wear resistance and corrosion resistance. 45# steel is widely used in machinery manufacturing, automobile manufacturing, shipbuilding and other fields.