Medium carbon steel has good hot working and cutting performance, but poor welding performance. Strength and hardness are higher than low carbon steel, while plasticity and toughness are lower than low carbon steel. Cold rolled or cold drawn materials can be used directly without heat treatment, or they can be used after heat treatment. The quenched and tempered medium carbon steel has good comprehensive mechanical properties. The highest achievable hardness is approximately HRC55 (HB538), with a σ b of 600-1100MPa. So among various applications with moderate strength, medium carbon steel is the most widely used, not only as a building material, but also extensively used in the manufacture of various mechanical parts.