1. Low carbon steel has good plasticity, low strength and hardness, good weldability and cold stamping processability, and can be used to make various standard parts, shaft sleeves, containers, etc;

2. High carbon steel has poor plasticity, high hardness, poor fatigue strength and poor machinability, and the toughness of shaft parts is not enough and easy to break. This kind of steel is suitable for making static pressure bearing and wear-resistant parts, such as heavy rail and roll. After proper heat treatment, spring, steel wire rope and other parts requiring high hardness and high wear resistance can also be made;

3. The main function of automobile transmission shaft is to support the rotating body and transmit power. The working conditions generally bear alternating torque and tension and compression load, and the journal and key parts bear large friction and wear. The main failure forms are fracture and local excessive wear, including fatigue fracture and overload fracture. Therefore, when selecting materials, the materials should have sufficient strength, stiffness and certain toughness, good wear resistance, high fatigue strength and good machinability. That is, the spindle is required to have good comprehensive mechanical properties.

4. Medium carbon steel can obtain good comprehensive mechanical properties after appropriate heat treatment, so as to achieve parts with tough core and wear-resistant surface.