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, poor machinability, insufficient toughness for shaft parts and is easy to break. This kind of steel is suitable for making static pressure bearing and wear-resistant parts, such as heavy rail and roller. After proper heat treatment, the spring, steel wire rope and other parts with high hardness and wear resistance can also be made;

3. The main function of automobile transmission shaft is to support the rotating body and transmit power. Generally, the working conditions will bear alternating torque and tension and compression load, and the journal and key parts will bear large friction and wear. The main failure modes are fracture and local excessive wear. Fracture includes fatigue fracture and overload fracture. Therefore, the material shall have sufficient strength

Rigidity 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. However, medium carbon steel can obtain good comprehensive mechanical properties after proper heat treatment, so as to achieve the parts with tough core and wear-resistant surface.