Automotive drive shaft and drive shaft suspension should be made of medium carbon steel.

1. Low carbon steel has good plasticity, but low strength and hardness, good weldability, can be cold stamping processing, can be used to manufacture all kinds of standard parts, bushings, containers, etc.

2. High carbon steel has poor plasticity, high hardness, poor fatigue strength and poor machinability, which leads to the lack of toughness of shaft parts and easy to fracture. This kind of steel is suitable for the manufacture of electrostatic pressure wear-resisting parts, such as heavy rail, roll, etc. After proper heat treatment, it can also be made into springs, steel wire rope and other parts that need high hardness and high wear resistance.

3. The main function of the automobile drive shaft is to support the rotation and transfer power. Working conditions generally bear alternating torque and tension and compression load, shaft journal and key components bear greater friction and wear. The main failure modes are fracture and local excessive wear, and the failure modes include fatigue fracture and overload fracture.

Therefore, in the selection of materials, the requirements of the material with sufficient strength, stiffness and a certain toughness, with good wear resistance, high fatigue strength and good workability. That is to say, the spindle is required to have good comprehensive mechanical properties.

4. After proper heat treatment (quenching and tempering, surface quenching, carburizing, etc.), the medium carbon steel can obtain better core toughness, surface wear resistance and other comprehensive mechanical properties.

It is recommended to choose alloy quenching and tempering steel (belonging to medium carbon steel category). Ordinary quenching and tempering steel has poor hardenability and low mechanical properties. It is only suitable for small size and light load parts. The alloying elements in the alloyed tempered steel can improve the hardenability, enhance the surface hardening effect of heat treatment such as quenching obviously, and do not reduce the toughness of the core. After heat treatment (tempering and tempering), alloy tempering and tempering steel has high strength, high wear resistance and good plastic toughness, that is, it has good comprehensive mechanical properties.