The ball head in the automobile steering gear is usually made of the following materials:

1. Cast iron: Cast iron is a common ball head material in directional machine, which has high strength and wear resistance. Cast iron ball heads are usually used in the steering gear system of heavy commercial vehicles or engineering vehicles, which can bear large loads and impacts.

2. Steel: Steel is another commonly used ball head material in directional machine, which has good strength and corrosion resistance. Steel ball heads are usually used in the steering system of most passenger cars and light commercial vehicles, which can provide stable steering performance.

3. Aluminum alloy: Aluminum alloy is a light and corrosion-resistant material, which is often used to manufacture the ball head in the steering gear of high-performance vehicles. Aluminum alloy ball head has good strength and durability, which can reduce vehicle weight and improve steering flexibility.

4. Stainless steel: Stainless steel is a kind of corrosion-resistant and oxidation-resistant material, which is often used in high-end vehicles or steering machine ball heads in special environments. Stainless steel ball head has good durability and stability, and can keep good working condition in harsh environment.

Generally speaking, the material selection of the ball head in the automobile steering gear depends on the vehicle type, the use environment and the performance requirements. The direction of different materials has its own characteristics and advantages, and the owner can choose the appropriate material to replace it according to the actual needs. When choosing the ball head in the steering machine, it is suggested to choose materials with reliable quality and good durability to ensure the flexible and accurate operation of the steering wheel and ensure driving safety.