The materials of automobile brake tubing are usually as follows:

1. Steel pipe: One of the commonly used materials for brake tubing is steel pipe, which is usually made of carbon steel or stainless steel. Carbon steel brake tubing has good strength and pressure resistance, and is suitable for general brake systems. Stainless steel brake tubing has better corrosion resistance and is suitable for high-demand brake systems.

2. Copper galvanized pipe: Copper galvanized pipe is a common material of brake tubing, which has good corrosion resistance and thermal conductivity and is suitable for some high-performance brake systems.

3. Aluminum alloy pipe: Aluminum alloy pipe is lightweight and has good corrosion resistance, but its strength is relatively low. It is usually used in some light vehicles or brake systems with low performance requirements.

4. Rubber hose: In addition to the metal pipe, the brake oil pipe can also be made of rubber hose. Rubber hose has the advantages of good flexibility and easy installation, and is suitable for some parts that need to be bent or moved.

5. Polyurethane pipe: Polyurethane pipe is a new type of brake oil pipe material, which has excellent pressure resistance and corrosion resistance and is suitable for high-performance and high-pressure brake systems.

Different materials of brake tubing are suitable for different types of vehicles and brake systems. Choosing the appropriate material of brake tubing can ensure the normal operation and safety performance of the brake system. When selecting the material of brake tubing, factors such as the service environment of the vehicle, the performance requirements of the brake system and the budget need to be considered.