What is the material of brake discs?
4 Answers
The material of brake discs adopts the domestic gray cast iron 250 standard, abbreviated as HT250, which is equivalent to the American G3000 standard. The requirements for the three main chemical elements are: C: 3.1~3.4, Si: 1.9~2.3, Mn: 0.6~0.9. More details are as follows: Mechanical performance requirements: tensile strength >=206MPa, bending strength >=1000MPa, deflection >=5.1mm, hardness should be between 187~241HBS. Alternative names: In English, brake discs are usually referred to as BRAKE-DISC or BRAKE-ROTORS, while brake drums are called BRAKE-DRUM. Additionally, in southern China, brake discs are also known as brake discs or brake rotors. In fact, they all refer to the same thing.
As someone who frequently works on my own car, I've found that the most common material for brake rotors is cast iron. This material is cheap and durable, capable of withstanding the high temperatures and pressures of daily driving. Cast iron brake rotors are used in most vehicles because of their low cost, simple manufacturing process, and effective heat dissipation, which helps the braking system function stably. However, they also have drawbacks, such as being prone to rust, especially in rainy or humid conditions. After prolonged parking, the rotor surface can corrode, affecting braking performance. Therefore, some high-end models have started using composite materials, such as coated cast iron, which resists rust and extends lifespan. When choosing materials, consider your driving habits. If you mostly drive in the city, cast iron is sufficient. But if you frequently drive in mountainous areas or at high speeds where heat buildup is significant, upgrading to a better material may be necessary for safety. Ultimately, material choice directly impacts braking effectiveness and cost-efficiency, so don’t forget to check rotor thickness and wear during maintenance.
After driving sports cars a few times, I noticed that high-performance vehicles use very different brake disc materials. Advanced materials like carbon ceramic are quite common, being exceptionally lightweight, offering quick braking response, and demonstrating strong heat resistance during track driving. Regular cast iron discs on ordinary cars are prone to deformation or wear under intense use, whereas carbon ceramic maintains stability, significantly enhancing handling safety. The downside is the high cost—one carbon ceramic disc can cost as much as ten cast iron discs, doubling maintenance expenses. Material choice also depends on the vehicle's purpose: economical family cars can stick with cast iron for affordability and easy parts availability, but speed-focused models justify the investment in carbon ceramic to prevent brake fade risks. Knowing this, I now pay closer attention to material specifications when buying a car to match my driving needs.
As a car owner, I've replaced brake discs myself and learned that they are mostly made of cast iron, which is affordable, costing a few hundred yuan per disc, and easy to purchase as new parts. During maintenance, I found that although cast iron discs are durable, they require regular rust prevention cleaning, such as wiping the disc surface dry after washing the car to avoid brake noise. Material differences affect replacement cycles; cast iron discs typically need inspection after tens of thousands of kilometers, while high-end cars use carbon ceramics, which have a longer lifespan. Be careful not to buy inferior materials, and check the thickness to ensure safety. Simply remember: the material determines braking efficiency and cost.
