Development of Disc Brake Rotors for Heavy- and Medium-Duty Trucks with High Thermal Fatigue Strength

Thermal fatigue strength has recently become the most important performance required of disc brake rotors for heavy- and medium-duty trucks. Accordingly, gray cast iron with added nickel has been used for disc brake rotors. In this study, an evaluation method for thermal fatigue strength during simulation tests has been established, and it has been found that thermal fatigue strength is improved as graphite in the microstructure gets refined. The graphite gets more refined in proportion to the added amount of nickel or as a result of cerium inoculation. Therefore, by combining cerium inoculation with nickel addition, a low-cost disc brake rotor for heavy- and medium-duty trucks with high thermal fatigue strength has been developed.