Study on the wear performance of high-speed railway brake materials at low temperatures under continuous braking conditions

Abstract

A simulated test was completed using pin-on-disc friction and wear test machine to simulate the wear performance of the high-speed railway braking disc and braking pad materials at different temperatures (20, 0, −10, −20, −30 °C) under continuous braking conditions. The results show that the low temperature has a significant effect on the wear characteristics of the brake material under continuous braking conditions. At the initial stage of continuous braking, the instantaneous coefficient of friction at low temperature reaches its maximum value at approximately 500 s, which is almost one half of the time of that at room temperature (20 °C). At each temperature, the instantaneous friction coefficient shows a trend of increasing firstly and then decreasing, and with the decrease in temperature, the average friction coefficient of brake disc material tends to increase at the stable stage of instantaneous friction coefficient. As the continuous braking time increases, the average coefficient of friction at low ambient temperatures is greater than that at room temperature (20 °C). As the temperature decreases, the wear rate of the brake material shows a trend of increasing and then decreasing. With the fall of temperature, the damage form of brake pad material changes from adhesion damage to abscission damage, while the brake disc damage changes from abrasive wear and adhesion wear to damage mixture of abrasive wear, adhesion wear and crack.