Influence of Braking Speed on the Friction and Wear Characteristics of High-Speed Railway Braking Materials under High Ambient Humidity Conditions

The friction and wear tests of high-speed railway braking materials for a variety of braking speeds (600, 400, and 200 rad/min) at 65% and 98% RH RH (RH: relative humidity) were carried out utilizing a friction-testing machine and humidity generator. The research results indicate that braking speeds and ambient humidity have a prominent influence on the friction and wear characteristics of high-speed railway braking materials. At 65% and 98% RH, the lower the braking speed, the lower the wear rate, and the better the wear resistance property of the braking material. Furthermore, at 600 rad/min, the wear rate of the braking material at 98% RH was smaller than that at 65% RH. However, at 200 rad/min, the wear rate of the braking material at 98% RH was greater compared to that at 65% RH. Concretely, at 600 rad/min, compared with 65% RH, the wear rate to the brake disc at 98% RH was reduced by about 9%, and the brake pin decreased by about 6%. However, at 200 rad/min, compared to 65% RH, the wear rate to the brake disc at 98% RH increased by about 39%, and the brake pin increased by about 37%.