Influence of ultrasonic vibration on friction and wear performance of brake disc

Abstract

In order to effectively improve the friction and wear performance of the brake disc without changing the raw materials and process flow, ultrasonic vibration was proposed and verified in this paper. During the casting process, ultrasonic waves with excitation frequency of 20 kHz and 25 kHz were applied to prepare the sample of the brake disc. Based on the Link3900 NVH test bench, the pressure, speed and temperature sensors were installed to obtain the variation rules of the average friction coefficient and friction stability coefficient under different working conditions. The friction samples were processed by ultrasonic cleaner and measured by high-precision electronic balance, the wear quality change rule at different times was obtained. The hardness study was carried out synchronously with the metallographic test by using the sample test method, thus the influence of ultrasonic vibration on the microstructure and surface hardness was obtained. Combining with the element distribution test results, the influence mechanism of ultrasonic vibration on wear resistance was explained by analyzing the micro wear morphology with electron probe microscope. The results show that applying ultrasonic vibration to the brake disc casting process can significantly improve the hardness, wear resistance and friction stability of the product, especially when the excitation frequency is 20 kHz, better effect can be achieved.