Influence of silicon carbide filters in cast iron composite brake blocks on brake performance and development of a production process

Abstract

Cast iron composite brake blocks, which include silicon carbide (SiC) ceramic filters, have been developed for increased speeds in conventional trains. However, it is assumed that they would cause thermal loads to increase because filters in them are much harder than cast iron. It is necessary to decrease them on wheel treads while maintaining the high friction coefficient characteristics during high-speed travel. Cast iron composite brake blocks in which the number of filters and the area fraction of SiC in the filter are varied have been tested on a full-scale dynamometer. They have been developed to provide excellent brake performance at high-speeds even if the area fraction of SiC on the friction surface is decreased. In addition, with the development of new production process, it has been possible to mass-produce cast iron composite brake blocks without increasing the length of the production process. Furthermore, it has been found that the brake block temperature is related to the friction coefficient and that SiC inclusion in the brake block prevents an increase in temperature and increases the friction coefficient.