The asbestos-free polymer based friction material filled by basalt and glass fibers obtained from Armenian minerals is developed for cargo railway brakes. The tribological characteristics of the developed material were revealed on a three-phase rational cycle of comparative tests. It is recommended to use them at the railways. Introduction. The comprehensive research towards the investigation of brake materials durability was carried out back in the 1980s, together with VNIIATI (TIIR, Yaroslavl, Russia). The basic regularity of high temperature friction and wear of the surface layers for traditional composite friction materials were established. They have opened new perspectives to create a more serviceable and, most importantly, environmentally safe friction materials. A new asbestos-free friction polymer materials type Bastenite have developed as a result based on combined binders, reinforcing fibers from Armenian deposit minerals (basalt and glass fibers) and friction additives (1,2). Railway transport in Armenia mainly uses shoes produced in Russia because of the lack of friction materials' domestic production. Widely used outputs of the Ural, Barnaul and Yaroslavl plants of asbestos products are applied. Therefore, the development of asbestos-free brake shoes for railway transport is an urgent task. To implement a large brake power on rail car in European countries sintered brake shoes are used with a stable all-weather friction coefficient, very high wear resistance, satisfactory thermal conductivity. They usually contain 40...50% bronze, 10...20% of aluminosilicates, 25...35% graphite and 5...15% iron powder, mixtures of which are formed into bricks in molds at high pressure and temperature, and run to a further heat treatment. Ingredients ratio varies depending on the average friction coefficient, due wear resistance, creating of a favorable impact on the tread-wheel, small wear of the working surface of the wheel without the formation of thermal cracks, freetings, burn marks, fouling and other defects. However, sintered shoes can cause large thermal load on the running surface of the wheels during braking process at high speeds and high power (up to 800 kW) on the wheel-set (3). Currently cast iron brake shoes are also applied in railway transport in a size, on the requirements of the European Railway Union. Technical requirements of these shoes regulated on the basis of TR-2571-028-00149386-2000 in the CIS countries (4).
Pogosian Albert, Meliksetyan Norik1, Mamulyan Nelson