DEVELOPMENT OF HEAVY-DUTY Al-GRAPHITE BASED BEARING MATERIALS AND THEIR CHARACTERIZATION

Abstract

Powder metallurgy is fast growing field for production of engineering components. Aluminium alloys, owing to their properties, have a strong potential for use as bearings. Their use in antifriction application in combination with graphite has evoked new interest among the material engineers. Particularly in view of the fact that tin and lead is now discarded in favor of' graphite due to cost and toxic effect respectively during manufacture and usage of bearings. An attempt is made to develop Al-1 and 2 wt. %graphite alloys by powder metallurgy route. Compacting and sintering is substituted by direct hot forging of A1-graphite powder system into finished shape such that porosity is completely eliminated. Wear characteristic of different composition in dry and lubricated condition was tested on pin-on-disc machine. Al-2% graphite has been found to be more wear resistant than Al-l% graphite in lubricated condition. Both the compositions (A1-1% and 2% graphite) wear less in lubricated condition than that in dry condition and these results are compared with Al-20.6% Pb and Al-20.3% Sn and it is found that A1-graphite wear much less than these alloys in the same pressure condition.