SOME ASPECTS OF THE PRODUCTION AND USE OF SINTERED FRICTION MATERIALS

Abstract

Over the past two decades the extent to which sintered friction materials have been taken into use to give both better performance and life and hence lower running costs, is considerable. The greatest advantage has been gained in this respect in the heavy earth-moving industry, where the material is subjected to severe duty in applications such as steering gear, main drive, and power-transmission clutches. In the aircraft industry benefits fall into a different category. Here the accent is on weight-saving and smooth torque-control characteristic, together with high heat absorption over a relatively short time of operation and less frequent cycles.

Sintered friction material contains copper or iron as the basic constituents and other elements are added to vary the properties under both oil-lubricated and dry conditions of operation. Powders are blended together, pressed into a compact, placed on a copper- or nickel-plated steel plate, and stacked for heat-treatment to b6nd the compacts to the steel. The heat-treatment is carried out under pressure in a bell-type furnace at temperatures from 700 to 1100°C, according to the composition of the material. Subsequent processing may include slotting, grinding; and grooving, depending upon the service conditions of the finished plate.

There are some applications in which, because of price, sintered materials are not yet used, but it is probable that these will be incorporated as a result of the developments in manufacturing and materials now taking place.

Notes

* Manuscript received 3 June 1965. Contribution to a Symposium on “Factors Influencing the Economics of the Manufacture of Sintered Metal Components” to be held in London on 21 and 22 October 1965.