Temperatures at the interface and inside an oscillatory sliding microcontact - theoretical part

J. Pezdirnik, J. Vižintin, B. Podgornik

Tribology International 32 (1999) 481–489.

Abstract

In machine parts a force is often transmitted from an oscillatory moving element to a stationary one or in the opposite direction. As the sliding contact surfaces of the elements do not have ideal shapes, a transverse force is sometimes transmitted only across asperities that stand out from one or from both sliding surfaces. These asperities can be deformed under a great enough force. For the case of plastic asperity deformation, the interface and subsurface temperatures at a single microcontact exposed to oscillatory sliding movement were calculated by means of a newly developed mathematical model. The calculated values for temperatures were compared with the temperatures which are known to be necessary for the observed changes in the microcontact's near subsurface microstructure for the tested steels and steel alloys. Experiments were carried out with real hydraulic valves and also with pairs of specimens which had geometric and functional testing parameters comparable to those of hydraulic valves at which surface spot damage sometimes occurs. Sometimes this damage resembles welded points.

Keywords: microcontact temperature, temperature gradient, microcontact interface, fretting, damage, sliding friction, asperity deformation, plastic deformation

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