The roles of adhesion, internal heat generation and elevated temperatures in normally loaded, sliding rough surfaces

TL;DR

This study investigates how adhesion, heat generation, and high temperatures influence galling wear in sliding rough surfaces, using a crystal plasticity model to predict behavior and compare with experimental data.

Contribution

It introduces a model that accounts for thermal effects and adhesion in galling prediction, highlighting the limited impact of localized heating and the temperature dependence of galling resistance.

Findings

Plastic and frictional heating have minimal effect on surface deformation.

Elevated temperatures decrease galling resistance due to material softening.

Model predictions align with literature but suggest other mechanisms also influence galling.

Abstract

The thermal effects of plastic and frictional heat generation and elevated temperature were examined along with the role of adhesion in the context of galling wear, using a representative crystal plasticity, normally loaded, sliding surface model. Galling frequency behaviour was predicted for 316L steel. Deformation of the surfaces was dominated by the surface geometry, with no significant effect due to variations in frictional models. Plastic and frictional heating were found to have a minimal effect on the deformation of the surface, with the rapid conduction of heat preventing any highly localised heating. There was no corresponding effect on the predicted galling frequency response. Isothermal, elevated temperature conditions caused a decrease in galling resistance, driven by the temperature sensitivity of the critical resolved shear stress. The extent of deformation, as quantified by the area of plastically deformed material and plastic reach, increased with temperature. Comparisons were made with literature results for several surface amplitude and wavelength conditions. Model results compared favourably with those in the literature. However, the reduction in predicted galling resistance with elevated temperature for a fixed surface was not as severe as observations in the literature, suggesting other mechanisms (e.g. phase transformations, surface coatings and oxides) are likely important.