International audienceThis study presents film thickness and friction measurements of the refrigerant R1233zd (E-1-chloro-3,3,3,trifluoropropene-1) in a tribological contact. For the film thickness, optical interferometry technique with glass–steel contact is used in a ball-disc configuration, whilst for the traction measurements (Stribeck and traction curves), a contact ceramic ball–steel disc is used. In both cases, the Wedeven Associates Machines-5 tribometer is employed. An attempt to model the film thickness results is also carried out. The model gives a reasonably good prediction with respect to the experiments
In the bearings’ segment of machine tools, there is a strong demand for high-performance steel solutions. The bearings may operate under severe conditions of contact pressures of up to 3 GPa; rotating at speed factors in excess of 3 million ndm. Such conditions pose a high risk of bearing seizure failure. Improving lubrication conditions is complex as the bearing operating temperature must be well controlled. Adhesive wear was found to occur in hybrid steel-ceramic contacts. Another relevant failure mode is micropitting. It is demonstrated that macroscopic hardness is insufficient to predict the resistance of steel microstructures to surface-initiated fatigue. In this regard, strain-hardening and the breadth of the range of hardness values of microstructure phases play an important role.
In the modelling and characterization of changes undergone by engineering surfaces from tribological processes, an automatic detection system is often required to minimize subjective elements of the assessment in the analysis. Microgeometry changes in tribological surfaces are indentations, scratches, micro-pits, micro-smearing marks and mild wear. The current paper presents some effective methods to detect depressions on machined surfaces (e.g. indentations, scratches and micropitting) and also mild wear (small changes in the actual surface topography). The theoretical background of the methods is discussed and application examples are illustrated. With this, it is expected that the reader can easily develop computer programs to implement the methods described here.
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