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Abstract
The lubrication condition of sliding concentrated steel contacts can be described in terms of transition diagrams, relating the mode of lubrication [i.e. (partial) elastohydrodynamic (EHD), boundary and virtually unlubricated] to load, speed and temperature.
Addition of 1 wt. percent zincdialkyldithiophosphate (ZDP) to mineral oil is found to increase the load-carrying capacity of both the EHD and the boundary film, provided that the lubricant contains free oxygen. Under argon cover, the beneficial effects of ZDP are lost.
Addition of 1 wt. percent dibenzyldisulfide (DBDS) affects only the load-carrying capacity of the boundary lubricant film. This effect is maintained under argon cover.
Increasing the percentage of chromium in the steel from 1.5 wt. percent to 5.6 wt. percent (simultaneously adding up to 1 wt. percent Mo and V), seriously impairs the load-carrying capacity of the boundary lubricant film, while that of the EHD film remains virtually unaffected. On the other hand, an increase in the amount of retained austenite (with corresponding coarsening of the structure and some decrease in hardness) mildly impairs boundary lubrication but enhances EHD lubrication.
The results are compared to those of other authors and conclusions are drawn with respect to correlations between the test methods used.
Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978
Notes
Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978