โ Scribed by J.A. Schey; G.M. Dalton
No coin nor oath required. For personal study only.
Bead-drawlng experiments were conducted with bare, hot-dlpped, electrogalvanlzed, and galvannealed steel sheets using parafflnlc base oils (of 4.5, 35, and 285 mmZ/s viscosity at 38 UC) with stearic acid, DBDS, TCP, and chlorlnated paraffin as additives. Values of coefficient of friction and optical and SEM examination indicated that mixed-film lubrication prevailed, with the boundary contact area decreasing with increasing lubricant viscosity. Sub-microscoplc features of electro-galvanized and galvannealed sheet helped in the retention of lubricants. Zinc on its own proved to be a poor lubricant. Additives were, in general, only moderately effective and in some instances even increased friction and surface damage.
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