Frictional characteristics of fatty-based oils in wire drawing

Abstract

Lubricity criteria of fatty-based oils (palm, groundnut and shea butter oils) in wire drawing operations have been qualitatively assessed based on friction values obtained from the experimental procedure of Evans and Avitzur ( J. Lubr. Technol. Trans. ASME, Ser. F, 90 (1) (1968) 72–89). for friction evaluation for processes like wire drawing and extrusion through open dies. The potentials of these oils as lubricants for steel drawing operations ranked in descending order as palm oil, shea butter and groundnut oil. Palm oil displayed a better performance than sodium stearate drawing lubricant used as standard. Although the performance of shea butter oil was nearly at par with the sodium stearate, the friction values obtained under these oils' lubrication conditions correlated well with the published frictional values obtained in steel drawing operations. The coefficient of friction of shea butter oil was the lowest in the drawing of copper. While the physicochemical properties of these local oils did enhance the performance of each oil as a drawing lubricant, the smut stains of the drawn steel and copper rods under palm oil were attributed to the generated metal and oxide debris that got entrapped in the polymeric film because of its tacky nature.