Lubricant Film Breakdown
ICFG Friction and Lubricant Benchmark Study
A simulative test based on a backward can extrusion twist test has been offered for testing of zinc phosphate coated and soap lubricated C-steel slugs provided by the International Cold Forging Group (ICFG). The backward can extrusion twist test allows for a direct friction stress measurement in a process experiencing high surface expansion and a high normal pressure, where the friction stress in the tool/workpiece interface can be determined while investigating possible beakdown of the lubricant film. In this study, no lubricant film breakdown and galling were observed. Friction was lowered significantly at higher tool temperatures. The test proved that it is important to evaluate possible lubricant break down of the best lubrication systems due to severe stressing of the lubrication systems at varying tool temperature.
To know more about the topic, please read the following publications
Groche, P., Kramer, P., Bay, N., Christiansen, P., Dubar, L., Hayakawa, K., … & Moreau, P. (2018). Friction coefficients in cold forging: A global perspective. CIRP Annals, 67(1), 261-264.