Evaluation of friction using double cup and spike forging test for dry-in-place coating and forming oils

Abstract

The friction characteristics of lubricants were evaluated using the double cup and spike forging tests. Friction calibration curves, i.e., plots of cup height ratio vs. punch stroke and spike height vs. punch stroke, were established through finite element (FE) simulations considering various friction factor values. The friction factor of the lubricants was determined by matching the relationships of the cup height ratio and spike height with the punch stroke obtained from experiments to those obtained from the FE simulations. Under the lubricating condition of dry-in-place coating with forming oil, the results showed that different tribo-testing methods yielded different friction factors. The friction factor determined was applied in the FE simulation of a cold forging process of a claw pole.