Tribological Behavior of Solid Lubricant Films on Bare and Coated Sheet Steel Products

Comparative studies have been made on the tribological behavior of liquid and solid lubricants on bare and coated sheet steel products using laboratory friction and forming equipment. Friction or wear tendencies were quantitatively assessed in terms of static and dynamic friction coefficients, percent elongation, surface morphology changes, and chatter. The effect of the temperature and solid film lubricant hardness on friction and wear was examined. The phenomenon of chatter was recorded from an accelerometer attached to the test die. Significant improvements in friction reduction and anti-galling and anti-chatter tendencies were observed on sheet steel products coated with solid lubricant films. A greater degree of formability, prior to failure, was demonstrated by the LDH test on samples coated with solid lubricant films. A combination of empirical results was used to successfully predict field performance; namely, improved formability and reduced galling severity on bare and coated sheet steel products coated with solid lubricant films during actual press line stamping conditions.