Physiothermodynamics of Lubricant Deposition on Hot Die Surfaces

This paper presents a methodology for studying lubricant behaviour during spraying on hot die surfaces. It consists of a single droplet test to study the thermo-physical phenomena and a “similitude” based approach to extend the results to geometrically complex nozzle sprays. This methodology is applied to the published results on the cooling of hot forging die surfaces and is found to predict both the magnitude and trends reasonably well. It is observed that graphite in water lubricants with high dilutions provide heat transfer coefficients similar to that of pure water while low dilutions provide lower coefficients and longer dryoff times.