• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.29-37
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• 2000

At present there are many theories as to how various lubricants used in forging perform the role of reducing friction. Little work has been carried out to determine the validity of these theories for solid lubricants. This paper covers the development and preliminary results of the experiments devised to illustrate the movement of graphite at the workpiece/tool interface in the work forging temperature range. The paper describes the results obtained from upsetting of rings between two flat dies for measurement of lubricant thickness and compaction of graphite for density-pressure relationship. These allowed the lubricant to be exposed to forging conditions and by applying the principles of Male's ring test the simple generation of a value fur friction factor could also be determined. The experiments have been undertaken to examine the behavior of lubricant for shot blasted surface and change of surface roughness. A simple computer model of the interface has been constructed characterizing the graphite layer in an attempt to simulate the boundary mechanics.