The Infiltration of Lubricants in a Porous Briquette During Pressing

Abstract

The migration of the boundary layer of lubricant in a porous briquette during pressing is investigated. It is found out that the density of briquettes compacted of a mixture of iron and graphite powders with the addition of animal fat hardly increases with increasing holding under the load, while the ejection pressure increases substantially. It is assumed that the ejection pressure increases due to the extrusion of a lubricant (from the layer between briquette and mold surface) into the pores of the briquette. This leads to a thinning disrupting the continuity of the lubrication layer and, accordingly, is giving rise to the external contact friction. The conducted studies allow not only predicting the behavior of viscous lubricants, but also enhancing the possibilities of impregnating the briquettes, sintered under high pressure in the mold in vacuum.