Fluid film lubrication for extrusion of metal

Claim 1

IN A METHOD WHEREIN A METAL BILLET OR WORKPIECE IS EXTRUDED FROM AN EXTRUSION CHAMBER AND THROUGH A DIE POSITIONED AT AN END OF SAID CHAMBER WHILE THE BILLET IS AT A HIGHER TEMPERATURE THAN THE EXTRUSION CHAMBER WALL AND THE DIE WALL, THE IMPROVEMENT WHICH COMPRISES HAVING INTERPOSED BETWEEN SAID BILLET AND SAID CHAMBER WALLS AND BETWEEN SAID BILLET AND SAID DIE WALLS, DURING THE EXTRUSION PROCESS, A PLURALITY OF CONTIGUOUS LAYERS OF GLASS HAVING DIFFERENT VISCOSITY CHARACTERISTICS, THE GLASS OF THE LAYER NEXT TO AND IN CONTACT WITH SAID BILLET HAVING THE HIGHEST FIBER SOFTENING POINT, AND SUCCEEDING LAYERS OF GLASS HAVING PROGRESSIVELY LOWER FIBER SOFTENING POINTS, EACH LAYER OF GLASS BEING MOLTEN AND OF A VISCOSITY EFFECTIVE TO WET AND COAT THE SURFACES IN CONTACT THEREWITH DURING EXTRUSION OF SAID BILLET, WHEREBY THE FORCE REQUIRED TO ACCOMPLISH SAID EXTRUSION IS LESS THAN IN THE ABSENCE OF SAID LAYER OF MOLTEN GLASS.