PURPOSE: To well lubricate an extruding part even in an extrusion process in which a dead metal part is formed, by previously providing a lubricating plate to the extruding bottom of an extrusion die in a forward extrusion process of metal.
CONSTITUTION: A lubricating plate 13 is obtained by mixing graphite powder serving as a solid lubricant and polyvinyl alcohol serving as a bonding agent and molding and solidifying them into a discoidal plate. A blank material 22 is put on the plate 13 provided to the extruding bottom of a mold 17, and is pressed from an upper side by a punch to extrude the material from a delivery part 20 of extrusion. The plate 13 flows with progress of extruding process and is extruded from the part 20 while adhering to the surface of the extrusion part of an extruded product, to mold the extruded product without extrusion corners.
ASAO HIROSHI
OKADA KENICHI
WATANABE SHINOBU
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