PURPOSE: To improve product quality by supplying an ignition additive through the through-hole provided to the central part of a mandrel to burn the carbonized lubricant stuck on the inside surface of a tubular product which is extruded successively, and removing the same simultaneously with the extrusion stage.
CONSTITUTION: A lubricant of org. base is interposed between a mandrel 6 and a billet 3, and a tubular product is extruded by means of a die 2 and the mandrel 6. At this time, a through-hole 8 is provided at the center of the mandrel 6, and an ignition additive or a mixture of the ignition additive and water is supplied to this inside surface of the pipe through said hole 8. Thereby, the unburned carbonized product existing in the pipe is completely burned by this together with high-temp. extrusion heat, and is removed from the inside of the pipe.
NOGUCHI MASATAKA
OOTE AKIRA
ARIMURA KAZUO
KIMURA TETSUO
IWAI AKIRA
HAYASHIDA NOBUO
