| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a metal tube by extrusion, a mandrel and an extruding machine by which the quality is improved by preventing defective thickness deviation in the peripheral direction and the longitudinal direction of the metal tube to be manufactured and preventing defective appearance because of defective seizure or the like. SOLUTION: The method of manufacturing the metal tube by the extrusion using the mandrel which is extended in the extruding direction of a metallic material and with which the inner periphery of the metal tube to be manufactured is formed, and a die with which the outer periphery of the metal tube is formed, comprises: a heating stage for heating the mandrel; a temperature adjusting stage where the temperature of the mandrel is adjusted to the target setting temperature of the extrusion and an extruding stage where the metallic material is extruded. The temperature adjusting stage includes: a work for heating the mandrel with a burner and applying a lubricant to the mandrel; a work for lowering the temperature of the mandrel by flowing a fluid in the inside of the mandrel and a work for confirming the temperature difference in the longitudinal direction in which the mandrel is extended. COPYRIGHT: (C)2010,JPO&INPIT
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