| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a metallic hollow material having high dimension accuracy. SOLUTION: A through-hole passing from the outer surface of the hollow material to the hollow part thereof is intermittently formed during an extrusion process for extrusion-molding the hollow material from a billet of a metallic material. Outside air is supplied to the hollow part from the through-hole, and this prevents the hollow part 71 from being excessively reduced in pressure. As a result, the deformation of the hollow material is reduced or prevented even when it is thin, and the metallic hollow material having the high dimension accuracy can be obtained. COPYRIGHT: (C)2010,JPO&INPIT
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