| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a metallic double pipe in which surface pressure can be generated on the interface between the internal pipe and the external pipe of an obtained metallic double pipe regardless of the yield strength of the internal pipe and the external pipe. SOLUTION: In the method of manufacturing the metallic double pipe 1 by bringing the outside of the internal pipe 1a into contact with the inside of the external pipe 1b by a cold drawing using an R die 2 as a working die, the radius of curvature of the approaching part 2a of the R die 2 is taken as 10-90 mm and, by performing diameter reduction by hollow sinking, the surface pressure is generated on the interface between the internal pipe 1a and the external pipe 1b. Similarly, even when a tapered die is used as a working die, by taking both angles of the approaching part as 8-30°, performing a diameter reducing work by thickening work and, furthermore, performing the diameter expanding work of the internal pipe with an inside expanding plug, the surface pressure is generated on the interface between the internal pipe and the external pipe of the double pipe regardless of the yield strength of the internal pipe and the external pipe. COPYRIGHT: (C)2011,JPO&INPIT
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