| 摘要 |
A double-walled tube is produced by providing an inner core tube and an outer casing tube, wherein the outer diameter of the inner core tube is smaller than the inner diameter of the outer casing tube, with consideration of manufacturing tolerances and/or noncircularity, by such a value that insertion of the core tube into the casing tube can easily be performed because of a sufficient amount of play, and the core tube is brought into abutment under the action of repeated, successive hardening steps with a stepped radial expansion, against the inner surface of the casing tube. |
