To provide a thin steel pipe for automobiles which has rigid closed sections and varied diameters in the longitudinal direction of the steel pipe and is appropriate as a structural member, and to provide a manufacturing technology therefor.
A high-tensile strength steel plate, whose thickness t is 0.4-5.0 mm and one or both sides of which are widened, is made spiral. In the spiral steel pipe, its outside diameter D is 300 mm or below, its thin pipe ratio V defined as V=t/D is 0.3-2%, and its section has varied diameters. The spiral steel pipe can be a structural member of an automobile by forming one or both ends of an expanded pipe or a contracted pipe. This makes it possible to manufacture a thin small-diameter steel pipe with the thin pipe ratio V which cannot be formed by an electric resistance welded steel pipe.
| WO/1982/002156 | DEVICE FOR HELICAL ARRANGEMENT OF BODIES OF HIGH-PRESSURE VESSELS |
| JPH08117843 | PRODUCTION OF COMPOSITE PIPE |
HIROSHIGE ITSURO
Fumio Yamamoto
Yukine Sekine
Kita Shizuo
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