PURPOSE: To obtain inexpensively a tension leg material of a production platform without forging by bending a square metallic plate in which a part corresponding to thick part of the tube is thick into a tubular body and welding the joint.
CONSTITUTION: A tube 1 to be manufactured consists of a thin part 2 and a thick part 3 bulged to outer diameter side. A plate 11 from which the tube 1 is manufactured is made by cutting the central part of a thick plate by machining. Or, it can be obtained easily by forming a thin part 16 in a plate 15 in which a thick part 17 is bulged vertically from the thin part 16 by increasing rolling reduction during rolling of the plate, and a plate 11 is made by scraping one side of the thick part 17. The length and width of the plate 11 are made as specified and thickness t3 of the thick part 13 is made slightly thicker than the thick part 3 of the tube. Then, the plate 11 is bent by a press bender etc. to make the radius of curvature of neutral face of thick part 3 of the tube nearly coincide with the radius of curvature of the thin part 2 of the tube. The joint 9 of the tubular body 8 is welded to obtain a tube 1.
TSUYAMA YOSHITO
NOUDO NOBUO
NISHIMURA SHIYOUZOU
NISHIMURA KOUKI KK
Next Patent: MANUFACTURE OF SPIRAL STEEL PIPE