Back to results
US 4,796,797 AGranted
Method for making thin-walled metal pipes
AssigneeNisshin Steel Co., Ltd.
InventorsTakefumi Nakako, Shoji Inoue, Akinobu Takezoe
Life of this patent
Estimating the term…
Abstract
In a method for making thin-walled metal pipes, application of a pre-deformation to a metal sheet by plastic bending longitudinally perpendicular thereto, and forming the metal sheet into a pipelike shape by use of the widthwise curvature resulting from residual stress of the metal sheet receiving such plastic bending, when its lengthwise curvature is reduced to zero, the metal sheet being joined together at its junction.
Claims9
A method for making thin-walled metal pipes, comprising the steps of:
- subjecting a metal sheet to lengthwise plastic bending by means of a small-diameter bending roll with an axis disposed perpendicularly thereto, a face of said metal sheet which is to define the inside of the metal pipe turning inward,
- causing said metal sheet to bend itself widthwise into a pipelike shape by use of widthwise curvature resulting from residual stress of the metal sheet after receiving such plastic bending by reducing the lengthwise curvature of the metal sheet to zero, and
- joining longitudinal edges of said metal sheet together.
Dependencies are inferred from the claim text.