The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 05, 1988
Filed:
Jul. 11, 1985
Shigetomo Matsui, Higashiosaka, JP;
Hisao Hasegawa, Kobe, JP;
Kawasaki Jukogyo Kabushiki Kaisha, Hyogo, JP;
Abstract
In the manufacture of welded pipes, edge buckling or waving of the strip is prevented by heating. In one method, during the process for bending the strip into a tubular form, the edges of the strip are heated so that tensile stress exerted thereon is reduced to a minimum and, thereafter, before the edges are abutted against each other, the strip is wholly heated so that the compressive stress exerted on the edges is reduced to a minimum. According to another mode, during the process for bending the strip gradually into a tubular form or during the process in which the edges of the strip are held in abutment against each other, the strip except its portions at the edges is substantially or partially heated so that the strip except its portions at the edges is subjected to compressive stress while the portions of the edges are subjected to tensile stress, and under these conditions the edges are welded together.