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:
Aug. 06, 2002
Filed:
Apr. 03, 2001
Johannes Gross-Weege, Krefeld, DE;
Detlef Ramdohr, Krefeld, DE;
Mannesmann AG, Düsseldorf, DE;
Abstract
The invention related to a process for producing pipes, especially large pipes, as per the UOE process, wherein the pipes, after internal and external seam welding, are incrementally calibrated by cold expansion up to half the pipe length. The cold expansion is also used for straightening. For this purpose, the pipe is clamped at the shortest possible distance in front of the expander head, the free pipe end is flexibley deformed, and the pipe is then cold expanded in a known manner. The prestress force thereby decreases and then, after the release of the clamping and the remaining prestress, the pipe moves incrementally by the amount of the expander step width, up to half the pipe length. The process is then repeated for the second pipe half.