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:
Oct. 25, 1994
Filed:
Nov. 29, 1993
Johann H Rohde, Ratingen, DE;
Burkhart Schifferings, Duisburg, DE;
Rolf Kummerling, Duisburg, DE;
Jochen Vochsen, Monchengladbach, DE;
Karl H Hausler, Korschenbroich, DE;
Gunther Voswinckel, Monchengladbach, DE;
Mannesmann Aktiengesellschaft, Dusseldorf, DE;
Abstract
A method of longitudinal rolling of seamless pipes in a continuous rolling procedure on an internal tool in a multiple-stand rolling train, wherein the rolls of successive rolling stands are mounted off set relative to each other. In accordance with the present invention, in a first of only two successive rolling passes, a roll thickness reduction is produced with opened roll groove sides in the roll groove bottom which reduction corresponds to or is slightly greater than the roll thickness of the finished pipe. In the second rolling pass, the side portion of the first rolling pass is reduced in the direction of the width to the wall thickness of the finished pipe in the roll groove bottom of the second rolling pass. By simultaneously applying a controlled tensile force on the pipe between the two rolling passes, the increase of the circumference of the pipe due to spreading is reduced by stretching the pipe in the direction of its longitudinal axis without reducing the wall thickness or with only a slight reduction of the wall thickness.