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:
Nov. 19, 2013
Filed:
Jan. 08, 2008
Akihito Yamane, Osaka, JP;
Akihito Yamane, Osaka, JP;
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Abstract
The present invention provides a mandrel mill and the like that is capable of not only enhancing the elongation ratio of the pipe or tube, but also suppressing a pinhole defect from occurring. The first means of the present invention provides a mandrel mill comprising a plurality of rolling stands in which two grooved rolls R, Rare disposed, respectively, the mandrel mill being characterized in that the roll diameter ratio for the first rolling stand and the second rolling stand is set at a value of 4.6 or over. The second means of the present invention provides a mandrel mill comprising a plurality of rolling stands in which three grooved rolls R, Rand Rare disposed, respectively, the mandrel mill being characterized in that the roll diameter ratio for the first rolling stand and the second rolling stand is set at a value of 2.8 or over.