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. 11, 1977
Filed:
Jul. 19, 1976
Seishiro Yoshiwara, Kitakyushu, JA;
Minoru Kawaharada, Kitakyushu, JA;
Samon Yanagimoto, Kitakyushu, JA;
Nippon Steel Corporation, Tokyo, JA;
Abstract
A method of producing a cylindrical metallic tubular body in a press roll piercing mill. The method involves applying a pressing force to a polygonal metal billet in the axial direction thereof while guiding the billet by means of a guide during its advance, rolling corner portions of the billet to a certain degree with a pair of rolling rolls having semicircular grooves disposed above and below the billet prior to the contacting of a plug with the center of the front end surface of the billet, and successively piercing the billet by means of the plug while the billet is rolled, the tip portion the plug being retained on the pass center line by the rolling rolls.