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:
Dec. 13, 2011
Filed:
Jan. 21, 2010
Tatsuya Okui, Osaka, JP;
Kouichi Kuroda, Osaka, JP;
Tadashi Kawakami, Osaka, JP;
Sumitomo Metal Industries, Ltd., Osaka-shi, JP;
Abstract
A plugincludes a first columnar portion, a tapered portion, and a second columnar portion. The first columnar portionhas an outside diameter D. The second columnar portionhas an outside diameter Dwhich is larger than the outside diameter D. The tapered portionis formed between the first columnar portionand the second columnar portion. The tapered portionhas a tapered surfaceprovided with an outside diameter which is gradually increased from the first columnar portionto the second columnar portion, and an axial direction length L. The outside diameters Dand D, and the axial direction length L meet the following expressions (1) to (4):0.25≦ρ≦2.00  (1),0.06≦2≦0.8  (2),2≦0.3×ρ+0.575  (3), and2≧0.1×ρ  (4)where ρ=(2−1)/1×100.Therefore, the cold drawing plug according to the present invention can reduce the tensile residual stress on the outer surface of a metal pipe after the cold drawing.