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. 12, 2006
Filed:
Jan. 13, 2006
Chihiro Hayashi, Sendai, JP;
Chihiro Hayashi, Sendai, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A piercing method for manufacturing a seamless pipe capable of suppressing the rotary forging effects and suppressing the redundant shear strain without excessive narrowing of the roll diameter is provided. This method is characterized by holding a feed angle β and a cross angle γ of main rolls in a range satisfying the following expressions (1) to (3), setting the relationship between outer diameter 'd' of the solid billet and the outer diameter 'd' and thickness “t” of a hollow piece after piercing so as to satisfy the following expression (4), and further setting the relationship between inlet diameter Dand outlet diameter Dof the main roll with the above-mentioned “d”, “d” and γ so as to satisfy the following expression (5)8°≦β≦20°  (1)5°≦γ≦35°  (2)15°≦β+γ≦50°  (3)1.5≦−ψ/ψ≦4.5  (4)()/(0.75+0.025γ)≦  (5)In the expression (4), ψ=1n(2t/d) and ψ=1n{2(d−t)/d}.