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:
Aug. 28, 2007
Filed:
Dec. 21, 2005
Kazuhiro Shimoda, Nishinomiya, JP;
Tomio Yamakawa, Kawanishi, JP;
Hiroyuki Semba, Sanda, JP;
Hirofumi Hori, Kainan, JP;
Tsuneo Kondo, Wakayama, JP;
Kazuhiro Shimoda, Nishinomiya, JP;
Tomio Yamakawa, Kawanishi, JP;
Hiroyuki Semba, Sanda, JP;
Hirofumi Hori, Kainan, JP;
Tsuneo Kondo, Wakayama, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A pierced shell of an austenitic stainless steel having a good inner surface condition is provided, and a means is established which can perform mass production on an industrial scale of a good quality seamless steel pipe of stainless steel. An austenitic stainless steel billet with a P content of at most 0.040% and an S content of at most 0.020% is pierced under conditions such that the pipe expansion ratio H (outer diameter of shell/diameter of billet to be worked) satisfies the following equation to obtain a tube shell of an austenitic stainless steel. {P(%)/(0.025×H−0.01)}+{S(%)/(0.015×H−0.01)}≦1. When manufacturing a seamless steel pipe of an austenitic stainless steel, the above-described shell is rolled to form a pipe.