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:
May. 17, 2011
Filed:
Sep. 01, 2005
Yasuhide Ishiguro, Chiyoda-ku, JP;
Yoshikazu Kawabata, Chiyoda-ku, JP;
Kei Sakata, Chiyoda-ku, JP;
Masayuki Sakaguchi, Chiyoda-ku, JP;
Masayoshi Ishida, Chiyoda-ku, JP;
Motoaki Itadani, Chiyoda-ku, JP;
Yasue Koyama, Chiyoda-ku, JP;
Yasuhide Ishiguro, Chiyoda-ku, JP;
Yoshikazu Kawabata, Chiyoda-ku, JP;
Kei Sakata, Chiyoda-ku, JP;
Masayuki Sakaguchi, Chiyoda-ku, JP;
Masayoshi Ishida, Chiyoda-ku, JP;
Motoaki Itadani, Chiyoda-ku, JP;
Yasue Koyama, Chiyoda-ku, JP;
JFE Steel Corporation, , JP;
Abstract
A steel pipe blank having a composition containing 0.5% or less C and 85% or more Fe in terms of mass percent is heated, and stretch-reducing is then performed so that the diameter decrease ratio is 15% or more and the rolling finishing temperature is (the Artransformation point−10)° C. or lower. Consequently, a structure in which the ratio of X-ray diffraction intensity obtained from the plane in which the <100> direction of crystal grains is preferentially oriented parallel to the circumference direction and the <011> direction of crystal grains is preferentially oriented parallel to the rolling direction of the steel pipe to that obtained for a three-dimensionally randomly oriented sample is 3.0 or more is formed, and the r-value is increased, thereby improving the magnetic properties of the steel pipe.