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:
Mar. 28, 2006
Filed:
Jun. 14, 2001
Takaaki Toyooka, Handa, JP;
Masanori Nishimori, Handa, JP;
Yoshikazu Kawabata, Handa, JP;
Akira Yorifuji, Handa, JP;
Motoaki Itadani, Handa, JP;
Takatoshi Okabe, Handa, JP;
Masatoshi Aratani, Handa, JP;
Takaaki Toyooka, Handa, JP;
Masanori Nishimori, Handa, JP;
Yoshikazu Kawabata, Handa, JP;
Akira Yorifuji, Handa, JP;
Motoaki Itadani, Handa, JP;
Takatoshi Okabe, Handa, JP;
Masatoshi Aratani, Handa, JP;
JFE Steel Corporation, Tokyo, JP;
Abstract
A steel tube having a composition which contains: 0.05 to 0.30% of C; 1.8 to 4.0% of Mn; Si; and Al is subjected to a diameter-reducing rolling process in which the total diameter-reduction rate is no less than 20% and the temperature at which the diameter-reducing rolling process is finished is no higher than 800° C., whereby a structure constituted of martensite and/or bainite or further of ferrite is obtained as a transformation product from the deformed γ. As a result, a steel tube having tensile strength of 1000 MPa or more and excellent three-point-bending property can be obtained. The composition of the steel tube of the present invention may further include at least one type of element selected from the group consisting of Cu, Ni, Cr and Mo, or at least one type of element selected from the group consisting of Nb, V, Ti and B, or at least of one type selected from the group consisting of REM and Ca.