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:
Apr. 19, 2011
Filed:
Apr. 27, 2010
Toshirou Tomida, Hyogo, JP;
Norio Imai, Hyogo, JP;
Mitsuru Yoshida, Sanda, JP;
Kaori Kawano, Neyagawa, JP;
Masayuki Wakita, Nishinomiya, JP;
Tamotsu Toki, Hyogo, JP;
Masanori Yasuyama, Hyogo, JP;
Hitomi Nishibata, Hyogo, JP;
Toshirou Tomida, Hyogo, JP;
Norio Imai, Hyogo, JP;
Mitsuru Yoshida, Sanda, JP;
Kaori Kawano, Neyagawa, JP;
Masayuki Wakita, Nishinomiya, JP;
Tamotsu Toki, Hyogo, JP;
Masanori Yasuyama, Hyogo, JP;
Hitomi Nishibata, Hyogo, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A cold-rolled steel sheet of carbon steel or low-alloy steel comprising C: 0.01 to 0.25% by mass with a ferrite main phase is has an average ferrite crystal grain diameter D (μm) at the depth of ¼ of the sheet thickness from the steel sheet surface satisfying formulas (5,6) and the increase rate X (μm/min) in average ferrite crystal grain diameter at 700° C. at the depth of ¼ of the sheet thickness from the steel sheet surface and D (μm) satisfying formula (3):1.2≦D≦9.3  (5)≦5.0−2.0·Cr+5000/(5+350·C+40·Mn)2  (6)≦0.1  (3)and, at said ¼ inch depth, the area percentage of ferrite crystal grains the crystal grain diameter d (μm) of which satisfying formula (4) is at least 80%:/3≦≦3  (4)wherein C, Cr and Mn represent mass % of the respective elements in the steel.