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:
Feb. 01, 2011
Filed:
Apr. 27, 2010
Toshirou Tomida, Hyogo, JP;
Norio Imai, Hyogo, JP;
Mitsuru Yoshida, Hyogo, 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, Hyogo, 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 steel sheet excellent in mechanical strength, workability and thermal stability and suited for use as a raw material in such fields of manufacturing automobiles, household electric appliances, machine structures, and of constructing buildings, and a manufacturing method thereof is provided. The steel sheet is a hot-rolled steel sheet of a carbon steel or low-alloy steel, the main phase of which is ferrite, and is characterized in that the average ferrite crystal grain diameter D(μm) at the depth of ¼ of the sheet thickness from the steel sheet surface satisfies the relations respectively defined by formulas (1) and (2) given below 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 said average crystal grain diameter D(μm) satisfy the relation defined by the formula (3) given below:1.2≦D≦7  formula (1)≦2.7+5000/(5+350·C+40·Mn)  formula (2)≦0.1  formula (3)wherein C and Mn represent the content (in % by mass) of the respective elements in the steel.