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. 16, 2010
Filed:
Sep. 02, 2004
Tatsuo Yokoi, Oita, JP;
Tetsuya Yamada, Oita, JP;
Osamu Kawano, Oita, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
An exemplary hot rolled steel sheet can included, in terms of percent by mass, C of 0.01 to 0.2%; Si of 0.01 to 2%; Mn of 0.1 to 2%; P of ≦0.1%; S of ≦0.03%; Al of 0.001 to 0.1%; N of ≦ 0.01%; and as a remainder, Fe and unavoidable impurities. For example, a microstructure can be substantially a homogeneous continuous-cooled microstructure, and an average grain size of the microstructure may be more than 8 μm and 30 μm or less. An exemplary method for manufacturing a hot rolled steel sheet can include subjecting a slab having the above composition to a rough rolling so as to obtain a rough rolled bar, subjecting the rough rolled bar to a finish rolling so as to obtain a rolled steel under conditions in which a finishing temperature is (Ar3 transformation point +50° C.) or more; and starting cooling the rolled steel after 0.5 seconds or more pass from the end of the finish rolling at a temperature of the Ar3 transformation point or more. At least in the temperature range from the Ar3 transformation point can be cooled to 500° C. at a cooling rate of 80°C./sec or more, a further cooling can be effectuated until the temperature is 500° C. or less to obtain a hot rolled steel sheet and coiling the hot rolled steel sheet.