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.

Date of Patent:
Nov. 29, 2022

Filed:

Nov. 22, 2018
Applicant:

Nippon Steel Corporation, Tokyo, JP;

Inventors:

Tetsuya Hirashima, Tokyo, JP;

Takeshi Toyoda, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/12 (2006.01); C22C 38/08 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01);
U.S. Cl.
CPC ...
C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

Provided is a hot rolled steel sheet comprising a predetermined composition wherein the hot rolled steel sheet comprises ferrite with an average orientation difference in the same grain of 0.5 to 5.0° in 30 to 70 vol %, the ferrite and martensite in a total of 90 vol % or more, and a balance microstructure of 10 vol % or less, has an average grain size of the ferrite of 0.5 to 5.0 μm, and has an average grain size of the martensite and the balance microstructure of 1.0 to 10 μm. Provided is a method for producing a hot rolled steel sheet comprising rolling where two or more consecutive passes of rolling including a final pass are performed under conditions of a rolling temperature: A point or more and less than Aepoint, a strain rate: 1.0 to 50/sec, and a time between passes: within 10 seconds and where a total strain amount of all passes satisfying the conditions is 1.4 to 4.0, cooling by a 20° C./sec or more average cooling rate, and coiling the steel sheet at room temperature or more and less than 300° C.


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