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:
Dec. 27, 2016

Filed:

Sep. 02, 2011
Applicants:

Izuru Minato, Kashima, JP;

Nobuaki Takahashi, Kashima, JP;

Akio Yamamoto, Kashima, JP;

Inventors:

Izuru Minato, Kashima, JP;

Nobuaki Takahashi, Kashima, JP;

Akio Yamamoto, Kashima, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C22C 38/50 (2006.01); C21D 8/02 (2006.01); C22C 38/58 (2006.01); F16L 9/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01);
U.S. Cl.
CPC ...
C22C 38/50 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/58 (2013.01); F16L 9/02 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/009 (2013.01);
Abstract

A high-strength steel sheet having improved HIC resistance and fracture resistance even when it is thick has a chemical composition comprising, in mass %, C: 0.02-0.07%, Si: 0.05-0.50%, Mn: 1.10-1.60%, P: at most 0.015%, S: at most 0.0030%, Nb: 0.005-0.030%, Ti: 0.005-0.020%, Al: 0.005-0.060%, Ca: 0.0005-0.0060%, N: 0.0015-0.0070%, at least one of Cu, Ni, Cr, and Mo in a total of greater than 0.1% to less than 1.5%, and a remainder of Fe and impurities and a steel structure composed of at least 10% by area of bainite and a remainder of ferrite and pearlite. The degree of segregation is less than 1.6 for Nb and less than 1.4 for Mn in the central portion of the thickness of the steel sheet.


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