Invention Grant
- Patent Title: High-strength H-beam steel exhibiting excellent low-temperature toughness and method of manufacturing same
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Application No.: US14359620Application Date: 2012-12-12
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Publication No.: US09644372B2Publication Date: 2017-05-09
- Inventor: Kazutoshi Ichikawa , Teruyuki Wakatsuki , Noriaki Onodera , Kohichi Yamamoto
- Applicant: Nippon Steel & Sumitomo Metal Corporation
- Applicant Address: JP Tokyo
- Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
- Current Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Birch, Stewart, Kolasch & Birch, LLP
- Priority: JP2011-274278 20111215
- International Application: PCT/JP2012/082254 WO 20121212
- International Announcement: WO2013/089156 WO 20130620
- Main IPC: E04C3/32
- IPC: E04C3/32 ; E04C3/04 ; C22C38/00 ; C22C38/12 ; B21B1/088 ; C22C38/14 ; C22C38/58 ; C22C38/02 ; C22C38/04 ; C21D8/02 ; C22C38/06 ; C22C38/08 ; C22C38/16 ; C22C38/26 ; C22C38/28 ; C22C38/32 ; C22C38/38 ; C21D8/00

Abstract:
This H-beam steel contains, in mass %, C, Si, Mn, Al, Ti, N, O, Nb, and B. The H-beam steel has composition in which the amount of Nb and the amount of B satisfy, in mass %, 0.070≦Nb+125B≦0.155, and has a metal structure in which, in a microstructure, an area fraction of bainite is not less than 70%, a total of an area fraction of pearlite and an area fraction of cementite is not more than 15%, and the remainder is at least one of ferrite and island martensite. The effective crystalline-grain size of the bainite is not more than 40 μm, and the thickness of a flange falls in a range of 12 to 40 mm.
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