Invention Grant
- Patent Title: High-strength hot rolled steel sheet with excellent bendability and low-temperature toughness, and method for manufacturing the same
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Application No.: US14352880Application Date: 2012-10-31
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Publication No.: US09752216B2Publication Date: 2017-09-05
- Inventor: Chikara Kami , Kazuhiko Yamazaki
- Applicant: JFE Steel Corporation
- Applicant Address: JP
- Assignee: JFE Steel Corporation
- Current Assignee: JFE Steel Corporation
- Current Assignee Address: JP
- Agency: DLA Piper LLP (US)
- Priority: JP2011-240051 20111101
- International Application: PCT/JP2012/006975 WO 20121031
- International Announcement: WO2013/065298 WO 20130510
- Main IPC: C22C38/32
- IPC: C22C38/32 ; C21D1/20 ; C21D8/02 ; C21D9/46 ; C22C38/02 ; C22C38/04 ; C22C38/06 ; C22C38/08 ; C22C38/12 ; C22C38/14 ; C22C38/16 ; C22C38/22 ; C22C38/24 ; C22C38/26 ; C22C38/28 ; C22C38/00

Abstract:
A high-strength hot rolled steel sheet with excellent bendability and low-temperature toughness includes a chemical composition including, in mass %, C: 0.08 to 0.25%, Si: 0.01 to 1.0%, Mn: 0.8 to 2.1%, P: not more than 0.025%, S: not more than 0.005% and Al: 0.005 to 0.10%, the balance including Fe and inevitable impurities, and a microstructure having a bainite phase and/or a tempered martensite phase as a main phase, the average grain diameter of prior austenite grains being not more than 20 μm as measured with respect to a cross section parallel to a rolling direction and not more than 15 μm as measured with respect to a cross section perpendicular to the rolling direction.
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