Invention Grant
- Patent Title: Rolled steel bar for hot forging
- Patent Title (中): 轧制钢棒热锻
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Application No.: US14358733Application Date: 2012-11-07
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Publication No.: US09574255B2Publication Date: 2017-02-21
- Inventor: Masashi Higashida , Hitoshi Matsumoto , Naoki Matsui , Yutaka Neishi , Taizo Makino
- 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: Clark & Brody
- Priority: JP2011-253412 20111121
- International Application: PCT/JP2012/078789 WO 20121107
- International Announcement: WO2013/077182 WO 20130530
- Main IPC: C22C38/02
- IPC: C22C38/02 ; C22C38/50 ; C22C38/46 ; C22C38/44 ; C22C38/42 ; C22C38/28 ; C22C38/22 ; C22C38/20 ; C22C38/06 ; C22C38/04 ; C22C38/00 ; C22C38/24 ; C21D9/00

Abstract:
A rolled steel bar has a composition consisting, by mass percent, of C: 0.27 to 0.37%, Si: 0.30 to 0.75%, Mn: 1.00 to 1.45%, S: 0.008% or more and less than 0.030%, Cr: 0.05 to 0.30%, Al: 0.005 to 0.050%, V: 0.200 to 0.320%, and N: 0.0080 to 0.0200%, the balance being Fe and impurities. The contents of P, Ti and O in the impurities are, by mass percent, P: 0.030% or less, Ti: 0.0040% or less, and O: 0.0020% or less. Y1 expressed by the formula is 1.05 to 1.18. Y1=C+(1/10)Si+(1/5)Mn+(5/22)Cr+1.65V−(5/7)S . C, Si, Mn, Cr, V, and S in the formula represent mass percent of the elements. A hot-forged part having a tensile strength of 900 MPa or higher and a transverse endurance ratio of 0.47 can be obtained by the rolled steel bar.
Public/Granted literature
- US20140322066A1 ROLLED STEEL BAR FOR HOT FORGING Public/Granted day:2014-10-30
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