Invention Grant
- Patent Title: Hot-pressed member and method for manufacturing same, and cold-rolled steel sheet for hot pressing and method for manufacturing same
-
Application No.: US16616602Application Date: 2018-03-30
-
Publication No.: US11377709B2Publication Date: 2022-07-05
- Inventor: Katsutoshi Takashima , Takashi Kobayashi , Yoshimasa Funakawa , Seiji Nakajima
- Applicant: JFE STEEL CORPORATION
- Applicant Address: JP Tokyo
- Assignee: JFE STEEL CORPORATION
- Current Assignee: JFE STEEL CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Kenja IP Law PC
- Priority: WOPCT/JP2017/024255 20170630
- International Application: PCT/JP2018/013714 WO 20180330
- International Announcement: WO2019/003538 WO 20190103
- Main IPC: B32B15/00
- IPC: B32B15/00 ; C21D9/46 ; B21D22/20 ; B21K29/00 ; B32B15/01 ; C21D1/18 ; C21D6/00 ; C21D8/02 ; C22C38/00 ; C22C38/02 ; C22C38/08 ; C22C38/16 ; C22C38/22 ; C22C38/26 ; C22C38/28 ; C22C38/32 ; C22C38/38 ; C23C2/06 ; C23C2/12 ; C23C2/40 ; C25D3/22 ; C25D3/54 ; C25D3/56

Abstract:
Disclosed is a hot-pressed member that can exhibit very high tensile strength after hot pressing, excellent delayed fracture resistance, and high tensile shear stress after resistance spot welding by properly adjusting its chemical composition and its microstructure such that at least 20 Nb-based precipitates having a grain size of less than 0.10 μm are present on average per 100 μm2 of a cross section parallel to a thickness direction of the member, a prior austenite average grain size is 8 μm or less, an average aspect ratio of prior austenite grains is 2.5 or less, and a volume fraction of martensite is 90% or more, and such that a standard deviation of Vickers hardness measured every 200 μm on a surface of the member is 40 or less.
Public/Granted literature
Information query