Invention Application
- Patent Title: STEEL SHEET FOR HOT PRESSING USE, PRESS-FORMED PRODUCT, AND METHOD FOR MANUFACTURING PRESS-FORMED PRODUCT
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Application No.: US16027424Application Date: 2018-07-05
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Publication No.: US20180312947A1Publication Date: 2018-11-01
- Inventor: Toshio MURAKAMI , Junya Naitou , Keisuke Okita , Shushi Ikeda
- Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
- Applicant Address: JP Kobe-shi
- Assignee: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
- Current Assignee: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
- Current Assignee Address: JP Kobe-shi
- Priority: JP2012-053844 20120309
- Main IPC: C22C38/54
- IPC: C22C38/54 ; C21D8/00 ; C21D1/673 ; C21D9/48 ; C22C38/50 ; C22C38/22 ; C22C38/24 ; C22C38/26 ; C22C38/34 ; C22C38/38 ; C22C38/04 ; C22C38/20 ; C22C38/32 ; C22C38/28 ; C22C38/14 ; C22C38/06 ; C22C38/02 ; C22C38/00

Abstract:
A steel sheet for hot pressing use according to the present invention has a specified chemical component composition, wherein some of Ti-containing precipitates contained in the steel sheet, each of which having an equivalent circle diameter of 30 nm or less, have an average equivalent circle diameter of 3 nm or more, the precipitated Ti amount and the total Ti amount in the steel fulfill the relationship represented by formula (1) shown below, and the sum total of the fraction of bainite and the fraction of martensite in the metal microstructure is 80 area % or more. Precipitated Ti amount (mass %)−3.4[N]>0.5×[total Ti amount (mass %)−3.4[N]] (1) (In the formula (1), [N] represents the content (mass %) of N in the steel.)
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