Title:
GALVANIZED STEEL SHEET AND MEMBER, AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2022/202716
Kind Code:
A1
Abstract:
Provided is a galvanized steel sheet having a tensile strength of 980 MPa or above, a high YS, and excellent ductility, work-hardening property, and hole-widening property. In the present invention: a base steel sheet has a prescribed component composition; ferrite, bainitic ferrite, tempered martensite, retained austenite, and fresh martensite have prescribed area ratios in the steel structure of the base steel sheet; the ratio SMA1/SMA of area ratios is 0.80 or below; and the ratio SMA2/SMA of area ratios is 0.20 or above. Here: SMA is the area ratio of a hard second phase made of retained austenite and fresh martensite; SMA1 is the total area ratio of island regions, from among island regions constituting the hard second phase, in which the circle-equivalent diameter is 2.0 μm or above and 20% or less of the circumferential length is in contact with the tempered martensite; and SMA2 is the total area ratio of island regions, from among the island regions constituting the hard second phase, in which at least 1% of the circumferential length is in contact with the bainitic ferrite.
Inventors:
HIGUCHI SHO (JP)
KAWASAKI YOSHIYASU (JP)
NAKAGAITO TATSUYA (JP)
KANAZAWA TOMOMI (JP)
YAMAMOTO SHUNSUKE (JP)
KAWASAKI YOSHIYASU (JP)
NAKAGAITO TATSUYA (JP)
KANAZAWA TOMOMI (JP)
YAMAMOTO SHUNSUKE (JP)
Application Number:
PCT/JP2022/012855
Publication Date:
September 29, 2022
Filing Date:
March 18, 2022
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C22C38/00; C21D9/46; C22C18/00; C22C38/06; C22C38/60; C23C2/06; C23C2/28
Domestic Patent References:
| WO2017164346A1 | 2017-09-28 | |||
| WO2016113788A1 | 2016-07-21 | |||
| WO2016171237A1 | 2016-10-27 | |||
| WO2020158065A1 | 2020-08-06 |
Foreign References:
| JP2004285385A | 2004-10-14 | |||
| JP3887235B2 | 2007-02-28 | |||
| JP5953693B2 | 2016-07-20 | |||
| JP6052472B2 | 2016-12-27 |
Other References:
YAMASHITA ET AL.: "Distribution of Carbon in Low-Carbon Steel in the Early Phase of Proeutectoid Ferrite by High Precision FE-EPMA", IRON AND STEEL, vol. 103, no. 11, 2017, pages 14 - 20
Attorney, Agent or Firm:
SUGIMURA Kenji (JP)
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