Title:
SKELETON MEMBER
Document Type and Number:
WIPO Patent Application WO/2022/234792
Kind Code:
A1
Abstract:
This skeleton member is formed by hot-stamping a steel sheet. The skeleton member is so formed as to have a closed cross-sectional part in which a cross-section perpendicular to the longitudinal direction of the member is closed. The closed cross-sectional part comprises: at least two flat portions each having a curvature radius greater than the maximum outside dimension of said cross-section; and a recessed bead portion formed between the two flat portions. The recessed bead portion has a pair of walls which have a curvature radius of at least 50 mm and which protrude from the respective opposing ends of the two flat portions toward the inside of the closed cross-sectional part by way of a pair of inflected parts that are inflected toward the interior of the closed cross-section. In each of the walls, the central part in the thickness direction has a Vickers hardness of at least 520 Hv. The width of each of the walls is 0.5-2.5 times the effective width We. A standard deviation ratio, which is determined by dividing the standard deviation of hardness frequency distribution at a surface part of the walls by the standard deviation of hardness frequency distribution at the central part in the thickness direction of the walls, is smaller than 1.0.
Inventors:
AITOH TAKAHIRO (JP)
TODA YURI (JP)
TABATA RYO (JP)
TODA YURI (JP)
TABATA RYO (JP)
Application Number:
PCT/JP2022/018963
Publication Date:
November 10, 2022
Filing Date:
April 26, 2022
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
B21D22/20; B21C37/15; B21D22/26; B62D21/15
Domestic Patent References:
| WO2020100886A1 | 2020-05-22 | |||
| WO2018151322A1 | 2018-08-23 |
Foreign References:
| JP2020153401A | 2020-09-24 | |||
| JP2021078463A | 2021-05-27 | |||
| JP2009286351A | 2009-12-10 |
Attorney, Agent or Firm:
MATSUNUMA Yasushi et al. (JP)
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