Title:
SQUARE STEEL PIPE, METHOD FOR MANUFACTURING SAME, AND BUILDING STRUCTURE
Document Type and Number:
WIPO Patent Application WO/2020/170775
Kind Code:
A1
Abstract:
Provided are: a square steel pipe; a method for manufacturing same; and a building structure using the square steel pipe. The present invention pertains to a square steel pipe having flat plate portions and corner portions, and having a specific composition, wherein in the microstructure of steel at a position 1/4t in the plate thickness t from the outer surface of the steel pipe, the ratio of the total area fraction of bainite and pearlite to the area fraction of ferrite is 2.0-20.0, and the ratio of the area fraction of bainite to the area fraction of pearlite is 5.0-20.0; YS is at least 350 MPa and TS is at least 520 MPa in the flat plate portions; the ratio of YS in the flat portions to YS in the corner portions is 0.80-0.90; the ratio of TS in the flat portions to TS in the corner portions is 0.90-1.00; the Charpy absorbed energy at -40°C in the flat portions is at least 100 J; and R in the corner portions is (2.3×t) to (2.9×t).
Inventors:
IDE SHINSUKE (JP)
MATSUMOTO AKIHIDE (JP)
MATSUMOTO ATSUSHI (JP)
OKABE TAKATOSHI (JP)
MATSUMOTO AKIHIDE (JP)
MATSUMOTO ATSUSHI (JP)
OKABE TAKATOSHI (JP)
Application Number:
PCT/JP2020/003842
Publication Date:
August 27, 2020
Filing Date:
February 03, 2020
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
B21C37/08; B21D5/06; C21D8/02; C21D8/10; C22C38/00; C22C38/06; C22C38/58; E04B1/24; E04C3/32
Domestic Patent References:
| WO2018110152A1 | 2018-06-21 |
Foreign References:
| JP2018095904A | 2018-06-21 | |||
| JP2018053281A | 2018-04-05 | |||
| JP2016011439A | 2016-01-21 | |||
| JP2014031546A | 2014-02-20 | |||
| JPH0569039A | 1993-03-23 | |||
| KR20140118313A | 2014-10-08 |
Attorney, Agent or Firm:
KUMASAKA Akira et al. (JP)
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