STEEL SHEET AND METHOD FOR MANUFACTURING STEEL SHEET

WIPO Patent Application WO/2023/166935

A1

The present invention provides a steel sheet which exhibits excellent ammonia stress corrosion cracking properties, low-temperature toughness of a base material, toughness of HAZ, strength characteristics, and in which reductions in flatness are suppressed, and a method for manufacturing the same.　This steel sheet has a predetermined component composition, and in particular, is configured such that: Ti/N is 2.00-4.00, and the equation 169 ≤ 5158 × Ti +25563 × N ≤ 360 is satisfied; the carbon equivalent (Ceq) of the component composition is 0.340-0.390; the volume fraction of the sum of ferrite and pearlite of a microstructure at a position at 1/4 of the sheet thickness is 90% or more; the average particle diameter of the ferrite is 5-20 μm; the yield strength of the steel sheet is 440 MPa or less, and the tensile strength is 490 MPa or more; the maximum value of the gap between the steel sheet surface and a 2 m long ruler is 14 mm or less when the long ruler is applied to the steel sheet surface along the rolling direction; and the sheet thickness is less than 13 mm.

TAKAYAMA NAOKI (JP)
HIRAIDE TAKASHI (JP)
SATO YUYA (JP)
TACHIBANA SHUNICHI (JP)

PCT/JP2023/004276

September 07, 2023

February 09, 2023

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JFE STEEL CORP (JP)

C22C38/00; C21D8/02; C22C38/14; C22C38/58

WO2020184683A1

2020-09-17

JPH11131178A	1999-05-18
JP2011105963A	2011-06-02
JP2020509174A	2020-03-26
JP2019214752A	2019-12-19

KUMASAKA Akira et al. (JP)

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