Title:
厚鋼板およびその製造方法
Document Type and Number:
Japanese Patent JP6665659
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a thick steel sheet excellent in HAZ low temperature toughness and arrest property and having sheet thickness of over 70 mm and a manufacturing method therefor.SOLUTION: There is provided a thick steel sheet having sheet thickness of over 70 mm, a chemical composition with C:0.04 to 0.12%, Si:0.05 to 0.50%, Mn:1.30 to 2.20%, P:0.020% or less, S:0.0010 to 0.0100%, Cu:0.05 to 1.00%, Ni:0.05 to 1.50%, Nb:0.005 to 0.050%, Ti:0.005 to 0.050%, sol.Al:0.005% or less, O:0.0010 to 0.0050%, N:0.0010 to 0.0100% and the balance Fe with impurities, Ceq. of 0.40 to 0.52, (a) average aspect ratio of a surface layer structure of 1.5 or more, (b) ferrite fraction of 1/4t part:15.0 to 40.0%, 1/2t part:10.0 to 40.0%, a structure other than ferrite and bainite of less than 5%, (c) average bainite fraction of 1/4t part:25.0 μm or less, 1/2t part:35.0 μm or less, (d) average effective crystal particle diameter of 1/4t part:22.0 μm or less, 1/2t part:32.0 μm or less, (e) MnS area ratio of a cross section of 10% or more and less than 90%, MnS percentage of a boundary surface of 10% or more and (f) a surface dispersion density of composite inclusions with a particle diameter of 0.5 to 5.0 μm of 10 to 100/mm.SELECTED DRAWING: None
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Inventors:
Inokari Genki
Kazuki Kasano
Keisuke Mori
Takahiro Kamo
Satoshi Kubo
Masahiro Oguri
Kazuki Kasano
Keisuke Mori
Takahiro Kamo
Satoshi Kubo
Masahiro Oguri
Application Number:
JP2016085150A
Publication Date:
March 13, 2020
Filing Date:
April 21, 2016
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
C22C38/00; C21C7/04; C21D8/02; C22C38/58
Domestic Patent References:
| JP1191765A | ||||
| JP2011246805A | ||||
| JP9157787A | ||||
| JP4337027A | ||||
| JP11293383A | ||||
| JP2001342537A |
Foreign References:
| WO2013150687A1 |
Attorney, Agent or Firm:
Patents corporation Blitas