Title:
STEEL PLATE EXCELLENT BRITTLE CRACK PROPAGATION STOPPING CHARACTERISTICS AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
Japanese Patent JP2018076573
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a thick high strength steel plate having sufficient arrest property as a steel for large sized structure, capable of industrial stable and effective manufacturing, and excellent in brittle crack propagation stopping characteristics, and having plate thickness of 50 mm or more, temperature of Kca=6000 N/mmof -10°C or less even with yield strength of 355 to 390 MPa class.SOLUTION: There is provided a high arrest property steel plate having a prescribed component, in which a micro structure includes ferrite:50 to 80%, pearlite:10% or less and bainite:20 to 50%, ferrite with circle equivalent diameter of 25 μm or more is 10% or less by area percentage in a surface layer area, average circle equivalent diameter of up to 20% of from ones with larger circle equivalent diameter of precipitate and inclusion by the number is 0.5 μm or less, and crack spread effective crystal particle diameter in an EBSD crystal orientation analysis in a rolling direction vertical cross section is d=(5.4×[Ni]+16)×(1.2-t/300) (μm).SELECTED DRAWING: None
Inventors:
SHIRAHATA HIROYUKI
MATSUO TAKESHI
OKAWA TEPPEI
IMASHIRO DAIKI
YANAGITA KAZUTOSHI
MATSUO TAKESHI
OKAWA TEPPEI
IMASHIRO DAIKI
YANAGITA KAZUTOSHI
Application Number:
JP2016220833A
Publication Date:
May 17, 2018
Filing Date:
November 11, 2016
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP
International Classes:
C22C38/00; C21D8/02; C22C38/14; C22C38/58
Domestic Patent References:
| JP2008248382A | 2008-10-16 | |||
| JP2012172258A | 2012-09-10 | |||
| JP2015183273A | 2015-10-22 | |||
| JP2008214652A | 2008-09-18 | |||
| JP2017150067A | 2017-08-31 |
Foreign References:
| WO2011148755A1 | 2011-12-01 |
Attorney, Agent or Firm:
Atsushi Aoki
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Fukuchi Ritsuo
Nakamura Asayuki
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Fukuchi Ritsuo
Nakamura Asayuki