Title:
HIGH-STRENGTH STEEL PLATE AND PROCESS FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2015/194619
Kind Code:
A1
Abstract:
Provided is a steel plate which has a high strength and stably exhibits excellent low-temperature toughness. The high-strength steel plate is characterized in that the steel plate satisfies a given composition and in that the structure satisfies the following (1) and (2) and the Vickers hardness of a portion thereof present at a depth of 1/4 the plate thickness is 180 or greater. (1) In the portion at a depth of 1/4 the plate thickness, crystal grains that each are surrounded by a large-angle grain boundary, which is a boundary between two adjoining crystals that have a difference in orientation of 15° or greater, have equivalent-circle diameters, the maximum value of which is 30 μm or less. (2) In the portion at a depth of 1/4 the plate thickness, the number density of crystal grains that each are surrounded by a large-angle grain boundary, which is a boundary between two adjoining crystals that have a difference in orientation of 15° or greater, and that have an equivalent-circle diameter of 15 μm or larger is 1.5×10-3 per μm2 or less.
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Inventors:
KANEKO MASAHITO
OKAZAKI YOSHITOMI
KAWANO HARUYA
IBANO AKIRA
OKAZAKI YOSHITOMI
KAWANO HARUYA
IBANO AKIRA
Application Number:
PCT/JP2015/067560
Publication Date:
December 23, 2015
Filing Date:
June 18, 2015
Export Citation:
Assignee:
KOBE STEEL LTD (JP)
International Classes:
C22C38/00; C21D8/02; C22C38/14; C22C38/58
Domestic Patent References:
| WO2011099408A1 | 2011-08-18 |
Foreign References:
| JP2011012315A | 2011-01-20 | |||
| JP2012229470A | 2012-11-22 | |||
| JP2009074111A | 2009-04-09 | |||
| JP2014043642A | 2014-03-13 | |||
| JP2014029019A | 2014-02-13 |
Attorney, Agent or Firm:
UEKI, Kyuichi et al. (JP)
Hisakazu Ueki (JP)
Hisakazu Ueki (JP)
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