Title:
HIGH-STRENGTH STEEL PLATE HAVING EXCELLENT BURRING WORKABILITY IN LOW TEMPERATURE RANGE AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2018/117470
Kind Code:
A1
Abstract:
The present invention relates to a high-strength steel plate having excellent burring workability in a low temperature range, which is mainly used for automobile chassis parts such as members, lower arms, wheel disks, etc.; and a manufacturing method therefor. The high-strength steel plate having excellent burring workability in a low temperature range is configured such that [C]* expressed by relational expression 1 of -0.015 to 0.015 is satisfied; Mn, Mo, Cr, and B satisfy relational expression 2; a microstructure thereof comprises a ferrite phase of 97% or more (including 100%) by area fraction; the number of coarse complex precipitates containing at least one of Ti, Nb, Mo, and V having a diameter of at least 10 ㎛ observed within a unit area of 1 cm2 is 1×107 or less; and the number of austenitic phases having a diameter of 10 ㎛ or more observed from grain boundaries within a unit area of 1 cm2 is 1×104 or less.
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Inventors:
SEO SEOK-JONG (KR)
KIM SUNG-IL (KR)
NA HYUN-TAEK (KR)
KIM SUNG-IL (KR)
NA HYUN-TAEK (KR)
Application Number:
PCT/KR2017/013941
Publication Date:
June 28, 2018
Filing Date:
November 30, 2017
Export Citation:
Assignee:
POSCO (KR)
International Classes:
C22C38/22; C21D8/02; C22C38/00; C22C38/02; C22C38/04; C22C38/06; C22C38/24; C22C38/28; C22C38/32
Foreign References:
| KR101019791B1 | 2011-03-04 | |||
| KR20150075541A | 2015-07-06 | |||
| JP2012193452A | 2012-10-11 | |||
| JP2012001775A | 2012-01-05 | |||
| KR20090115877A | 2009-11-09 | |||
| JPH06293910A | 1994-10-21 | |||
| JPH07278731A | 1995-10-24 | |||
| JPH09241790A | 1997-09-16 | |||
| JPH0649591A | 1994-02-22 | |||
| US4502897A | 1985-03-05 |
Other References:
See also references of EP 3556890A4
Attorney, Agent or Firm:
C&S PATENT AND LAW OFFICE (KR)
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