Title:
STEEL SHEET HAVING EXCELLENT RESISTANCE TO LIQUID METAL EMBRITTLEMENT CRACKS AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2019/004662
Kind Code:
A1
Abstract:
The present invention relates to a steel sheet having an excellent resistance to liquid metal embrittlement cracks and a method for manufacturing the same. An embodiment of the present invention provides a steel sheet having an excellent resistance to liquid metal embrittlement cracks and a method for manufacturing the same, the steel sheet comprising, by weight %, : 0.04 to 0.35% of C; 0.99% or less of Al + Si; 3.5 to 10% of Mn; 0.05% or less of P (excluding 0%); not more than 0.02% of S (excluding 0%); not more than 0.02% of N (excluding 0%); the balance being Fe; and other unavoidable impurities, wherein a microstructure contains, by a volume fraction, 10% or more of retained austenite, 60% or more of annealed martensite, and 20% or less of alpha martensite and epsilon martensite, and the average thickness of a Mn-depleted layer is 0.5 ㎛ or more from a product surface. According to one aspect of the present invention, it is possible to increase cracking resistance occurring during spot welding, and thus it is possible to manufacture an ultra-high strength high ductility steel sheet capable of cold press forming without reducing material performance even after welding.
Inventors:
LEE SEA-WOONG (KR)
LEE KYOO-YOUNG (KR)
RYU JOO-HYUN (KR)
KANG KI-CHEOL (KR)
LEE KYOO-YOUNG (KR)
RYU JOO-HYUN (KR)
KANG KI-CHEOL (KR)
Application Number:
PCT/KR2018/007085
Publication Date:
January 03, 2019
Filing Date:
June 22, 2018
Export Citation:
Assignee:
POSCO (KR)
International Classes:
C22C38/04; C21D8/02; C21D9/46; C22C38/02; C22C38/06; C23C2/06; C23C2/12; C23C2/40
Foreign References:
| JP2003138345A | 2003-05-14 | |||
| KR20140075789A | 2014-06-19 | |||
| KR20120073407A | 2012-07-05 | |||
| KR20160078839A | 2016-07-05 | |||
| KR20120113806A | 2012-10-15 | |||
| CN101638749A | 2010-02-03 | |||
| CN103060678A | 2013-04-24 | |||
| KR20140000574A | 2014-01-03 |
Other References:
See also references of EP 3647452A4
Attorney, Agent or Firm:
C&S PATENT AND LAW OFFICE (KR)
Download PDF: