Title:
STRUCTURAL ULTRA-THICK STEEL MATERIAL HAVING EXCELLENT SURFACE PORTION NRL-DWT PHYSICAL PROPERTIES AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2022/045704
Kind Code:
A1
Abstract:
The present invention relates to a structural ultra-thick steel material having excellent surface portion NRL-DWT physical properties and a method for manufacturing same and, in particular, to a structural ultra-thick steel material and a method for manufacturing same, the structural ultra-thick steel material comprising, by wt%, 0.05-0.09% of C, 0.1-0.4% of Si, 0.01-0.05% of Al, 1.8-2.1% of Mn, 0.3-1.0% of Ni, 0.005-0.040% of Nb, 0.005-0.03% of Ti, 0.1-0.5% of Cu, 100 ppm or less of P, 40 ppm or less of S, and the remainder of Fe and other inevitable impurities, and the steel material having a microstructure in which the fraction of polygonal ferrite from the surface portion to 5 mm directly below the surface portion is 50% or greater, and the grain size of a t/4 microstructure having a high boundary angle of 15° or greater, as measured by EBSD, is 15 µm or less.
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Inventors:
LEE HAKCHEOL (KR)
Application Number:
PCT/KR2021/011219
Publication Date:
March 03, 2022
Filing Date:
August 23, 2021
Export Citation:
Assignee:
POSCO (KR)
International Classes:
C22C38/04; C21D8/02; C22C38/02; C22C38/06; C22C38/08; C22C38/12; C22C38/14; C22C38/16
Foreign References:
| KR20150053616A | 2015-05-18 | |||
| KR101917456B1 | 2018-11-09 | |||
| KR20160121712A | 2016-10-20 | |||
| US20170137911A1 | 2017-05-18 | |||
| JP2012172258A | 2012-09-10 |
Attorney, Agent or Firm:
DAE-A INTELLECTUAL PROPERTY CONSULTING (KR)
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