Title:
AUSTENITIC STAINLESS STEEL AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2023/022351
Kind Code:
A1
Abstract:
The present invention provides austenitic stainless steel comprising, by wt%, 0.005-0.03% of C, 0.1-1% of Si, 0.1-2% of Mn, 0.01-0.4 of Cu, 0.01-0.2 of Mo, 6-9% of Ni, 16-19% of Cr, 0.01-0.2% of N, and the remainder of Fe and inevitable impurities, wherein an austenitic stability parameter (ASP) value, as calculated by 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu)-18.5Mo, is 30-60, a [100*N]/[Ni+Cu] value is 1.4 or more, the average size of crystal grains is less than 5 µm, and the fraction (%) of crystal grains having a size of 5 µm or more is less than 10%. The present invention provides a method for manufacturing austenitic stainless steel, the method comprising the steps of: manufacturing a slab by continuously casting austenitic stainless steel, the austenitic stainless steel comprising, by wt%, 0.005-0.03% of C, 0.1-1% of Si, 0.1-2% of Mn, 0.01-0.4 of Cu, 0.01-0.2 of Mo, 6-9% of Ni, 16-19% of Cr, 0.01-0.2% of N, and the remainder of Fe and inevitable impurities, wherein an austenitic stability parameter (ASP) value, as calculated by 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu)-18.5Mo, is 30-60, a [100*N]/[Ni+Cu] value is 1.4 or more, the average size of crystal grains is less than 5 µm, and the fraction (%) of crystal grains having a size of 5 µm or more is less than 10%; hot-rolling and annealing and pickling the slab, followed by cold rolling to a cold reduction rate of 60% or more; and annealing at an annealing temperature in the range of 800-850 °C.
Inventors:
KIM SANGSEOK (KR)
PARK MINAM (KR)
LEE JAEPIL (KR)
JUNG ILCHAN (KR)
PARK MINAM (KR)
LEE JAEPIL (KR)
JUNG ILCHAN (KR)
Application Number:
PCT/KR2022/008906
Publication Date:
February 23, 2023
Filing Date:
June 23, 2022
Export Citation:
Assignee:
POSCO CO LTD (KR)
International Classes:
C22C38/58; C21D8/02; C22C38/00; C22C38/44; C23G1/02
Domestic Patent References:
| WO2016043125A1 | 2016-03-24 |
Foreign References:
| KR20210052502A | 2021-05-10 | |||
| KR20170056007A | 2017-05-22 | |||
| JP2003193202A | 2003-07-09 | |||
| KR20200075656A | 2020-06-26 | |||
| KR20210078228A | 2021-06-28 | |||
| KR20220030722A | 2022-03-11 | |||
| JP2020050940A | 2020-04-02 |
Attorney, Agent or Firm:
SELIM INTELLECTUAL PROPERTY LAW FIRM (KR)
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