IP Library Granted Patent US 9,869,002
Granted Patent B2
US 9,869,002 · App. 14/962,424 · Granted Jan 16, 2018

Method for manufacturing duplex stainless steel sheet having reduced inclusions

Inventors: Sung Jin Park (Pohang-si, KR); Man Jin Ha (Pohang-si, KR); Dae Sung Lee (Pohang-si, KR)
Assignee: POSCO
C21D3/04C21C5/005C21C7/0075C21C7/0087C21C7/06C21C7/064C21C7/0685C22C38/001C22C38/002C22C38/02C22C38/42C22C38/58B22D11/002B22D11/0622
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Quick Facts
Patent No.
US 9,869,002
App. No.
14/962,424
Granted
Jan 16, 2018
Kind
B2
Abstract

There is provided a method for manufacturing a duplex stainless steel sheet having reduced inclusions through argon oxygen decarburization (AOD), ladle treatment (LT), and twin roll strip casting. The method includes deoxidizing molten steel using silicon (Si) during the AOD, wherein the molten steel has a silicon (Si) content of 0.55 wt % to 0.75 wt % at the end of the AOD.

Claims (6)

1. A method for manufacturing a duplex stainless steel sheet, the method comprising: argon oxygen decarburization (AOD), ladle treatment (LT), and twin roll strip casting,

wherein the AOD comprises: deoxidizing molten steel with silicon (Si),

wherein the molten steel has a silicon (Si) content of 0.55 wt % to 0.75 wt % at an end of the AOD, and

wherein the duplex stainless steel sheet comprises, by wt %, carbon (C): 0.02% to 0.06%, silicon (Si): 0.55% to 0.75%, manganese (Mn): 2.8% to 3.2%, phosphorus (P): 0.035% or less, sulfur (S): 0.003% or less, chromium (Cr): 19.0% to 21.0%, nickel (Ni): 0.5% to 1.5%, copper (Cu): 0.3% to 1.2%, nitrogen (N): 0.2% to 0.28%, and a balance of iron (Fe) and inevitable impurities.

2. The method of claim 1 , wherein in the AOD, slag has a basicity of 2.2 to 2.5.

3. The method of claim 1 , wherein the molten steel has a tapping temperature of 1680° C. to 1710° C. in the AOD.

Assignments (3)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 26, 2022
From: POSCO HOLDINGS INC.
To: POSCO CO., LTD
Reel/Frame 061777/0943 →
CHANGE OF NAME Recorded Sep 28, 2022
From: POSCO
To: POSCO HOLDINGS INC.
Reel/Frame 061561/0831 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 8, 2015
From: PARK, SUNG JIN; HA, MAN JIN; LEE, DAE SUNG
To: POSCO
Reel/Frame 037238/0566 →
Priority Claims (1)
KR 10-2014-0178294 · Dec 11, 2014 · national
Continuity (1)
Related Publication 20160168655A1 · Jun 16, 2016