Invention Grant
- Patent Title: Cold-rolled steel sheet having excellent high-temperature properties and room-temperature workability
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Application No.: US16957833Application Date: 2018-12-18
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Publication No.: US11578379B2Publication Date: 2023-02-14
- Inventor: Jai-Ik Kim
- Applicant: POSCO
- Applicant Address: KR Pohang-si
- Assignee: POSCO
- Current Assignee: POSCO
- Current Assignee Address: KR Pohang-si
- Agency: Morgan, Lewis & Bockius LLP
- Priority: KR10-2017-0180293 20171226
- International Application: PCT/KR2018/016157 WO 20181218
- International Announcement: WO2019/132384 WO 20190704
- Main IPC: B32B15/01
- IPC: B32B15/01 ; C22C38/26 ; C22C38/22 ; C22C38/06 ; C22C38/04 ; C22C38/00 ; C23C30/00 ; C21D6/00 ; C21D8/02 ; C21D9/46 ; H01M50/116 ; H01M50/124 ; H01M50/119 ; B32B15/04 ; C23C2/04 ; C23C28/02 ; B32B15/18 ; C23C2/26 ; C23C28/00 ; C23C2/28 ; C22C38/12 ; C23C2/40 ; C22C38/18

Abstract:
The present disclosure provides a cold-rolled steel sheet having excellent high-temperature properties and room-temperature workability, including, by weight: carbon (C): 0.0005 to 0.003%, manganese (Mn): 0.20 to 0.50%, aluminum (Al): 0.01 to 0.10%, phosphorus (P): 0.003 to 0.020%, nitrogen (N): 0.0005 to 0.004%, sulfur (S): 0.015% or less, niobium (Nb): 0.005 to 0.040%, chromium (Cr): 0.10 to 0.50%, tungsten (W): 0.02 to 0.07%, and a balance of iron (Fe) and other inevitable impurities, wherein C, Nb, and W satisfy the following relationship 1, a microstructure comprises 95 area % or more of polygonal ferrite and 5 area % or less of acicular ferrite, and
the cold-rolled steel sheet comprises (Nb,W)C-based precipitates having an average size of 0.005 to 0.10 μm and a method for manufacturing the same: 0.00025≤(2×Nb/93)×(W/184)/(C/12)≤0.0015 [Relationship 1] where, C, Nb, and W are in weight %.
the cold-rolled steel sheet comprises (Nb,W)C-based precipitates having an average size of 0.005 to 0.10 μm and a method for manufacturing the same: 0.00025≤(2×Nb/93)×(W/184)/(C/12)≤0.0015 [Relationship 1] where, C, Nb, and W are in weight %.
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