Invention Publication
- Patent Title: COLD ROLLED STEEL SHEET HAVING EXCELLENT WELDABILITY, STRENGTH, AND FORMABILITY, AND METHOD FOR MANUFACTURING SAME
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Application No.: US18684593Application Date: 2022-08-25
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Publication No.: US20240352551A1Publication Date: 2024-10-24
- Inventor: Young-Roc IM , Sang-Ho UHM , Young-Ha KIM
- Applicant: POSCO CO., LTD
- Applicant Address: KR Gyeongsangbuk-do
- Assignee: POSCO CO., LTD
- Current Assignee: POSCO CO., LTD
- Current Assignee Address: KR Gyeongsangbuk-do
- Priority: KR 20210112968 2021.08.26
- International Application: PCT/KR2022/012744 2022.08.25
- Date entered country: 2024-02-16
- Main IPC: C21D9/46
- IPC: C21D9/46 ; C21D1/18 ; C21D1/84 ; C21D6/00 ; C21D8/02 ; C22C38/00 ; C22C38/02 ; C22C38/06 ; C22C38/22 ; C22C38/26 ; C22C38/28 ; C22C38/32 ; C22C38/38

Abstract:
Provided is a cold-rolled steel sheet including: by weight %, C: 0.10 to 0.16%, Si: 0.3 to 0.8%, Al: 0.01 to 0.5%, Mn: 2.0 to 3.0%, Cr: 0.001 to 0.5%, Mo: 0.001 to 0.5%, B: 0.0001 to 0.001%, Nb: 0.001 to 0.05%, Ti: 0.001 to 0.05%, P: 0.04% or less (excluding 0%), S: 0.01% or less (excluding 0%), N: 0.01% or less (excluding 0%), a remainder of Fe, and other unavoidable impurities, as a microstructure, by area %, ferrite: 10% or less (excluding 0%), retained austenite: more than 1% to 5% or less, martensite: 25% or more but less than 50%, and bainite: 35% or more but less than 70%. An average size of martensite-austenite (MA) in the bainite is 0.35 to 0.55 μm.
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