Dual-phase steel and manufacturing method therefor
A dual-phase steel with optimized chemical composition and manufacturing process achieves high mechanical performance and low cost by controlling C, Si, Mn, Al, Nb, Ti, and B contents, resulting in a 80 kg-grade steel with improved strength and elongation without Mo and Cr.
Patent Information
- Application Number
- EP2023856628
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-08-23
- Filing Date
- 2023-08-22
- Publication Date
- 2025-07-02
AI Technical Summary
Existing dual-phase steels face challenges in achieving high mechanical performance while maintaining low cost, due to high C, Si, or large amounts of alloying elements like Cr and Mo, which affect weldability, surface quality, and phosphatability, and increase production costs.
A dual-phase steel composition comprising C: 0.09% - 0.11%, Si: 0.1% - 0.3%, Mn: 1.4% - 1.6%, Al: 0.01% - 0.03%, Nb: 0.01% - 0.03%, Ti: 0.01% - 0.03%, and B: 0.0020% - 0.0030%, with optimized manufacturing processes including hot rolling, cold rolling, annealing, and tempering, to achieve a strength of 80 kg grade without precious alloying elements.
The solution results in a dual-phase steel with excellent mechanical properties, including yield strength of ≥420 MPa, tensile strength of ≥800 MPa, and A50-gauge-length elongation at break of ≥18%, while reducing production costs by avoiding Mo and Cr.
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Abstract
Citation Information
Patent Citations
A cold-rolled steel sheet having a tensile strength of 780 MPA or more an excellent local formability and a suppressed increase in weld hardness
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