High strength steel product and method of manufacturing the same

US12428690B2 · kind B2 · utility

Assignee

• SSAB TECHNOLOGY AB · SE

Inventors

• Vili Kesti · Raahe, FI
• Tommi Liimatainen · Raahe, FI
• Mikko Hemmilä · Helsinki, FI
• Pasi Suikkanen · Raahe, FI
• Erik Nymann · Nordstraße, SE
• Martin Lind · Munich, DE
• Robin Nilsson · Nordstraße, SE
• Juha Pyykkönen · Raahe, FI

Key dates

• Filing date: May 20, 2021
• Grant date: Sep 30, 2025
• Expiry date: Jun 17, 2042

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D2211/005
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A hot-rolled strip steel product having a chemical composition consisting of, in terms of weight percentages (wt. %): 0.025%-0.070% C, 0%-1.10% Si, 0.50%-2.0% Mn, <0.020% P, <0.050% S, <0.010% N, 0%-0.60% Cr, 0%-0.20% Ni, 0%-0.25% Cu, 0%-0.20% Mo, 0%-0.15% Al, 0%-0.050% Nb, 0.020%-0.20-% V, 0.020%-0.15% Ti, 0%-0.0010% B, remainder Fe and inevitable impurities, wherein the strip steel product has a microstructure comprising of, in terms of volume percentages (vol. %), ferrite ≥90%, wherein the ferrite structure comprises 10%-50% quasi-polygonal ferrite and a reminder of ferrite structure is polygonal ferrite and/or bainite: and wherein the steel strip product has an average ferrite grain size of <10 μm, an average hole expansion ratio of ≥50%, a yield strength (Rp0.2%) longitudinal to rolling direction of ≥660 MPa and a tensile strength of ≥760 MPa.