Publication number: 20230235425
Abstract: A hot-rolled strip steel product is described having a chemical composition consisting of, in terms of weight percentages (wt. %): 0.030%-0.10% C, 0%-1.10% Si, 0.50%-2.0% Mn, <0.020% P, <0.010% S,<0.010% N, 0%-0.60% Cr, 0%-0.20% Ni, 0%-0.25% Cu, 0%-0.30% Mo, 0%-0.15% Al, 0%-0.10% Nb, 0.10%-0.30% V, <0.020% Ti, 0%-0.0010% B, remainder being Fe and inevitable impurities, wherein the hot rolled strip steel product has a a microstructure comprising, in terms of volume percentages (vol. %), ferrite?90, wherein the ferrite structure comprises bainite, at least 50% of polygonal ferrite and at most 10% quasi-polygonal ferrite, and wherein the steel strip product has an average hole expansion ratio?50%, a yield strength (Rp0.2%) longitudinal to rolling direction of ?660 MPa and a tensile strength?760 MPa.
Type:
Application
Filed:
May 20, 2021
Publication date:
July 27, 2023
Inventors:
Vili Kesti, Ari Hirvi, Tommi Liimatainen, Mikko Hemmilä, Pasi Suikkanen, Erik Nymann, Martin Lind, Robin Nilsson, Juha Pyykkönen
Publication number: 20230203609
Abstract: A hot-rolled steel is described having a yield strength (Rp0.2) of at least 1100 MPa along and/or transverse to a rolling direction which has a chemical composition of (in mass-%): C: 0.10-0.2, Si: 0-0.7, Mn: 1.1-2.2, Nb: 0-0.06, Ti: 0-0.15, V: more than 0.03 and ?0.25, Al: 0.01-0.15, B: 0.0005-0.010, Cr: 0.1-1.7, Mo: 0.15-0.8, Cu: 0-1.5, Ni: 0.3-2.5, P: 0-0.015, S: 0-0.008 Zr: 0-0.2, Ca: 0-0.004, the balance Fe and unavoidable impurities, whereby a) when 0.1<C<0.11 then Mn?1.6 and V>0.14 and Mo?0.5 (in mass-%), b) when 0.11?C<0.125 then Mn?1.45 and V?0.13 and Mo?0.35 (in mass-%), c) when 0.125?C<0.15, then Mn?1.35 and V?0.12 and Mo?0.20 (in mass-%), and d) when C?0.15 and V>0.11, then Mn?1.3 and Mo?0.15 (in mass-%) or when C?0.15 and V 0.03-0.11, then Mn>1.3 and Mo>0.15 and Nb>0.02 and Cr+Cu+Ni>1.4 (in mass-%).
Type:
Application
Filed:
January 16, 2019
Publication date:
June 29, 2023
Inventors:
Tommi Liimatainen, Mikko Hemmilä, Ari Hirvi, Teijo Limnell, Tuomo Saarinen, Tuomas Antola, Pasi Lehtikangas, Sakari Tihinen, Vili Kesti, Saija Martinmäki