Patent ID: 10214792

Abstract:
The invention relates to a hot-rolled steel sheet having a tensile strength greater than 800 MPa and an elongation at break greater than 10%, the composition of which comprises, the contents being expressed by weight: 0.050%≤C≤0.090%, 1%≤Mn≤2%, 0.015%≤Al≤0.050%, 0.1%≤Si≤0.3%, 0.10%≤Mo≤0.40%, S≤0.010%, P≤0.025%, 0.003%≤N≤0.009%, 0.12%≤V≤0.22%, Ti≤0.005%, Nb≤0.020% and, optionally, Cr≤0.45%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the microstructure of the sheet or the part comprising, as a surface fraction, at least 80% upper bainite, the possible complement consisting of lower bainite, martensite and residual austenite, the sum of the martensite and residual austenite contents being less than 5%.