Arcelormittal

Tom Watershoot

Antoine Moulin

Catherine Vinci

Gloria Restrepo Gacess

Veronique Sardoy

Mohamed Goune

The present invention provides a cold-rolled and annealed Dual-Phase steel sheet having a tensile strength from 980 to 1100 MPa. The composition includes the contents being expressed by weight: 0.055%≤C≤0.095%, 2%≤Mn≤2.6%, 0.005%≤Si≤0.35%, S≤0.005%, P≤0.050%, 0.1≤Al≤0.3%, 0.05%≤Mo≤0.25%, 0.2%≤Cr≤0.5%, Cr+2 Mo≤0.6%, Ni≤0.1%, 0.010≤Nb≤0.040%, 0.010≤Ti≤0.050%, 0.0005≤B≤0.0025%, and 0.002%≤N≤0.007%. The remainder of the composition includes iron and inevitable impurities resulting from the smelting. A microstructure of the steel sheet is 40 to 65% ferrite, 35 to 50% martensite and 0 to 10% bainite. A non-recrystallized ferrite fraction is less than or equal to 15%.

Very high-strength, cold-rolled, dual steel sheets

The present invention provides a cold-rolled and annealed Dual-Phase steel sheet having strength from 980 to 1100 MPa and a breaking elongation greater than 9%. The composition includes the contents being expressed by weight: 0.055%&#x2264;C&#x2264;0.095%, 2%&#x2264;Mn&#x2264;2.6%, 0.005%&#x2264;Si&#x2264;0.35%, S&#x2264;0.005%, P&#x2264;0.050%, 0.1&#x2264;Al&#x2264;0.3%, 0.05%&#x2264;Mo&#x2264;0.25%, 0.2%&#x2264;Cr&#x2264;0.5%, Cr+2Mo&#x2264;0.6%, Ni&#x2264;0.1%, 0.010&#x2264;Nb&#x2264;0.040%, 0.010&#x2264;Ti&#x2264;0.050%, 0.0005&#x2264;B&#x2264;0.0025%, and 0.002%&#x2264;N&#x2264;0.007%. The remainder of the composition includes iron and inevitable impurities resulting from the smelting. A manufacturing method is also provided.

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Lokeren, Belgium

Tom Watershoot