Arcelormittal

Valérie Daeschler

Frédéric Bonnet

Manuel Bobadilla

Bertrand Bele

A steel sheet has a composition comprising, by weight: 0.010%&#x2264;C&#x2264;0.080%, 0.06%&#x2264;Mn&#x2264;3%, Si&#x2264;1.5%, 0.005%&#x2264;Al&#x2264;1.5%, S&#x2264;0.030%, P&#x2264;0.040%, Ti and B such that: 3.2%&#x2264;Ti&#x2264;7.5% and (0.45&#xd7;Ti)&#x2212;1.35&#x2264;B&#x2264;(0.45&#xd7;Ti)&#x2212;0.43, optionally Ni&#x2264;1%, Mo&#x2264;1%, Cr&#x2264;3%, Nb&#x2264;0.1%, V&#x2264;0.1%, the remainder being iron and unavoidable impurities resulting from the smelting. The steel sheet has a structure consisting of ferrite, at most 10% of austenite, and precipitates comprising eutectic precipitates of TiB, the volume fraction of TiBprecipitates with respect to the whole structure being of at least 9%, the proportion of TiBprecipitates having a surface area lower than 8 &#x3bc;mbeing of at least 96%.

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Roncourt, France

Valérie Daeschler