A process for fabricating a steel sheet is provided. The process includes soaking a steel sheet. The steel has a composition including iron, carbon, manganese, silicon, aluminum, sulfur, phosphorus and nitrogen and at least one metallic element X chosen among vanadium, titanium, niobium, molybdenum, and chromium. A quantity Xp of metallic element under the form of carbides, nitrides or carbonitrides is, by weight: 0.030%≦Vp≦0.40%; 0.030%≦Tip≦0.50%; 0.040%≦Nbp≦0.40%; 0.14%≦Mop≦0.44%; or 0.070%≦Crp≦0.6%. The soaking step occurs under a pure nitrogen or argon atmosphere with a dew point lower than −30° C. at a soaking temperature θ between 250 and 900° C. and with a dynamic circulation of a regenerated atmosphere.