Abstract: A cold-rolled and annealed ferritic steel sheet is provided. The steel has a composition comprising, expressed by weight: 0.001?C?0.15%; Mn?1%; Si?1.5%; 7.5%?AI?10%; 0.020%?Ti?0.5%; S?0.050%; and P?0.1%. A balance of the composition includes iron and inevitable impurities resulting from the smelting. The structure includes kappa (?) precipitates and equiaxed ferrite, an average grain size d? of the equiaxed ferrite is less than 50 microns, and a linear fraction f of intergranular ? precipitates is less than 30%. The linear fraction f is defined by f = ? ( A ) ? di ? ( A ) ? Li . ?(A)di denotes the total length of grain boundaries containing ? precipitates relative to an area (A) and ?(A)Li denotes the total length of the grain boundaries relative to the area (A). A content of carbon in solid solution is less than 0.005% by weight, and the cold-rolled and annealed ferritic steel sheet has a thickness between 0.6 mm and 1.5 mm.

Abstract: The invention relates to a hot-rolled ferritic steel sheet, the composition of the steel of which comprises, the contents being expressed by weight: 0.001?C?0.15%, Mn?1%, Si?1.5%, 6%?Al?10%, 0.020%?Ti?0.5%, S?0.050%, P?0.1%, and, optionally, one or more elements chosen from: Cr?1%, Mo?1%, Ni?1%, Nb?0.1%, V?0.2%, B?0.010%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the average ferrite grain size dIV measured on a surface perpendicular to the transverse direction with respect to the rolling being less than 100 microns.

Abstract: The invention relates to a hot-rolled ferritic steel sheet, the composition of the steel of which comprises, the contents being expressed by weight: 0.001?C?0.15%, Mn?1%, Si?1.5%, 6%?Al?10%, 0.020%?Ti?0.5%, S?0.050%, P?0.1%, and, optionally, one or more elements chosen from: Cr?1%, Mo?1%, Ni?1%, Nb?0.1%, V?0.2%, B?0.010%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the average ferrite grain size dIV measured on a surface perpendicular to the transverse direction with respect to the rolling being less than 100 microns.