Abstract: A cold rolled and annealed steel sheet is provided which includes by weight: 0.6<C<1.3%, 15?Mn<35%, 6.0?Al<15%, Si?2.40%, S?0.015%, P?0.1%, N?0.1%, possibly one or more optional elements chosen among Ni, Cr and Cu in an individual amount of up to 3% and possibly one or more elements chosen among B, Ta, Zr, Nb, V, Ti, Mo, and W in a cumulated amount of up to 2.0%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, the microstructure of said sheet comprising at least 0.1% of intragranular kappa carbides, wherein at least 80% of such kappa carbides have an average size below 30 nm, optionally up to 10% of granular ferrite, the remainder being made of austenite, the average grain size and average aspect ratio of the austenite being respectively below 6 ?m and comprised between 2 and 10 and the average grain size and average aspect ratio of the ferrite, when present, being respectively below 5 ?m and below 3.

Abstract: A cold rolled and annealed steel sheet includes by weight: 0.6<C<1.3%,15.0<Mn<35%, 6.0<Al<15%, Si<2.40%, S<0.015%, P<0.1%, N<0.1%, iron and inevitable impurities, optionally one or more of Ni, Cr and Cu in an individual amount of up to 3% and optionally one or more of B, Ta, Zr, Nb, V, Ti, Mo, and W in a cumulated amount of up to 2.0%, a microstructure of the sheet comprising at least 0.1% of intragranular kappa carbides, at least 80% of the kappa carbides have an average size below 30 nm, the remainder being made of austenite, an average grain size of the austenite being below 6 ?m, an average aspect ratio of the austenite being between 1.5 and 6, an average grain size of the ferrite, when present being below 5 ?m, and an average aspect ratio of the ferrite, when present, being below 3.0.

Abstract: A cold rolled and annealed steel sheet including by weight: 0.6<C<1.3%, 15?Mn<35%, 6?Al<15%, Si?2.40%, S?0.03%, P?0.1%, N?0.1%, possibly one or more optional elements chosen among Ni, Cr and Cu in an individual amount of up to 3% and possibly one or more elements chosen among B, Ta, Zr, Nb, V, Ti, Mo, and W in a cumulated amount of up to 2.0%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, the microstructure of the sheet including of ordered ferrite between 1% and 10%, optionally of up to 10% of kappa carbides, the remainder being made of austenite, and, the density of the steel sheet being equal or below 7.2 and the FWHM for the austenite matrix is between 0.700 and 1.100.

Abstract: A cold rolled and annealed steel sheet is provided which includes by weight: 0.6<C<1.3%, 15?Mn<35%, 6.0?Al<15%, Si?2.40%, S?0.015%, P?0.1%, N?0.1%, possibly one or more optional elements chosen among Ni, Cr and Cu in an individual amount of up to 3% and possibly one or more elements chosen among B, Ta, Zr, Nb, V, Ti, Mo, and W in a cumulated amount of up to 2.0%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, the microstructure of said sheet comprising at least 0.1% of intragranular kappa carbides, wherein at least 80% of such kappa carbides have an average size below 30 nm, optionally up to 10% of granular ferrite, the remainder being made of austenite, the average grain size and average aspect ratio of the austenite being respectively below 6 ?m and comprised between 2 and 10 and the average grain size and average aspect ratio of the ferrite, when present, being respectively below 5 ?m and below 3.

Abstract: A cold rolled and annealed steel sheet includes by weight: 0.6<C<1.3%, 15.0?Mn<35%, 6.0?Al<15%, Si?2.40%, S?0.015%, P?0.1%, N?0.1%, optionally one or more elements chosen among Ni, Cr and Cu in an individual amount of up to 3% and optionally one or more elements chosen among B, Ta, Zr, Nb, V, Ti, Mo, and W in a cumulated amount of up to 2.0%, the remainder of the composition making up of iron and inevitable impurities resulting from elaboration, a microstructure of said sheet comprising at least 0.1% of intragranular kappa carbides, wherein at least 80% of said kappa carbides have an average size below 30 nm, optionally up to 10% of granular ferrite, the remainder being made of austenite, an average grain size of the austenite being below 6 ?m, an average aspect ratio of the austenite being between 1.5 and 6, an average grain size of the ferrite, when present being below 5 ?m, and an average aspect ratio of the ferrite, when present, being below 3.0.