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 method of production of a cold rolled and heat treated steel sheet having the following steps: providing a cold rolled steel sheet with a composition with the following elements, expressed in percent by weight: 0.10%?carbon?0.6%; 4%?manganese?20%; 5%?aluminum?15%; 0?silicon?2% aluminium+silicon+nickel?6.5%; and optionally at least one of certain optional elements; a remainder being composed of iron and unavoidable impurities caused by processing; heating the cold rolled steel sheet up to a soaking temperature between 750 and 950° C. during less than 600 seconds, then cooling the sheet down to room temperature; and reheating the steel sheet to a soaking temperature of 150° C. to 600° C. during 10 s to 1000 h, then further cooling the sheet.

Abstract: A cold rolled and heat treated steel sheet having a composition including the following elements, expressed in % by weight: 0.1%?carbon?0.6% 4%?manganese?20% 5%?aluminum?15% 0?silicon?2% aluminium+silicon+nickel?6.5% and can possibly contain one or more of the following optional elements: 0.01%?niobium?0.3%, 0.01%?titanium?0.2% 0.01%?vanadium?0.6% 0.01%?copper?2.0% 0.01%?nickel?2.0% cerium?0.1% boron?0.01% magnesium?0.05% zirconium?0.05% molybdenum?2.0% tantalum?2.0% tungsten?2.0% the remainder being composed of iron and unavoidable impurities caused by processing, wherein the microstructure of said steel sheet includes in area fraction, 10 to 50% of austenite, the austenite phase optionally including intragranular kappa carbides, the remainder being regular ferrite and ordered ferrite of D03 structure (Fe,Mn,X)3Al, optionally including up to 2% of intragranular kappa carbides (Fe,Mn)3AlCx said steel sheet presenting a ultimate tensile strength higher than or equal to 900 MPa.

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 heat treated steel sheet having a composition including the following elements, expressed in % by weight: 0.1%?carbon?0.6% 4%?manganese?20% 5%?aluminum?15% 0?silicon?2% aluminium+silicon+nickel?6.5% and can possibly contain one or more of the following optional elements: 0.01%?niobium?0.3%, 0.01%?titanium?0.2% 0.01%?vanadium?0.6% 0.01%?copper?2.0% 0.01%?nickel?2.0% cerium?0.1% boron?0.01% magnesium?0.05% zirconium?0.05% molybdenum?2.0% tantalum?2.0% tungsten?2.0% the remainder being composed of iron and unavoidable impurities caused by elaboration, wherein the microstructure of said steel sheet includes in area fraction, 10 to 50% of austenite, the austenite phase optionally including intragranular kappa carbides, the remainder being regular ferrite and ordered ferrite of D03 structure (Fe,Mn,X)3Al, optionally including up to 2% of intragranular kappa carbides (Fe,Mn)3AlCx said steel sheet presenting a ultimate tensile strength higher than or equal to 900 MPa.

Abstract: A method of production of a cold rolled and heat treated steel sheet has the following steps: providing a cold rolled steel sheet with a composition including the following elements, expressed in percent by weight: 0.15%?carbon?0.6%, 4%?manganese?20%, 5%?aluminum?15%, 0?silicon?2%, aluminium+silicon?6.5%, a remainder being composed of iron and unavoidable impurities caused by elaboration; heating said cold rolled steel sheet up to a soaking temperature between 800 and 950° C. during less than 600 seconds, then cooling the sheet down to a temperature in a range of 600° C. to room temperature, reheating the steel sheet to a soaking temperature of 150° C. to 600° C. during 10 s to 250 h, then cooling the sheet.

Abstract: A rolled steel sheet is provided. The rolled steel sheet has a mechanical strength greater than or equal to 600 MPa and an elongation at fracture that is greater than or equal to 20%. A a method for its fabrication is also provided. The chemical composition of the steel sheet includes 0.10?C?0.30%, 6.0?Mn?15.0%, 6.0?Al?15.0%, and optionally one or more elements selected from among: Si?2.0%, Ti?0.2%, V?0.6% and Nb?0.3%. The remainder of the composition includes iron and the unavoidable impurities resulting from processing. The ratio of the weight of manganese to the weight of aluminum is such that Mn Al > 1.0 . The microstructure of the sheet includes ferrite, austenite and up to 5% Kappa precipitates in area fraction.

Abstract: A cold rolled and heat treated steel sheet having a composition containing the following elements, expressed in percent by weight: 0.15%?carbon?0.6%; 4%?manganese?20%; 5%?aluminum?15%; 0?silicon?2%; aluminium+silicon?6.5%; and possibly one or more of the following elements: 0.01%?niobium?0.3%; 0.01%?titanium?0.2%; 0.01%?vanadium?0.6%; 0.01%?copper?2.0%; 0.01%?nickel?2.0%; cerium?0.1%; boron?0.01%; magnesium?0.05%; zirconium?0.05%; molybdenum?2.0%; tantalum?2.0%; tungsten?2.0%; the remainder being composed of iron and unavoidable impurities caused by elaboration, wherein the microstructure of said steel sheet contains in area fraction, 10 to 50% of austenite, the reminder being regular ferrite and ordered ferrite of D03 structure. A manufacturing method and use of the steel sheet for making vehicle parts is also described.

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.

Abstract: A cold rolled and hot dip coated steel sheet presenting a tensile strength above 1000?50×Al MPa, a uniform elongation above 15% and a low density is provided. The steel includes, by weight percent: 0.1?C?0.5%, 3.5?Mn?10.0%, 0?Al?9.0%, Si?5.0%, Ti?0.2%, V?0.2%, Nb?0.2%, S?0.004%, P?0.025%, 0.5?Si+Al?9.0%, B?0.0035, Cr?1%, The balance being Fe and impurities and the microstructure containing 25% to 90% of ferrite, 10% to 50% of austenite, kappa precipitates lower than 5% and martensite lower than 25%. The steel is able to be coated using total oxidation.

Abstract: A rolled steel sheet is provided. The rolled steel sheet has a mechanical strength greater than or equal to 600 MPa and an elongation at fracture that is greater than or equal to 20%. A a method for its fabrication is also provided. The chemical composition of the steel sheet includes 0.10?C?0.30%, 6.0?Mn?15.0%, 6.0?Al?15.0%, and optionally one or more elements selected from among: Si?2.0%, Ti?0.2%, V?0.6% and Nb?0.3%. The remainder of the composition includes iron and the unavoidable impurities resulting from processing. The ratio of the weight of manganese to the weight of aluminum is such that Mn Al > 1.0 . The microstructure of the sheet includes ferrite, austenite and up to 5% Kappa precipitates in area fraction.