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%, aluminum+ silicon?6.5%, a remainder being composed of iron and unavoidable impurities caused by processing; heating said cold rolled steel sheet up to a soaking temperature between 80° 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 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%; aluminum+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 processing, 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 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 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 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 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: Steel sheet, the composition of the steel of which comprises, the contents being expressed by weight: 0.08%?C?0.23%, 1%?Mn?2%, 1?Si?2%, Al?0.030%, 0.1%?V?0.25%, Ti?0.010%, S?0.015%, P?0.1%, 0.004%?N?0.012%, and, optionally, one or more elements chosen from: Nb?0.1%, Mo?0.5%, Cr?0.3%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting.

Abstract: Steel sheet, the composition of the steel of which comprises, the contents being expressed by weight: 0.08%?C?0.23%, 1%?Mn?2%, 1?Si?2%, Al?0.030%, 0.1%?V?0.25%, Ti?0.010%, S?0.015%, P?0.1%, 0.004%?N?0.012%, and, optionally, one or more elements chosen from: Nb?0.1%, Mo?0.5%, Cr?0.3%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting.