Abstract: A cold-rolled flat steel product has a tensile strength of 750-940 MPa, a high strength, an improved weldability and optimized shaping properties, and can be produced at low cost. The cold-rolled flat steel product consists of a steel composed, in percent by mass, of C: 0.040-0.100%; Mn: 2.10-2.50%; Si: 0.10-0.40%; Cr: 0.30-0.90%; Ti: 0.020-0.080%, B: 0.0005-0.0020%; N: 0.003-0.010%; Al: up to 0.10%; Ca: up to 0.005%; P: up to 0.025%; S: up to 0.010%; optionally one or more of the following elements: Mo: up to 0.20%; Nb: up to 0.050%; Cu: up to 0.10%; V: up to 0.020%; Ni: up to 0.10%, the remainder being iron and unavoidable impurities, and total content of impurities is limited to at most 0.5% by mass and contents of phosphorus (“P”) and sulfur (“S”) belong to the impurities.

Abstract: A hot-rolled flat steel product having a thickness of <1.5 and consisting of, in % by mass, C: 0.04-0.23%, Si: 0.04 0.54%, Mn: 1.4-2.9%, Ti+V, wherein 0.005%<%Ti+%V<0.15%, and optionally one or more elements of Al, Cr, Mo, and B, where AI: 0.01-1.5%, 0.02<%Mo+%Cr<1.4%, and B: 0.0005-0.005%, and the remainder consisting of iron and inevitable impurities. The structure of the flat steel product consists of, in percent by area, in sum, 50-90% ferrite and bainite ferrite, 5-50% martensite, 2-15% residual austenite and <10% other structure elements. The flat steel product has a yield point Rp0.2>290 MPa, a tensile strength Rm>490 MPa and an elongation at break A80 where A80[%]=B?Rm/37 with 31<B<51. To at least one surface of the flat steel product, a Zn coating is applied by hot-dip coating. Also a method for producing a flat steel product of this kind.

Abstract: The invention relates to a method for producing a shaped sheet-metal part from a panel or a semifinished part made of a material consisting of steel with at least 60 wt. % Fe and a residual austenite content of at least 5%, in which the panel or the semifinished part is at least partially cooled to a temperature below ?20° C. before the shaping and is shaped at a temperature below ?20° C. in a forming tool. The object of providing a method for producing load-compliantly configured components, which on the one hand permits industrial-scale use of low-temperature forming and is configured particularly simply, is achieved by reducing the material temperature of the panel or semifinished part to below ?20° C. is carried out in a thermally regulated cooling apparatus.

Abstract: A multi-phase steel including in % wt. C: 0.14-0.25%, Mn: 1.7-2.5%, Si: 0.2-0.7%, Al: 0.5-1.5%, Cr: <0.1%, Mo: <0.05%, Nb: 0.02-0.06%, S: up to 0.01%, P: up to 0.02%, N: up to 0.01% and optionally at least one of Ti, B, and V according to the following stipulation: Ti: up to 0.1%, B: up to 0.002%, V: up to 0.15%, with the remainder iron and unavoidable impurities, wherein the microstructure has at least 10% vol. ferrite and at least 6% vol. residual austenite and the steel has a tensile strength Rm of at least 950 MPa, a yield point ReL of at least 500 MPa and an elongation at break A80 measured in the transverse direction of at least 15%. A method of producing the multi-phase steel.

Abstract: The invention relates to a method for producing a shaped sheet-metal part from a panel or a semifinished part made of a material consisting of steel with at least 60 wt. % Fe and a residual austenite content of at least 5%, in which the panel or the semifinished part is at least partially cooled to a temperature below ?20° C. before the shaping and is shaped at a temperature below ?20° C. in a forming tool. The object of providing a method for producing load-compliantly configured components, which on the one hand permits industrial-scale use of low-temperature forming and is configured particularly simply, is achieved by reducing the material temperature of the panel or semifinished part to below ?20° C. is carried out in a thermally regulated cooling apparatus.

Abstract: A multi-phase steel including in % wt. C: 0.14-0.25%, Mn: 1.7-2.5%, Si: 0.2-0.7%, Al: 0.5-1.5%, Cr: <0.1%, Mo: <0.05%, Nb: 0.02-0.06%, S: up to 0.01%, P: up to 0.02%, N: up to 0.01% and optionally at least one of Ti, B, and V according to the following stipulation: Ti: up to 0.1%, B: up to 0.002%, V: up to 0.15%, with the remainder iron and unavoidable impurities, wherein the microstructure has at least 10% vol. ferrite and at least 6% vol. residual austenite and the steel has a tensile strength Rm of at least 950 MPa, a yield point ReL of at least 500 MPa and an elongation at break A80 measured in the transverse direction of at least 15%. A method of producing the multi-phase steel.

Abstract: A multi-phase steel which in addition to iron and unavoidable impurities includes (in % wt.) C: 0.14-0.25%, Mn: 1.7-2.5%, Si: 1.4-2.0%, Al: <0.1%, Cr: <0.1%, Mo: <0.05%, Nb: 0.02-0.06%, S: up to 0.01%, P: up to 0.02%, N: up to 0.01% and optionally one of Ti, B, and V according to the following stipulation: Ti: ?0.1%, B: ?0.002%, V: ?0.15%. A cast semi-finished product, is hot rolled starting at an initial temperature of 1100-1300° C. and ending at a final temperature of 820-950° C., coiled at 400-750° C., cold rolled into the cold flat product at degrees of 30-80%, and subjected to a heat treatment including continuous annealing at 20° C.+Ac1-Ac3 and overageing at 350-500° C.

Abstract: A dual-phase steel, a flat product and processes for the production thereof. The dual-phase steel having a strength of at least 950 MPa, good deformability, and good surface finish. It is possible, when a simple production process is used, for the flat product produced from this steel to be formed into a complexly formed component, such as part of a car body, either uncoated or provided with an anti-corrosion coating. The steel according to the invention has a structure comprising 20-70% martensite, up to 8% retained austenite and the remainder ferrite and/or bainite and has the following composition (in % by weight): C: 0.050-0.105%, Si: 0.20-0.60%, Mn: 2.10-2.80%, Cr: 0.20-0.80%, Ti: 0.02-0.10%, B: <0.0020%, Mo: <0.25%, Al: <0.10%, Cu: up to 0.20%, Ni: up to 0.10%, Ca: up to 0.005%, P: up to 0.2%, S: up to 0.01%, N: up to 0.012%, remainder iron and unavoidable impurities.

Abstract: A dual-phase steel, a flat product produced therefrom and a process for the production thereof. The dual-phase steel has, in addition to a strength of at least 950 MPa and good deformability, a surface finish which, when a simple production process is used, makes it possible for the flat product produced from this steel to be formed into a complexly formed component, such as a part of a car bodywork, in an uncoated state or in a state provided with an anti-corrosion coating. The steel according to the invention comprises 20-70% martensite, up to 8% retained austenite and the remainder ferrite and/or bainite and comprises (in % by weight): C: 0.10-0.20%, Si: 0.10-0.60%, Mn: 1.50-2.50%, Cr: 0.20-0.80%, Ti: 0.02-0.08%, B: <0.0020%, Mo: <0.25%, Al: <0.10%, P: ?0.2%, S: ?0.01%, N: ?0.012%, the remainder iron and unavoidable impurities.