Abstract: A cold rolled steel strip or sheet has a composition consisting of (in wt. %): C 0.15-0.25; Si 0.5-1.6; Mn 2.2-3.2; Cr?0.8; Mo?0.2; Al 0.03-1.0; Nb?0.04; V?0.04; Ti 0.01-0.04; B 0.001-0.010; TUB 5-30; Cu?0.15; Ni?0.15; Ca?0.01; balance Fe apart from impurities, where the cold rolled steel has a multiphase microstructure comprising a matrix mainly composed of tempered martensite and has a tensile strength (Rm) of at least 1380 MPa.

Abstract: The invention relates to a cold rolled steel sheet having a composition consisting of (in wt. %): C 0.15-0.25; Si 0.5-1.6; Mn 2.2-2.8; Cr?0.8; Mo?0.2; Al 0.03-1.0; Nb?0.04; V?0.04; Ti 0.02-0.04; B 0.001-0.005; balance Fe apart from impurities, wherein the impurity contents of Cu and Ni are limited to ?0.15, the cold rolled steel has a multiphase microstructure comprising a matrix of bainitic ferrite and ?10 vol. % polygonal ferrite and the tensile strength (Rm) is 980-1500 MPa.

Abstract: High strength galvannealed steel sheet having, a) a composition consisting of (in wt. %): C 0.10-0.2, Mn 2.0-3.0, Si 0.2-0.5, Cr 0.1-0.7, Ti 0.01-0.07, Al?0.2, Nb<0.05, Mo<0.1, optionally B 0.001-0.005, balance Fe apart from impurities, b) a multiphase microstructure comprising (in vol. %) retained austenite 4-20, martensite 5-25, bainitic ferrite ?10, polygonal ferrite ?10, balance bainite+tempered martensite 50-90, c) a tensile strength (Rm) 1180-1300 MPa, a yield strength (Rp0.2) 800-970 MPa, an elongation (A50) ?8%, or an elongation (A80) ?6%, and d) a bendability value Ri/t of ?4 for a sample having the size of 35 mm×100 mm, wherein Ri is the bending radius in mm and t is the thickness in mm of the steel sheet.

Abstract: A resistance spot welded joint of at least two steel sheets and a method of producing a resistance spot welded joint of at least two steel sheets, wherein at least one of the steel sheets is provided with a Zn containing layer, the steel sheet has a tensile strength of at least 980 MPa, a multiphase microstructure comprising bainite, bainitic ferrite and tempered martensite in a total amount of at least of 75 volume % and retained austenite in an amount of 3-20 volume % and wherein the steel sheet provided with the Zn containing layer has a composition consisting of (in wt. %): C 0.1-0.3; Si 0.2-3.0; Mn 1.0-3.0; Cr?2.0; Mo?0.5; Al?2.0; Nb?0.2; V?0.2; Ti 0.01-0.15; B 0.0005-0.01; and balance Fe apart from impurities, wherein the heat affected zone in the spot welded joint is free from cracks having a length of more than 500 ?m.

Abstract: A method for producing steel sheets, in particular for body shell sheets of vehicles, in which a steel alloy of a desired composition is melted, poured, and then rolled into sheet form, the steel alloy being an “interstitial free” steel (IF steel) and the steel sheet being annealed after the rolling and subsequently provided with a metallic anti-corrosion coating and then dressed, wherein in order to achieve a low Wsa value with the narrowest possible spread, a niobium content of >0.01% by weight, preferably >0.011% by weight, is added to the alloy.

Abstract: A method for producing steel sheets, in particular for body shell sheets of vehicles, in which a steel alloy of a desired composition is melted, poured, and then rolled into sheet form, the steel alloy being an interstitial free steel (IF steel) and after the rolling, the steel sheet being annealed and dressed and then provided with a metallic anti-corrosion coating by means of an electrolytic process or by means of vapor deposition, wherein in order to achieve a low Wsa value with the narrowest possible spread, a niobium content of >0.01% by weight, preferably >0.011% by weight, is added to the alloy of the steel.

Abstract: A method for producing steel sheets, in particular for body shell sheets of vehicles, in which a steel alloy of a desired composition is melted, poured, and then rolled into sheet form, the steel alloy being a bake-hardening steel (BH steel) and the steel sheet being annealed after the tolling and subsequently provided with a metallic anti-corrosion coating and then dressed, wherein in order to achieve a low Wsa value with the narrowest possible spread, a niobium content of >0.01% by weight, preferably >0.011% by weight, is added to the alloy.

Abstract: A high strength cold rolled steel sheet has a composition consisting of the following elements (in wt. %): C 0.07-0.15, Mn 2.3-3.2, Si 0.6-1.2, Cr 0.05-0.5, Al?0.2 Nb?0.1, balance Fe apart from impurities, a multiphase microstructure comprising a matrix of bainitic ferrite, and a tensile strength (Rm) of 980-1100 MPa.

Abstract: The present invention relates to high strength cold rolled steel sheet suitable for applications in automobiles, construction materials and the like, specifically high strength steel excellent in formability. In particular, the invention relates to cold rolled steel sheets having a tensile strength of at least 780 MPa.

Abstract: A high strength galvannealed steel sheet having, a) a composition consisting of the following elements (in wt. %): C 0.10-0.2 Mn 2.0-3.0 Si 0.2-0.5 Cr 0.1-0.7 Ti 0.01-0.07 Al?0.2 Nb<0.05 Mo<0.1 optionally B 0.001-0.005 balance Fe apart from impurities, b) a multiphase microstructure comprising (in vol. %) retained austenite 4-20 martensite 5-25 bainitic ferrite?10 polygonal ferrite?10 balance bainite+tempered martensite 50-90, c) at least one of the following mechanical properties a tensile strength (Rm) 1180-1300 MPa a yield strength (Rp0.2) 800-970 MPa an elongation (A50)?8% an elongation (A80)?6%, and d) a bendability according to a 90° V Bend test value Ri/t of ?4 for a sample having the size of 35 mm×100 mm, wherein Ri is the bending radius in mm and t is the thickness in mm of the steel sheet.

Abstract: The present invention relates to high strength cold rolled steel sheet suitable for applications in automobiles, construction materials and the like, specifically high strength steel excellent in formability. In particular, the invention relates to cold rolled steel sheets having a tensile strength of at least 780 MPa.