Abstract: An aluminum-based coating of a flat steel product is applied in a hot-dipping method and comprises a mass percentage of silicon within a given range. The coating for a flat steel product, in particular for press mold hardening components, offers a shortened required minimum oven dwell time and a sufficiently large processing window when heating in an oven. This is achieved in that the surface of the coating has a degree of absorption for thermal radiation ranging between 0.35 and 0.95 prior to an annealing treatment, where the degree of absorption relates to an oven temperature ranging from 880 to 950° C. during the austenitizing annealing treatment. The invention additionally relates to an improved method for producing a flat steel product with an aluminum-based coating, to an inexpensive method for producing press-hardened components from such flat steel products, and to a press-hardened component made of such flat steel products.

Abstract: A method for producing a steel strip containing, in addition to iron as the main component and unavoidable impurities, one or more of the following oxygen-affine elements in wt. %: Al: more than 0.02, Cr: more than 0.1, Mn: more than 1.3 or Si: more than 0.1, where the surface of the steel strip is cleaned, oxidation-treated and annealed. The treated and annealed steel strip is subsequently coated with a hot-dip coat. In order to be less cost-intensive and to achieve uniform, reproducible adhesion conditions for the coat, the steel strip is oxidation-treated prior to the annealing at temperatures below 200° C., where on the surface of the steel strip, with the formation of oxides with iron from the steel strip, an oxide layer is formed, which contains iron oxide and is reduction-treated during the course of the annealing under a reducing atmosphere to achieve a surface consisting substantially of metallic iron.

Abstract: The invention relates to a method for coating a steel sheet or steel strip to which an aluminium-based coating is applied in a dip-coating process and the surface of the coating is freed of a naturally occurring aluminium oxide layer. In order to provide a low-cost method for coating steel sheets or steel strips that makes the steel sheets or steel strips outstandingly suitable for the production of components by means of press hardening and for the further processing thereof, it is proposed that transition metals or transition metal compounds are subsequently deposited on the freed surface of the coating to form a top layer. The invention also relates to a method for producing press-hardened components from the aforementioned steel sheets or steel strips with an aluminium-based coating.

Abstract: A method for producing a press-mold-hardened part includes providing a steel strip having an aluminium-based coating; applying an inorganic, iron-containing conversion layer to the aluminium-based coating with a layer weight in relation to iron of 3-30 mg/m2; cold-rolling the steel strip to form a flexibly rolled strip with strip sections of different sheet thickness; cutting an initial sheet metal blank out of the flexibly rolled strip, with the blank having different sheet thicknesses with thinnest and thickest sheet sections; press-mold-hardening the initial sheet metal blank to form a part. Alternatively, the cold-rolling can take place before the cutting, and the application of the conversion layer can take place before or after the cutting, or, instead of the cold-rolling, at least two steel strip sections having an aluminium-based coating and different sheet thicknesses can be welded together, where the application of the conversion layer can take place before or after welding.

Abstract: A cold-rolled or hot-rolled steel strip having a metal coating, the steel strip having iron as the main constituent and, in addition to carbon, an Mn content of 4.1 to 8.0 wt. % and optionally one or more of the alloy elements Al, Si, Cr, B, Ti, V, Nb and/or Mo. The surface of the uncoated steel strip is cleaned, a layer of pure iron is applied to the cleaned surface, an oxygen-containing iron-based layer is applied to the layer of pure iron and contains more than five mass percent oxygen. The steel strip is then annealed and, to attain a surface consisting substantially of metallic iron, is subjected to a reduction treatment in a reducing furnace while being annealed. The steel strip is then coated with the metallic coating by hot dipping. Uniform and reproducible adhesion conditions are hereby achieved for the metallic coating on the steel strip surface.

Abstract: A cold- or hot-rolled steel strip with a metallic coating, the steel strip having iron as the main constituent and, in addition to carbon, an Mn content of 8.1 to 25.0 wt. % and optionally one or more of the alloying elements Al, Si, Cr, B, Ti, V, Nb and/or Mo. The uncoated steel strip is first cleaned, a layer of pure iron is applied to the cleaned surface, an oxygen-containing, iron-based layer containing more than five mass percent of oxygen is applied to the layer of pure iron. The steel strip is then annealed and is reduction-treated in a reducing furnace atmosphere during the annealing treatment to obtain a surface consisting mainly of metallic iron. The steel strip is then hot-dip coated with the metallic coating. This creates uniform and reproducible bonding conditions for the coating on the steel strip surface.

Abstract: In a component made of press-form-hardened, aluminium-based coated steel sheet, the coating has a covering which contains aluminum and silicon applied in the hot-dip process. The press-form-hardened component in the transition region between steel sheet and covering has an inter-diffusion zone I, wherein, depending on the layer application of the covering before heating and press hardening, the thickness of the inter-diffusion zone I obeys the following formula: I [?m]<(1/35)×application on both sides [g/m2]+(19/7). Formed on the inter-diffusion zone I is a zone having various intermetallic phases having an average total thickness between 8 and 50 ?m, on which zone there is in turn arranged a covering layer containing aluminum oxide and/or hydroxide having an average thickness of at least 0.05 ?m to at most 5 ?m.

Abstract: An aluminum-based coating of a flat steel product is applied in a hot-dipping method and comprises a mass percentage of silicon within a given range. The coating for a flat steel product, in particular for press mold hardening components, offers a shortened required minimum oven dwell time and a sufficiently large processing window when heating in an oven. This is achieved in that the surface of the coating has a degree of absorption for thermal radiation ranging between 0.35 and 0.95 prior to an annealing treatment, where the degree of absorption relates to an oven temperature ranging from 880 to 950° C. during the austenitizing annealing treatment. The invention additionally relates to an improved method for producing a flat steel product with an aluminum-based coating, to an inexpensive method for producing press-hardened components from such flat steel products, and to a press-hardened component made of such flat steel products.

Abstract: A method for producing a steel strip containing, in addition to iron as the main component and unavoidable impurities, one or more of the following oxygen-affine elements in wt. %: Al: more than 0.02, Cr: more than 0.1, Mn: more than 1.3 or Si: more than 0.1, where the surface of the steel strip is cleaned, oxidation-treated and annealed. The treated and annealed steel strip is subsequently coated with a hot-dip coat. In order to be less cost-intensive and to achieve uniform, reproducible adhesion conditions for the coat, the steel strip is oxidation-treated prior to the annealing at temperatures below 200° C., where on the surface of the steel strip, with the formation of oxides with iron from the steel strip, an oxide layer is formed, which contains iron oxide and is reduction-treated during the course of the annealing under a reducing atmosphere to achieve a surface consisting substantially of metallic iron.

Abstract: In an aluminium-based coating for steel sheets or steel strips, the coating includes an aluminium-based coat applied in a hot-dip coating method, a covering layer containing aluminium oxide and/or hydroxide being arranged on the coat. The covering layer is produced by plasma oxidation and/or hot water treatment at temperatures of at least 90° C., advantageously at least 95° C., and/or steam treatment at temperatures of at least 90° C., advantageously at least 95° C. Alternatively, the covering layer containing aluminium oxide and/or hydroxide can be produced by anodic oxidation, the coat being produced in a molten bath with a Si content of between 8 and 12 wt. %, and an Fe content of between 1 and 4 wt. %, the remainder being aluminium.

Abstract: In a component made of press-form-hardened, aluminium-based coated steel sheet, the coating has a covering which contains aluminum and silicon applied in the hot-dip process. The press-form-hardened component in the transition region between steel sheet and covering has an inter-diffusion zone I, wherein, depending on the layer application of the covering before heating and press hardening, the thickness of the inter-diffusion zone I obeys the following formula: I [?m]<( 1/35)×application on both sides [g/m2]+( 19/7). Formed on the inter-diffusion zone I is a zone having various intermetallic phases having an average total thickness between 8 and 50 ?m, on which zone there is in turn arranged a covering layer containing aluminum oxide and/or hydroxide having an average thickness of at least 0.05 ?m to at most 5 ?m.

Abstract: The invention relates to a method for coating a steel sheet or steel strip to which an aluminium-based coating is applied in a dip-coating process and the surface of the coating is freed of a naturally occurring aluminium oxide layer. In order to provide a low-cost method for coating steel sheets or steel strips that makes the steel sheets or steel strips outstandingly suitable for the production of components by means of press hardening and for the further processing thereof, it is proposed that transition metals or transition metal compounds are subsequently deposited on the freed surface of the coating to form a top layer. The invention also relates to a method for producing press-hardened components from the aforementioned steel sheets or steel strips with an aluminium-based coating.

Abstract: In a method for improving the weldability of high-manganese-containing steel strips which contain (in % by weight) from 6 to 30% of manganese, up to 1% of carbon, up to 15% of aluminum, up to 6% of silicon, up to 6.5% of chromium, up to 4% of copper and also total additions of titanium and zirconium of up to 0.7% and total additions of niobium and vanadium of up to 0.5%, balance iron including unavoidable steel-accompanying elements the steel strips are coated with a zinc-containing corrosion protection layer.

Abstract: in an aluminium-based coating for steel sheets or steel strips, the coating includes an aluminium-based coat applied in a hot-dip coating method, a covering layer containing aluminium oxide and/or hydroxide being arranged on the coat. The covering layer is produced by plasma oxidation and/or hot water treatment at temperatures of at least 90° C., advantageously at least 95° C., and/or steam treatment at temperatures of at least 90° C., advantageously at least 95° C. Alternatively, the covering layer containing aluminium oxide and/or hydroxide can be produced by anodic oxidation, the coat being produced in a molten bath with a Si content of between 8 and 12 wt. %, and an Fe content of between 1 and 4 wt. %, the remainder being aluminium.

Abstract: A composite pipe includes a carrier pipe and at least one protective pipe. The carrier pipe is produced from a non-corrosion resistant steel, which has at least a partially austenitic structure, with the following chemical composition (in wt. %): C: 0.005 to 1.4; Mn: 5 to 35; the remainder being iron including unavoidable elements accompanying steel, with the optional alloying of the following elements (in wt. %): Ni: 0 to 6; Cr: 0 to 9; Al: 0 to 15; Si: 0 to 8; Mo: 0 to 3; Cu: 0 to 4; V: 0 to 2; Nb: 0 to 2; Ti: 0 to 2; Sb: 0 to 0.5; B: 0 to 0.5; Co: 0 to 5; W: 0 to 3; Zr: 0 to 4; Ca: 0 to 0.1; P: to 0.6; S: 0 to 0.2; N: 0.002 to 0.3. In a method for producing a composite pipe of this type, the carrier pipe and the at least one protective pipe are mechanically or metallurgically connected to one another.

Abstract: In a method for improving the weldability of high-manganese-containing steel strips which contain (in % by weight) from 6 to 30% of manganese, up to 1% of carbon, up to 15% of aluminum, up to 6% of silicon, up to 6.5% of chromium, up to 4% of copper and also total additions of titanium and zirconium of up to 0.7% and total additions of niobium and vanadium of up to 0.5%, balance iron including unavoidable steel-accompanying elements the steel strips are coated with a zinc-containing corrosion protection layer.

Abstract: A zinc-based anti-corrosion coating is disclosed for steel sheets or steel strips, which for the purpose of hardening are at least in parts heated to a temperature above Ac3 and then cooled at a temperature situated at least partially above the critical cooling speed, the anti-corrosion coating being a coating applied by hot dipping. In addition to at least 75% by weight zinc and possible unavoidable impurities, the coating also contains 0.5 to 15.0% by weight manganese and 0.1 to 10.