Salzgitter Flachstahl Gmbh

Volkswagen Ag

Bednorz Gmbh & Co. Kg

Thomas Koll

Friedrich Luther

Marc Debeaux

Matthias Graul

Haucke-Frederik Hartmann

Jan-Frederik Lass

Stefan Mütze

Frank Beier

Christian Fritzsche

Stefan MÜTZE

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&#xb0; 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.

Aluminum-based coating for flat steel products for press mold hardening components, and method for producing same

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 [&#x3bc;m]&#x3c;(1/35)&#xd7;application on both sides [g/m]+(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 &#x3bc;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 &#x3bc;m to at most 5 &#x3bc;m.

Component made of press-form-hardened, aluminum-based coated steel sheet, and method for producing such a component

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&#xb0; C., advantageously at least 95&#xb0; C., and/or steam treatment at temperatures of at least 90&#xb0; C., advantageously at least 95&#xb0; 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.

Method for producing press-hardened components consisting of steel sheets or steel strips comprising an aluminium-based coating, and pressed-hardened component therefrom

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Braunschweig, Germany

Thomas Koll