Salzgitter Flachstahl Gmbh

Volkswagen Ag

Salzgetter Flachstahl Gmbh

Technische Universitat Braunschweig

Marc Debeaux

Wolfgang Kowalsky

Hans-Hermann Johannes

Friedrich Luther

Thomas Koll

Frank Beier

Stefan Mütze

Kai Köhler

Matthias Graul

Peter Palzer

Haucke-Frederik Hartmann

Jan-Frederik Lass

Nils Köpper

Kerstin Körner

Christian Fritzsche

Matthias Böttger

Henning Hopf

Nils KÖPPER

Stefan MÜTZE

Georgeou Zacharias

Kai KÖHLER

Björn Wiegmann

Steffen Schaumburg

Alexander Cichosch

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

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&#xb0; 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.

Method for producing a steel strip with improved bonding of metallic hot-dip coatings

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.

Method for coating steel sheets or steel strips and method for producing press-hardened components therefrom

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

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.

Method for improving the weldability of high manganese content steel strips

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Hildesheim, Germany

Marc Debeaux