Thyssenkrupp Rasselstein Gmbh

Thyssen Krupp Ag

Andrea Marmann

Christoph Molls

Helmut Oberhoffer

Reiner Sauer

Dirk Matusch

Sebastian Hartung

Gerhard Menzel

Hans-Peter Rink

Monika Malejczyk

Martin Schleich

Tatjana Kasdorf

Tanja Lommel

Thomas Lenz

Rainer Görtz

Michael Wild

Paul Michels

Rainer Goertz

Rainer Gortz

Rainer Götz

A method of producing a metal strip coated with a coating, said coating containing chromium metal and chromium oxide and being electrolytically deposited from an electrolyte solution that contains a trivalent chromium compound and at least one salt for increasing conductivity and at least one acid or one base for setting a desired pH value, onto the metal strip by bringing the metal strip into electrolytically effective contact with the electrolyte solution during an electrolysis time. The metal strip is successively passed at a predefined strip travel speed in a strip travel direction through a plurality of electrolysis tanks successively arranged in the strip travel direction. At least the first electrolysis tank, as viewed in the strip travel direction, or a front group of electrolysis tanks is filled with a first electrolyte solution and the last electrolysis tank, as viewed in the strip travel direction, or a rear group of electrolysis tanks is filled with a second electrolyte solution. The second electrolyte solution contains no additional components apart from the trivalent chromium compound as well as the at least one salt and the at least one acid or base and is especially free of organic complexing agents and free of buffering agents.

Method of producing a metal strip coated with a coating of chromium and chromium oxide using an electrolyte solution with a trivalent chromium compound and electrolysis system for implementing the method

A method for the production of a metal strip coated with a coating. The coating containing chromium metal and chromium oxide and is electrolytically deposited from an electrolyte solution that contains a trivalent chromium compound onto the metal strip by bringing the metal strip, which is connected as the cathode, into contact with the electrolyte solution. An effective deposition of the coating with a high chromium oxide portion is achieved by successively passing the metal strip at a predefined strip travel speed through a plurality of electrolysis tanks arranged successively in a strip travel direction. The first electrolysis tank is set to a low current density; a second electrolysis tank, which follows in the strip travel direction, is set to a medium current density; and a last electrolysis tank is set to a high current density, where the low current density is greater than 20 A/dm.

Method for the production of a metal strip coated with a coating of chromium and chromium oxide using an electrolyte solution with a trivalent chromium compound

A method for producing a metal strip coated with a coating that contains chromium metal and chromium oxide and is electrolytically deposited from an electrolyte solution that contains a trivalent chromium compound onto the metal strip by bringing the metal strip, which is connected as the cathode, into contact with the electrolyte solution. An efficient deposition of coating with a high proportion of chromium oxide is obtained by successively passing the metal strip through a plurality of electrolysis tanks. The electrolyte solution in at least the last electrolysis tank, as viewed in the strip travel direction, or in a rear group of electrolysis tanks has an average temperature of at most 40&#xb0; C., and the electrolysis time, during which the metal strip is in electrolytically effective contact with the electrolyte solution in the last electrolysis tank or in the rear group of electrolysis tanks is less than 2.0 seconds.

A method of thermally treating black plate which is coated with a conversion coating. The conversion-coated black plate is heated during a thermal treatment time from 0.1 seconds to 30 seconds to a temperature in the range of 240&#xb0; C. to 320&#xb0; C. The heat treatment makes it possible to improve the adhesion of the conversion coating to the black plate surface. In one application of the method, the heat treatment is carried out in a process for the production of corrosion-resistant black plate, in which prior to, during or after the heat treatment, an organic coating in the form of paint or a polymer coating is applied to the conversion coating of the black plate.

Method of thermally treating black plate coated with a conversion coating

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Piesport, Germany

Andrea Marmann