Process for Producing an Active Cathodic Anti-Corrosion Coating on Steel Elements

Abstract

The invention relates to a process for producing an active anti-corrosion coating on steel components. In order to develop an active anti-corrosion coating that can be applied on an industrial scale using conventional means (e.g. dipping, spraying or flooding) and is intended for hot-formed and, in particular, press-hardened steel parts provided with antiscaling means, the invention proposes a process comprising the following process steps: a. Using a steel element provided with an antiscaling layer; b. Annealing the steel element at a temperature above 600° C. in an annealing furnace for the purpose of hardening, semi-hot or hot forming or press hardening and thus producing a reaction layer; c. Applying an anti-corrosion coating to the annealed reaction layer.

1 - 22 . (canceled) 
   
   
       23 . Process for producing an active cathodic anti-corrosion coating on steel elements, comprising the following process steps:
 a. Using a steel element provided with an antiscaling layer, said antiscaling layer consisting of an aluminum alloy, a coating containing an aluminum pigment, a magnesium alloy, a coating containing a magnesium pigment, a zinc alloy or a coating containing a zinc pigment;   b. Annealing the steel element at a temperature above 600° C. in an annealing furnace for the purpose of hardening, semi-hot or hot forming or press hardening and thus producing a reaction layer;   c. Applying an anti-corrosion coating containing a binder and a metallic pigment to the annealed reaction layer.   
   
   
       24 . Process according to  claim 23 , wherein annealing is performed at a temperature above 850° C. 
   
   
       25 . Process according to  claim 23 , wherein annealing is performed conductively or inductively in gas-operated or electrically-operated annealing furnaces. 
   
   
       26 . Process according to  claim 23 , wherein the oxygen content in the annealing-furnace atmosphere is 0-10%. 
   
   
       27 . Process according to  claim 23 , wherein the anti-corrosion layer is applied to the annealed reaction layer from the liquid phase in a wet-chemical process, in particular in a spraying, flooding, rolling or dipping process. 
   
   
       28 . Process according to  claim 27 , wherein the layer thickness of the anti-corrosion layer is less than 50 μm, preferably less than 20 μm and best of all less than 10 μm. 
   
   
       29 . Process according to  claim 27 , wherein the anti-corrosion layer is diluted with solvents prior to application. 
   
   
       30 . Process according to  claim 23 , wherein after the anti-corrosion layer has been applied, it is dried at a temperature between room temperature and 400° C., preferably between room temperature and 250° C. 
   
   
       31 . Process according to  claim 23 , wherein the anti-corrosion layer contains between 10 and 100 wt. %, preferably between 50 and 100 wt. % and best of all between 70 and 95 wt. % metallic zinc pigment and/or magnesium pigment. 
   
   
       32 . Process according to  claim 23 , wherein the anti-corrosion layer contains up to 50 wt. % metallic aluminum pigment. 
   
   
       33 . Process according to  claim 23 , wherein the binder used in the anti-corrosion layer contains 5 to 100 wt. % metal oxides, in particular titanium, aluminum or zirconium oxides. 
   
   
       34 . Process according to  claim 23 , wherein the binder used in the anti-corrosion layer contains up to 50 wt. % binder produced by the sol-gel process, silicones, siloxanes or waxes. 
   
   
       35 . Process according to  claim 23 , wherein the anti-corrosion layer contains solid-state lubricants, in particular graphite or boron nitride. 
   
   
       36 . Process according to  claim 23 , wherein the steel element is in the form of sheet, coil, component or other solid body. 
   
   
       37 . Process according to  claim 23 , wherein the steel element consists of an assembly of components made of diverse alloy steels—with or without metallic coatings such as aluminum or zinc coatings or coatings containing metal pigments—and joined together by way of standard joining processes, such as welding, bonding, bolting or riveting. 
   
   
       38 . Process according to  claim 23 , wherein, prior to being annealed, the steel element is provided wholly or partially with a coating that influences the heating-up behavior of the steel part or of parts thereof. 
   
   
       39 . Use of the process according to  claim 23  for producing anti-corrosive components or assemblies for machine construction, in particular for vehicle construction, building, in particular steelwork, for process engineering, aerospace, power plants and power-plant engineering, electrical engineering, medical engineering, sports equipment, horticulture and landscape gardening, toolmaking, agricultural machinery, furniture, kitchens, household appliances, toys, sports articles, camping equipment, caravans, window and door frames, heating installations, heat exchangers, air conditioners, escalators, conveyors, oil platforms, jewelry, locomotives, rails, transport systems, cranes, furnaces, engines and engine attachments, pistons, sealing rings, exhaust systems, ABS and braking systems, brake discs, chassis components, wheels, wheel rims, sanitary articles, lamps and design articles.