Method for producing an anti-corrosion coating for hardenable sheet steels and an anti-corrosion coating for hardenable sheet steels

Abstract

The invention relates to a method for producing an anti-corrosion coating for hardenable sheet steels, wherein at least two metal layers are deposited one after another onto the steel substrate; the one metal layer is a zinc layer or zinc-based layer and the other layer is a layer composed of a metal that forms baser intermetallic phases with Zn or Fe and has a higher oxidation potential than Zn, namely Ni, Cu, Co, Mn, or Mo, or a layer based on these metals; and an anti-corrosion coating for hardenable sheet steels.

1 . A method for producing hardened sheet steel components, comprising:
 depositing at least two metal layers, one after another, onto a steel substrate, wherein the at least two metal layers act as an anti-corrosion coating and form a band composed of a quench-hardenable steel alloy; a first metal layer is a zinc layer or zinc-based layer and a second metal layer is a layer composed of a metal that forms baser intermetallic phases with Zn or Fe and has a higher oxidation potential than Zn, namely Ni, Cu, Co, Mn, or Mo, or a layer based on these metals; and the steel substrate has the following general alloy composition, respectively indicated in percentage by weight:   
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   carbon (C) 
                   0.08-0.6 
                 
                     
                   manganese (Mn) 
                    0.8-3.0 
                 
                     
                   aluminum (Al) 
                    0.01-0.07 
                 
                     
                   silicon (Si) 
                   0.01-0.5 
                 
                     
                   chromium (Cr) 
                   0.02-0.6 
                 
                     
                   titanium (Ti) 
                    0.01-0.08 
                 
                     
                   nitrogen (N) 
                   <0.02 
                 
                     
                   boron (B) 
                   0.002-0.02 
                 
                     
                   phosphorus (P) 
                   <0.01 
                 
                     
                   sulfur (S) 
                   <0.01 
                 
                     
                   molybdenum (Mo) 
                   <1 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
         traces of iron and smelting-related impurities; 
         stamping blanks from the band provided with the anti-corrosion coating; and either 
         heating the blanks to a temperature>Ac 3  and keeping the blanks at this temperature if need be, and then shaping the blanks in a press-hardening tool and quench-hardening the blanks in order to produce the sheet steel component; or 
         cold forming the blanks into a sheet steel component and then heating the sheet steel component to a temperature>Ac 3  and quench-hardening the sheet steel component in a form-hardening die. 
       
     
     
         2 . The method according to  claim 1 , comprising using a material with the following alloy composition as the steel substrate, respectively indicated in percentage by weight: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   carbon (C) 
                   0.08-0.34 
                 
                     
                   manganese (Mn) 
                   1.00-3.00 
                 
                     
                   aluminum (Al) 
                   0.03-0.06 
                 
                     
                   silicon (Si) 
                   0.01-0.20 
                 
                     
                   chromium (Cr) 
                   0.02-0.3  
                 
                     
                   titanium (Ti) 
                   0.03-0.04 
                 
                     
                   nitrogen (N) 
                   <0.007 
                 
                     
                   boron (B) 
                   0.002-0.006 
                 
                     
                   phosphorus (P) 
                   <0.01 
                 
                     
                   sulfur (S) 
                   <0.01 
                 
                     
                   molybdenum (Mo) 
                   <1 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
         traces of iron and smelting-related impurities. 
       
     
     
         3 . The method according to  claim 1 , comprising applying the zinc layer or zinc-based layer electrolytically or using a hot-dip method. 
     
     
         4 . The method according to  claim 1 , comprising applying the nickel, copper, or manganese layer electrolytically or using a roller application method. 
     
     
         5 . The method according to  claim 1 , comprising applying the nickel, copper, or manganese layer with a thickness of 0.5 μm to 2 μm with electrolytic deposition or with a thickness of 250 nm to 700 nm with roller application. 
     
     
         6 . The method according to  claim 3 , comprising depositing the zinc layer or zinc-based layer with a thickness of 6 μm to 30 μm. 
     
     
         7 . The method according to  claim 1 , comprising first depositing the layer composed of nickel, copper, or manganese onto the steel substrate and then depositing the zinc layer or zinc-based coating onto the steel substrate. 
     
     
         8 . The method according to  claim 1 , comprising depositing the zinc coating or zinc-based coating onto the layer composed of nickel, copper, or manganese electrolytically or using hot-dip galvanization. 
     
     
         9 . The method according to  claim 1 , comprising first applying the zinc layer or zinc-based layer to the steel substrate electrolytically or using a hot-dip coating method and then applying the nickel layer to the zinc layer electrolytically or applying the nickel layer to the zinc layer using a roller application method. 
     
     
         10 . The method according to  claim 1 , comprising repeatedly applying the layer sequence, alternating between the nickel, copper, and manganese layer and the zinc or zinc-based layer. 
     
     
         11 . An anti-corrosion layer for use in the method according to  claim 1 , the anti-corrosion layer comprising at least two layers, one layer is present that is composed of nickel, copper, or manganese and on top of or underneath it, a zinc layer or zinc-based layer is present. 
     
     
         12 . The anti-corrosion layer according to  claim 11 , wherein the zinc layer or zinc-based layer is deposited electrolytically or using a hot-dip method. 
     
     
         13 . The anti-corrosion layer according to  claim 11 , wherein the nickel, copper, or manganese layer is applied electrolytically or using a roller application method. 
     
     
         14 . The anti-corrosion layer according to  claim 11 , wherein the nickel, copper, or manganese layer has a thickness of 0.5 μm to 2 μm with electrolytic deposition or a thickness of 250 nm to 700 nm with a roller application method. 
     
     
         15 . The anti-corrosion layer according to  claim 11 , wherein the zinc layer or zinc-based layer has a thickness of 6 μm to 30 μm. 
     
     
         16 . The anti-corrosion layer according to  claim 11 , wherein the layer composed of nickel, copper, or manganese is positioned on the steel substrate and the zinc layer or zinc-based coating is positioned on top of it. 
     
     
         17 . The anti-corrosion layer according to  claim 11 , wherein a zinc layer or zinc-based coating, which has been deposited electrolytically or using hot-dip coating, is applied to the steel substrate and the nickel layer is positioned on the zinc layer, the nickel layer being applied electrolytically or using a roller application method. 
     
     
         18 . The anti-corrosion layer according to  claim 11 , wherein a repeated sequence of the layers nickel, copper, and manganese on the one hand and zinc or zinc-based layers on the other is present on the steel substrate.