US20100175794A1 - Process for Producing an Active Cathodic Anti-Corrosion Coating on Steel Elements - Google Patents
Process for Producing an Active Cathodic Anti-Corrosion Coating on Steel Elements Download PDFInfo
- Publication number
- US20100175794A1 US20100175794A1 US12/733,140 US73314008A US2010175794A1 US 20100175794 A1 US20100175794 A1 US 20100175794A1 US 73314008 A US73314008 A US 73314008A US 2010175794 A1 US2010175794 A1 US 2010175794A1
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- US
- United States
- Prior art keywords
- process according
- coating
- steel
- corrosion
- annealing
- Prior art date
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- Abandoned
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 53
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 51
- 239000010959 steel Substances 0.000 title claims abstract description 51
- 239000011248 coating agent Substances 0.000 title claims abstract description 48
- 238000005260 corrosion Methods 0.000 title claims abstract description 45
- 238000000137 annealing Methods 0.000 claims abstract description 16
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 238000007598 dipping method Methods 0.000 claims abstract description 4
- 238000005507 spraying Methods 0.000 claims abstract description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 15
- 239000000049 pigment Substances 0.000 claims description 15
- 229910052782 aluminium Inorganic materials 0.000 claims description 13
- 238000003466 welding Methods 0.000 claims description 10
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 9
- 239000011230 binding agent Substances 0.000 claims description 9
- 239000001039 zinc pigment Substances 0.000 claims description 9
- 229910052725 zinc Inorganic materials 0.000 claims description 8
- 239000011701 zinc Substances 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 5
- 230000000712 assembly Effects 0.000 claims description 5
- 238000000429 assembly Methods 0.000 claims description 5
- 239000012298 atmosphere Substances 0.000 claims description 5
- 238000010276 construction Methods 0.000 claims description 5
- 239000011777 magnesium Substances 0.000 claims description 5
- 229910052749 magnesium Inorganic materials 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 239000000956 alloy Substances 0.000 claims description 3
- 239000000314 lubricant Substances 0.000 claims description 3
- 229910044991 metal oxide Inorganic materials 0.000 claims description 3
- 150000004706 metal oxides Chemical class 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- 239000001993 wax Substances 0.000 claims description 3
- 229910000838 Al alloy Inorganic materials 0.000 claims description 2
- 229910052582 BN Inorganic materials 0.000 claims description 2
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 2
- 229910000861 Mg alloy Inorganic materials 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 229910001297 Zn alloy Inorganic materials 0.000 claims description 2
- 238000004870 electrical engineering Methods 0.000 claims description 2
- 238000010413 gardening Methods 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- 238000003898 horticulture Methods 0.000 claims description 2
- 238000009434 installation Methods 0.000 claims description 2
- 238000005304 joining Methods 0.000 claims description 2
- 239000007791 liquid phase Substances 0.000 claims description 2
- 230000003137 locomotive effect Effects 0.000 claims description 2
- 238000010327 methods by industry Methods 0.000 claims description 2
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical class [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 2
- 229920001296 polysiloxane Polymers 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- -1 siloxanes Chemical class 0.000 claims description 2
- 238000003980 solgel method Methods 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 238000007704 wet chemistry method Methods 0.000 claims description 2
- 229910001928 zirconium oxide Inorganic materials 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims 1
- 229910000760 Hardened steel Inorganic materials 0.000 abstract description 3
- 239000004411 aluminium Substances 0.000 description 11
- 238000003618 dip coating Methods 0.000 description 10
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 9
- 230000015572 biosynthetic process Effects 0.000 description 7
- 230000007797 corrosion Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 238000005422 blasting Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000008199 coating composition Substances 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 229910018125 Al-Si Inorganic materials 0.000 description 2
- 229910000680 Aluminized steel Inorganic materials 0.000 description 2
- 229910018520 Al—Si Inorganic materials 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- FPCJKVGGYOAWIZ-UHFFFAOYSA-N butan-1-ol;titanium Chemical compound [Ti].CCCCO.CCCCO.CCCCO.CCCCO FPCJKVGGYOAWIZ-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000011253 protective coating Substances 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 229910002012 Aerosil® Inorganic materials 0.000 description 1
- 229910021364 Al-Si alloy Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005269 aluminizing Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- PALQHNLJJQMCIQ-UHFFFAOYSA-N boron;manganese Chemical compound [Mn]#B PALQHNLJJQMCIQ-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 239000012456 homogeneous solution Substances 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000007130 inorganic reaction Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 235000011007 phosphoric acid Nutrition 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000007592 spray painting technique Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- CPUDPFPXCZDNGI-UHFFFAOYSA-N triethoxy(methyl)silane Chemical compound CCO[Si](C)(OCC)OCC CPUDPFPXCZDNGI-UHFFFAOYSA-N 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- 239000000080 wetting agent Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/08—Anti-corrosive paints
- C09D5/10—Anti-corrosive paints containing metal dust
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/48—Stabilisers against degradation by oxygen, light or heat
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/60—Additives non-macromolecular
- C09D7/61—Additives non-macromolecular inorganic
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2202/00—Metallic substrate
- B05D2202/10—Metallic substrate based on Fe
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2701/00—Coatings being able to withstand changes in the shape of the substrate or to withstand welding
- B05D2701/40—Coatings being able to withstand changes in the shape of the substrate or to withstand welding withstanding welding
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/08—Metals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- the invention relates to a process for producing an active anti-corrosion coating on steel components.
- Hot-forming processes are being used increasingly to manufacture high-strength steel components of the sort required, for example, as structural body components for vehicle construction.
- One particular type of hot forming is the process referred to as press hardening, during which specialty steels (usually manganese-boron steels) are heated to austenizing temperature, hot-formed and quench-hardened in the forming tool.
- a martensitic microstructure of high mechanical strength is obtained, which makes it possible to manufacture components that are thin and therefore light in weight, yet high in strength.
- Austenizing takes place at temperatures above 850° C. At this temperature, pronounced scale formation occurs at the steel surface. The scale forms so quickly that even parts which are heated in an atmosphere of protective gas, e.g.
- the scale is apt to flake off, and is rough and brittle. It therefore damages components as well as forming tools, and has to be removed at high cost from the component following press hardening, for example by blasting.
- the regular cleaning of the forming tools which is necessary substantially increases cycle times, and the material removed by blasting has to be compensated for by using thicker metal sheet.
- For press hardening therefore, it is usual to use steel sheet which has been provided with a coating that protects against scaling.
- the EP 1 013 785 A1 describes the use of hot-dip aluminized steel types. These are coated with an approximately 20-30 ⁇ m thick layer of an Al—Si alloy, which is applied by hot-dip coating.
- This Al—Si coating does indeed offer a certain degree of corrosion protection for hot-dip aluminized sheet steel while it is in storage, which means that sheets and coils need not be oiled for storage and transport purposes; however, after the annealing process employed during hot-forming, the anti-corrosive effect of the coating is very much reduced. This becomes evident when, for example, hot-dip aluminized steel sheet that has been annealed at 950° C. is examined using the salt spray test according to German standard DIN 50021.
- a refined form of the wet-chemical antiscaling coating described which is the subject of the WO 2007/076766 A2, does possess the required electrical conductivity for resistance spot welding and cataphoretic dip-coating and can thus remain on the component after it has been press-hardened. Under normal conditions of press-hardening, the electrical resistance of these sheets is in the region of ⁇ 5 mOhm following the hardening process. If the component is subsequently to be subjected to a welding process, in particular a resistance spot welding process, or to cataphoretic hot-dip coating, the observance of process parameters that will lead to the formation of electrically conductive reaction layers when the steel sheet with its antiscaling coating is annealed is particularly important.
- the use a protective-gas atmosphere e.g.
- a general advantage of the wet-chemical antiscaling coatings described over hot-dip aluminizing is that on heating to austenizing temperature, no diffusion layer needs to be formed and therefore cycle times are shorter. Besides, on heating, there is no danger in this case of any melting, meaning that inductive or conductive heating methods may be used during press-hardening.
- WO 2005/021820 A1, WO 2005/021821 A1 and WO 2005/021822 A1 describe methods of manufacturing various hardened steel parts.
- a protective coating consisting of zinc combined with another element having an affinity for oxygen (especially aluminium) is applied to the steel.
- this protective coating is applied by means of a hot-dip process, in the WO 2005/021820 A1 and WO 2005/021822 A1 by means of a hot-dip or an electroplating process.
- these coatings which contain zinc as the main element, are extremely susceptible to oxidisation and vaporisation at the austenizing temperatures required for a press-hardening process. Even traces of dirt (e.g.
- the object of the invention is to develop an active anti-corrosion coating that can be applied on an industrial scale using conventional means (e.g. dipping, spraying, flooding or rolling) and is intended for hot-formed and, in particular, press-hardened steel parts provided with antiscaling means.
- conventional means e.g. dipping, spraying, flooding or rolling
- the invention is thus based on using a special antiscaling coating on steel in order to prevent scale formation during hot-forming and particularly during press-hardening at temperatures above 600° C.
- An embodiment of the invention consists in that annealing is effected at a temperature above 850° C.
- hardenable steels are annealed conductively or inductively in gas-operated or electrically-operated annealing furnaces.
- An advantageous embodiment of the invention consists in that the oxygen content in the annealing-furnace atmosphere is 0-10%.
- the antiscaling layer consists of an aluminium alloy, aluminium pigments, a coating containing an aluminium pigment, a magnesium alloy, magnesium pigments, a coating containing a magnesium pigment, a zinc alloy, zinc pigments or a coating containing a zinc pigment;
- the antiscaling layer has a maximum electrical resistance of 10 mOhm, preferably a maximum of 5 mOhm.
- the finished component has a maximum electrical resistance of 10 mOhm, preferably a maximum of 5 mOhm.
- the two preceding measures ensure that resistance spot welding is possible.
- 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.
- the layer thickness of the anti-corrosion layer is less than 50 ⁇ m, preferably less than 20 ⁇ m and best of all less than 10 ⁇ m.
- the anti-corrosion layer is diluted with solvents prior to application.
- the anti-corrosion layer once applied, is dried at a temperature between room temperature and 400° C., preferably between room temperature and 250° C.
- the anti-corrosion layer contains a binder and metallic pigment.
- 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.
- the anti-corrosion layer contains up to 50 wt. % metallic aluminium pigment.
- a preferred embodiment of the invention consists in that the binder used in the anti-corrosion layer contains 5 to 100 wt. % metal oxides, in particular titanium, aluminium or zirconium oxides.
- the binder used in the anti-corrosion layer contains up to 50 wt. % binder produced by the sol-gel process, silicones, siloxanes or waxes.
- the anti-corrosion layer contains solid-state lubricants, in particular graphite or boron nitride.
- the invention consists in that the steel element is in the form of sheet, coil, component or other solid body.
- a special embodiment of the invention consists in that the coated substrate is a steel element that has undergone a hardening process.
- the steel element was shaped in a hydroforming process.
- coated substrate is a steel element that has been provided with an antiscaling layer which is of a kind customary for the hardening process and which remains on the component.
- the steel element consists of an assembly of components made of diverse alloy steels—with or without metallic coatings such as aluminium or zinc coatings or coatings containing metal pigments—and joined together by way of standard joining processes, such as welding, bonding, bolting or riveting.
- a preferred embodiment of the invention consists in that, prior to being annealed, the steel element is provided wholly or partially with a coating that influences the heating-up behaviour of the steel part or of parts thereof.
- the steel element with a homogeneous, heat-absorbing coating, for example a black one, in order to reduce the heating-up time, the furnace time and/or the diffusion time, or with an inhomogeneous coating with heat-absorbing and heat-reflecting areas distributed over the surface of the steel element, for example a partial black coating and a partial silver coating so that, by way of this variation in the absorption of infrared rays at the surface, the energy input may be selectively controlled from area to area, allowing, for example, the formation of different hardening zones.
- This measure may of course be combined with the previously described assembly, where the steel element comprises diverse components joined together.
- An embodiment of the invention consists in that the components or assemblies of components provided with the anti-corrosion layer can be welded with each other, with customarily weldable alloy steels or with steel grades provided with metallic coatings.
- a special embodiment of the invention consists in that the electrical resistance of the steel element used is not influenced significantly by the anti-corrosion layer.
- the scope of the invention extends to use of the process according to the invention 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, jewellery, locomotives, rails, transport systems, cranes, furnaces, engines and engine attachments, pistons, sealing rings, exhaust systems, ABS and braking systems, brake discs, chassis components, wheels, rims, sanitary articles, lamps and design articles.
- Degreased 22MnB5A steel strip moving at 60 m/min is roll-coated in a coil coating line with a coating material according to WO 2007/076766 A2.
- the coating material is hardened at a PMT (Peak Metal Temperature) of 200-250° C.
- PMT Peak Metal Temperature
- the coated steel strip is cut into tailored blanks and pre-drawn in a cold-forming process to a preform.
- the preform is heated in a nitrogen atmosphere having a maximum oxygen content of 10 vol. % to a temperature of 950° C. in an electrically operated continuous furnace for 4 minutes, transferred to the forming tool and hot-formed there, and then quench-hardened by cooling to 200° C. within 20 s.
- a suitable anti-corrosion coating for the press-hardened parts described is produced as follows:
- the coating solution is applied to the entire surface of the press-hardened part using a paint spray gun (e.g. Sata Jet, 1.2 mm nozzle) such as to produce a layer thickness of 3-10 ⁇ m after drying and hardening.
- a paint spray gun e.g. Sata Jet, 1.2 mm nozzle
- the coating solution hardens at room temperature within an hour of application, or within 20 minutes at 180° C.
- a component provided with an aluminium antiscaling coating (e.g. Usibor) is subjected as in Example 1 to a press-hardening process.
- a suitable anti-corrosion coating for this component is produced as follows:
- a mixture of 40 g methyltriethoxysilane (from Fluka) and 10 g tetraethoxysilane (from Fluka) is hydrolysed by stirring 15 g of 1% orthophosphoric acid into it. After 5 hours of stirring, the reaction mixture is single-phase and is stirred into the aforementioned dispersion to produce a homogeneous solution.
- the coating solution is prepared in a quantity sufficient to fill a suitably controlled dip tank.
- the component is lowered by means of a crane into the dip tank filled with coating solution, and after its entire surface has been homogeneously wetted, is lifted out again. After any excess coating solution has dripped off, the component is transferred to a furnace where the coating is hardened for 20 minutes at 180° C.
- the composite entity comprisng steel, aluminium and anti-corrosion layer has a resistance of ⁇ 10 mOhm and can be joined readily with other sheets by means of resistance spot welding.
- Body components are produced by means of press-hardening from steel blanks with an Al—Si dip-coating and from steel blanks coated according to the WO 2007/076766 A2. These are joined with uncoated steel components by means of resistance spot welding to form an assembly.
- a suitable anti-corrosion coating for this assembly is produced as follows:
- an aluminium oxide powder e.g. Aeroxide Alu C from Degussa
- a zinc powder e.g. Standart Zink Flake AT from Eckart
- Aerosil R 972 from Degussa
- 20 g of a suitable powdered wax e.g. Licowax C from Clariant
- a suitable powdered wax e.g. Licowax C from Clariant
- the coating solution is applied to the entire surface of the press-hardened assembly using spray painting equipment (e.g. HVLP pressurized-air nozzles with a diameter of 1.2 mm) such as to produce a layer thickness of 3-10 ⁇ m after drying and hardening.
- the solution is also sprayed particularly into cavities, gaps and joints. Hardening is effected for 20 minutes at a temperature of 180° C.
- the components and assemblies from the examples 1-3 are each coated with a 3-10 ⁇ m thick silver-grey anti-corrosion layer that adheres firmly to the substrate. After being exposed in a salt-spray test as per DIN EN ISO 9227 for 1000 h, the coatings showed no red-rust formation, neither on the surface nor at the cruciform injury site.
- the coated components and assemblies have an electrical resistance of ⁇ 10 mOhm and can be welded to other steel parts, for example to assemble a vehicle body.
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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.
Description
- The invention relates to a process for producing an active anti-corrosion coating on steel components.
- Hot-forming processes are being used increasingly to manufacture high-strength steel components of the sort required, for example, as structural body components for vehicle construction. One particular type of hot forming is the process referred to as press hardening, during which specialty steels (usually manganese-boron steels) are heated to austenizing temperature, hot-formed and quench-hardened in the forming tool. A martensitic microstructure of high mechanical strength is obtained, which makes it possible to manufacture components that are thin and therefore light in weight, yet high in strength. Austenizing takes place at temperatures above 850° C. At this temperature, pronounced scale formation occurs at the steel surface. The scale forms so quickly that even parts which are heated in an atmosphere of protective gas, e.g. in a continuous furnace, will undergo scale formation when they come into contact with atmospheric oxygen on being transferred from the furnace to the forming tool. In the case of production lines configured for the forming of piece numbers in vehicle manufacturing, it is not justifiable either from economical or constructional aspects to operate the entire section of the line—from heating to forming—under protective gas.
- As it forms, the scale is apt to flake off, and is rough and brittle. It therefore damages components as well as forming tools, and has to be removed at high cost from the component following press hardening, for example by blasting. The regular cleaning of the forming tools which is necessary substantially increases cycle times, and the material removed by blasting has to be compensated for by using thicker metal sheet. For press hardening, therefore, it is usual to use steel sheet which has been provided with a coating that protects against scaling.
- The EP 1 013 785 A1 describes the use of hot-dip aluminized steel types. These are coated with an approximately 20-30 μm thick layer of an Al—Si alloy, which is applied by hot-dip coating. This Al—Si coating does indeed offer a certain degree of corrosion protection for hot-dip aluminized sheet steel while it is in storage, which means that sheets and coils need not be oiled for storage and transport purposes; however, after the annealing process employed during hot-forming, the anti-corrosive effect of the coating is very much reduced. This becomes evident when, for example, hot-dip aluminized steel sheet that has been annealed at 950° C. is examined using the salt spray test according to German standard DIN 50021. After just a few days, red-rust formation is apparent over the entire surface. After the entire vehicle body has been assembled and phosphated, the affected parts can be subjected to cataphoretic dip-coating. This provides them with adequate corrosion protection for use in certain applications. However, if the cataphoretic dip coating is damaged, no adequate active corrosion protection is ensured anymore. Under normal conditions of direct press-hardening, the electrical resistance of hot-dip aluminized sheet is in the region of <1 mOhm following the hardening process.
- Another form of protection against scaling, which is described in the WO 2006/040030 A1, is based on the wet-chemical coating of steel sheet or coil with a coating composition consisting of an organosilicon binder, aluminium particles and solid lubricants. This can be hot- or cold-formed and protects against scaling during hot-forming. After the hot-forming (press-hardening) process, the inorganic reaction layer is removed by blasting. The time and energy needed to do so is markedly less than that required to remove scale. Removal of this layer by blasting is necessary because it does not have the required electrical conductivity for the subsequent resistance spot welding. After the bare metal sheets have been welded, these too are phosphated and subjected to cataphoretic dip-coating.
- A refined form of the wet-chemical antiscaling coating described, which is the subject of the WO 2007/076766 A2, does possess the required electrical conductivity for resistance spot welding and cataphoretic dip-coating and can thus remain on the component after it has been press-hardened. Under normal conditions of press-hardening, the electrical resistance of these sheets is in the region of <5 mOhm following the hardening process. If the component is subsequently to be subjected to a welding process, in particular a resistance spot welding process, or to cataphoretic hot-dip coating, the observance of process parameters that will lead to the formation of electrically conductive reaction layers when the steel sheet with its antiscaling coating is annealed is particularly important. The use a protective-gas atmosphere (e.g. nitrogen or argon) or of a furnace atmosphere with a reduced oxygen content (−10%) has proved advantageous. Short heating times likewise lead to high electrical conductivity and hence to low electrical resistance in the <3 mOhm range, thus promoting weldability. After welding, phosphating and cataphoretic dip-coating, the parts in question show adequate corrosion protection for use in certain areas. However, in this case too, there is no active corrosion protection that will protect the steel in the event of damage to the cataphoretic dip-coating.
- A general advantage of the wet-chemical antiscaling coatings described over hot-dip aluminizing is that on heating to austenizing temperature, no diffusion layer needs to be formed and therefore cycle times are shorter. Besides, on heating, there is no danger in this case of any melting, meaning that inductive or conductive heating methods may be used during press-hardening.
- The applications WO 2005/021820 A1, WO 2005/021821 A1 and WO 2005/021822 A1 describe methods of manufacturing various hardened steel parts. In each case, a protective coating consisting of zinc combined with another element having an affinity for oxygen (especially aluminium) is applied to the steel. In the WO 2005/021821 A1, this protective coating is applied by means of a hot-dip process, in the WO 2005/021820 A1 and WO 2005/021822 A1 by means of a hot-dip or an electroplating process. However, these coatings, which contain zinc as the main element, are extremely susceptible to oxidisation and vaporisation at the austenizing temperatures required for a press-hardening process. Even traces of dirt (e.g. dust) on the surface will burn and lead to rejection of the part. The three applications cited are based on the AT 412878 B (“High-strength corrosion-protected sheet-steel component”), in which the cathodic anti-corrosion effect of the coating is explicitly described. In practice, however, even if suitable components with undamaged surfaces are obtained within a narrow processing window, the cathodic anti-corrosion effect of the zinc is no longer the same after annealing as it was originally, and the diffusion of iron from the base material into the coating causes the components to corrode and form red rust relatively easily. The same applies to the zinc coating described in EP 1439240A1, which is protected from vaporizing under press-hardening conditions by an additional layer of zinc oxide.
- The object of the invention is to develop an active anti-corrosion coating that can be applied on an industrial scale using conventional means (e.g. dipping, spraying, flooding or rolling) and is intended for hot-formed and, in particular, press-hardened steel parts provided with antiscaling means.
- This object is established according to the invention by a process according to the preamble and 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.
- In an alternative embodiment this object is established by a process according to the preamble and comprising the following process steps:
-
- a. Using a steel element provided with an antiscaling layer;
- b. Applying an anti-corrosion coating to the antiscaling layer.
- c. Annealing the steel element at a temperature above 600° C. in an annealing furnace for the purpose of hardening, of semi-hot or hot forming or of press hardening and thus producing a reaction layer.
- The invention is thus based on using a special antiscaling coating on steel in order to prevent scale formation during hot-forming and particularly during press-hardening at temperatures above 600° C.
- Surprisingly, it was found that special coating compositions consisting of a metal oxide and metal pigment, in particular zinc pigment or zinc pigment and aluminium pigment, protect steel effectively against corrosion even when the layer thickness is in the lower μm range and irrespective of whether these coating compositions are applied directly onto the metallic steel surface or onto the reaction layer formed from the antiscaling coating during annealing. Highly resistant edge protection is imparted to the component, and the anti-corrosion coating can also be overpainted, phosphated or dip-coated, especially by the process of cataphoretic dip-coating, without any problem.
- An embodiment of the invention consists in that annealing is effected at a temperature above 850° C.
- According to the invention, hardenable steels are annealed conductively or inductively in gas-operated or electrically-operated annealing furnaces.
- An advantageous embodiment of the invention consists in that the oxygen content in the annealing-furnace atmosphere is 0-10%.
- It is also within the scope of the invention that the antiscaling layer consists of an aluminium alloy, aluminium pigments, a coating containing an aluminium pigment, a magnesium alloy, magnesium pigments, a coating containing a magnesium pigment, a zinc alloy, zinc pigments or a coating containing a zinc pigment;
- It is also within the scope of the invention that, after the forming process, the antiscaling layer has a maximum electrical resistance of 10 mOhm, preferably a maximum of 5 mOhm.
- It is additionally to advantage that the finished component has a maximum electrical resistance of 10 mOhm, preferably a maximum of 5 mOhm.
- The two preceding measures ensure that resistance spot welding is possible.
- It is furthermore expedient that 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.
- According to the invention, 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.
- It is within the scope of the invention that the anti-corrosion layer is diluted with solvents prior to application.
- In an embodiment of the invention the anti-corrosion layer, once applied, is dried at a temperature between room temperature and 400° C., preferably between room temperature and 250° C.
- It is furthermore within the scope of the invention that the anti-corrosion layer contains a binder and metallic pigment.
- In this connection it has proved advantageous that 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.
- It is also to advantage in this connection that the anti-corrosion layer contains up to 50 wt. % metallic aluminium pigment.
- A preferred embodiment of the invention consists in that the binder used in the anti-corrosion layer contains 5 to 100 wt. % metal oxides, in particular titanium, aluminium or zirconium oxides.
- It is also within the scope of the invention that the binder used in the anti-corrosion layer contains up to 50 wt. % binder produced by the sol-gel process, silicones, siloxanes or waxes.
- It is furthermore within the scope of the invention that the anti-corrosion layer contains solid-state lubricants, in particular graphite or boron nitride.
- The invention consists in that the steel element is in the form of sheet, coil, component or other solid body.
- A special embodiment of the invention consists in that the coated substrate is a steel element that has undergone a hardening process.
- It is also within the scope of the invention that the steel element was shaped in a hydroforming process.
- Another special embodiment consists in that the coated substrate is a steel element that has been provided with an antiscaling layer which is of a kind customary for the hardening process and which remains on the component.
- It is furthermore within the scope of the invention that the steel element consists of an assembly of components made of diverse alloy steels—with or without metallic coatings such as aluminium or zinc coatings or coatings containing metal pigments—and joined together by way of standard joining processes, such as welding, bonding, bolting or riveting.
- A preferred embodiment of the invention consists in that, prior to being annealed, the steel element is provided wholly or partially with a coating that influences the heating-up behaviour of the steel part or of parts thereof.
- It is possible in this context to provide the steel element with a homogeneous, heat-absorbing coating, for example a black one, in order to reduce the heating-up time, the furnace time and/or the diffusion time, or with an inhomogeneous coating with heat-absorbing and heat-reflecting areas distributed over the surface of the steel element, for example a partial black coating and a partial silver coating so that, by way of this variation in the absorption of infrared rays at the surface, the energy input may be selectively controlled from area to area, allowing, for example, the formation of different hardening zones. This measure may of course be combined with the previously described assembly, where the steel element comprises diverse components joined together.
- An embodiment of the invention consists in that the components or assemblies of components provided with the anti-corrosion layer can be welded with each other, with customarily weldable alloy steels or with steel grades provided with metallic coatings.
- A special embodiment of the invention consists in that the electrical resistance of the steel element used is not influenced significantly by the anti-corrosion layer.
- Finally, the scope of the invention extends to use of the process according to the invention 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, jewellery, locomotives, rails, transport systems, cranes, furnaces, engines and engine attachments, pistons, sealing rings, exhaust systems, ABS and braking systems, brake discs, chassis components, wheels, rims, sanitary articles, lamps and design articles.
- The invention is described below by reference to embodiments.
- Degreased 22MnB5A steel strip moving at 60 m/min is roll-coated in a coil coating line with a coating material according to WO 2007/076766 A2. The coating material is hardened at a PMT (Peak Metal Temperature) of 200-250° C. The coated steel strip is cut into tailored blanks and pre-drawn in a cold-forming process to a preform. The preform is heated in a nitrogen atmosphere having a maximum oxygen content of 10 vol. % to a temperature of 950° C. in an electrically operated continuous furnace for 4 minutes, transferred to the forming tool and hot-formed there, and then quench-hardened by cooling to 200° C. within 20 s.
- A suitable anti-corrosion coating for the press-hardened parts described is produced as follows:
- 23.6 g of an aluminium pigment paste (e.g. Decomet Hochglanz Al 1002/10 from Schlenk) and 138.1 g of a zinc pigment paste (Stapa TE Zinc AT from Eckart) are stirred into 74.4 g of 1-butanol solvent and mixed in homogeneously for 20 minutes using a dissolver running at a speed of 1000 rpm. 163.3 g tetrabutylorthotitanate (from Fluka) are stirred into this solution. Prior to further processing, 5 g of Byk 348 wetting agent (from Byk Chemie) are added.
- The coating solution is applied to the entire surface of the press-hardened part using a paint spray gun (e.g. Sata Jet, 1.2 mm nozzle) such as to produce a layer thickness of 3-10 μm after drying and hardening. The coating solution hardens at room temperature within an hour of application, or within 20 minutes at 180° C.
- A component provided with an aluminium antiscaling coating (e.g. Usibor) is subjected as in Example 1 to a press-hardening process.
- A suitable anti-corrosion coating for this component is produced as follows:
- 138.1 g of a zinc pigment paste (Stapa TE Zinc AT from Eckart) are stirred into 400 g of 1-butanol solvent and mixed in homogeneously for 20 minutes using a dissolver running at a speed of 1000 rpm. 163.3 g tetrabutylorthotitanate (from Fluka) are stirred into this dispersion.
- A mixture of 40 g methyltriethoxysilane (from Fluka) and 10 g tetraethoxysilane (from Fluka) is hydrolysed by stirring 15 g of 1% orthophosphoric acid into it. After 5 hours of stirring, the reaction mixture is single-phase and is stirred into the aforementioned dispersion to produce a homogeneous solution.
- The coating solution is prepared in a quantity sufficient to fill a suitably controlled dip tank. The component is lowered by means of a crane into the dip tank filled with coating solution, and after its entire surface has been homogeneously wetted, is lifted out again. After any excess coating solution has dripped off, the component is transferred to a furnace where the coating is hardened for 20 minutes at 180° C.
- After the treatment, the composite entity comprisng steel, aluminium and anti-corrosion layer has a resistance of <10 mOhm and can be joined readily with other sheets by means of resistance spot welding.
- Body components are produced by means of press-hardening from steel blanks with an Al—Si dip-coating and from steel blanks coated according to the WO 2007/076766 A2. These are joined with uncoated steel components by means of resistance spot welding to form an assembly.
- A suitable anti-corrosion coating for this assembly is produced as follows:
- 33.0 g of an aluminium oxide powder (e.g. Aeroxide Alu C from Degussa), 41.3 g of a zinc powder (e.g. Standart Zink Flake AT from Eckart) and 4.5 g Aerosil R 972 (from Degussa) are added to 250 g of 1-butanol solvent. Prior to further processing, 20 g of a suitable powdered wax (e.g. Licowax C from Clariant) are added to the mixture and mixed in homogeneously for at least two hours using a dissolver.
- The coating solution is applied to the entire surface of the press-hardened assembly using spray painting equipment (e.g. HVLP pressurized-air nozzles with a diameter of 1.2 mm) such as to produce a layer thickness of 3-10 μm after drying and hardening. The solution is also sprayed particularly into cavities, gaps and joints. Hardening is effected for 20 minutes at a temperature of 180° C.
- The components and assemblies from the examples 1-3 are each coated with a 3-10 μm thick silver-grey anti-corrosion layer that adheres firmly to the substrate. After being exposed in a salt-spray test as per DIN EN ISO 9227 for 1000 h, the coatings showed no red-rust formation, neither on the surface nor at the cruciform injury site. The coated components and assemblies have an electrical resistance of <10 mOhm and can be welded to other steel parts, for example to assemble a vehicle body.
Claims (18)
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.
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DE102007038215.6 | 2007-08-13 | ||
DE102007038215A DE102007038215A1 (en) | 2007-08-13 | 2007-08-13 | Process for producing an active corrosion protection coating on steel components |
PCT/DE2008/001298 WO2009021489A2 (en) | 2007-08-13 | 2008-08-12 | Process for producing an active cathodic anti-corrosion coating on steel components |
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EP (1) | EP2191030A2 (en) |
JP (1) | JP2010535944A (en) |
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JP2020506981A (en) * | 2017-01-09 | 2020-03-05 | ヘンケル・アクチェンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフト・アウフ・アクチェンHenkel AG & Co. KGaA | Curable protective coating composition |
US11186883B2 (en) | 2017-01-09 | 2021-11-30 | Henkel Ag & Co. Kgaa | Curable protective coating composition |
CN110869221A (en) * | 2017-07-21 | 2020-03-06 | 舍弗勒技术股份两合公司 | Wheel bearing device with coating |
EP3655258B1 (en) | 2017-07-21 | 2022-05-18 | Schaeffler Technologies AG & Co. KG | Wheel bearing unit with coating |
DE102021105576A1 (en) | 2021-03-09 | 2022-09-15 | Bayerische Motoren Werke Aktiengesellschaft | Method of manufacturing a hot-formed predetermined component from sheet metal |
Also Published As
Publication number | Publication date |
---|---|
KR20100052534A (en) | 2010-05-19 |
DE102007038215A1 (en) | 2009-02-19 |
WO2009021489A3 (en) | 2010-02-18 |
JP2010535944A (en) | 2010-11-25 |
CN101815805B (en) | 2013-06-26 |
EP2191030A2 (en) | 2010-06-02 |
CN101815805A (en) | 2010-08-25 |
WO2009021489A2 (en) | 2009-02-19 |
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