Steel sheet with temporary double corrosion protection layer for optimized coating process

Abstract

The invention relates to a flattened rolled steel sheet, comprising a steel substrate and a metal coating which is arranged on one or both sides of the steel substrate and which consists of zinc or an aluminum alloy, characterized in that the metal coating comprises a double-layer temporary corrosion protection layer, the double-layer temporary corrosion protection layer includes an intermediate layer containing an organosilicon compound as a first layer and a second layer containing or consisting of a corrosion protection oil disposed on the first layer.

Description

[0001] This invention relates to a flat-rolled steel sheet comprising a steel substrate and a metallic coating composed of zinc or aluminum alloy disposed on one or both sides of the steel substrate. The metallic coating is characterized by comprising a double-layer temporary corrosion protection layer, the double-layer temporary corrosion protection layer comprising an intermediate layer containing an organosilicon compound as a first layer and a second layer disposed thereon containing or composed of a corrosion-protecting oil. The invention also relates to a method for manufacturing such a steel sheet and its use in the manufacture of painted components.

[0002] Metal sheets, such as steel, used in the automotive industry, are typically coated with metal coatings, such as zinc coatings (Z) with a very low aluminum content derived from the melt, zinc-based coatings (ZM) with an aluminum-to-magnesium ratio derived from the melt, zinc or zinc-based coatings (ZF) after hot-dip galvanizing and heat treatment, and electroplated zinc coatings (ZE). Alternatively, steel materials are coated with metal coatings composed of aluminum alloys (thermo-aluminized aluminum alloys, fal AS).

[0003] This type of sheet metal is particularly used in the manufacture of automobiles or white goods (such as electric cookers, refrigerators, freezers, washing machines, dryers, and dishwashers). This requires a paint finish free of optical defects such as spots, color variations, orange peel, etc.

[0004] Because the additional steps following metal coating and leveling rolling are typically performed at different times and / or locations, these metal sheets are provided with a temporary corrosion protection layer, and optionally, a functional coating is applied before this (i.e., beneath the temporary corrosion protection layer). For subsequent painting, the layer on the metal coating must typically be removed again. Removal is usually achieved via one or more cleaning steps. It is possible that cleaning is not fully achieved, meaning that residues of the coating and / or temporary corrosion protection layer remain at least in sub-areas of the leveled rolled steel sheet. These residues, contaminant residues such as debris, dust, or other particles, as well as oil from the equipment used, preferentially accumulate in the leveling rolling grooves both before and after cleaning. Due to the dipole moment of the metal oxides on the surface of the metal coating, the polar ends of polarizable or dipole compounds or amphiphilic molecules coated thereon are also more strongly bound to the surface. Therefore, the surface cleanliness is degraded. This adversely affects pre-treatment and post-treatment processes (e.g., phosphating and painting) that require oil-free and contaminant-free surfaces. This situation particularly leads to uneven coating of other treatment agents. This means that the coating of other reagents and / or layers will be uneven in thickness, and optical defects may also occur. Uneven primer thickness and optical defects will both lead to uneven coating, such as uneven KTL deposition, and consequently reduced corrosion resistance.

[0005] The object of this invention is to provide a flat-rolled metal sheet having a metallic coating with a temporary corrosion protection layer, which on the one hand ensures good corrosion protection before further processing of the metal sheet, and on the other hand facilitates further processing of the metal sheet. This means that the corrosion protection layer must not exhibit the aforementioned defects or create any other obstacles in the process steps up to painting and the final finished product. In particular, the painting should be optically flaw-free with as few process steps as possible. This first requires the application of a complete, uniform, and homogeneous temporary corrosion protection layer, especially since the pearl-like / worm-like structures known to those skilled in the art in CuSO4 testing should no longer be visible after coating. Furthermore, compared to prior art processes, the metal sheet with the temporary corrosion protection layer should require very few (if any) new process steps or equipment. Therefore, the components of the temporary corrosion protection layer must be precisely matched to each other. Other aspects, such as environmental protection, sustainability, and especially health, should also be considered.

[0006] Another objective is to reduce the amount of waste, preferably hazardous waste (as listed in the waste list of Article 7 of Directive 2008 / 98 / EC of 30 December 2014), and especially chromium and / or nickel compounds. Painted panels, without prior phosphating, should exhibit the same optical appearance and / or corrosion resistance as metal panels pretreated with phosphates and / or chromium, particularly with trivalent / divalent zinc phosphating.

[0007] Another object of the present invention is to provide a coating assembly having an improved corrosion protection layer, improved paint adhesion and reduced subfilm migration after damage and / or improved gravel protection compared to the prior art.

[0008] This objective is achieved by the features of claim 1.

[0009] The present invention provides a flat-rolled steel plate comprising a steel substrate and a flat-rolled metal coating disposed on one or both sides of the steel substrate and composed of zinc or aluminum alloy, characterized in that the metal coating comprises a double-layer temporary corrosion protection layer comprising an intermediate layer containing an organosilicon compound as a first layer and a second layer disposed thereon containing or composed of corrosion protection oil.

[0010] In this context, the term "leveled rolled steel sheet" is understood only as illustrative, in one alternative, an electrolytically applied metallic coating is applied to the leveled rolled steel sheet, while in another alternative, a substrate with the metallic coating is leveled. Ultimately, the steel sheet in both alternatives has a texture produced by contact with the leveling rolls. In the case of electrolytic coating, the resulting coating accurately reflects the leveled rolled surface; the coating does not alter the texture. The coating is applied to one or both sides of the steel substrate, preferably both sides.

[0011] The intermediate layer is bonded to the metal coating via chemisorption (i.e., through chemical bonds). In the broadest sense, chemical bonds are ionic bonds, covalent bonds, coordinate bonds, or weak bonds via electrostatic attraction or van der Waals forces.

[0012] In one alternative, the intermediate layer is generated through a chemical reaction between an aqueous treatment dispersion and a metal substrate, resulting in a chemical change in the adsorbate (i.e., the aqueous treatment dispersion) and / or the adsorbent (i.e., the metal coating). In another alternative, components of the aqueous dispersion are covalently bonded to components of the metal coating.

[0013] In one embodiment, the intermediate layer contains or is composed of a polymer, such as an organic polymer based on acrylic acid or its derivatives. In an alternative, the intermediate layer contains or is composed of the following:

[0014] -1 / 4 to 3 parts by weight of a polymer selected from the group consisting of maleic acid / polyacrylic acid copolymer, modified polyacrylic acid, or polyacrylic acid.

[0015] -1 part by weight of phosphate component, and

[0016] -Optionally 1 / 10 to 5 / 10 parts by weight of a metal-containing component selected from the group consisting of Zn, Ca, Mg and / or Al.

[0017] In another alternative, the intermediate layer contains or is composed of an organosilicon compound, preferably selected from one or more compounds comprising or consisting of the following: silanes, silanols, siloxanes, alkoxysilanes, derivatives of silanes, siloxanes and / or alkoxysilanes, and polymers and derivatives thereof. Preferred derivatives are selected from one or more compounds comprising or consisting of the following: silanes, siloxanes, alkoxysilanes having a functional group, such as -OR, where R is H or an alkyl group, preferably C1 to C7, vinyl, phenyl, benzyl; -NR2, where R is H or an alkyl group, preferably C1 to C7, vinyl, phenyl, benzyl; condensation products obtained by dehydration of hydrolyzed alkoxysilanes (i.e., silanols or alkoxysilanes having hydroxyl groups); at least one silane, silanol and / or siloxane having at least one alkoxy group, at least one amide group, at least one amino group, at least one urea group, and condensation products, copolymers and polymers of at least two of the above compounds.

[0018] Alternatively or additionally, the aforementioned silanes, silanols, siloxanes, alkoxysilanes, and their derivatives are selected from the group comprising or consisting of: bis-tris(methoxy / ethoxy)silylalkanes, such as bis-triethoxysilyl ethane, methyltrimethoxysilane, tetraethoxysilane, aminopropyltriethoxysilane, 4-aminodialkylalkyldialkoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltriethoxysilane, γ-aminoalkyltrialkoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-alkylaminoisoalkyltrialkoxysilane, Poly(aminoalkyl)alkyldialkoxysilane, aminoalkylaminoalkyltrialkoxysilane, N-(γ-trialkoxysilylalkyl)dialkyltriamine; aminoalkylaminoalkyldialkoxysilane, aminoalkyltrialkoxysilane, bis-aminosilane, bis-diaminosilane, bis-(trialkoxysilylalkyl)amine, such as bis(trimethoxysilylpropyl)amine and / or bis(triethoxysilylpropyl)amine, bis-(trialkoxysilyl)ethane, N-(aminoalkyl)aminoalkyldialkoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, ureopropyltrimethoxysilane γ-Ureylalkyltrialkoxysilane, bis-trimethoxysilylpropylurea; 3-[2-(2-aminoalkylamino)alkylamino]alkyltrialkoxysilane, 3-(2-aminoethylamino)propyldimethoxymethylsilane, N-(3-(trialkoxysilyl)alkyl)alkylene diamine, N-β-(aminoalkyl)-γ-aminoalkyltrialkoxysilane, 4-amino-dialkylalkyltrialkoxysilane, 3-(trimethoxysilyl)propyl methacrylate, γ-(trialkoxysilyl)dialkyltriamine, 3-glycidyl etheroxypropyltrimethoxysilane, 3-triethoxy The compounds are silyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine and / or N-2-aminoalkyl-3-aminopropyltrialkoxysilane, wherein the alkyl group is preferably selected from the group consisting of or composed of: methyl, ethyl and / or propyl, such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, and combinations of at least two of the above compounds and / or their polymers.

[0019] In the context of this invention, siloxanes should be understood to refer to compounds of the following formula: In this formula, R is H or an alkyl group, preferably C1 to C7 and n = 0 to 20. Polymers in which R = alkyl are called silicones. Alkoxysilanes have the general formula (RO)4-Si, where R is an alkyl group, preferably C1 to C7.

[0020] In an alternative, the aqueous dispersion may further contain an inorganic salt, such as a salt having the following: a cation selected from the group consisting of or composed of: Zr 4+ Zn 2+ Ca 2+ Mg 2+ And Al 3+ Preferred copper and anions selected from the group consisting of or including the following: Cl - NO3 - SO4 2- and PO4 3- In one alternative, Cu exists as an oxide. In another alternative, the aqueous dispersion does not contain dispersed copper oxalate.

[0021] The intermediate layer is preferably coated as an aqueous dispersion. In this dispersion, at least a portion of the organosilicon compound is in a hydrolyzed or alkoxylated form. At least a portion of the organosilicon compound reacts to form a polymer, such as a polysiloxane. In the form of hydrolyzed or alkoxylated organosilicon compounds and / or polysiloxanes, they react with the hydroxyl groups of the metal to eliminate water or alcohol and form a strong bond with the substrate. During and subsequently during drying, the organosilicon compounds now covalently bonded to the surface condense with each other to form a network structure, which accordingly forms a homogeneous intermediate layer uniformly distributed on the coating surface.

[0022] In the context of this invention, the term "aqueous dispersion" refers to compositions in which particles and / or droplets are dispersed in water, as well as compositions in which colloidal and / or molecular dispersions are dispersed. In one alternative, the aqueous dispersion contains an organic solvent, particularly an alcohol, preferably methanol or ethanol, or a lower ketone or ether having up to seven, preferably five, carbon atoms.

[0023] In one embodiment, the Si content of the intermediate layer is at least 1.0 mg / m². 2 Preferably at least 2.5 mg / m 2 Preferably at least 5.0 mg / m³ 2 Especially at least 7.5 mg / m 2 And at most 100.0 mg / m 2 Or 75.0 mg / m 2 Preferred concentration: up to 50.0 mg / m³ 2 Or 40.0 mg / m 2 Especially preferred is a dose of up to 30.0 or 20.0 mg / m³. 2 Especially at most 15.0 or 12.5 mg / m³ 2Quantitative determination of the coating weight is performed, for example, by X-ray fluorescence analysis (XRF) or GDOES (glow discharge optical emission spectroscopy). The coating weight of a specific element in the intermediate layer is expressed as a specified mass / unit area, which should be understood to mean that the intermediate layer contains the reported mass of the corresponding element (regardless of form, i.e., elemental, atomic, ionic, or oxidized state) per unit area. In cases where the Si concentration in the steel sheet (i.e., the steel substrate) would interfere with the determination of Si in the intermediate layer (i.e., potentially leading to erroneous results), those skilled in the art shall make reference or differential measurements in areas of the steel sheet where the intermediate layer is absent or where the layer has been removed for measurement purposes. The reported values ​​relate to the abundance of elemental Si (silicon) and are independent of its form of existence; that is, it is irrelevant whether the element exists as a neutral atom, as an ion, or as a compound, such as an organic compound (e.g., an alcohol, ester, polymer, or complex), oxide, salt, or hydroxide.

[0024] In one embodiment, the Cu content of the intermediate layer is at least 0.1 mg / m³. 2 Preferably at least 1.0 mg / m³ 2 Preferably at least 2.0 mg / m³ 2 Or at least 3.0 mg / m 2 Especially at least 4.0 mg / m 2 And at most 100.0 mg / m 2 Or 75.0 mg / m 2 Preferred concentration: up to 50.0 mg / m³ 2 Or 40.0 mg / m 2 Especially preferred is a dose of up to 30.0 or 20.0 mg / m³. 2 Especially at most 15.0 or 10.0 mg / m³ 2 The quantitative determination of the coating weight can be performed, for example, by X-ray fluorescence analysis (XRF) or GDOES (glow discharge optical emission spectroscopy) similar to that used for Si.

[0025] The second layer of the double-layer temporary corrosion protection layer contains or is composed of corrosion protection oil, preferably mineral oil, and particularly preferably contains 15-60% by weight, preferably 20-50% by weight, of naphthenic base oil, which contains 1.0% to 10% by weight, preferably 1.2-8% by weight, of Na salt and / or Ca salt of benzenesulfonic acid, wherein mono-C10-16-alkyl derivatives and / or mono-C16-24-alkyl derivatives are organic groups.

[0026] Compared to layer structures without an intermediate layer as employed according to the present invention, the intermediate layer not only ensures temporary corrosion protection but also reduces or prevents the adsorption of polarizable or polar molecules on the corrosion-protected metal coating.

[0027] One embodiment also relates to a steel sheet according to the invention, characterized in that the intermediate layer contains a rheology modifier. Since the intermediate layer is coated in the form of an aqueous solution or an aqueous dispersion, the rheological properties, especially the viscosity, of the solution or dispersion are crucial. An aqueous dispersion containing the compound of the subsequent intermediate layer and the rheology modifier is a system in which the components are precisely matched to each other and also to the substrate. In this matching, the polarity of the composition and the substrate is particularly considered.

[0028] In an alternative, the additive used is a substance derived from the additive class, such as layered silicates, associative thickeners, synthetic layered silicates, liquid rheology modifiers, or activity enhancers for pyrolytic silica. The rheology modifier is preferably selected from the group consisting of or composed of: acrylate thickeners, carboxymethyl cellulose, methyl cellulose, polyurea thickeners, polyurethane thickeners, layered silicates, pyrolytic silica, gelatin, alginates, monosaccharides and / or polysaccharides, especially xanthan gum, guar ether, and xanthan gum.

[0029] It is particularly preferred to combine the above-mentioned organosilicon compounds with rheology modifiers containing or based on polyurethanes or polysaccharides or heteropolysaccharides, preferably modified polysaccharides or heteropolysaccharides, such as guar gum and / or xanthan gum, especially swelling-delayed guar gum ethers or xanthan gum molecules or modified xanthan gum molecules.

[0030] The combination of the subsequent intermediate layer composition and rheology modifiers ensures complete wetting of the substrate surface. This results in a uniform, homogeneous dried intermediate layer. Homogeneity refers to the property of a layer having the same macroscopic properties across all regions. Furthermore, the rheology modifiers can reduce the thickness of the intermediate layer compared to the absence of them.

[0031] In one embodiment, as an alternative to or supplement to rheology modifiers, the intermediate layer contains other additives, such as poly(meth)acrylic acid and its derivatives as polymers that do not dissolve into smaller compounds under alkaline conditions, or aluminum hydroxide as a high surface area additive that physically delays excessively rapid dissolution in alkaline solutions. Tribological additives that improve molding properties may also be added.

[0032] An aqueous dispersion containing a subsequent intermediate layer (i.e., including rheology modifiers and optional other additives or components) is a composition in which all components are precisely matched to each other and also to the substrate. The stability of the aqueous dispersion, such as particle density, separation rate distribution, and particle size distribution, must be considered. These and other stability criteria, as well as the methods used to determine stability, can be determined according to ISO 13318, ISO / TR 13097:2013, and / or ISO / TR 18811:2018. The aqueous dispersion, without mechanical mixing or stirring, shows no particle settling, particularly at the operating temperature, for at least 60 minutes, preferably 120 minutes, particularly preferably 180 minutes, especially 240 minutes or longer. Matching to the substrate can be verified, for example, via a CuSO4 test.

[0033] The present invention also provides the use of the above-mentioned organosilicon compound as corrosion protection, particularly as a corrosion protective layer. The present invention further provides the use of the above-mentioned organosilicon compound combined with the above-mentioned rheology modifier as corrosion protection, particularly as a corrosion protective layer. The rheology modifier is embedded in the corrosion protective layer of the organosilicon compound. Therefore, the focus is on the first corrosion protective layer of the organosilicon compound containing the rheology modifier.

[0034] The aforementioned intermediate layer forms a complete, uniform, and homogeneous layer. This can be demonstrated by the so-called CuSO4 test. For this purpose, the steel plate coated with the aqueous dispersion is dried and optionally rinsed before drying. The oil-free, grease-free surface is immersed in a 5% by weight CuSO4 solution for approximately 10 seconds. It is then rinsed by gentle swirling in deionized water.

[0035] During immersion in CuSO4 solution, the exposed metal areas react with free copper ions, and metallic copper is deposited as a black or metallic precipitate. In areas that have undergone inertization treatments (passivation or sealing, etc.), less copper is deposited (if any) and the deposit is less deep. This is clearly visible in the contrast of light and dark areas in cases of uneven coating. A pearl-like / worm-like structure, known to those skilled in the art, is formed, i.e., a series of light or dark dots, which can be 0.2 to 1.0 mm or more in width and several centimeters in length, or in some cases, whose length can extend across the entire width of the plate. The metal plate with the intermediate layer according to the invention did not show any pearl-like or worm-like structure in the CuSO4 test. Therefore, in the context of the invention, a complete, uniform, and homogeneous intermediate layer is a layer that, after degreasing / deoiling, does not show any pearl-like or worm-like structure in the CuSO4 test as described above.

[0036] The steel plate according to the invention may further have other functional coatings, such as an adhesion promoting layer, a forming aid, a passivation layer, or a combination thereof.

[0037] In an alternative, the intermediate layer / the aqueous dispersion coated thereon may or may not contain an epoxy-based adhesive system.

[0038] The present invention provides a hot-dip galvanized and leveled rolled steel sheet comprising a steel substrate and a leveled rolled metal coating disposed on one or both sides of the steel substrate, and containing not only zinc and unavoidable impurities, but also aluminum in a content of 0.1 wt% to 8 wt% and optionally magnesium in a content of 0.1 wt% to 8 wt%, characterized in that the metal coating comprises a double temporary corrosion protection layer.

[0039] The Z or ZM coating applied in the hot-dip galvanizing process comprises a zinc alloy containing not only zinc (balance) and unavoidable impurities, but also other elements, such as aluminum in a content of 0.1 wt% to 8 wt% and optionally magnesium in a content of 0.1 wt% to 8 wt%. Impurities that may be present in the melt bath include elements selected from the group consisting of Si, Sb, Bi, Zr, Ni, Cr, Pb, Ti, Ca, Mn, Sn, La, Ce, Fe, and Cr, in a content, individually or cumulatively, of up to 0.5 wt%, particularly up to 0.4 wt%, preferably up to 0.3 wt%. Impurities that may be present in the coating include elements selected from the group consisting of Si, Sb, Bi, Zr, Ni, Cr, Pb, Ti, Ca, Mn, Sn, La, Ce, Fe, and Cr, in a content, individually or cumulatively, of up to 0.5 wt%, particularly up to 0.4 wt%, preferably up to 0.3 wt%, wherein, in an alternative, the concentration of Fe may be higher due to the aforementioned diffusion. The balance is zinc. Steel sheets cut from steel strips or steel sheet assemblies made therefrom with zinc-based corrosion-protective coatings exhibit very good cathodic corrosion protection and have been used in automotive manufacturing for many years. If the aim is to improve corrosion protection, the coating contains aluminum at a content of at least 0.8 wt%, particularly at least 1.0 wt%, preferably at least 1.1 wt%, and optionally at least 0.8 wt%, particularly at least 1.0 wt%, of magnesium. Alternatively, the coating contains aluminum at a content of up to 8.0 wt%, preferably up to 7.0 wt%, particularly preferably up to 5.0 wt%, especially up to 4.0 wt%, and optionally up to 8.0 wt%, preferably up to 7.0 wt%, particularly preferably up to 5.0 wt%, especially up to 4.0 wt%, of magnesium. In an alternative, these concentrations are determined according to or based on DIN EN ISO 10111:2019 and / or DIN EN ISO 11885:2009 as a wet chemical coating determination.

[0040] In particular, to establish a Z or ZM coating of a predetermined thickness (which can be 1 μm to 60 μm per side in its solid state), the still-liquid melt applied to the steel strip is wiped off by passing the steel strip coated with the liquid melt through a wiping device, which includes, for example, an injector, especially a slit injector, etc., which, after leaving the melt bath, acts on both sides of the steel strip with a gaseous wiping medium to wipe off the liquid melt. This allows for the achievement of an asymmetric coating, i.e., different coatings on both sides. The thickness of the Z or ZM coating can be adjusted independently on each side in each case to be at least 4 μm, preferably at least 5 μm and at most 58 μm, preferably 5 μm and at most 55 μm. In a particular embodiment, the coating thickness is independently on each side in each case to be at least 1 μm, preferably at least 2 μm, particularly preferably at least 3 μm, especially at least 5 μm and at most 25 μm, preferably at most 20 μm, particularly preferably at most 15 μm, especially at most 10 μm. In an alternative, the coating thickness is determined by weight by dissolution and converted to thickness based on mass, according to DIN EN ISO 10111, or by metallography of microsections.

[0041] Below the minimum limit, sufficient cathodic corrosion protection cannot be ensured; above the maximum limit, problems may occur when connecting the steel plate or components made therefrom according to the invention to other components.

[0042] In an alternative, the coating weight of the Z or ZM coating is 1 g / m². 2 Up to 650 g / m 2 That is, 0.5 g / m per side 2 Up to 320 g / m 2 10 g / m 2 Up to 500 g / m 2 That is, 5 g / m on each side 2 Up to 250 g / m 2 In another alternative, asymmetric coating can also be performed.

[0043] The present invention also relates to hot-dip galvanized and leveled rolled steel sheets as described above, wherein the metal coating contains unavoidable impurities in addition to zinc and 0.1% to 1.0% aluminum, and has been annealed (at a temperature above the melting point of zinc) after hot-dip galvanizing. Coatings treated in this manner consist only of iron-zinc compounds, relating to metal sheets with so-called ZF coatings.

[0044] The present invention also provides a flat-rolled steel sheet as described above, wherein the metal coating contains not only zinc but also unavoidable impurities, and optionally 0.001% to 1%, preferably 0.01% to 1% aluminum, and is electroplated onto the flat-rolled substrate (electroplated zinc coating (ZE)). Such a sheet is defined, for example, in DIN EN 10152:2017-06, but according to the present invention, hot-rolled strip can also be used as the metal sheet substrate.

[0045] The present invention also provides a flat-rolled steel sheet as described above, wherein the metal coating is composed of a silicon-aluminum alloy. A suitable aluminum alloy typically comprises: 0.1-15 wt% Si, preferably more than 1 wt% Si, optionally 2-4 wt% Fe, optionally up to 5 wt% alkali metal or alkaline earth metal, preferably up to 1 wt% alkali metal or alkaline earth metal, and optionally up to 15 wt% Zn, preferably up to 10 wt% Zn, and optional other components whose total content does not exceed 2 wt%, the balance being aluminum and unavoidable impurities. In preferred variants, the Si content is 1.0-3.5 wt% or 7-12 wt%, especially 8-10 wt%. In preferred variants, the optional content of the alkali metal or alkaline earth metal includes 0.1-1.0 wt% Mg, especially 0.1-0.7 wt% Mg, preferably 0.1-0.5 wt% Mg. In addition, the optional content of alkali metals or alkaline earth metals may include at least 0.0015% by weight of Ca, especially at least 0.01% by weight of Ca.

[0046] This anti-corrosion coating is preferably formed by hot-dip galvanizing the flat steel product. In the case of hot-dip galvanizing, iron diffuses from the steel substrate into the liquid coating, resulting in an alloy layer and an Al base layer on the flat steel product upon solidification. The alloy layer consists of 35-60% by weight of Fe and optional other components (the total content of which does not exceed 5.0% by weight), with the balance being aluminum. The Al base layer consists of 1.0-15% by weight of Si, optionally 2-4% by weight of Fe, optionally up to 5.0% by weight of alkali metals or alkaline earth metals, optionally up to 10% by weight of Zn and optional other components (the total content of which does not exceed 2.0% by weight), with the balance being aluminum.

[0047] The thickness of the aluminum alloy-based metal coating is 5-60 μm, especially 10-40 μm. The coating weight for the anti-corrosion coating, particularly in the case of double-sided anti-corrosion coatings, is 30-360 g / m². 2 Or, in the case of a single-sided variant, 15-180 g / m². 2 The preferred coating weight for metal coatings is 100-200 g / m² when applying a double-sided coating. 2 For single-sided coating, 50-100 g / m2 .

[0048] Hot-dip plating is a process well known to those skilled in the art. Hot-dip plating may further include one or more of the following steps: cleaning the substrate before hot-dip plating; heating the substrate; wiping the melt with a sprayer after hot-dip plating to establish the desired coating; cooling the coated substrate to harden the melt; optionally applying a flat-rolled reagent; optionally applying other functional coatings, such as an adhesion promoter layer, a molding aid, a passivation layer, or a combination thereof.

[0049] Leveling rolling is well known to those skilled in the art and is described, for example, in the manual "Umformen", Günter Spur, ISBN: 978-3-446-43004-4, page 155. The surface of a leveled rolled steel sheet can exhibit a random surface structure. This is produced using leveling rolls with a surface textured using a so-called EDT process. Alternatively, the surface of a leveled rolled steel sheet can exhibit a deterministic surface structure. This is produced using leveling rolls with a surface textured using laser technology. It is even conceivable that a surface with a pseudo-random surface structure can be obtained after leveling rolling. These surface structures have a (quasi-)random appearance composed of random elements with repeating structures.

[0050] Prior to applying the first protective corrosion layer, a cleaning step may be performed, preferably an alkaline cleaning step, which may use a cleaning agent, followed by rinsing and optionally a drying step.

[0051] One embodiment provides a steel sheet having a Cr-free double-layer temporary corrosion protection layer. Cr-free should be understood to mean that Cr is present at a concentration of at most 1000 ppm, preferably 500 ppm, and especially 100 ppm [according to VdL Guide 01 "VdL-Richtlinie Deklaration Beschichtungsstoffe" on declarations of paints, varnishes, coatings, putties, fillers, primers and related products, May 2019 (7th edition), German Association of Paint and Printing Ink Industries (Registered Association) (Verband der deutschen Lack- und Druckfarbenindustrie e. V.)].

[0052] According to the present invention, the steel substrate used is hot-rolled strip or cold-rolled strip. These can be obtained by processes known to those skilled in the art. The steel substrate can be in the form of steel strip, so-called coil, or so-called billet, which is preferably obtained by cutting segments from hot or cold-rolled strip by appropriate processes.

[0053] Another embodiment uses a steel plate, characterized in that the steel substrate comprises an alloy containing or consisting of the following elements, in weight percent:

[0054] -C: 0.0003% to 0.250%,

[0055] -Si: 0.0005% to 0.70%,

[0056] -Mn: 0.0005% to 2.0%,

[0057] -P: Maximum 0.15%,

[0058] -S: Maximum 0.050%,

[0059] -N: Maximum 0.10%,

[0060] -Al: 0.0050% to 1.50%,

[0061] -Optionally, one or more of the following elements:

[0062] -Nb: Maximum 0.20%,

[0063] -Ti: 0.20%,

[0064] -V: 0.0050% to 0.10%,

[0065] -B: Maximum 0.030%, and / or

[0066] -Cu: up to 0.80%, and / or

[0067] -Cr: up to 0.80%, and / or

[0068] -Ni: up to 0.20%, and / or

[0069] -Mo: up to 0.150%, and / or

[0070] -Sn: Maximum 0.10%,

[0071] - The balance is iron and unavoidable impurities.

[0072] In an alternative, the substrate is a steel sheet made of an interstitial freien alloy according to DIN EN 10346. The IF alloy of the steel substrate contains or is composed of the following elements, in weight percent:

[0073] -C: 0.0003% to 0.015%, especially 0.0005% to 0.010%, preferably 0.001% to 0.005%.

[0074] -Si: 0.0005% to 0.50%, especially 0.0010% to 0.40%, preferably 0.0010% to 0.30%.

[0075] -Mn: 0.0005% to 1.60%, especially 0.010% to 1.55%, preferably 0.010% to 1.50%.

[0076] -P: up to 0.10%, especially up to 0.080%, preferably 0.0002% to 0.060%.

[0077] -S: up to 0.050%, especially up to 0.040%, preferably 0.0003% to 0.030%.

[0078] -N: up to 0.10%, especially up to 0.080%, preferably 0.0001% to 0.070%.

[0079] -Al: 0.0010% to 1.0%, especially 0.0010% to 0.90%, preferably 0.0010% to 0.80%.

[0080] -One or two of the following elements:

[0081] -Nb: 0.0001% to 0.20%, especially 0.0002% to 0.10%, preferably 0.0003% to 0.050%,

[0082] -Ti: 0.0005% to 0.20%, especially 0.010% to 0.150%, preferably 0.010% to 0.120%.

[0083] -Optionally, one or more of the following elements:

[0084] -B: Maximum 0.0050% and / or maximum 0.20% Cu and / or maximum 0.20% Cr and / or maximum 0.20% Ni and / or maximum 0.150% Mo and / or maximum 0.10% Sn.

[0085] - The balance is iron and unavoidable impurities.

[0086] IF steel does not contain interstitial alloying elements, meaning that no iron atoms in the metal lattice are blocked by carbon or nitrogen atoms. This results in a very soft steel with excellent formability. It is particularly used for complex deep-drawn parts in automotive manufacturing. This type of steel is available under the standard names DX52D, DX53D, DX54D, DX55D, DX56D, DX57D, HX160YD, HX180YD, HX220YD, and HX260YD. These are cold-rolled steels.

[0087] In an alternative, the substrate is a steel sheet made of a bake-hardening alloy according to DIN EN 10346. The bake-hardening alloy of the steel substrate contains or is composed of the following elements, in weight percent:

[0088] -C: 0.0004% to 0.080%, especially 0.0010% to 0.060%, preferably 0.0010% to 0.040%.

[0089] -Si: 0.0005% to 0.50%, especially 0.0010% to 0.40%, preferably 0.010% to 0.20%.

[0090] -Mn: 0.0005% to 1.50%, especially 0.0010% to 1.40%, preferably 0.0020% to 1.20%.

[0091] -P: up to 0.150%, especially up to 0.10%, preferably 0.0010% to 0.050%.

[0092] -S: up to 0.050%, especially up to 0.040%, preferably 0.0005% to 0.030%.

[0093] -N: up to 0.050%, especially up to 0.030%, preferably 0.0002% to 0.010%.

[0094] -Al: 0.0050% to 1.0%, especially 0.010% to 0.50%, preferably 0.010% to 0.150%.

[0095] -Optionally, one or more of the following elements:

[0096] -Nb: maximum 0.040% and / or Ti: maximum 0.030% and / or B: maximum 0.0030% and / or Cu: maximum 0.20% and / or Cr: maximum 0.20% and / or Ni: maximum 0.20% and / or Mo: maximum 0.150% and / or Sn: maximum 0.10%.

[0097] - The balance is iron and unavoidable impurities.

[0098] BH steel is characterized by a significant increase in yield strength during paint baking (typically at 170°C for 20 minutes), while maintaining excellent formability. These steels also typically exhibit very good dent stiffness, which is why they are preferred for housing applications. This type of steel is available under the standard names HX180BD, HX220BD, HX260BD, and HX300BD. These are cold-rolled steels.

[0099] In an alternative, the substrate is a steel sheet made of a multiphase alloy according to DIN EN 10346. The multiphase alloy of the steel substrate contains or is composed of the following elements, in weight percent:

[0100] -C: 0.050% to 0.250%, especially 0.060% to 0.250%, preferably 0.070% to 0.250%.

[0101] -Si: 0.020% to 0.50%, especially 0.020% to 0.40%, preferably 0.020% to 0.30%.

[0102] -Mn: 1.30% to 2.0%, especially 1.40% to 1.90%, preferably 1.50% to 1.80%.

[0103] -P: Maximum 0.10%, especially maximum 0.080%, preferably maximum 0.060%.

[0104] -S: Maximum 0.050%, especially maximum 0.040%, preferably maximum 0.030%.

[0105] -N: Maximum 0.10%, especially maximum 0.050%, preferably maximum 0.030%.

[0106] -Al: 0.010% to 0.150%, especially 0.010% to 0.10%, preferably 0.010% to 0.090%.

[0107] -Optionally, one or more of the following elements:

[0108] -Cu: maximum 0.80% and / or Cr: maximum 0.70% and / or Nb: maximum 0.10% and / or Ti: maximum 0.20%,

[0109] - The balance is iron and unavoidable impurities.

[0110] This type of steel is available under the standard names HCT490X, HCT590X, or HCT780X. These are cold-rolled steels.

[0111] In an alternative, the substrate is a steel sheet made of microalloyed alloy according to DIN EN 10268. The alloy of the steel substrate contains or is composed of the following elements, in weight percent:

[0112] -C: 0.020% to 0.20%, especially 0.020% to 0.150%, preferably 0.020% to 0.140%.

[0113] -Si: 0.010% to 0.70%, especially 0.010% to 0.60%, preferably 0.010% to 0.50%.

[0114] -Mn: 0.020% to 2.0%, especially 0.020% to 1.90%, preferably 0.020% to 1.80%.

[0115] -P: Maximum 0.070%, especially maximum 0.060%, preferably maximum 0.050%.

[0116] -S: Maximum 0.050%, especially maximum 0.040%, preferably maximum 0.030%.

[0117] -N: Maximum 0.080%, especially maximum 0.060%, preferably maximum 0.040%.

[0118] -Al: 0.010% to 1.0%, especially 0.010% to 0.50%, preferably 0.010% to 0.10%.

[0119] -At least one of the following elements:

[0120] -Nb: 0.010% to 0.150%, especially 0.010% to 0.120%, preferably 0.010% to 0.10% and / or

[0121] -Ti: 0.010% to 0.20%, especially 0.010% to 0.180%, preferably 0.010% to 0.150% and / or

[0122] -V: 0.0050% to 0.10%, especially 0.0060% to 0.10%, preferably 0.0090% to 0.10% and / or

[0123] -Optionally, one or more of the following elements:

[0124] -B: Maximum 0.0050% and / or Cu maximum 0.40% and / or Cr maximum 0.50%,

[0125] - The balance is iron and unavoidable impurities.

[0126] Microalloyed steels possess a fine-grained microstructure, giving them high fatigue strength, optimal weldability, and a high yield strength. They are particularly useful for complex deep-drawn components in automotive manufacturing. Exemplary steels of this type are available under the standard names HC260LA, HC300LA, HC340LA, HC380LA, HC420LA, HC460LA, HC500LA, and HC550LA. These are cold-rolled steels.

[0127] The present invention also relates to a method for manufacturing the flattened and rolled steel sheet as described above, comprising the following steps:

[0128] a) Provide a flat-rolled steel sheet having the metal coating described above as a steel substrate.

[0129] b) Apply the first layer as an intermediate layer to the steel plate from step a.

[0130] c) Apply a second layer containing or composed of corrosion-protecting oil to the intermediate layer from step b.

[0131] Step a uses the steel plate described above as the steel substrate.

[0132] In step b, the first intermediate layer is applied in the form of an aqueous dispersion onto a leveled and rolled steel sheet. The coating is performed by spraying, dipping, or coating processes, preferably using a roller coater or chemical coater at an ambient temperature of 10-50°C, preferably 20-40°C.

[0133] The aqueous dispersion contains the polymer or organosilicon compound as described above, wherein the concentration of elemental Si is at least 0.002% by weight, preferably at least 0.02% by weight, particularly preferably at least 0.08% by weight or 0.12% by weight, especially at least 0.16% by weight, and at most 25.0% by weight or 5.0% by weight, preferably at most 2.5% by weight or 1.25% by weight, particularly preferably at most 0.75% by weight, especially at most 0.60% by weight.

[0134] Alternatively, based on at least one organosilicon compound, the aqueous dispersion contains at least 0.0002% by weight, preferably at least 0.002% by weight, particularly preferably at least 0.02% by weight or 0.050% by weight, especially at least 0.08% by weight and at most 25.0% by weight or 5.0% by weight, preferably at most 2.5% by weight or 0.5% by weight, particularly preferably at most 0.375% by weight, especially at most 0.30% by weight of the above-mentioned organosilicon compound.

[0135] In one embodiment, the aqueous dispersion contains one or more of the above-mentioned rheology additives, as described above.

[0136] The rheology modifier is present at an active substance concentration of at least 0.01% by weight, preferably at least 0.025% by weight, particularly preferably at least 0.05% by weight, especially at least 0.075% by weight and at most 5.0% by weight or 2.5% by weight, preferably at most 1.0% by weight, particularly preferably at most 0.75% or 0.5% by weight, especially at most 0.25% by weight or 0.15% by weight.

[0137] Alternatively, the aqueous dispersion is an alkaline aqueous dispersion with a pH of at least 8.0, preferably at least 9.0, particularly preferably at least 9.5, especially at least 10.0 and at most 13.0, preferably at most 12.5, particularly preferably at most 12.0 or 11.0, especially at most 10.5.

[0138] In another alternative, the aqueous dispersion has a density of at least 0.90 g / cm³ at 20°C. 3 Preferably at least 0.95 g / cm³ 3 Preferably, it has a concentration of at least 1.00 g / cm³. 3 And at most 1.30 g / cm 3 Preferred concentration: up to 1.20 g / cm³ 3 Especially preferred at up to 1.10 g / cm³ 3 Especially at most 1.0 g / cm 3 .

[0139] In another alternative, the dynamic viscosity (in mPa•s) of the aqueous dispersion at 20°C is at least 0.6, preferably at least 0.75, particularly preferably at least 0.9, especially at least 1.0, and at most 2.0, preferably at most 5.0, particularly preferably at most 10.0, and especially at most 15.0.

[0140] In one embodiment, the aqueous dispersion is Cr-free. For the term Cr-free (chromium-free), see above. In one embodiment, the dispersion contains Cu (ionic or oxidized) at a concentration such that the dried intermediate layer contains 1.0 to 100 mg / m³. 2 Copper, as described above.

[0141] Another embodiment relates to the above method, wherein after coating the aqueous dispersion, the steel plate is rinsed and then dried, preferably in a so-called no-rinse process where drying is performed without prior rinsing.

[0142] Alternatively, other functional coatings may be applied, such as adhesion promoters, molding aids, passivation layers, or combinations thereof.

[0143] The present invention also provides the use of the steel plate according to the invention, which has the above-mentioned temporary corrosion protection layer, for manufacturing painted components.

[0144] The present invention also provides a method for manufacturing a painted component, comprising the following steps:

[0145] d) Provide the steel plate according to the present invention or the steel plate manufactured by the above method,

[0146] e) Clean the steel plate so that the retained Si coating weight is at least 0.2 mg / m². 2 The middle layer, and

[0147] f) Coated with a layer containing Si and / or Zr.

[0148] It is preferred that step e of the method according to the invention is performed by treating the steel plate from step d with at least one cleaning agent. According to the invention, the cleaning agent can be acidic, neutral, or alkaline.

[0149] In a preferred embodiment, an alkaline cleaning agent is used. In an alternative, the alkaline cleaning agent is an alkaline aqueous dispersion with a pH of at least 8.0, preferably at least 9.0, particularly preferably at least 10.0, especially 11.0 and at most 14.0, preferably at most 13.0, particularly preferably at most 12.0, and especially at most 11.5. A cleaning-active substance, such as a surfactant, is preferably present in an amount deemed suitable by those skilled in the art. According to the invention, it is preferred when any other component of the cleaning agent is selected, for example, from the group consisting of sodium hydroxide or potassium hydroxide and mixtures thereof. Step e can also be carried out by applying mechanical energy, for example by scrubbing the surface to be cleaned or by applying water and / or the cleaning agent to the surface under high pressure. Step g of the method according to the invention is preferably carried out at a temperature of 20°C to 80°C.

[0150] Therefore, step e includes removing a portion of the second temporary corrosion protective layer containing or composed of corrosion protective oil and the intermediate layer containing organosilicon compounds. Consequently, an intermediate layer remains uniformly distributed on the surface of the metal coating on the metal plate, with a lower layer weight than before the cleaning in step e. The Si content of this residual intermediate layer is at least 0.5 mg / m³. 2 Preferably at least 5.0 mg / m³ 2 Especially preferred is at least 7.5 mg / m³ 2 Especially at least 10.0 mg / m 2 Or at least 11.0 mg / m 2 And at most 80.0 mg / m 2 Or 50.0 mg / m 2 Preferably, it is up to 40.0 mg / m³.2 Or 30.0 mg / m 2 Particularly preferred is a dose of up to 25.0 or 20.0 mg / m³. 2 Especially at most 15.0 or 12.5 mg / m³ 2 .

[0151] In one embodiment, the Cu content of the residual intermediate layer is at least 0.05 mg / m³. 2 Preferably at least 1.0 mg / m³ 2 Or at least 2.5 mg / m 2 Particularly preferred is at least 3.0 mg / m³ 2 Or at least 3.5 mg / m 2 Especially at least 4.0 mg / m 2 And at most 80.0 mg / m 2 Or 50.0 mg / m 2 Preferably, it is up to 40.0 mg / m³. 2 Or 30.0 mg / m 2 Particularly preferred is a dose of up to 20.0 or 15.0 mg / m³. 2 Especially at most 12.5 or 10.0 mg / m³ 2 .

[0152] The quantitative determination of the residual layer weight is performed, for example, by X-ray fluorescence analysis (XRF) or GDOES (glow discharge optical emission spectroscopy) of Si and / or Cu as described above, especially using commercially available handheld XRF equipment.

[0153] In one embodiment, step f includes applying other layers as an aqueous dispersion, similar to the intermediate layer described above. This layer contains an organosilicon compound selected from the organosilicon compounds described above.

[0154] The coating contains 0.1 mg / m 2 Preferably at least 0.5 mg / m 2 Or 1.0 mg / m 2 A minimum of 5.0 mg / m² is particularly preferred. 2 Especially at least 10.0 mg / m 2 And at most 500.0 mg / m 2 Or 300.0 mg / m 2 Preferred dosage up to 200.0 mg / m³ 2 Or 100.0 mg / m 2 A maximum of 75.0 or 50.0 mg / m³ is preferred. 2 Especially up to 25.0 mg / m 2 The Si layer.

[0155] Alternatively or additionally, a coating containing 0.5 mg / m 2 Preferably at least 1.0 mg / m 2 Or 2.0 mg / m 2 A minimum of 5.0 mg / m² is particularly preferred. 2 Especially at least 10.0 mg / m 2 And at most 200.0 mg / m 2 Or 100.0 mg / m 2 Preferred dosage up to 50.0 mg / m² 2 , with a preferred dosage of up to 30.0 mg / m 2 Especially up to 25.0 mg / m 2 The Zr layer also acts as an aqueous dispersion.

[0156] In an alternative, the aqueous dispersion containing the organosilicon compound further includes zirconium (Zr) and is coated such that Zr is present in the layer at the concentration described above in each case.

[0157] In another alternative, a dispersion containing an organosilicon compound and optionally Zr, containing Cu, is coated such that the Cu content of the layer is at least 0.1 mg / m³. 2 Preferably at least 1.0 mg / m³ 2 Especially preferred is at least 2.0 mg / m³ 2 Or at least 3.0 mg / m 2 Especially at least 4.0 mg / m 2 And at most 500.0 mg / m 2 Or 200.0 mg / m 2 Preferably, it is up to 100.0 mg / m³. 2 Or 50.0 mg / m 2 Particularly preferred is a dose of up to 30.0 or 20.0 mg / m³. 2 Especially at most 15.0 or 10.0 mg / m² 2 The quantitative determination of the coating weight can be performed, for example, by X-ray fluorescence analysis (XRF) or GDOES (glow discharge optical emission spectroscopy) similar to that used for Si.

[0158] The coating of this layer / multilayer is also performed as described above, while adhering to the respective reported concentrations.

[0159] Another embodiment relates to the above method, wherein rinsing is performed after coating the aqueous dispersion, followed by drying, preferably in a so-called no-rinse process where pre-rinsing is not required.

[0160] In one embodiment, the method includes one of the additional steps, preferably selected from or consisting of the following:

[0161] - Cut the blank from the steel plate from step d;

[0162] - The blank is shaped;

[0163] - Connect the formed blank with other parts, preferably made of metal, especially steel, to obtain an assembly.

[0164] - After the cleaning and coating described in steps e and f above, paint is applied, preferably KTL paint.

[0165] In one version, all layers applied to the metal coating are free of chromium, nickel, and / or manganese.

[0166] In principle, several methods are generally applicable to the coating of solutions or dispersions as described above. For flat strip products and smaller production volumes, solutions or dispersions can be applied by hand brushing, spraying, and rolling processes. In the automotive industry, dip-coating and spraying processes, or a combination of both, are most commonly used because they offer no limitations on the amount, shape, and size of the surface to be coated and / or painted, and allow for high throughput. Oil coating can also be performed electrostatically.

[0167] Therefore, the present invention also provides a painted assembly, preferably an assembly manufactured as described above with a KTL paint coating and optional other paint layers, which provides improved corrosion protection, improved paint adhesion, reduced subfilm migration after damage, and improved gravel protection compared to assemblies manufactured using steel plates without a uniform and continuous intermediate layer.

[0168] In the context of this invention, all of the different embodiments or alternatives described above may be combined. Example

[0169] 1. Sample preparation:

[0170] To verify the effectiveness of the present invention, samples RF (reference), ZW1, ZW2, and ZW3 were cut from conventionally produced IF steel strip. In each case, the steel substrate was made of commercially available steel of grade M3A33, the composition of which is reported in Table 1.

[0171] Table 1

[0172]

[0173] The balance consists of iron and unavoidable impurities.

[0174] The reported quantities are expressed as a percentage by weight.

[0175] The steel strip sampled from it has a Zn-Al-Mg coating (“ZM coating”), which is applied to its surface in a conventional manner by melt dip coating and consists of 1.6% by weight Al, 1.2% by weight Mg, the balance Zn and unavoidable impurities.

[0176] For further experimentation, blanks were cut from the ZM-coated steel strip and further processed on a pilot scale.

[0177] After hot-dip galvanizing, the blank is coated with a suitable dispersion using a chemical coating machine, as follows:

[0178] RF: ZM, no intermediate layer, no further processing;

[0179] ZW1: ZM+ intermediate layer, coated as an aqueous dispersion containing an organosilicon compound with a Si element content of 0.2% by weight;

[0180] ZW2: ZM+ intermediate layer, as an aqueous dispersion coating, the aqueous dispersion contains 0.2% by weight of an organosilicon compound with Si element content + 0.5% by weight of polyurethane thickener Agocel AC 6240;

[0181] ZW3: ZM+ intermediate layer, as an aqueous dispersion coating, which contains 0.2% by weight of an organosilicon compound with Si content + 5% by weight of polyurethane thickener Agocel AC 6240.

[0182] The blank was coated with oil using an ANTICORIT PL 3802 39 S roller coater.

[0183] 2. CuSO4 test:

[0184] The billet is degreased or deoiled with gasoline or n-heptane and then immersed in a 5% CuSO4 solution for about 6 seconds. It is then rinsed by gentle swirl in DM (deionized) water and visually inspected.

[0185] Samples with intermediate layers (ZW1, ZW2, ZW3) did not exhibit the typical dark precipitates found on untreated surfaces, but the contrast between light and dark was clearly visible on the reference RF in the form of pearl-like or worm-like structures.

[0186] The results show that the metal plate according to the invention achieves the stated purpose, and in particular provides excellent temporary corrosion protection, which allows painting to be carried out without optical defects.

Claims

1. A flat-rolled steel plate comprising a steel substrate and a metallic coating of zinc or aluminum alloy disposed on one or both sides of the steel substrate, characterized in that, The metal coating includes a double temporary corrosion protection layer, which includes an intermediate layer containing an organosilicon compound as the first layer and a second layer containing or composed of corrosion protection oil disposed on the first layer.

2. The steel plate according to claim 1, characterized in that, The Si coating weight of the intermediate layer is at least 1.0 mg / m³. 2 And at most 100 mg / m 2 .

3. The steel plate according to any one of the preceding claims, characterized in that, The intermediate layer contains rheology additives.

4. The steel plate according to any one of the preceding claims, characterized in that, The intermediate layer contains an organosilicon compound, one or more compounds selected from the group consisting of: silanes, silanols, siloxanes, alkoxysilanes, derivatives of silanes, silanols, siloxanes and / or alkoxysilanes, and polymers and derivatives thereof.

5. The steel plate according to any one of the preceding claims, characterized in that, The copper coating weight of the intermediate layer is 1 mg / m³. 2 Up to 100 mg / m 2 .

6. The steel plate according to any one of the preceding claims, characterized in that, The metal coating is composed of zinc or a zinc alloy, which contains not only zinc and unavoidable impurities, but also aluminum in a content of 0.001% to 8% by weight and optionally magnesium in a content of 0.1% to 8% by weight.

7. The steel plate according to any one of claims 1 to 6, characterized in that, The metal coating is composed of a silicon-containing aluminum alloy.

8. The steel plate according to any one of the preceding claims, characterized in that, The steel substrate comprises an alloy containing or composed of the following elements, in weight percent: C: 0.0003% to 0.250%; Si: 0.0005% to 0.70%; Mn: 0.0005% to 2.0%; P: Maximum 0.15%; S: Maximum 0.050%; N: Maximum 0.10%; Al: 0.0050% to 1.50%; Optionally, one or more of the following elements: Nb: Maximum 0.20%, Ti: 0.20%; V: 0.0050 to 0.10%; B: Maximum 0.030%; and / or Cu: up to 0.80%; and / or Cr: up to 0.80%; and / or Ni: up to 0.20%; and / or Mo: up to 0.150%; and / or Sn: Maximum 0.10%, The balance consists of iron and unavoidable impurities.

9. A method for manufacturing a leveled rolled steel plate according to any one of claims 1 to 8, comprising the following steps: a: Provides flattened, rolled, metal-coated steel sheets. b: Apply the first intermediate layer to the steel plate from step a. c: Apply a second corrosion protection layer to the intermediate layer.

10. The method according to claim 9, characterized in that, The first intermediate layer is coated as an aqueous alkaline dispersion and optionally dried without prior rinsing.

11. Use of the steel plate according to any one of claims 1 to 7 or the steel plate manufactured according to any one of claims 8 to 10 for manufacturing painted components.

12. A method for manufacturing a painted component, comprising the following steps: d: Manufacturing the steel plate according to any one of claims 1 to 7 or the steel plate manufactured according to any one of claims 8 to 10. e: Clean the steel plate so that the retained Si coating layer weight is at least 0.2 mg / m². 2 The intermediate layer of Si, and f: Apply a Si and / or Zr layer to the cleaned steel sheet from step e.

13. The method according to claim 12, wherein, Step f produces a product containing 0.1 mg / m 2 Up to 500 mg / m 2 Si and / or 0.5 mg / m 2 Up to 200 mg / m 2 The Zr layer.

14. The method of claim 12 or 13, further comprising at least one of the following additional steps: The blank is cut from the steel plate. The blank is then shaped. The formed blank is joined with other parts, preferably made of metal, especially steel, to obtain an assembly.

15. The method according to any one of claims 12 to 14, characterized in that, In step g, the steel plate from step f is painted.

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