EP4110971A1 - Verfahren zum elektrolytischen verzinken von stahlband mit einer konditionierten zinkschicht - Google Patents
Verfahren zum elektrolytischen verzinken von stahlband mit einer konditionierten zinkschichtInfo
- Publication number
- EP4110971A1 EP4110971A1 EP21707719.7A EP21707719A EP4110971A1 EP 4110971 A1 EP4110971 A1 EP 4110971A1 EP 21707719 A EP21707719 A EP 21707719A EP 4110971 A1 EP4110971 A1 EP 4110971A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- tin
- solution
- zinc
- steel strip
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- 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
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/60—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using alkaline aqueous solutions with pH greater than 8
- C23C22/62—Treatment of iron or alloys based thereon
-
- 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
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- 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
- C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
- C23C2/24—Removing excess of molten coatings; Controlling or regulating the coating thickness using magnetic or electric fields
-
- 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
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
- C23C22/50—Treatment of iron or alloys based thereon
-
- 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
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/82—After-treatment
-
- 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
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
-
- 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
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/02—Pretreatment of the material to be coated
-
- 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
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/10—Oxidising
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
- C25D5/50—After-treatment of electroplated surfaces by heat-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/02—Stamping using rigid devices or tools
- B21D22/022—Stamping using rigid devices or tools by heating the blank or stamping associated with heat treatment
Definitions
- the invention relates to a method for electrolytically galvanizing steel strip, in which the zinc corrosion protection layer is conditioned.
- anti-corrosion layers on metal strips can be organic coatings, for example paints, although these paints can also contain anti-corrosion agents.
- metal coatings can consist of an electrochemically noble metal or consist of an electrochemically less noble metal.
- barrier protective layer In the case of a coating made of an electrochemically more noble metal or a metal that passivates itself, such as aluminum, one speaks of a barrier protective layer, whereby, for example, when aluminum is applied to steel, the steel material suffers corrosion if this barrier protective layer is no longer in places is available, for example due to mechanical damage.
- a common barrier protective layer of steel is the aforementioned aluminum layer, which is usually applied by hot-dip coating.
- an electrochemically less noble metal is applied as a protective layer, because in the event of mechanical damage to the corrosion anti-corrosion coating except for the steel material, the electrochemically less noble metal is first corroded before the steel material itself is exposed to corrosion.
- the most commonly used cathodic protective coating on steel is zinc coating.
- a common galvanizing process is so-called hot-dip galvanizing (also known as hot-dip galvanizing).
- Steel is immersed continuously (e.g. strip and wire) or piece by piece (e.g. components) at temperatures of around 450 ° C to 600 ° C in a melt of liquid zinc (the melting point of zinc is 419.5 ° C).
- the zinc melt conventionally has a zinc content of at least 98.0% by weight in accordance with DIN EN ISO 1461.
- a resistant alloy layer of iron and zinc is formed on the steel surface and above it is a firmly adhering pure zinc layer, the composition of which corresponds to the zinc melt.
- the zinc layer has a thickness of 5 ⁇ m to 40 ⁇ m.
- the zinc layer can have a thickness of 50 ⁇ m to 150 ⁇ m.
- electrolytic galvanizing galvanic galvanizing
- steel strips or steel plates are not immersed in a zinc melt, but in a zinc electrolyte.
- the steel to be galvanized is introduced into the solution as a cathode and an electrode made of the purest possible zinc is used as the anode. Electricity is passed through the electrolyte solution.
- the zinc present in ionic form (oxidation level +11) is reduced to metallic zinc and deposited on the steel surface.
- electrolytic galvanizing allows thinner layers of zinc to be applied.
- the zinc layer thickness is proportional to the strength and duration of the current flow, whereby - depending on the workpiece and anode geometry - a layer thickness distribution is created over the entire workpiece.
- Careful surface pretreatment is required to ensure the adhesion and uniformity of the zinc layer. This can be, for example, degreasing, alkaline cleaning, pickling, rinsing and / or pickling.
- one or more subsequent treatments can be carried out, such as phosphating, oiling, applying organic coatings (KTL - cathodic dip painting).
- KTL - cathodic dip painting not only pure metal layers are usually deposited.
- alloys that are deposited; in addition to pure aluminum coatings, there are also coatings that contain aluminum and zinc and coatings that contain small amounts of aluminum in addition to a predominant zinc content, which may also contain other elements, such as zinc, nickel, chromium and magnesium and other elements, as well as mixtures thereof.
- Steel grades that become high-strength through quench hardening are particularly often used.
- a common type of steel that can be hardened by quench hardening are the so-called boron-manganese steels, such as the most commonly used 22MnB5, but also derivatives of this steel, such as 22MnB8, 30MnB8.
- Such steel grades can be easily deformed and cut to size in the unhardened state.
- the first and somewhat older method is the so-called press hardening.
- press hardening a flat plate is cut out of a steel strip made of a quench-hardenable steel alloy, for example a 22MnB5 or a similar manganese-boron steel.
- This flat blank is then heated to such an extent that the steel structure appears in the form of gamma iron or austenite.
- the so-called austenitizing temperature AC3 must be exceeded, at least if complete austenitizing is desired.
- this temperature can be between 820 ° C. and 900 ° C., such steel blanks, for example, being heated to about 900 ° C. to 930 ° C. and held at this temperature until the structure changes completely. Then such a steel blank is transferred in the hot state in a press, in which the hot steel blank is brought into the desired shape with a single press stroke by means of an upper tool and a lower tool, each of which is correspondingly shaped.
- press tools that is to say forming tools, energy is withdrawn from the steel very quickly.
- the heat must be extracted so quickly that the so-called critical hardening speed is exceeded, which is usually between 20 ° and 25 ° Kelvin per second.
- austenite does not change back into a ferritic initial structure, but a martensitic structure is achieved. Due to the fact that austenite can dissolve considerably more carbon in its lattice than martensite, carbon precipitates lead to lattice distortion, which leads to the high hardness of the end product. As a result of the rapid cooling, the martensitic state is stabilized, so to speak. As a result, hardnesses or tensile strengths R m of more than 1500 MPa can be achieved. Hardness profiles can also be set by means of suitable measures, which will not be discussed in more detail, such as complete or partial rewarming.
- press hardening Another, somewhat more recent way of producing hardened steel components, especially for bodywork, is press hardening developed by the applicant.
- press hardening a flat steel plate is cut out of a steel strip and this flat steel plate is then formed in the cold state.
- this reshaping does not take place with a single press stroke, but rather, as is customary in conventional press lines, for example in a five-step process.
- This process allows considerably more complex shapes, so that in the end a complex-shaped component, such as the B-pillar or a longitudinal member of a motor vehicle, can be produced.
- this component is likewise austenitized in a furnace and transferred in the austenitized state to a molding tool, the molding tool having the contour of the final component.
- the preformed component is preferably shaped before heating in such a way that after heating and thus also after thermal expansion has taken place, this component already largely corresponds to the final dimensions of the hardened component.
- This austenitized blank is inserted into the mold in the austenitized state and the mold is closed.
- the component is touched on all sides by the molding tool and held in a clamping manner, and the contact with the molding tool also removes the heat in such a way that a martensitic structure is created. In the clamped state, shrinkage cannot take place, so that the hardened end component with the corresponding final dimensions can be removed from the mold after hardening and cooling.
- Corrosion protection coatings for components to be hardened are, however, exposed to different requirements than corrosion protection coatings for components that are not hardened.
- the high temperatures that arise during hardening must be withstood by the anti-corrosion coatings. Since it has long been known that hot-dip aluminized coatings can also withstand high temperatures, press hardening steels were first developed, which have a protective layer made of aluminum. Such coatings are able to withstand not only the high temperatures, but also the deformation in the hot state.
- the disadvantage is that no hot-dip aluminizing is usually used on conventional steel grades, but hot-dip galvanizing and it is fundamentally problematic to use different corrosion protection systems, especially if there is a risk of contact corrosion.
- zinc coatings are considerably less complicated than aluminum coatings when it comes to forming, as aluminum coatings tend to peel off or crack at conventional forming temperatures. This does not happen with zinc.
- DE 10 2010 037 077 B4 discloses a method for conditioning the surface of hardened corrosion-protected components made of sheet steel, the sheet steel being a sheet steel coated with a metallic coating and being heated and quenched for hardening. After hardening, the oxides present on the anti-corrosion coating due to the heating are removed, the component being subjected to vibratory grinding for conditioning the surface of the metallic coating, i.e. the anti-corrosion layer, the anti-corrosion coating being a zinc-based coating and the Surface conditioning is carried out in such a way that oxides lying or adhering to the corrosion protection layer are abraded and, in particular, a microporosity is exposed.
- Such protective layers usually only occur with zinc coatings, while aluminum coatings often do not have to be cleaned or only have to be subjected to less complex cleaning.
- a sol-gel preconditioning of the layer to reduce oxide layer formation and increase weldability is known.
- the aim is to create an anti-oxidation coating for press-hardening steel materials on the basis of binders containing silane and titanium and oxidic pigments, which are apparently applied in the sol-gel process.
- solvents such as methanol are used here, which cannot be used on steel production plants.
- the coating is said to fall off by itself after press hardening, although tests with titanium and silicon-based coatings took place in 2015/16 and were not successful with either a thick or a thin wet film.
- the coating does not fall off by itself, nor is it suitable for industrial applications.
- a ceramic-based coating with a thickness of ⁇ 25 ⁇ m is known from EP 2 536 857 B1, which is intended to consist essentially of S1O2, Al2O2 and MgO, with metallic fibers made of tin if necessary. It was found here that such a coating leads to the sheet metal no longer being weldable, and delamination of the paint also occurs.
- the object of the invention is to create a method for the electrolytic galvanizing of steel strip in which the high-temperature-suitable zinc alloy anti-corrosion layer is conditioned in such a way that radiant cleaning after a high-temperature process is unnecessary.
- Another object is to create an electrolytically galvanized steel strip which is designed in such a way that it is not necessary to clean off an oxide skin after a high-temperature process.
- a cleaning post-treatment is a manageable and well-established process, but a higher workload is generated.
- the cycle time may have to be adapted.
- the oxide growth during the hardening process can be designed in such a way that subsequent mechanical surface conditioning, such as, for example, centrifugal blasting, vibratory grinding or dry ice blasting, is unnecessary.
- the electrolytic deposition or co-deposition of tin on the zinc alloy coating or the application of salt solutions in particular containing tin, such as salt solutions of the Stan nate, after the electrolytic galvanizing, apparently modify the surface in such a way that one as well cleaning is always unnecessary.
- this is preferably deposited or co-deposited in a final electrolysis stage in order to deposit it on the surface of the zinc layer or near the surface together with zinc.
- the coating is applied after the electrolytic deposition of the zinc layer or a zinc-aluminum layer, this is expediently carried out as metallic tin in the PVD or CVD process or by means of a salt solution, in particular via a roll coating process.
- stannate comprises the salts of tin acids (II) and - (IV).
- Zinc stannate ZnSnC Zinc stannate ZnSnC.
- an aqueous alkaline solution is applied as the salt solution by means of a roll coater to a galvanized surface after the electrolytic deposition or skin pass and before the cold forming or annealing and hardening process.
- very thin layers are used, which are aqueous 1-5 ⁇ m and when dried are 50-150 nm thick.
- the tin coverage when using stannates is 30-90 mg tin per m 2 in the form of K2 [Sn0 3 ].
- the surface resistance is very low and even in a paint infiltration test, only a very low paint infiltration tendency could be determined.
- significantly fewer oxides can be detected, which is revealed by the metallic sheen of the annealed sheet.
- a such silvery is a problem as it indicates a lack of through reaction.
- Investigations have shown that the zinc-iron crystals of the zinc layer have reacted through.
- a good formation of the phosphate crystals during the phosphating could be determined. This was not to be expected in this form, as expert knowledge indicates that tin has a negative effect on phosphating.
- the invention thus relates to a method for conditioning the surface of a steel strip coated with an electrolytically deposited zinc alloy anti-corrosion layer, which is subjected to a temperature increase to change the structure of the steel, with tin being deposited or co-deposited with zinc during the electrolytic coating of the steel strip is such that tin is present on the surface or near the surface or tin is applied in metallic or ionic form after the electrolytic coating.
- the tin is applied in ionic form or in metallic form, the tin being applied in ionic form from a salt solution and in metallic form using a CVD or PVD process.
- the tin is applied from an alkaline or acidic solution.
- an aqueous stannate solution is applied, which is adjusted to be basic or acidic.
- the tin in the solution is complexed with citric acid.
- the aqueous solution is applied with a layer thickness of 1-5 ⁇ m, in particular 1-3 ⁇ m, the dried layer thickness being 50-150 nm, in particular 75-125 nm, in particular 80-100 nm.
- the tin coating is 30-90 mg tin / m 2 , in particular 40-80 mg tin / m 2 , and in particular 50-60 mg tin / m 2 .
- a solution with a solution concentration of 150-250 g / l K 2 SnOs * 3H 2 0 is used.
- a solution with 150-250 g / l K 2 Sn0 3 * 3H 2 0 and 15-25 g / l KOH is used.
- a solution which has a pH of 12.5-13.5.
- a solution which has a pH of 4-5.5 and in which the tin is complexed with citric acid.
- citric acid is contained in an amount of 35-40 g / l for complexing the tin, the pH being 4-5.5.
- the solution concentration is 200 g / l K 2 Sn0 3 * 3H 2 0 with 20 g / l KOH.
- the invention is an electrolytically galvanized steel strip coated with 40-80 mg tin / m 2 .
- the tin is deposited in a metallic or ionic form.
- the tin is deposited from a salt solution, in particular stannate solution, or by means of PVD or CVD processes.
- the invention relates to the use of an aforementioned steel strip, produced with an aforementioned method, in a method in which a steel sheet is heated for the purpose of austenitizing and then reshaped and quench hardened or reshaped, austenitized and quench hardened.
- FIG. 1 the production route in conventional hot-stamping
- FIG. 2 the production route in conventional press hardening
- FIG. 3 a steel sheet after annealing without conditioning and a steel sheet after annealing with an annealing coating according to the invention
- FIG. 4 an electron micrograph of the surface conditioned according to the invention after annealing
- FIG. 5 the element distribution at four different measuring points
- FIG. 6 the surface of a galvanized steel sheet after annealing with an annealing time of 45 seconds and 200 seconds;
- FIG. 7 the surface of the steel sheet after annealing with a surface conditioning according to the invention after 45 seconds and 200 seconds;
- FIG. 8 the electrical resistance of the sheet metal surface for untreated and treated surfaces
- FIG. 9 the infiltration of paint in the case of surfaces not conditioned according to the invention and conditioned according to the invention after six weeks according to the VDA test.
- the surface of a galvanized sheet metal, in particular sheet steel, which is reshaped and hardened in a press hardening process in one stage or in a press hardening process in several stages, is initially cold formed and then heated as a raw component, transferred to a form hardening tool and therein hardened is conditioned with tin or stannates.
- tin is preferably deposited on the existing zinc layer in a final electrolysis stage or co-deposited with zinc so that tin is present on the surface or near the surface.
- the tin content should be 30-90 mg / m 2 .
- the electrolytically galvanized strip passes through a CVD or PVD device after the galvanization and possibly cleaning processes, in which the specified amount of tin is deposited on the galvanized surface.
- the tin is applied as a salt solution, in particular in the roll coating process, after electroplating and any necessary cleaning steps.
- a stannate solution is used.
- stannates that can be used have already been listed; a potassium stannate solution is particularly suitable, with one way in principle being the application of stannate or tin in ionic form to the surface.
- Both basic and acidic solutions can be used here and, in particular, solutions in which the tin is complexed can be used.
- an aqueous layer thickness of 1-5 ⁇ m is aimed for, with a getrockne th layer thickness of 50-150 nm and a tin coverage of 30-90 mg tin / m 2 in the form of K 2 [Sn0 3 ].
- FIGS. 1 and 2 show conventional processes in which a galvanized steel sheet, in which the zinc layer contains an element with an affinity for oxygen, for example aluminum, is either austenitized before forming or austenitized after forming and quench hardened in a press . After hardening, both sheets have a glass-like, hard layer on the surface, in particular made of aluminum oxide, which is preferably cleaned off.
- the conditioning of the surface with very small amounts of tin obviously affects the formation of the vitreous or hard layer to such an extent that it does not arise in this form or is conditioned to such an extent that it does not have to be cleaned.
- a conventionally produced hardened steel plate shows a greenish beige appearance on the surface, which is caused by oxides.
- the sheet When conditioned with a stannate solution, the sheet shows a silvery surface (FIG. 3). While in conventional processes silvery surfaces indicate a lack of thorough reaction of the tin layers with the underlying steel, this is not the case with the invention. Measurements have shown that the zinc layer has acted through in the same way. However, there are few oxides formed on the surface, the surface resistance as a measure of the suitability for spot welding and the infiltration of paint are very low.
- FIG. 2 a surface designed and conditioned according to the invention can be seen in an electron microscopic view, a basic solution of potassium stannate with potassium hydroxide having been applied with a roll coater before the heat treatment.
- the concentration of the solution which is used for conditioning by means of roll coating, is chosen so that with a wet film of 1 ⁇ m 50-60 mg tin / m 2 are deposited.
- a layer applied in this way causes a modification of the oxide layer that forms during annealing, so that mechanical cleaning by means of a centrifugal wheel or other mechanical processes is no longer necessary.
- a solution which effects conditioning according to the invention has a solution concentration of 180-220 g / l K2Sn03 * 3H20.
- 15-25 g / l KOH can be added to the solution so that a pH value of approx. 13, i.e. 12.5-13.5 is established.
- the tin can be complexed in a suitable manner to the extent that a clear, precipitate-free solution is obtained by adding citric acid in an amount of 30 - 50 g / l is added, resulting in a pH of about 4.8.
- FIG. 6 the surface of a conventional sheet metal which has not been conditioned according to the invention can be seen again after 45 seconds and 200 seconds of annealing at 870.degree. Both sheets show the beige-green color already mentioned.
- FIG. 7 the surfaces of two metal sheets which have been conditioned according to the invention can be seen after an annealing time of 45 seconds and 200 seconds at 870.degree. The differences in the surface color are clearly visible.
- the surface conditioning according to the invention also provides an advantage in terms of corrosion in terms of the infiltration of the paint, because as the results in FIG is infiltrated to a greater extent than with other sheets.
- the conditioning according to the invention was presented in particular on the basis of the stannates.
- the titanates, oxalates and zirconates also have essentially the same chemical reaction. Accordingly, it can be assumed that these are equally effective, in particular the corresponding tin compounds.
- the tin seems to be particularly effective, which is why the surface conditioning succeeds even when the tin is metallic.
- the deposition of the tin on the surface with the help of the stannates, i.e. in ionic form, has the advantage that it can be applied in a comparatively simple manner using a roll coating process.
- the application can be done inline on the belt before it is cut into individual blanks.
- the blanks cut out of the strip can be coated accordingly.
- the blanks are then formed into a component blank, in particular in a multi-stage process. Coating only the component blank with the Zinnver bond or the tin is also conceivable. However, it has been shown that the tin or tin salt coating also tolerates the forming processes well.
- a component blank obtained in this way is heated to a temperature that causes a structural change towards austenite.
- the austenitized component blank is then fed to a form hardening tool in which the component blank is hardened in one stroke by means of the contact of an upper and lower tool, which essentially have the shape of the blank or correspond to it. Because the material as the component blank is in contact with the, in particular, cooled tools, the heat is withdrawn from the steel material so quickly that martensitic hardening occurs.
- the advantage of the invention is that it is possible to condition the surface of a steel sheet provided for form hardening or press hardening in such a way that mechanical final cleaning to remove oxidic surface layers can be dispensed with, so that such sheets can be produced in the same way as, for example, hot-dip aluminized sheets , can be processed, but with the advantage that a high cathodic corrosion protection effect is achieved compared to hot-dip aluminized sheets.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Electrochemistry (AREA)
- Electroplating Methods And Accessories (AREA)
- Coating With Molten Metal (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP20160205.9A EP3872231A1 (de) | 2020-02-28 | 2020-02-28 | Verfahren zum konditionieren der oberfläche eines mit einer zinklegierungs-korrosionsschutzschicht beschichteten metallbandes |
PCT/EP2021/054964 WO2021170861A1 (de) | 2020-02-28 | 2021-03-01 | Verfahren zum elektrolytischen verzinken von stahlband mit einer konditionierten zinkschicht |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4110971A1 true EP4110971A1 (de) | 2023-01-04 |
Family
ID=69743010
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20160205.9A Withdrawn EP3872231A1 (de) | 2020-02-28 | 2020-02-28 | Verfahren zum konditionieren der oberfläche eines mit einer zinklegierungs-korrosionsschutzschicht beschichteten metallbandes |
EP21707719.7A Withdrawn EP4110971A1 (de) | 2020-02-28 | 2021-03-01 | Verfahren zum elektrolytischen verzinken von stahlband mit einer konditionierten zinkschicht |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20160205.9A Withdrawn EP3872231A1 (de) | 2020-02-28 | 2020-02-28 | Verfahren zum konditionieren der oberfläche eines mit einer zinklegierungs-korrosionsschutzschicht beschichteten metallbandes |
Country Status (4)
Country | Link |
---|---|
EP (2) | EP3872231A1 (de) |
CN (1) | CN115279945A (de) |
CA (1) | CA3172957A1 (de) |
WO (1) | WO2021170861A1 (de) |
Family Cites Families (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1082099A (en) * | 1965-01-04 | 1967-09-06 | Republic Steel Corp | Method of forming zinc coating on steel and coated steel article formed by such method |
JPS4937693B1 (de) * | 1968-04-25 | 1974-10-11 | ||
US3869261A (en) * | 1974-05-22 | 1975-03-04 | Usui Kokusai Sangyo Kk | Corrosion-resistant composite coating to be formed on steel materials and method of forming the same |
GB2276887B (en) * | 1993-04-05 | 1997-12-10 | Berkman Louis Co | Coated metal |
AU686502B2 (en) * | 1995-03-28 | 1998-02-05 | Nippon Steel & Sumitomo Metal Corporation | Rust-preventive steel sheet for fuel tank and process for producing the sheet |
JP3908912B2 (ja) * | 2001-02-22 | 2007-04-25 | 新日本製鐵株式会社 | 半田濡れ性、耐錆性、耐ホイスカー性に優れた環境対応型電子部品用表面処理鋼板 |
WO2003035942A2 (en) * | 2001-08-03 | 2003-05-01 | Elisha Holding Llc | An electrolytic and electroless process for treating metallic surfaces and products formed thereby |
DE602004021802D1 (de) | 2003-04-23 | 2009-08-13 | Sumitomo Metal Ind | Heisspressgeformtes produkt und herstellungsverfahren dafür |
BE1015823A3 (fr) * | 2003-12-17 | 2005-09-06 | Ct Rech Metallurgiques Asbl | Procede de revetement d'une surface metallique par une couche ultrafine. |
JP4577238B2 (ja) * | 2006-03-01 | 2010-11-10 | 住友金属工業株式会社 | 濃厚塩化物環境での長期耐久性に優れる樹脂被覆鋼材とその製造方法 |
BRPI0711143B1 (pt) * | 2006-05-02 | 2018-01-30 | Jfe Steel Corporation | Método para fabricação de chapa de aço galvanizada por imersão a quente e chapa de aço galvanizada por imersão a quente |
DE102007021364A1 (de) * | 2007-05-04 | 2008-11-06 | Henkel Ag & Co. Kgaa | Metallisierende Vorbehandlung von Zinkoberflächen |
DE102007022174B3 (de) | 2007-05-11 | 2008-09-18 | Voestalpine Stahl Gmbh | Verfahren zum Erzeugen und Entfernen einer temporären Schutzschicht für eine kathodische Beschichtung |
KR20100092009A (ko) | 2007-12-11 | 2010-08-19 | 이데미쓰 고산 가부시키가이샤 | 고분자 화합물 및 그것을 사용한 유기 전기발광 소자 |
JP2009179859A (ja) * | 2008-01-31 | 2009-08-13 | Nippon Paint Co Ltd | 複層塗膜形成方法 |
DE102009051673B3 (de) * | 2009-11-03 | 2011-04-14 | Voestalpine Stahl Gmbh | Herstellung von Galvannealed-Blechen durch Wärmebehandlung elektrolytisch veredelter Bleche |
DE102009047522A1 (de) * | 2009-12-04 | 2011-06-09 | Henkel Ag & Co. Kgaa | Mehrstufiges Vorbehandlungsverfahren für metallische Bauteile mit Zink- und Eisenoberflächen |
CA2789925C (en) | 2010-02-19 | 2016-06-07 | Tata Steel Nederland Technology Bv | Strip, sheet or blank suitable for hot forming and process for the production thereof |
DE102010037077B4 (de) | 2010-08-19 | 2014-03-13 | Voestalpine Stahl Gmbh | Verfahren zum Konditionieren der Oberfläche gehärteter korrosionsgeschützter Bauteile aus Stahlblech |
DE102012212598A1 (de) * | 2012-07-18 | 2014-02-20 | Henkel Ag & Co. Kgaa | Verzinnende Vorbehandlung von verzinktem Stahl in Gegenwart von Pyrophosphat |
WO2018126471A1 (en) | 2017-01-09 | 2018-07-12 | Henkel Ag & Co. Kgaa | A curable protective coating composition |
-
2020
- 2020-02-28 EP EP20160205.9A patent/EP3872231A1/de not_active Withdrawn
-
2021
- 2021-03-01 WO PCT/EP2021/054964 patent/WO2021170861A1/de unknown
- 2021-03-01 EP EP21707719.7A patent/EP4110971A1/de not_active Withdrawn
- 2021-03-01 CN CN202180020478.9A patent/CN115279945A/zh active Pending
- 2021-03-01 CA CA3172957A patent/CA3172957A1/en active Pending
Also Published As
Publication number | Publication date |
---|---|
CA3172957A1 (en) | 2021-09-02 |
EP3872231A1 (de) | 2021-09-01 |
WO2021170861A1 (de) | 2021-09-02 |
CN115279945A (zh) | 2022-11-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2290133B1 (de) | Verfahren zum Herstellen eines mit einem metallischen, vor Korrosion schützenden Überzug versehenen Stahlbauteils und Stahlbauteil | |
EP1658390B1 (de) | Verfahren zum herstellen eines gehärteten stahlbauteils | |
EP2683843B1 (de) | Stahlflachprodukt und verfahren zum herstellen eines stahlflachprodukts | |
EP2045360B1 (de) | Verfahren zum Herstellen eines Stahlbauteils durch Warmformen und durch Warmformen hergestelltes Stahlbauteil | |
EP3215656B1 (de) | Verfahren zum herstellen einer korrosionsschutzbeschichtung für härtbare stahlbleche und korrosionsschutzschicht für härtbare stahlbleche | |
EP2848709A1 (de) | Verfahren zum Herstellen eines mit einem metallischen, vor Korrosion schützenden Überzug versehenen Stahlbauteils und Stahlbauteil | |
EP2848715B1 (de) | Verfahren zum herstellen eines mit einem metallischen, vor korrosion schützenden überzug versehenen stahlbauteils | |
WO2010089273A1 (de) | Verfahren zum herstellen eines beschichteten stahlbauteils durch warmformen und durch warmformen hergestelltes stahlbauteil | |
EP1693477A1 (de) | Beschichtetes Stahlblech oder -band | |
EP3250727B1 (de) | Bauteil aus pressformgehärtetem, auf basis von aluminium beschichtetem stahlblech und verfahren zur herstellung eines solchen bauteils | |
DE202004021264U1 (de) | Korrosionsschicht und gehärtetes Stahlbauteil | |
EP2513346A2 (de) | Verfahren zum herstellen eines gut umformbaren stahlflachprodukts, stahlflachprodukt und verfahren zur herstellung eines bauteils aus einem solchen stahlflachprodukt | |
EP2987889A1 (de) | Oberflächenveredeltes Stahlblech und Verfahren zu dessen Herstellung | |
DE102019100140A1 (de) | Aluminiumbasierte Beschichtung für Stahlflachprodukte zur Pressformhärtung von Bauteilen und Verfahren zur Herstellung hierzu | |
EP4110970B1 (de) | Verfahren zum herstellen gehärteter stahlbauteile mit einer konditionierten zinkkorrosionsschutzschicht | |
EP4110971A1 (de) | Verfahren zum elektrolytischen verzinken von stahlband mit einer konditionierten zinkschicht | |
EP4110972B1 (de) | Verfahren zum herstellen gehärteter stahlbauteile mit einer konditionierten zinklegierungskorrosionsschutzschicht | |
DE69218916T2 (de) | Blech aus aluminium-legierung mit verbesserter pressverformbarkeit und verfahren zur herstellung | |
EP3585917A1 (de) | Verfahren zum beschichten von stahlblechen oder stahlbändern und verfahren zur herstellung von pressgehärteten bauteilen hieraus | |
DE1913167B2 (de) | Verfahren zur Herstellung von teil weise verzinkten Blechen oder Bandern aus Eisenwerkstoffen |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: UNKNOWN |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE |
|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
|
17P | Request for examination filed |
Effective date: 20220817 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Effective date: 20230210 |