Method for hot-dip galvanising, and hot-dip galvanised component

Abstract

The present invention relates to a method for hot-dip galvanising at least one component having at least one opening and / or edge, wherein, in order to apply a galvanising layer to the component, the component is dipped into a galvanising bath filled with molten zinc comprising a zinc alloy and is removed from the bath again after being galvanised. According to the invention, at least one recess that adjoins the opening and / or the edge of the component and opens into the opening and / or edge has been made in the component prior to galvanising, said recess being intended to receive zinc alloy running off.

Description

[0001] Hot-dip galvanizing process and hot-dip galvanized component

[0002] The present invention relates to the technical field of galvanizing components, in particular iron-based or iron-containing components and / or steel-based or steel-containing components (steel components), by means of hot-dip galvanizing (hot-dip galvanizing).

[0003] In particular, the present invention relates to a method for hot-dip galvanizing at least one component having at least one opening and / or edge. Furthermore, the present invention relates to a hot-dip galvanized component that is or has been produced according to the aforementioned method.

[0004] In particular, hot-dip galvanizing is carried out in discontinuous operation (so-called batch galvanizing). Components containing iron and / or steel are preferred.

[0005] Metallic components of any kind made of ferrous material, especially steel components, often require effective corrosion protection due to their application. Steel components for motor vehicles (motor vehicles), such as cars, trucks, commercial vehicles, etc., in particular, require effective corrosion protection that can withstand long-term stress.

[0006] In this context, it is known to protect steel-based components against corrosion by means of galvanizing. During galvanizing, the steel is coated with a generally thin layer of zinc to protect it from corrosion. Various galvanizing processes can be used to galvanize steel components, i.e., to coat them with a metallic zinc coating. These include, in particular, hot-dip galvanizing (also known as hot-dip galvanizing), spray galvanizing (flame spraying with zinc wire), diffusion galvanizing (Sherard galvanizing), electrolytic galvanizing, non-electrolytic galvanizing using zinc flake coatings, and mechanical galvanizing.There are significant differences between the aforementioned galvanizing processes, particularly with regard to the process execution, but also with regard to the nature and properties of the resulting zinc layers or coatings. Arguably the most important process for corrosion protection of steel using metallic zinc coatings is hot-dip galvanizing (hot-dip galvanizing). This involves immersing steel continuously (e.g., strip and wire) or piece by piece (e.g., components) at temperatures of approximately 450°C to 600°C in a heated vat containing molten zinc or a molten zinc alloy (melting point of zinc: 419.5°C), so that a resistant zinc alloy layer forms on the steel surface.

[0007] In hot-dip galvanizing, a distinction is made between discontinuous batch galvanizing (cf., for example, EN ISO 1461 and DIN 50997) and continuous strip galvanizing (DIN EN 10143 and DIN EN 10346). Both batch galvanizing and strip galvanizing are standardized processes. Strip galvanized steel is a preliminary or intermediate product (semi-finished product) that is further processed after galvanizing, particularly by forming, punching, cutting, etc., whereas components to be protected by batch galvanizing are usually first completely or at least partially manufactured and only then hot-dip galvanized (which provides all-round protection against corrosion). Batch galvanizing and strip galvanizing differ depending on the application conditions in terms of the phase structure and the thickness of the resulting zinc coatings, which can result in different protection durations.The zinc layer thickness of strip-galvanized sheets is typically in the range of 10 to 35 micrometers, whereas the zinc layer thickness of batch-galvanized steel parts is typically in the range of 50 to 200 micrometers and even more.

[0008] Hot-dip galvanizing provides both active and passive corrosion protection. Passive protection is provided by the barrier effect of the zinc coating. Active corrosion protection is achieved through the cathodic effect of the zinc coating. Compared to more noble metals in the electrochemical series, such as iron, zinc acts as a sacrificial anode, protecting the underlying iron from corrosion until it itself is completely corroded. Hot-dip galvanizing, known as batch galvanizing according to EN ISO 1461, involves hot-dip galvanizing mostly larger steel components and structures. Steel-based blanks or (semi-)finished workpieces (components) are immersed in the molten zinc bath after pretreatment. Immersion allows for easy access to interior surfaces, weld seams, and hard-to-reach areas of the workpieces or components to be galvanized.

[0009] Conventional hot-dip galvanizing is based primarily on dipping iron or steel components into a zinc bath, forming a zinc coating on the surface of the components. To ensure the adhesion, integrity, and uniformity of the zinc coating, careful surface pretreatment and, if necessary, preparation of the components to be galvanized is generally required. This typically includes degreasing followed by rinsing, subsequent acid pickling followed by rinsing, and finally fluxing followed by drying.

[0010] The typical process sequence for conventional batch galvanizing using hot-dip galvanizing is usually as follows. For reasons of process economy and cost-effectiveness, during batch galvanizing of identical or similar components (e.g., series production of automotive components), these are typically brought together or grouped for the entire process (in particular by means of a common product carrier, e.g., designed as a crossbeam or frame, or a common holding or fastening device for a large number of these identical or similar components). For this purpose, a plurality of components are attached to the product carrier using holding devices, such as slings, tie wires, or the like. The components are then fed in a grouped state via the product carrier to the subsequent treatment steps or stages.However, the components can also be treated individually during batch galvanizing using hot-dip galvanizing. First, the component surfaces are degreased to remove grease and oil residues. Typically, aqueous alkaline or acidic degreasing agents are used as degreasing agents. Cleaning in the degreasing bath is followed by a rinsing process, typically by immersion in a water bath, to prevent degreasing agents from being carried over into the subsequent pickling process step with the galvanized material. This is particularly important when switching from alkaline degreasing to an acidic base.

[0011] This is usually followed by a pickling treatment (pickling), which serves primarily to remove inherent contaminants, such as rust and scale, from the steel surface. Pickling is typically carried out in diluted hydrochloric acid, with the duration of the pickling process depending, among other things, on the state of contamination (e.g., degree of rust) of the galvanized material and the acid concentration and temperature of the pickling bath. To prevent or minimize the carryover of acid and / or salt residues with the galvanized material, a rinsing process (rinsing step) usually follows the pickling treatment.

[0012] This is usually followed by fluxing (flux treatment), in which the previously degreased and pickled steel surface is treated with a flux, which typically consists of an aqueous solution of inorganic chlorides, most commonly a mixture of zinc chloride (ZnCl) and ammonium chloride (NH4Cl). On the one hand, the flux is designed to provide a final, intensive, ultra-fine cleaning of the steel surface before the steel surface reacts with the molten zinc, to dissolve the oxide layer on the zinc surface, and to prevent further oxidation of the steel surface until the galvanizing process. On the other hand, the flux increases the wettability between the steel surface and the molten zinc.Flux treatment is typically followed by drying to create a solid flux film on the steel surface and remove adhering water, thus preventing subsequent undesirable reactions (particularly the formation of water vapor) in the molten zinc bath. The components pretreated in this manner are then hot-dip galvanized by immersion in the molten zinc bath. During hot-dip galvanizing, the zinc content of the melt is at least 98.0 wt.% according to DIN EN ISO 1461. After immersion of the galvanized material in the molten zinc (or zinc alloy), it remains in the molten zinc bath for a sufficient period of time, in particular until the galvanized material has reached its temperature and is coated with a layer of zinc.Typically, the surface of the molten zinc is cleaned, particularly of oxides, zinc ash, flux residues, and the like, before the galvanized part is withdrawn from the molten zinc. The component hot-dip galvanized in this way is then subjected to a cooling process (e.g., in air or in a water bath). Finally, the holding devices for the component, such as slings, tie wires, or the like, are removed. Following the galvanizing process, a sometimes complex post-processing or finishing treatment usually follows. This involves removing excess zinc residues, in particular so-called drips from the zinc solidifying on the edges, as well as oxide or ash residues adhering to the component, as far as possible.

[0013] One criterion for the quality of hot-dip galvanizing is the thickness of the zinc coating in pm (micrometers). The DIN EN ISO 1461 standard specifies the minimum coating thicknesses required for batch galvanizing, depending on the material thickness. In practice, the coating thicknesses are significantly higher than the minimum coating thicknesses specified in DIN EN ISO 1461. Generally, zinc coatings produced by batch galvanizing have a thickness in the range of 50 to 200 micrometers and even more.

[0014] During the galvanizing process, a coating of iron / zinc alloy layers of varying composition forms on the steel part as a result of the mutual diffusion of the liquid zinc with the steel surface. When the hot-dip galvanized articles are removed, a layer of zinc – also known as the pure zinc layer – remains adhered to the uppermost alloy layer, which corresponds in composition to the molten zinc. Due to the high temperatures during hot-dip dipping, a relatively brittle layer based on an alloy (solid solution) between iron and zinc initially forms on the steel surface, followed by the pure zinc layer. While this relatively brittle iron / zinc alloy layer improves the adhesion to the base material, it impedes the formability of the galvanized steel.Higher silicon contents in steel, such as those used to so-called "slaking" the steel during production, lead to increased reactivity between the zinc melt and the base material and, consequently, to strong growth of the iron / zinc alloy layer. This results in the formation of relatively thick overall layers. While this enables very long-lasting corrosion protection, the increasing zinc layer thickness also increases the risk of the layer flaking off under mechanical stress, especially local, sudden impacts, thus compromising the corrosion protection effect.

[0015] To counteract the previously described problem of the rapidly growing, brittle, and thick iron / zinc alloy layer, and to enable thinner layer thicknesses while simultaneously providing high corrosion protection during galvanizing, it is known from the prior art to add additional aluminum to the zinc melt or liquid zinc bath. For example, adding 5 wt.% aluminum to a liquid zinc melt produces a zinc / aluminum alloy with a lower melting point than pure zinc. By using a zinc / aluminum melt (Zn / Al melt) orA liquid zinc / aluminium bath (Zn / Al bath) allows, on the one hand, significantly lower layer thicknesses for reliable corrosion protection to be achieved (generally below 50 micrometres); on the other hand, the formation of the brittle iron / tin alloy layer is avoided, since the aluminium - without being bound to a specific theory - first forms a barrier layer on the steel surface of the component in question, onto which the actual zinc layer is then deposited.

[0016] Components hot-dip galvanized with a zinc / aluminum melt can therefore be easily formed, but still exhibit improved corrosion protection properties - despite the significantly lower layer thickness compared to conventional hot-dip galvanizing with a virtually aluminum-free zinc melt. A zinc / aluminum alloy used in the hot-dip galvanizing bath exhibits improved fluidity properties compared to pure zinc. In addition, zinc coatings produced by hot-dip galvanizing using such zinc / aluminum alloys exhibit greater corrosion resistance (two to six times better than that of pure zinc), improved formability, and better paintability than zinc coatings formed from pure zinc. Furthermore, this technology can also be used to produce lead-free zinc coatings. Such a hot-dip galvanizing process using a zinc / aluminum melt orUsing a zinc / aluminum hot-dip galvanizing bath is known, for example, from WO 2002 / 042512 A1 and the relevant publication equivalents to this patent family (e.g., EP 1 352 100 B1, DE 601 24 767 T2, and US 2003 / 0219543 A1). Suitable fluxes for hot-dip galvanizing using zinc / aluminum molten baths are also disclosed therein, since flux compositions for zinc / aluminum hot-dip galvanizing baths are different from those for conventional hot-dip galvanizing with pure zinc. The process disclosed therein enables corrosion protection coatings to be produced with very thin layer thicknesses (generally well below 50 micrometers and typically in the range of 2 to 20 micrometers) and with very low weight at a high cost-effectiveness, which is why the process described therein is used commercially under the name microZINQ® process.

[0017] A disadvantage of the conventional batch galvanizing process is that when the components are removed from the molten zinc, the zinc inevitably runs off and drips from the edges and corners of the component, as well as from openings within the component. This creates so-called zinc snags on the edges and in the openings. In the worst case, smaller openings in the component become clogged with solidified molten zinc. The subsequent removal of this "excess," which subsequently solidifies, and which is usually done manually, represents a significant cost and effort factor, especially when galvanizing large quantities and / or meeting strict tolerance requirements.For example, in the case of a fully loaded product carrier that immerses a number of components to be galvanized into the zinc melt, it is generally not possible to reach all components on the product carrier and remove the zinc noses of the individual components directly at the galvanizing point.

[0018] Ultimately, components commonly produced by batch galvanization are left with zinc nibs and / or partially or completely clogged openings on the galvanized components, which must be removed by manual reworking. In this regard, it should be noted that reworking does not just mean cleaning or repair, but also includes visual inspection. Due to the nature of the process, all components are likely to have zinc nibs and / or clogged openings, which must be removed accordingly. Therefore, all components must be inspected individually. This inspection alone, without any subsequent work steps that may be necessary, represents a very significant effort, especially when large numbers of components are involved in large-scale production with very high quality requirements.

[0019] The object of the present invention is to avoid the aforementioned disadvantages or at least to reduce them substantially.

[0020] To achieve the aforementioned object, the present invention - according to a first aspect of the present invention - proposes a method for hot-dip galvanizing according to claim 1. Further and / or advantageous embodiments of the hot-dip galvanizing method according to the invention are the subject of the relevant subclaims.

[0021] Furthermore, the present invention - according to a second aspect of the present invention - relates to a hot-dip galvanized component which is produced by the method according to claim 1, according to the independent product claim.

[0022] It is understood that in the following explanations, configurations, embodiments, advantages and the like which are explained below only with regard to one aspect of the invention for the purpose of avoiding repetition, naturally also apply accordingly with regard to the other aspects of the invention without this requiring separate mention.

[0023] Furthermore, the person skilled in the art may, depending on the application or the individual case, deviate from the range specifications given below if necessary, without departing from the scope of the present invention.

[0024] In addition, all values ​​or parameters or the like mentioned below can generally be determined using standardized or explicitly specified determination procedures or, if not, using determination or measurement methods that are familiar to a person skilled in the art.

[0025] With that in mind, the present invention will now be explained in detail below. The invention relates to a method for hot-dip galvanizing at least one component having at least one opening and / or edge. To apply a galvanizing layer to the component, the component is immersed in a galvanizing bath filled with a zinc melt containing a zinc alloy. After galvanizing, the component is immersed in a galvanizing bath filled with a zinc alloy. According to the invention, prior to galvanizing, at least one recess adjacent to the opening and / or edge of the component is formed in the component, which recess is intended to receive draining zinc alloy.

[0026] In particular, the present invention relates to batch galvanizing, preferably in discontinuous operation.

[0027] The component can be immersed in the galvanizing bath by means of a conveyor device, a product carrier, or the like. It can also be provided that the component is immersed in the galvanizing bath together with other components. An arrangement in a basket, which is immersed in the galvanizing bath via a conveyor device, can also be implemented according to the invention.

[0028] Surprisingly, within the scope of the present invention, it is possible to provide a component that, after hot-dip galvanizing, is at least substantially free of unwanted zinc protrusions on edges and / or has openings that are not clogged by zinc adhesions or deposits. According to the invention, this is achieved by additionally creating a recess in the component before hot-dip galvanizing. Thus, a separate, additional step for processing the component is required prior to hot-dip galvanizing, but this can also be implemented simultaneously during edge production or the creation of the openings in the component.

[0029] In connection with the tests conducted during the development of the invention, it was determined that, despite the additional process step of creating the recess in the component, a more efficient process sequence can be ensured, particularly since complex, manual post-processing of the hot-dip galvanized component can be avoided or at least reduced. Thus, the recess ensures that a "predefined" area is present on the component for draining zinc deposits, which can become clogged in a desired and defined manner. By clogging the recess with draining zinc or zinc deposits after hot-dip galvanizing, the opening and / or the edge itself can remain at least substantially free of unwanted zinc adhesions or zinc deposits. Thus, a predefined recess is used to accommodate zinc deposits after hot-dip galvanizing.

[0030] When zinc deposits, zinc nibs, or the like are mentioned in the context of the present invention, this refers to the flowing zinc melt containing a zinc alloy, which solidifies after appropriate cooling. Accordingly, zinc adhesions and / or zinc deposits can, if necessary, also contain other components in addition to zinc / zinc alloy.

[0031] Furthermore, it is understood that the recess is not considered as part of the opening and / or edge, but represents a separate area which is, however, open towards the opening or the edge.

[0032] As a result, the invention differs from the prior art in that a supplementary recess is specifically introduced into the component before immersion in the zinc bath and preferably in connection with the manufacture of the component - depending on the size of the opening and / or the length of the edge of the component. Particularly preferably, the recess is dimensioned or formed depending on the dimensions of the opening and / or edge assigned to it. In this context, it is understood that not every opening and / or edge of the component necessarily has to be provided with a recess. According to the invention, however, at least one opening and / or at least one edge of the component is equipped with the recess assigned to this opening and / or edge.

[0033] Preferably, recesses are assigned to such openings and / or edges or are introduced into the component adjacent to the opening and / or edge, where zinc deposits clogging the opening and / or adhering to the edge are to be avoided, and / or where such deposits would result in significantly increased processing effort with corresponding manual post-processing. This applies in particular to openings and / or edges where particular dimensional accuracy is required for subsequent use.

[0034] A particular advantage of the invention is that by introducing the recess into the component, an exact and / or targeted manipulation of the component can be carried out in order to ensure its dimensional accuracy without reworking.

[0035] If necessary, it can also be provided that the recess and / or the edge is provided with a corresponding recess during the manufacture of the component itself. Nevertheless, the recess should be understood as an independent area, since the recess is specifically used to be at least partially, preferably completely, filled with draining molten zinc, so that the opening and / or the edge can remain at least essentially free of unwanted zinc adhesions or deposits. This can significantly reduce the amount of post-processing required, or even eliminate it entirely.

[0036] Consequently, the invention offers the possibility of significantly reducing undesirable zinc adhesions and / or zinc deposits, since the galvanizing process can be optimized by the recesses.

[0037] In connection with the present invention, it has been found that, taking into account the fact that post-processing is sometimes no longer necessary with the invention, the overall production time for manufacturing galvanized components can actually be reduced compared to the prior art. The invention therefore ultimately delivers higher productivity, particularly since the manual post-processing required in the prior art is very time-consuming. This is especially true if the recess has to be introduced into the component after it has been manufactured, before hot-dip galvanizing. Such introduction can be achieved by punching, milling, laser cutting, or the like. Ultimately, the cost of additionally introducing the recess is disproportionate to the very complex post-processing required in the prior art. As a result, the invention produces components of higher quality.The invention also offers economic advantages over the state of the art from an economic perspective, since the production time can be reduced by up to 20%, taking into account the fact that post-processing is no longer necessary or is sometimes very minimal.

[0038] In terms of the process, the galvanizing layer generally solidifies at least substantially within 0.02 to 10 minutes, preferably between 0.5 and 3 minutes, after emerging from the molten zinc bath. Once the hot-dip galvanizing layer on the component has solidified, the recess designed for the edge or opening can ensure that excess zinc deposits are received in the recess and solidify therein, and that the opening or edge is particularly preferably at least substantially free of unwanted zinc deposits or zinc protrusions or the like, which protrude in particular beyond the predetermined galvanizing layer.

[0039] In the context of the present invention, "zinc noses / unwanted zinc deposits" is also to be understood in particular as referring to excess or unwanted zinc / zinc alloy which, after solidification, protrudes and / or protrudes beyond the specified (regular) layer thickness of the hot-dip galvanizing layer.

[0040] Particularly preferably, the component is galvanized over its entire surface and has a (desired) galvanizing layer as a zinc deposit throughout. However, zinc nibs are unwanted, additional deposits.

[0041] In a particularly preferred embodiment of the invention, the recess is designed in such a way that when the component is pulled out of the galvanizing bath, zinc alloy running off the component surface - that is to say in particular before the zinc alloy has solidified - collects from the area of ​​the opening and / or the edge in the recess or runs into it. Preferably, the zinc alloy running off the component surface collects in the receptacle in such a way that after this run-off amount of zinc alloy has solidified, it no longer projects into the opening and / or protrudes over the edge and / or preferably in such a way that the opening and / or the edge is free of any protruding and / or excess zinc alloy compared to the applied hot-dip galvanizing layer and / or preferably in such a way that the opening is at least substantially free of zinc alloy clogging the opening.According to the invention, it is thus possible to completely absorb the draining zinc alloy in the recess, in particular by keeping the opening and / or the edge free of unwanted zinc alloy. This drastically reduces the previously mentioned post-processing effort of the galvanized component. In particular, it can be avoided that an opening after hot-dip galvanizing no longer has the original or nominal dimensions required for its subsequent function, but instead becomes completely or partially clogged with the zinc alloy.

[0042] Furthermore, in a further particularly preferred embodiment of the inventive concept, it can be provided that the component is removed from the galvanizing bath in such a way that the recess is arranged in the lower region facing away from the withdrawal direction and / or in the lower half of the opening and / or the edge facing away from the withdrawal direction, in particular at the lower apex and / or at the lowest point and / or lowest region of the opening and / or the edge when positioned on the product carrier during the galvanizing process. Such an arrangement is particularly advantageous because the draining zinc alloy is subject to the force of gravity when withdrawn from the galvanizing bath and thus drains or is pulled downwards. By arranging the recess, particularly preferably in the lower region of the opening and / or edge, the draining zinc alloy can then be caught so that it does not protrude over the edge or protrude into the opening.This lower area of ​​the component is defined by the method and location of the component when it is immersed in the galvanizing bath and subsequently removed from the bath. Ultimately, the lower area must face downward after the component has been held or secured for immersion into the melt. Accordingly, the recess is also open upward immediately after the component has been removed from the melt into the opening.

[0043] Preferably, the recess, viewed from above onto the opening and / or the edge, is at least substantially circular segment-shaped, arc-shaped, triangular, and / or rectangular. In principle, a wide variety of shapes are possible for the recess. However, in the development of the invention, it has been shown that the aforementioned shapes can be incorporated into the component relatively easily without significant processing complexity, and that efficient collection of the draining zinc alloy can be ensured.

[0044] The recess can be created prior to hot-dip galvanizing by drilling and / or milling and / or by a thermal and / or non-thermal cutting process, such as laser, oxyacetylene, plasma, and / or waterjet cutting. Thus, according to the invention, the recess can be created in the component using different processes depending on the component-specific parameters and / or the component material. Different processes are suitable, for example, for different recesses and / or openings or edges. The opening can be circular and / or elliptical in cross-section and / or formed as an elongated hole.

[0045] Particularly preferably, in further embodiments, the opening can be provided to represent a material removal point in the component, whereby the opening can be designed as a breakthrough and / or a drainage opening, but does not have to be. In practice, openings of different shapes and types are problematic because they become clogged when emerging from the zinc alloy. According to the invention, this can now be avoided by the targeted introduction of the recess(es).

[0046] Furthermore, the opening can have a clear diameter of at least 5 mm, preferably at least 8 mm, more preferably at least 10 mm, before the recess is formed. The principle of using the recess according to the invention can ultimately also be applied to larger openings of up to 50 cm, preferably 25 cm, more preferably 10 cm.

[0047] In principle, various galvanizing processes are suitable for the present invention. Galvanizing can be carried out using a conventional, quasi-pure zinc melt or a zinc alloy with a higher concentration, for example, with aluminum. The various galvanizing processes are regulated by corresponding standards, to which reference is made below.

[0048] A particularly preferred distinction is made between standard galvanization according to EN ISO 1461 (as of March 2023) and thin-layer galvanization according to DIN 50997 (as of March 2023). In the development of the invention, it has been shown that certain ratios between the radius of the opening, which is in particular circular or has a different shape, and the volume of the recess are particularly advantageous. In the case of a non-circular opening, the radius of the opening is understood to mean, in particular, the maximum radius. The maximum radius is determined by half the maximum clear diameter of the opening.

[0049] In a further embodiment of the present invention, it is particularly preferred that, in particular for galvanizing according to EN ISO 1461 (as of March 2023), the ratio of the radius of the opening to the volume of the recess, in particular with a preferably maximum component thickness up to and including 3 mm, with a diameter of the opening less than or equal to 10 mm, is less than 30 cm / cm 3 is preferably less than 20 cm / cm 3 , especially between 1 to 20 cm / cm 3 and / or greater than 1 cm / cm 3 is preferably greater than 5 cm / cm 3 , and / or with an opening diameter of more than 10 mm less than 90 cm / cm 3 , preferably less than 50 cm / cm 3 , especially between 1 to 40 cm / cm 3 , amounts.

[0050] In developing the invention, it was determined that different ratios are preferably provided for different opening widths. The radius ratio can also depend on the component thickness. For example, it can be provided that for components with a greater component thickness, the ratio of r / V (i.e. the ratio of the radius of the opening to the volume of the recess) should also be greater. The recess can also be adjusted accordingly for different maximum opening widths. The aforementioned ratios ultimately indicate that, depending on the different sizes of the opening, the recess is designed according to the (expected) amount of zinc deposit that is draining. For example, in developing the invention, it was determined that, depending on the different dimensions of the openings, different recesses are particularly preferably required.It is therefore understandable that a larger opening should also be provided with a larger recess compared to a smaller opening with a smaller recess, and the like. The aforementioned r / V ratios particularly preferably reflect this relationship and provide the expert with an opportunity to appropriately incorporate the recess into the component depending on the respective opening. Furthermore, for a component thickness greater than 3 mm, especially for galvanization according to EN ISO 1461 (as of March 2023), the ratio of the radius of the opening to the volume of the recess is less than 50 cm / cm for an opening diameter of less than or equal to 10 mm. 3 , preferably less than 40 cm / cm 3 , especially between 1 to 30 cm / cm 3 , and / or if the diameter of the opening is greater than 10 mm, less than 100 cm / cm 3 , preferably less than 80 cm / cm 3 , especially between 1 and 70 cm / cm3 The aforementioned component thickness greater than 3 mm is particularly preferably the maximum component thickness. Thus, the r / V ratio can be particularly preferably adjusted depending on the component thickness (up to and including 3 mm and from 3 mm). Accordingly, appropriate dimensioning of the respective recess can be ensured depending on the different components and the openings provided in the respective components.

[0051] In the case of thin-layer galvanizing according to DIN 50997 (as of March 2023), the ratio of the radius of the opening to the volume of the recess (r / V ratio) for a diameter of the opening less than or equal to 10 mm for a preferably maximum component thickness less than or equal to 3 mm is particularly preferably less than 20 cm / cm 3 , preferably less than 15 cm / cm 3 , especially between 1 to 20 cm / cm 3 , and / or if the diameter of the opening is greater than 10 mm, less than 100 cm / cm3 , preferably less than 70 cm / cm 3 , especially between 1 to 60 cm / cm 3 .

[0052] Adjusting the r / V ratio can also be particularly advantageous for thin-film galvanizing, depending on different component thicknesses. For example, in particular for thin-film galvanizing according to DIN 50997 (as of March 2023), the ratio of the radius of the opening to the volume of the recess (r / V ratio) can be less than 30 cm / cm for an opening diameter of less than or equal to 10 mm for a component thickness greater than 3 mm, preferably a maximum. 3 , preferably less than 20 cm / cm 3 , especially between 1 to 30 cm / cm 3 , and / or if the diameter of the opening is greater than 10 mm, less than 100 cm / cm 3 , preferably less than 80 cm / cm 3 , especially between 1 and 70 cm / cm 3 , amount to.

[0053] The aforementioned preferred r / V ratios were determined based on tests conducted during the development of the invention. It has been shown that for a thin-layer galvanization, particularly a hot-dip galvanized layer with a thinner layer thickness compared to standard galvanization, appropriately adjusted r / V ratios, as mentioned above, can be used with particular preference.

[0054] Depending on the respective galvanizing process, the diameter of the opening, and the component thickness, the volume of the recess can then be efficiently specified. In this context, it should be understood that the aforementioned ratios can also be understood to ensure a certain degree of variation depending on the geometric shape of the recess.

[0055] Furthermore, the hot-dip galvanizing layer can particularly preferably be applied to the component with a layer thickness in the range of 3 μm to 400 μm, preferably between 1 and 100 μm. The layer thickness can also vary depending on the respective galvanizing process. Unlike dripping zinc scum, the hot-dip galvanizing layer represents the desired zinc adhesion and ultimately protects the component, which preferably contains iron and / or steel, from corrosion.

[0056] Furthermore, the component is particularly preferably withdrawn from the galvanizing bath at a speed of 0.05 to 1.5 m / min, preferably 0.1 to 0.8 m / min. Speeds of the aforementioned type have proven particularly useful for transporting the zinc deposits into the recess.

[0057] The temperature of the zinc melt during hot-dip galvanizing can be between 400 °C and 500 °C. For hot-dip galvanizing according to EN ISO 1461 (as of March 2023), the galvanizing temperature range is particularly preferred between 430 °C and 470 °C, more preferably between 435 °C and 465 °C. For thin-film galvanizing according to DIN 50997 (as of March 2023), a somewhat lower galvanizing temperature can be provided if required, with the galvanizing temperature for the aforementioned thin-film galvanizing being between 400 °C and 450 °C, preferably between 415 °C and 425 °C.

[0058] The viscosity of the zinc melt during hot-dip galvanizing can be influenced by the temperature and alloy composition. In particular, the viscosity during hot-dip galvanizing according to EN ISO 1461 (as of March 2023) is between 0.025 and 0.04 poise, in particular between 0.035 and 0.039 poise, more preferably in the range of 0.037 poise + / - 5%, preferably at a galvanizing temperature of 435°C and more preferably at a galvanizing temperature above 435°C, in particular at 465°C + / - 20%, between 0.025 and 0.039 poise, more preferably between 0.33 and 0.035 poise, and in particular 0.034 poise + / - 5%.

[0059] For thin-layer galvanizing according to DIN 50997 (as of March 2023), a slightly lower viscosity may be required. For example, at a zinc melt temperature of 400 °C + / - 20%, the viscosity can be 0.023 to 0.038 poise, in particular between 0.030 to 0.034 poise, and preferably 0.032 + / - 20% poise. At a galvanizing temperature above 400 °C, in particular at a zinc melt temperature of 450 °C + / - 20%, the viscosity can be 0.020 to 0.030 poise, preferably between 0.023 to 0.029 poise, and in particular 0.027 + / - 20% poise.

[0060] In principle, the method according to the invention is also suitable for high-temperature galvanizing, in which a virtually pure zinc melt is preferably used in a temperature range between 520 and 620 °C. In this case, the drainage behavior of the zinc melt is very good due to the lower viscosity, so that using the recess according to the invention, a very high degree of hole-freeness for different openings is generally achieved, approaching 100% hole-freeness. A further advantage of the aforementioned galvanizing temperatures is that the temperature difference between the temperature in the hot-dip galvanizing bath and the solidification temperature of the zinc melt is very large, preferably approximately 100 K + / - 30%. This creates the possibility of a relatively long post-processing period, particularly if the zinc melt solidifies later.Thus, the recess according to the invention is also advantageous for high-temperature galvanizing, since the zinc also has sufficient time to reach the corresponding recess.

[0061] In principle, the temperature difference between the temperature in the zinc melt and the solidification temperature of the galvanizing layer can be significantly less than 100 K, and in particular between 10 K and 100 K, preferably between 20 K and 70 K, and more preferably between 25 K and 50 K, particularly for both standard galvanizing and thin-layer galvanizing according to the aforementioned standards. The cooling rate depends on the surface-to-mass ratio of the component, but is generally between 0.02 and 10 minutes for different applications, preferably between 1 and 3 minutes, after leaving the zinc melt or upon emerging from the zinc melt.

[0062] The aforementioned method is particularly preferably used for comparatively large openings, in particular with a maximum diameter of more than 20 mm. However, it has also been found according to the invention that the method is also suitable for smaller holes or openings and, in particular, leads to a significantly lower post-processing effort. In this case, it may not be possible to guarantee that the opening is 100% free of holes for diameters significantly smaller than 10 mm. Nevertheless, the recess created in the opening can lead to a reduction in post-processing effort. This is due in particular to the fact that the recess creates an area that is ultimately intended to absorb excess molten zinc. Even when the holes are not 100% free of holes, the previously discussed advantages of reduced post-processing arise.The aforementioned diameters can refer to round holes, but also to non-round holes, such as elongated holes and / or slots. In this case, the aforementioned diameter indicates, in particular, the maximum inside diameter of the opening.

[0063] Advantageously, the component is pretreated, in particular cleaned, before hot-dip galvanizing. Various process steps can be provided for cleaning. Particularly preferred are the process steps, in particular in the following order, before hot-dip galvanizing:

[0064] (a) degreasing treatment of the component, in particular in at least one degreasing bath; then

[0065] (b) if necessary, rinsing the component degreased in process step (a); then

[0066] (c) pickling treatment of the component degreased in process step (a) and optionally rinsed in process step (b), in particular in at least one pickling bath; then

[0067] (d) optionally rinsing the component pickled in process step (c); then (e) fluxing the component pickled in process step (c) and optionally rinsed in process step (d) using a flux composition in a flux bath,

[0068] (f) optionally drying treatment of the component subjected to the flux treatment in process step (e), wherein process steps (a) to (f) are optionally carried out several times, preferably in a bundle and / or individually, as required.

[0069] The aforementioned treatment ensures that the component can be optimally prepared for hot-dip galvanizing. Efficient cleaning is also beneficial for adhering zinc deposits, as it allows for a galvanizing layer that extends evenly across the component surface.

[0070] Furthermore, it is understood that, if necessary, individual process steps can be performed multiple times depending on the different components. Some process steps are also optional, as indicated in particular by "if necessary." Individual process steps can also be performed multiple times in a "grouped" / "bundled" manner. For example, process steps (a) to (c) can be performed twice for a component, which can then be passed on to process steps (d) to (f). The sequence of the previously specified process steps can also be adjusted as needed depending on the specific requirements of the component.

[0071] Furthermore, the present invention relates to a hot-dip galvanized component, wherein the component has been subjected to a process of the aforementioned type.

[0072] The hot-dip galvanized component thus has a recess in which solidified zinc alloy or molten zinc is collected or arranged, and further preferably has at least one opening and / or edge to which the recess is assigned. In particular, partially, preferably completely, solidified molten zinc is provided in the recess, the layer thickness or maximum height of which exceeds the layer thickness of the actual galvanizing layer, i.e., is in particular greater than 200 μm. In connection with the hot-dip galvanized components, reference may be made to the aforementioned explanations of the process, which, as explained above, can also apply to the hot-dip galvanized component in the same way.

[0073] Further features, advantages and possible applications of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawing and the drawing itself. All described and / or illustrated features, individually or in any combination, form the subject matter of the present invention, regardless of their summary in the claims or their reference back to them.

[0074] It shows:

[0075] Fig. 1 is a schematic perspective view of a galvanizing process according to the invention in a galvanizing bath,

[0076] Fig. 2 is a further schematic perspective view of a galvanizing of components according to the invention in a galvanizing bath,

[0077] Fig. 3 is a schematic perspective view of a component according to the invention before hot-dip galvanizing,

[0078] Fig. 4 is a schematic perspective view of a hot-dip galvanized component according to the invention,

[0079] Fig. 5 is a further schematic perspective view of a further embodiment of a hot-dip galvanized component according to the invention,

[0080] Fig. 6 is a schematic cross-sectional view of another embodiment of a hot-dip galvanized component and

[0081] Fig. 7 is a schematic representation of part of a method for hot-dip galvanizing according to the invention. Fig. 1 shows a galvanizing bath 6 which is at least partially filled with a zinc melt 5. The zinc melt 5 comprises and / or consists of a zinc alloy. Fig. 1 schematically illustrates that a component 1 is immersed in the galvanizing bath 6 or in the zinc melt 5 of the galvanizing bath 6 for applying a galvanizing layer 4 to the component and is then immersed again after galvanizing. The component 1 has an opening 2 and / or an edge 3. Fig. 1 shows that the component 1 has at least one opening 2. In Fig. 1, the component 1 is immersed in the galvanizing bath 6 via a conveyor device 15, in particular via a hook-like construction of the conveyor device 15.

[0082] Fig. 2 illustrates that a plurality of components 1 can also be introduced into the galvanizing bath 6 together - for example, via a product carrier 16, as shown in Fig. 2. The product carrier 16 can in particular be attached to a conveyor device 15 or formed as part of the conveyor device 15. Thus, a plurality of components 1 can also be galvanized together, in which case at least one component 1 has at least one opening 2 and / or edge 3. However, particularly preferably, all components 1 can also have at least one opening 2 and / or edge 3.

[0083] Fig. 1 further shows that the component 1 has a recess 7, which was introduced prior to galvanizing. The recess 7 borders on the opening 2 and / or the edge 3, preferably directly, or merges into it. The recess 7 is provided to receive draining zinc alloy and is accordingly open to the opening 2 or edge 3. Draining zinc alloy accumulates in the region of the recess 7 when the component 1 is pulled out of the galvanizing bath 6 in the direction of the withdrawal direction F, which is schematically illustrated in Fig. 1.

[0084] Accordingly, Fig. 1 shows a method for hot-dip galvanizing at least one component 1 having an opening 2 or an edge 3, wherein the component 1 is immersed in a galvanizing bath 6 containing a zinc melt 5 containing a zinc alloy in order to apply a galvanizing layer 4 to the component 1 and is then immersed again after galvanizing, wherein before galvanizing at least one recess 7 adjacent to the opening 2 and / or the edge 3 of the component 1 has been made in the component 1, which recess is provided for receiving draining zinc alloy and / or draining zinc melt 5. In Fig. 2, the openings 2 are shown schematically, so that the method according to the invention is also implemented here.

[0085] The introduction of the recess 7 is not shown in detail in Figs. 1 and 2, but this introduction takes place during a process step that is carried out before hot-dip galvanizing. Ultimately, the dimensions of the recess 7 are preferably individually adapted to the respective opening 2 and / or edge 3 and are introduced into the component 1 accordingly. The recess 7 can ensure, after hot-dip galvanizing, at least a substantial absence of holes and / or the prevention of zinc noses on edges 3, since the recess 7 creates a predetermined area in which excess or draining zinc melt 5 can collect or accumulate, thereby preventing unwanted zinc noses, protruding zinc deposits, or the like. This leads to a drastically reduced post-processing effort for the galvanized components 1.

[0086] Fig. 6 shows a schematic cross-section of a component 1 which has been provided with a corresponding galvanizing layer 4 on both outer sides. The galvanizing layer 4 protrudes from / over the ungalvanized component surface 8 and is, in particular, at least substantially uniform in relation to the layer thickness 14. However, it is understood that non-uniform galvanizing layers 4 can also be realized in the method according to the invention, in particular wherein the openings 2 can be kept at least substantially free of the zinc melt 5.

[0087] In particular, the recess 7 is not considered as part of the opening 2, but represents a separate receiving area.

[0088] In Fig. 3, different openings 2 are shown on a component 1, each of which is assigned a differently designed recess 7. Different geometric shapes for the recess 7 enable the corresponding absorption of running zinc alloy when the component 1 is pulled out. In this context, it is understood that different shapes of the opening 2 - for example, non-circular openings 2 - or the like can also be realized. The recess 7 can be selected depending on the design of the opening 2 and / or other process parameters. It is also understood that the component 1 has at least one opening 2 and / or edge 3 which is equipped with a corresponding recess 7. Fig. 3 is merely intended to schematically illustrate that fundamentally different shapes of the recess 7 can be considered. Fig. 4 shows the opening 2 shown in Fig.3 shows the component 1 after hot-dip galvanizing with the galvanizing layer 4 applied to the component surface 8.

[0089] Fig. 4 further illustrates that the recess 7 is filled with zinc alloy after hot-dip galvanizing, leaving the opening 7—which is not included in the area or volume of the recess 7—at least essentially free. Even if the opening 2 has become at least partially clogged, the recess 7 still provides the advantage of drastically simplifying post-processing, since, in particular, the entire hole or opening 2 has not become clogged with zinc alloy.

[0090] Fig. 5 shows a component 1 having edges 3. For at least one edge 3 (also in the embodiment shown in Fig. 5 for several edges 3), a recess 7 has been introduced, which is designed accordingly after hot-dip galvanizing to receive draining zinc alloy or molten zinc 5. The appropriately dimensioned recess 7 ensures that when the component 1 is pulled out of the galvanizing bath 6, the zinc alloy runs off the component surface 8 and collects in the recesses 7 in the area of ​​the edges 3, so that after the zinc alloy has solidified, no zinc noses or the like protrude from the edge 3.

[0091] The recesses 7 shown in Fig. 3 are designed such that when the component 1 is pulled out of the galvanizing bath 6 from the component surface 8, zinc alloy from the region of the opening 2 and / or the edge 3 collects in the recess 7, preferably such that after the drained zinc alloy has solidified, it no longer projects into the opening 2 and / or protrudes beyond the edge 3 or preferably such that the opening 2 and / or the edge 3 is free of excess zinc alloy compared to the applied hot-dip galvanizing layer 4 and / or preferably such that the opening 2 is at least substantially free of zinc alloy clogging the opening 2. In further embodiments, which are not shown in detail here, small parts of the opening 2 can also be partially clogged with zinc alloy.However, an area of ​​the opening 2 which is free of zinc alloy is still provided, which drastically simplifies the post-processing effort, since the opening 2 is in particular not completely blocked by the zinc alloy.

[0092] Fig. 1 shows that the recess 7 is arranged in the lower region facing away from the withdrawal direction F or in the lower half of the opening 2 and / or the edge 3 facing away from the withdrawal direction F - the relevant arrangement results for the component 1 upon emergence from the galvanizing bath 6. In particular, the recess 7 is introduced in the lower apex and / or at the lowest point and / or region of the opening 2 and / or the edge 3. The relevant lower apex 10 of the opening 2 only results when the corresponding withdrawal direction F and / or the design of the conveyor device 15 or the holding point of the component 1 and the withdrawal movement from the zinc melt 5 caused by the conveyor device 15 are known.

[0093] Fig. 3 shows different shapes of the recess 7. The recess 7 can have an at least substantially circular segment-shaped, arc-shaped, triangular, and / or rectangular shape in a plan view of the opening 2 and / or the edge 3. Different circular segment-shaped and / or rectangular shapes are also possible, as shown in Fig. 3. Finally, the shape of the recess 7 can be selected based on the shape of the corresponding opening 2, the expected amount of zinc to be discharged, and / or other component-specific parameters.

[0094] It is not shown in detail how the recess 7 can be created before the hot-dip galvanizing of the component 1. The recess 7 can be created in the component 1 in particular by drilling and / or milling. Alternatively or additionally, it is also possible to create the recess 7 in the component 1 by a thermal or non-thermal cutting process, such as laser, oxyacetylene, plasma and / or water jet cutting. The recess 7 can be formed together with the opening 2 / edge 3, but also in a subsequent process step. Fig. 3 shows that the opening 2 and the recess 7 are designed as a breakthrough and / or as a drainage opening.

[0095] Furthermore, Fig. 3 shows that the opening 2 has a circular or elliptical cross-section. Not shown in detail is the fact that the opening 2 can also be designed as an elongated hole.

[0096] Before the recess 7 is formed, the opening 2 can have a clear diameter 11, as schematically illustrated in Fig. 3, of at least 5 mm, in particular of at least 10 mm. Even smaller diameters 11 can be provided with a corresponding recess 7. In this case, 100% hole-freeness may not be guaranteed after galvanizing, but the advantageous effect of preventing clogging of the opening 2 is nevertheless ensured. Particularly preferably, the opening 2 can have a maximum clear diameter of 50 cm, preferably 20 cm.

[0097] When forming the recess 7, certain ratios between the radius 12, the opening 2 and the volume of the recess 7 are particularly advantageous. In particular for galvanizing according to EN ISO 1461 (as of March 2023), the ratio of the radius 12 of the opening 2 to the volume of the recess 7 can be less than 30 cm / cm, especially for a component thickness of 13 up to and including 3 mm, preferably for a maximum component thickness of 13 up to and including 3 mm, and for a diameter 11 of the opening 2 of less than or equal to 10 mm. 3 , especially between 1 to 20 cm / cm 3 , and / or greater than 5 cm / cm 3 be.

[0098] In the case of galvanizing according to EN ISO 1461 (as of March 2023) and preferably with a maximum component thickness of 13 up to and including 3 mm, with a diameter 11 of the opening 2 greater than 10 mm, the above-mentioned ratio between the radius 12 of the opening 2 and the volume of the recess 7 can be less than 90 cm / cm 3, especially between 1 to 40 cm / cm 3 , amount to.

[0099] The aforementioned r / V ratios can change particularly preferably for component thicknesses 13 greater than 3 mm. Thus, for a component thickness 13 greater than 3 mm, particularly for galvanization according to EN ISO 1461 (as of March 2023), the ratio of the radius 12 of the opening 2 to the volume of the recess 7 with a diameter 11 of the opening 2 less than or equal to 10 mm is less than 50 cm / cm 3 , especially between 1 to 30 cm / cm 3 , and / or with a diameter 11 of the opening 2 of greater than 10 mm less than 100 cm / cm 3 , especially between 1 and 70 cm / cm 3The aforementioned conditions apply in particular to a maximum component thickness 13 of greater than 3 mm. The precise dimensioning of the recess 7 may also depend on the shape of the opening 2 and the expected viscosity of the zinc melt 5, but may in particular be within the aforementioned range.

[0100] For thin-layer galvanizing according to DIN 50997 (as of March 2023), the above-mentioned ratios can be adjusted or optimized. For example, for thin-layer galvanizing according to DIN 50997 (as of March 2023), the ratio of the radius 12 of the opening 2 to the volume of the recess 7 with a diameter n of the opening 2 of less than or equal to 10 mm for a, preferably maximum, component thickness 13 of less than or equal to 3 mm can be less than 20 cm / cm. 3 , especially between 1 to 20 cm / cm 3, with a diameter of the opening 2 of greater than 10 mm, the ratio of the radius 12 of the opening 2 to the volume of the recess 7 with a preferably maximum component thickness 13 of less than or equal to 3 mm with a diameter 11 of the opening 2 of greater than

[0101] 10 mm less than 100 cm / cm 3 , especially between 1 to 60 cm / cm 3 , amount to.

[0102] If the components 1 are somewhat thicker, the ratios of r / V can also be adjusted. For a thin-layer galvanization according to DIN 50997 (as of March 2023), the ratio of the radius 12 of the opening 2 to the volume of the recess 7 can be less than 30 cm / cm for a diameter 11 of the opening 2 of less than or equal to 10 mm for a, preferably maximum, component thickness 13 of greater than 3 mm. 3 , especially between 1 to 30 cm / cm 3 , and / or with a diameter

[0103] 11 of the opening 2 larger than 10 mm smaller than 100 cm / cm 3 , especially between 1 and 70 cm / cm 3 , lay.

[0104] The applied hot-dip galvanizing layer 4 can, in particular, have a layer thickness 14 in the range between 3 μm and 400 μm, wherein the hot-dip galvanizing layer 4 has been applied to the component 1, as schematically shown in Fig. 6. The speed at which the component 1 is withdrawn from the zinc melt 5, as shown, for example, in Fig. 1, can be adjusted according to the component 1 and the zinc melt 5 used. However, the speed can, in particular, be between 0.1 and 0.8 m / min.

[0105] Before hot-dip galvanizing, component 1 can be pretreated accordingly. For pretreatment, steps (a) to (f) can be provided, as shown in Fig. 7. The process steps can be carried out in the order shown in Fig. 7 (i.e., one after the other). However, it can also be provided that at least one of the process steps (a) to (f) is swapped and / or performed multiple times and / or repeated. Thus, optionally, process steps (a) to (f) can each be performed multiple times as needed and / or their order can be swapped. In particular, the following steps are provided:

[0106] (a) degreasing treatment of the component 1 , in particular in at least one degreasing bath; then

[0107] (b) if necessary, rinsing the component 1 degreased in process step (a); then

[0108] (c) pickling treatment of the component 1 degreased in process step (a) and optionally rinsed in process step (b), in particular in at least one pickling bath; then

[0109] (d) if necessary, rinsing the component 1 pickled in process step (c); then

[0110] (e) flux treatment of the component 1 pickled in process step (c) and optionally rinsed in process step (d) by means of a flux composition in a flux bath,

[0111] (f) if necessary, drying treatment of the component 1 subjected to flux treatment in process step (e).

[0112] Process steps (a) to (f) are, as previously explained, also shown in Fig. 7. Hot-dip galvanizing can be carried out following process step (f). The introduction of the recess 7 into the component 1 can also be carried out between one of steps (a) to (f), before step (a) and / or after step (f) - but in any case before hot-dip galvanizing. After hot-dip galvanizing, the galvanized component 1 can be quenched if necessary. A subsequent post-treatment may follow to cool the component 1, during which, for example, passivation, sealing, and / or organic or inorganic coating of the galvanized component 1 can be carried out. Any subsequent processing of the component 1 that may still be required can then also be carried out. However, this post-processing is significantly simplified by the inventive introduction of the recess 7.

[0113] As previously explained, the components 1 can be immersed into the galvanizing bath 6 together or separately - depending on the respective components 1 .

[0114] Furthermore, the invention also relates to a hot-dip galvanized component 1, as shown, for example, in Fig. 4. The hot-dip galvanized component 1 is manufactured according to a method of the aforementioned embodiments. Accordingly, the hot-dip galvanized component 1 has at least one opening 2 and / or edge 3, to which a corresponding recess 7 is assigned, which, after hot-dip galvanizing, is at least partially, preferably completely, filled with draining zinc alloy or molten zinc 5. After hot-dip galvanizing, at least part of the opening 2 is free of the zinc alloy, preferably completely free. If an edge 3 is provided to which a recess 7 is assigned, the edge 3 is in particular at least substantially free of unwanted zinc projections or zinc deposits protruding from the regularly provided hot-dip galvanizing layer 4. List of reference symbols:

[0115] 1 Component Opening Edge Galvanizing layer Zinc melt Galvanizing bath Recess Component surface

[0116] 9 lower half of 2, 3

[0117] 10 lower vertex

[0118] 11 clear diameter of 2

[0119] 12 radius of 2

[0120] 13 Component thickness

[0121] 14 Layer thickness

[0122] 15 Conveyor system

[0123] 16 product carriers

[0124] F Pull-out direction

Claims

Patent claims:

1. A method for hot-dip galvanizing at least one component (1) having at least one opening (2) and / or edge (3), wherein the component (1) is immersed in a galvanizing bath (6) filled with a zinc melt (5) containing a zinc alloy in order to apply a galvanizing layer (4) to the component (1), and is immersed again after galvanizing, characterized in that before galvanizing, at least one recess (7) adjacent to the opening (2) and / or the edge (3) of the component (1) and opening into the opening (2) and / or edge (3) has been introduced into the component (1), which recess is provided for receiving draining zinc alloy.

2. Method according to claim 1, characterized in that the recess (7) has been formed in such a way that when the component (1) is pulled out of the galvanizing bath (6), zinc alloy running off the component surface (8) from the area of the opening (2) and / or the edge (3) collects in the recess (7), preferably in such a way that after solidification of this run-off amount of zinc alloy, it does not protrude into the opening (2) and / or protrudes beyond the edge (3) and / or preferably in such a way that the opening (2) and / or edge (3) is free of excess zinc alloy compared to the applied hot-dip galvanizing layer (4) and / or preferably in such a way that the opening (2) is at least substantially free of zinc alloy clogging the opening (2).

3. Method according to claim 1 or 2, characterized in that the component (1) is immersed from the galvanizing bath (6) in such a way that the recess (7) is arranged in the lower region facing away from the withdrawal direction (F) and / or in the lower half (9) of the opening (2) and / or the edge (3) facing away from the withdrawal direction (F), in particular in the lower apex (10) and / or in the lowest point and / or region of the opening (2) and / or the edge (3).

4. Method according to one of the preceding claims, characterized in that the recess (7) in plan view of the opening (2) and / or edge (3) is at least substantially circular segment-shaped, arc-shaped, triangular and / or rectangular.

5. Method according to one of the preceding claims, characterized in that the recess (7) has been introduced before hot-dip galvanizing by drilling and / or milling and / or a thermal or non-thermal cutting process, such as laser, autogenous, plasma or water jet cutting.

6. Method according to one of the preceding claims, characterized in that the opening (2) and / or the recess (7) is designed as an opening and / or as a drainage opening in the component (1) and / or that the opening (2) is circular and / or elliptical in cross section and / or as an elongated hole.

7. Method according to one of the preceding claims, characterized in that the opening (2) before the introduction of the recess (7) has a clear diameter (11) of at least 5 mm, preferably at least 8 mm, more preferably at least 10 mm, and / or that the opening (2) has a maximum clear diameter (11) of 50 cm, preferably 25 cm, more preferably 10 cm.

8. Method according to one of the preceding claims, characterized in that, in particular for galvanizing according to EN ISO 1461 (as of March 2023), the ratio of the radius (12) of the opening (2) to the volume of the recess (7), in particular with a, preferably maximum, component thickness (13) up to and including 3 mm, with a diameter (11) of the opening (2) less than or equal to 10 mm less than 30 cm / cm 3 , preferably less than 20 cm / cm 3 , especially between 1 to 20 cm / cm 3 , and / or larger than 1 cm / cm 3 , preferably greater than 5 cm / cm 3, and / or with a diameter (11 ) of the opening (2) greater than 10 mm less than 90 cm / cm 3 , preferably less than 50 cm / cm 3 , especially between 1 to 40 cm / cm 3 , amounts.

9. Method according to one of the preceding claims, characterized in that, in particular for galvanizing according to EN ISO 1461 (as of March 2023), the ratio of the radius (12) of the opening (2) to the volume of the recess (7) with a, preferably maximum, component thickness (13) greater than 3 mm with a diameter (11) of the opening (2) less than or equal to 10 mm less than 50 cm / cm 3 , preferably less than 40 cm / cm 3 , especially between 1 to 30 cm / cm 3 , and / or with a diameter (11 ) of the opening (2) greater than 10 mm less than 100 cm / cm 3 , preferably less than 80 cm / cm 3 , especially between 1 and 70 cm / cm 3 , amounts.

10. Method according to one of the preceding claims, characterized in that in a thin-layer galvanizing according to DIN 50997 (as of March 2023), the ratio of the radius (12) of the opening (2) to the volume of the recess (7) with a diameter (11) of the opening (2) less than or equal to 10 mm for a, preferably maximum, component thickness (13) less than or equal to 3 mm less than 20 cm / cm 3 , preferably less than 15 cm / cm 3 , especially between 1 to 20 cm / cm 3 , and / or with a diameter (11 ) of the opening (2) greater than 10 mm less than 100 cm / cm 3 , preferably less than 70 cm / cm 3 , especially between 1 to 60 cm / cm 3 , amounts.

11. Method according to one of the preceding claims, characterized in that in a thin-layer galvanizing according to DIN 50997 (as of March 2023), the ratio of the radius (12) of the opening (2) to the volume of the recess (7) with a diameter (11) of the opening (2) less than or equal to 10 mm for a, preferably maximum, component thickness (13) greater than 3 mm less than 30 cm / cm 3 , preferably less than 20 cm / cm 3 , especially between 1 to 30 cm / cm 3 , and / or with a diameter (11) of the opening (2) greater than 10 mm less than 100 cm / cm 3 , preferably less than 80 cm / cm 3 , especially between 1 and 70 cm / cm 3 , amounts.

12. Method according to one of the preceding claims, characterized in that the hot-dip galvanizing layer is applied to the component (1) with a layer thickness (14) in the range from 3 pm to 400 pm, preferably 4 to 100 pm.

13. Method according to one of the preceding claims, characterized in that the component (1) is pulled out of the galvanizing bath (6) at a speed of 0.05 to 1.5 m / min, preferably 0.1 to 0.8 m / min.

14. Method according to one of the preceding claims, characterized in that the following process steps are provided before carrying out the hot-dip galvanizing, preferably in the order listed below: (a) degreasing treatment of the component (1), in particular in at least one degreasing bath; then (b) if necessary, rinsing the component (1) degreased in process step (a); then (c) pickling treatment of the component (1) degreased in process step (a) and optionally rinsed in process step (b), in particular in at least one pickling bath; then (d) if necessary, rinsing the component (1) pickled in process step (c); then (e) flux treatment of the component (1) pickled in process step (c) and optionally rinsed in process step (d) by means of a flux composition in a flux bath, (f) if necessary, drying treatment of the component (1) subjected to the flux treatment in process step (e), wherein process steps (a) to (f) are optionally carried out several times each, if required.

15. Hot-dip galvanized component (1), wherein the component (1) has been subjected to a process according to one of claims 1 to 14.

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