HOT-DIP GALVANIZATION SYSTEM AND HOT-DIP GALVANIZATION METHOD, IN PARTICULAR FOR MASS PRODUCTION

Abstract

The invention relates to a system and a method for the hot-dip galvanization of motor-vehicle components, preferably for mass-production hot-dip galvanization of a plurality of identical or similar motor-vehicle components, in particular in batches, preferably for batch galvanization, especially preferably for high-precision hot-dip galvanization.

Claims

1-13. (canceled)

14. A hot-dip galvanizing system for the large-scale hot-dip galvanization of a multiplicity of identical or similar automotive components, wherein the system comprises a hot-dip galvanizing device for hot-dip galvanizing the automotive components: a galvanizing bath comprising a zinc/aluminum alloy in a liquid molten form, a conveying device comprising at least one goods carrier for conveying a group of automotive components to be fastened on the goods carrier, and a flux application device for the application of a flux to the surface of the automotive components, wherein the system further comprising a handling device for supplying, immersing and emersing a separated and singled out automotive component to, into and from the galvanizing bath comprising the zinc/aluminum alloy in a liquid molten form, wherein the handling device comprises at least one handling means disposed between the flux application device and the hot-dip galvanizing device, wherein the handling means is configured or equipped such that it separates and withdraws a single of the automotive components from the group of automotive components and subsequently supplies it to the hot-dip galvanizing device for individual hot-dip galvanizing of the separated and singled out the automotive components and wherein the handling means is configured or equipped such that a separated and singled out automotive component is immersed into an immersion region of the galvanizing bath, then moved from the immersion region to an adjacent emersion region and then emersed in the emersion region.

15. The system as claimed in claim 14, wherein the system further comprises at least one of a degreasing device for degreasing the automotive components and a surface-treating device for the chemical, mechanical or chemical and mechanical surface-treatment of the automotive components.

16. The system as claimed in claim 15, wherein the separation and singling of the automotive components from the goods carrier via the handling device is provided subsequent to one of the degreasing, the surface-treatment and the flux application.

17. The system as claimed in claim 14, wherein the handling means is configured such that all automotive components separated and singled out from the goods carrier are guided in an identical way through the galvanizing bath.

18. The system as claimed in claim 14, wherein the system further comprises a stripping device subsequent to the emersion region of the galvanizing bath.

19. The system as claimed in claim 14, wherein the handling means is configured such that all automotive components separated and singled out from the goods carrier are moved in an identical way after emersion such that drip edges and streaks are removed.

20. The system as claimed in claim 14, wherein the system further comprises at least one of (i) a rinsing device, (ii) a drying device provided subsequent to the flux application device, (iii) a cooling device provided subsequent to the hot-dip galvanizing device, and (iv) an after-treating device provided subsequent to the hot-dip galvanizing device and to the optional cooling device.

21. A hot-dip galvanizing method for the large-scale hot-dip galvanization of a multiplicity of identical or similar automotive components, using a zinc/aluminum alloy in a liquid molten form, wherein the method comprises the following steps: the automotive components, in a grouped state together with a plurality of further automotive components, are fastened on an goods carrier of a conveying device, wherein the automotive components are provided, on their surface, with a flux and wherein the automotive components are then subjected to hot-dip galvanizing in a galvanizing bath comprising a zinc/aluminum alloy in a liquid molten form, wherein, for hot-dip galvanizing, the automotive components are supplied, in a separated and singled out state, to the galvanizing bath, are then immersed therein and are subsequently emerged therefrom, wherein hot-dip galvanizing is carried out in the separated and singled out state of each of the automotive components and wherein each single automotive component of the plurality of grouped automotive components, in a separated and singled out state, is immersed into an immersion region of the galvanizing bath, then moved from the immersion region to an adjacent emersion region and subsequently emerged in the emersion region.

22. The method as claimed in claim 21, wherein the automotive components, prior to the hot-dip galvanizing, are subjected to at least one of a degreasing treatment and a chemical, mechanical or chemical and mechanical surface-treatment.

23. The method as claimed in claim 22, wherein the automotive components, after the degreasing and surface-treatment, are rinsed and wherein the automotive components, after the hot-dip galvanizing, are cooled.

24. The method as claimed in claim 21, wherein a single automotive component, in the separated and singled out state, is moved from the immersion region to the emersion region only after the end of the reaction time of the flux with the zinc/aluminum alloy.

25. The method as claimed in claim 21, wherein all automotive components, in the separated and singled out state, are each guided in an identical way through the galvanizing bath.

26. The method as claimed in claim 21, wherein all automotive components, in the separated and singled out state, are each guided, after emersion, in an identical way past a stripping device for stripping off the liquid zinc/aluminum alloy.

27. The method as claimed in claim 21, wherein all automotive components, in the separated and singled out state, are each moved in an identical way after emersion such that drip edges and streaks of the liquid zinc/aluminum alloy are removed.

28. The method as claimed in claim 21, wherein all method steps or operations subsequent to the hot-dip galvanizing are carried out each in the separated and singled out state of the automotive component.

29. The method as claimed in claim 21, wherein the galvanizing bath comprises zinc and aluminum in a zinc/aluminum weight ratio in the range of from 55-99.999: 0.001-45.

30. The method as claimed in claim 21, wherein the method is performed using a system according to claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 shows a schematic sequence of the individual stages of the method of the invention,

[0037] FIG. 2 shows a schematic representation of a system of the invention and of the sequence of the method of the invention in one method step,

[0038] FIG. 3 shows a schematic representation of a system of the invention and of the sequence of the method of the invention in a further method step, and

[0039] FIG. 4 shows a schematic representation of a system of the invention and of the sequence of the method of the invention in a further method step.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The invention relates to a system for the hot dip galvanizing of automotive components, preferably for the large-scale (high-volume) hot dip galvanizing of a multiplicity of identical or similar automotive components, especially in discontinuous operation, preferably for batch galvanizing, in particular for high-precision hot dip galvanizing, having a hot dip galvanizing device for hot dip galvanizing the automotive components, where the hot dip galvanizing device comprises a galvanizing bath containing a zinc/aluminum alloy in liquid melt form.

[0041] In accordance with the invention, in a system of the aforesaid kind, the object of the invention is achieved in that a handling device is provided for the preferably automated supplying, immersing, and emersing (removing) of a separated (isolated) and singled out component to, into, and from the galvanizing bath, comprising the zinc/aluminum alloy in liquid melt form, of the hot dip galvanizing device.

[0042] In accordance with the method, the invention accordingly concerns a method for hot dip galvanizing automotive acomponents, preferably for large-scale (high-volume) galvanizing a multiplicity of identical or similar automotive components, especially in discontinuous operation, preferably for batch galvanizing are subjected to hot dip galvanizing in a galvanizing bath containing a zinc/aluminum alloy in liquid melt form.

[0043] In accordance with the invention, in the aforesaid method, during the hot dip galvanizing, the automotive components in the separated and singled out state, preferably automated, are supplied to the galvanizing bath, immersed therein, and subsequently emersed (removed) therefrom.

[0044] As a result, the invention differs from the prior art in that the automotive components to be galvanized as part of a large-scale hot dip galvanizing are supplied in the separated and singled out state to the galvanizing bath of the zinc/aluminum alloy. This measure, which at first glance appears to be uneconomic and entailing operational delay in a large-scale production process, in comparison to a grouped or simultaneous galvanizing of a plurality of automotive components, has surprisingly proven particularly preferable for the production of automotive components hot dip galvanized with high precision.

[0045] On the basis of economic aspects, the solution according to the invention was initially shunned, since in the prior-art batch galvanizing operation, depending on size and weight, automotive components numbering in some cases several hundred are suspended from a goods carrier and galvanized simultaneously and jointly. Separating (isolating) and singling the automotive components from the goods carrier ahead of galvanizing, and galvanizing them in the separated and singled out state, in the first instance, therefore, causes a considerable increase in the time duration of the galvanizing operation itself.

[0046] However, in connection with the invention it has been recognized that specifically in the case of automotive components, in particular those made of high-strength and ultra high-strength steels, which are temperature-sensitive, there is a need for targeted and optimized handling during the actual galvanizing operation. In the case of individual galvanizing in connection with the system of the invention and/or the method of the invention, it is readily possible to ensure that the automotive components are each subject to identical operating parameters. For sprung steels or for chassis and bodywork components consisting of high-strength and ultra high-strength steels particularly, such as for example press-hardened forming parts, this plays a considerable part. Through the separation (isolation) and singling of the automotive components for galvanizing it is possible for the reaction times between the steel and the zinc melt to be the same in each case. The ultimate result of this is a constant zinc layer thickness. Moreover, as a result of the galvanization, the characteristic values of the automotive components are influenced identically, since the invention ensures that the automotive components are each exposed to identical operating parameters.

[0047] A further, considerable advantage of the invention comes about from the fact that with the separation (isolation) and singling according to the invention, each automotive component can be manipulated and treated precisely, by means, for example, of specific rotational and steering movements of the automotive component during extraction from the melt. As a result, the afterworking cost and complexity can be reduced significantly or even in some cases avoided entirely. The invention affords the possibility, moreover, that zinc ash accumulations can be significantly reduced and in some cases even avoided. This is possible because the process according to the invention can be controlled in such a way that an automotive component for galvanizing, in the separated and singled out state, after having been immersed, is moved away from the immersion site and moved toward a site remote from the immersion site. This is followed by emersion. While the zinc ash rises in the region of the immersion site, and is located on the surface of the immersion site, there are few residues of zinc ash, or none, at the emersion site. As a result of this specific technique, zinc ash accumulations can be considerably reduced or even avoided.

[0048] In connection with the present invention it has been determined that, taking account of the afterwork sometimes no longer necessary in the case of the invention, the overall production time associated with the manufacture of galvanized automotive components can in fact be reduced relative to the prior art, and hence that the invention, ultimately, affords a higher productivity, more particularly because the manual afterworking in the prior art is very time-consuming.

[0049] A further system-based advantage associated with separated and singled out galvanizing is that the galvanizing vessel required need not be broad and deep, but instead only narrow. This reduces the surface area of the galvanizing bath, which in that way can be shielded more effectively, allowing a critical reduction in the radiation losses.

[0050] All in all, by means of the invention with the separated and singled out galvanizing, resulting automotive components have higher quality and cleanliness on the surface; the automotive components as such have each been subjected to identical operating conditions and therefore possess the same characteristic component values. From an economic standpoint as well, the invention affords economic advantages over the prior art, since the production time can be reduced by up to 20%, taking account of the afterworking which is no longer necessary or in some cases is greatly limited.

[0051] Device-related, the system of the invention, in addition to the hot dip galvanizing device and the handling device, preferably comprises a series of further devices upstream and/or downstream of the actual hot dip galvanizing or hot dip galvanizing device, respectively. The system of the invention preferably comprises a conveying device and/or a degreasing device and/or a surface working device and/or a flux application device and/or at least one rinsing device and/or a drying device and/or a quenching device and/or an aftertreating device. The aforesaid devices will be addressed in detail below.

[0052] The conveying device comprises at least one goods carrier for conveying or transporting an automotive component or group of automotive components to be fastened on the goods carrier. Moreover, the conveying device may also comprise a plurality of conveying means with identically or differently configured goods carriers on each of which it is possible to fasten either a separated and singled out automotive component or else a group of automotive components. The conveying device is therefore provided for conveying a separated and singled out automotive component and/or a group of automotive components to the individual aforesaid devices, particularly the degreasing device and/or surface treating device, more particular pickling device, and/or the flux application device and/or the drying device. Furthermore, the conveying device may also be provided and configured for conveying or transporting automotive components in the separated and singled out or grouped state to the cooling device and/or aftertreating device.

[0053] Furthermore, the system of the invention preferably comprises a degreasing device for degreasing the automotive components. The degreasing device may in principle be decentralized, and hence need not necessarily be located in the same compartment or building as the other aforesaid devices. Nevertheless, a decentralized degreasing device also belongs to the system of the invention. In the degreasing device, the automotive components can be degreased as a group, i.e., in the grouped state, or else in the separated and singled out state. The transport of the automotive components to the degreasing device and away from it is accomplished preferably via the aforesaid conveying device.

[0054] Furthermore, the system of the invention preferably comprises a surface working device for the chemical, more particularly wet-chemical, and/or mechanical surface treatment of the automotive components. The surface treating device is configured more particularly as a pickling device for pickling the surface of the automotive components. Pickling of the automotive components may take place in the separated and singled out or in the grouped state. The transport of the automotive components in the separated and singled out or grouped state to the surface treating device and away from it is accomplished preferably via the aforesaid conveying device.

[0055] The system of the invention, moreover, preferably comprises a flux application device for the application of flux to the surface of the automotive components. Application of flux to the automotive components may be carried out in the separated and singled out state of the automotive components or else in the grouped state with a plurality of further automotive components at the same time. The transport or conveying of the automotive components, whether in the separated and singled out state or else in the grouped state, to the flux application device and away from it is accomplished preferably via the conveying device, in which case the automotive components are fastenedseparately and singled out or groupedon the goods carrier of the conveying device.

[0056] Furthermore, the system of the invention preferably comprises a drying device subsequent to the flux application device, so that the flux, following application to the surface of the automotive components, is dried. This prevents liquid being entrained from the flux solution into the galvanizing bath.

[0057] In particular, the system of the invention is configured such that the aforesaid devices are disposed in the sequence identified below in relation to the operational direction: [0058] the optionally decentralized degreasing device for degreasing the automotive components in the separated and singled out or grouped state of the automotive components, [0059] the surface treating device, more particularly pickling device, for the chemical, more particularly wet-chemical, and/or mechanical surface treatment of the automotive components, preferably for the pickling of the surface of the automotive components in the separated and singled out or grouped state of the automotive components, [0060] the flux application device for application of flux to the surface of the automotive components in the separated and singled out or grouped state of the automotive components, [0061] the drying device for drying the flux applied to the surface of the automotive components, and [0062] the hot dip galvanizing device for hot dip galvanizing the automotive components in the separated and singled out state.

[0063] In the case of the invention it is possible, after an initial grouping of the components via the and/or on the goods carrier, to carry out separation and singling after the surface treatment or after the application of flux.

[0064] Device-related, the separation and singling of the components from the goods carrier via the handling device is then provided subsequent to the degreasing or subsequent to the surface treatment, more particularly pickling, or subsequent to the application of flux.

[0065] In trials conducted, it was found, from the standpoint of costs versus benefits, that it is most useful for the components to be separated and singled out from the goods carrier after the application of flux, and hence for the handling device to be located between the hot dip galvanizing device and the flux application device. With this embodiment of the invention, the degreasing, the surface treatment, and the application of the flux take place in the grouped state of the components, with only the galvanizing being performed in the separated and singled out state.

[0066] In accordance with the apparatus, for a preferred embodiment of the invention, provision is made for the handling device to have at least one handling means disposed between the flux application device and the hot dip galvanizing device. In that case this handling means is preferably configured such that it takes one of the automotive components from the group of automotive components and subsequently supplies said component to the hot dip galvanizing device for individual hot dip galvanizing. The handling means here may take off or withdraw the automotive component directly from the goods carrier, or else may take the automotive component from the group of automotive components already deposited by the goods carrier. Here it is understood that in principle it is also possible for there to be more than one handling means, in other words that a plurality of separated and singled out automotive components are hot dip galvanized simultaneously in the respectively separated and singled out state. In this connection, then, it is also understood that at least the galvanizing operation on the separated and singled out components is carried out identically, even if automotive components from different handling means are guided simultaneously or with a time stagger and independently of one another through the hot dip galvanizing device or the galvanizing bath.

[0067] In the case of an alternative embodiment of the system of the invention and of the associated method, the handling means, while being configured so as to take one of the automotive components from the group of automotive components, nevertheless does not supply the automotive component it has taken directly to the galvanizing stage. The handling means may transfer the automotive component, taken from the group of automotive components, tofor examplea conveying system belonging to the handling device, for example an goods carrier or a monorail track, via which the separated and singled out automotive component is then galvanized in the separated and singled out state. Ultimately, in terms of system, in this embodiment the handling device comprises at least two handling means, namely a first handling means that performs the separation and singling of the automotive components from the group of automotive components, and at least one second handling means, in the manner of a conveying system, for example, which then guides the separated and singled out automotive component through the galvanizing bath.

[0068] In the case of a further, preferred embodiment of the invention, the handling means is configured such that a separated and singled out automotive component is immersed into an immersion region of the bath, then moved from the immersion region to an adjacent emersion region, and is subsequently emersed in the emersion region. As already observed above, zinc ash occurs at the surface of the immersion region, as a reaction product of the flux with the zinc melt. By moving the automotive component immersed into the zinc melt from the immersion region toward the emersion region, there is little or no zinc ash at the surface of the emersion region. In this way, the surface of the emersed galvanized automotive component remains free or at least substantially free from zinc ash accumulations. Here it is understood that the immersion region is adjacent to the emersion region, in other words relating to regions of the galvanizing bath that are spatially separate from one another and in particular do not overlap.

[0069] In the case of one preferred embodiment of the aforesaid concept of the invention, moreover, provision is made for the automotive component after immersion to remain in the immersion region of the galvanizing bath at least until the reaction time between the automotive component surface and the zinc/aluminum alloy of the galvanizing bath is at an end. This ensures that the zinc ash, which moves upward within the melt, spreads out only on the surface of the immersion region. The automotive component can be moved subsequently into the emersion region, which is substantially free from zinc ash, and can be emersed there.

[0070] In trials conducted in connection with the invention, it was found that it is useful if the automotive component spends between 20% to 80%, preferably at least 50%. of the galvanizing duration in the region of the immersion region, and only thereafter is moved into the emersion region. From a technical system standpoint, this means that the handling device and/or the one or more associated handling means are, by corresponding control, designed and, as and when necessary, harmonized with one another in such a way that the aforesaid method sequence can be carried out without problems.

[0071] Particularly in the case of automotive components made from temperature-sensitive steels, and in the case of customer-specific requirements for automotive components with maximally identical product properties, provision is made, in accordance with the system and the method, for the handling means or the handling device to be configured such that all automotive components in the separated and singled out state are guided in an identical way, more particularly with identical movement, in identical arrangement and/or with identical time, through the galvanizing bath. Ultimately this can easily be achieved by corresponding control of the handling device and/or of the at least one assigned handling means. As a result of the identical handling, identical automotive components, in other words automotive components consisting in each case of the same material and having in each case the same shape, have product properties that are identical in each case. These properties include not only the same zinc layer thicknesses but also identical characteristic values of the galvanized automotive components, since the latter have each been guided identically through the galvanizing bath.

[0072] A further advantage afforded by the invention as a result of the separation and singling, in accordance with the system and the method, is that zinc bumps can more easily be avoided. Provided for this purpose, in accordance with the system, is a stripping device subsequent to the emersion region, and in the case of one preferred embodiment of this concept of the invention, the handling means or the handling device is configured such that after emersion, all automotive components in the separated and singled out state are guided past the stripping device for the stripping of liquid zinc in an identical way. In the case of an alternative embodiment, but one which can also be realized in combination with the stripping device, provision is made for all automotive components in the separated and singled out state to be moved identically after emersion in such a way that drip edges and streaks of liquid zinc are removed, more particularly drip off and/or are spread uniformly over the automotive component surfaces. Through the invention, consequently, it is therefore possible for each individual automotive component to be guided in a defined way not only through the galvanizing bath but also to be guided either in a defined positioning, as for example an inclined attitude of the automotive component, and moved past one or more strippers, and/or for the automotive component to be moved, through specific rotational and/or steering movements after emersion, in such a way that zinc bumps are at least substantially avoided.

[0073] Moreover, the system of the invention preferably comprises a plurality of rinsing devices, optionally with a plurality of rinsing stages. Hence there is preferably a rinsing device provided subsequent to the degreasing device and/or subsequent to the surface treating device. Through the individual rinsing devices it is ultimately ensured that the degreasing agents used in the degreasing device and/or the surface treatment agents used in the surface treating device are not entrained into the subsequent method stage.

[0074] In the case of one preferred development of the invention, the hot dip galvanizing device is followed by a cooling device, more particularly a quenching device, at which the automotive component after the hot dip galvanizing is cooled and/or quenched, respectively.

[0075] Furthermore, in particular subsequent to the cooling device, there may be an after-treating device provided. The aftertreating device is used in particular for passivation, sealing or coloring of the galvanized automotive components. Alternatively, the aftertreating stage may encompass for example afterworking, more particularly the removal of impurities and/or the removal of zinc bumps. As observed above, however, the afterworking step in the case of the invention is reduced considerably relative to the method known in the prior art, and in some cases, indeed, is superfluous.

[0076] Furthermore, in the case of the invention, in accordance with the system and/or the method, the galvanizing bath comprises zinc and aluminum in a zinc/aluminum weight ratio in the range of 55-99.999:0.001-45, preferably 55-99.97:0.03-45, more particularly 60-98:2-40, preferably 70-96:4-30. Alternatively or additionally, the galvanizing bath has the composition below, wherein the weight specifications are based on the galvanizing bath and all of the constituents of the composition in total result in 100 wt %: [0077] (i) zinc, more particularly in amounts in the range from 55 to 99.999 wt %, preferably 60 to 98 wt %, [0078] (ii) aluminum, more particularly in amounts in the range from 0.1 to 45 wt %, preferably 2 to 40 wt %, [0079] (iii) optionally silicon, more particularly in amounts in the range from 0.0001 to 5 wt %, preferably 0.001 to 2 wt %, [0080] (iv) optionally at least one further ingredient and/or optionally at least one impurity, more particularly from the group of the alkali metals such as sodium and/or potassium, alkaline earth metals such as calcium and/or magnesium and/or heavy metals such as cadmium, lead, antimony, bismuth, more particularly in total amounts in the range from 0.0001 to 10 wt %, preferably 0.001 to 5 wt %.

[0081] In connection with trials conducted it was found that in the case of zinc baths having the composition indicated above, it is possible to achieve very thin and very homogeneous coatings on the automotive component, these coatings also satisfying the exacting requirements with regard to automotive component quality in automotive engineering.

[0082] Alternatively or additionally, the flux has the following composition, where the weight specifications are based on the flux and all of the constituents of the composition result in total in 100 wt %: [0083] (i) zinc chloride (ZnCl.sub.2), more particularly in amounts in the range from 50 to 95 wt %, preferably 58 to 80 wt %; [0084] (ii) ammonium chloride (NH.sub.4Cl), more particularly in amounts in the range from 5 to 50 wt %, preferably 7 to 42 wt %; [0085] (iii) optionally at least one alkali metal salt and/or alkaline earth metal salt, preferably sodium chloride and/or potassium chloride, more particularly in total amounts in the range from 1 to 30 wt %, preferably 2 to 20 wt %; [0086] (iv) optionally at least one metal chloride, preferably heavy metal chloride, more preferably selected from the group of nickel chloride (NiCl.sub.2), manganese chloride (MnCl.sub.2), lead chloride (PbCl.sub.2), cobalt chloride (CoCl.sub.2), tin chloride (SnCl.sub.2), antimony chloride (SbCl.sub.3) and/or bismuth chloride (BiCl.sub.3), more particularly in total amounts in the range from 0.0001 to 20 wt %, preferably 0.001 to 10 wt %; [0087] (v) optionally at least one further additive, preferably wetting agent and/or surfactant, more particularly in amounts in the range from 0.001 to 10 wt %, preferably 0.01 to 5 wt %.

[0088] Alternatively or additionally, the flux application device, more particularly the flux bath of the flux application device, contains the flux in preferably aqueous solution, more particularly in amounts and/or in concentrations of the flux in the range from 200 to 700 g/l, more particularly 350 to 550 g/l, preferably 500 to 550 g/l, and/or the flux is used as a preferably aqueous solution, more particularly with amounts and/or concentrations of the flux in the range from 200 to 700 g/I, more particularly 350 to 550 g/I, preferably 500 to 550 g/I.

[0089] In trials with a flux in the aforesaid composition and/or concentration especially in conjunction with the above-described zinc/aluminum alloy, it was found that very low layer thicknesses, in particular of less than 20 m, are obtained, this being associated with a low weight and reduced costs. Especially in the automotive sector, these are essential criteria.

[0090] Further features, advantages, and possible applications of the present invention are apparent from the description hereinafter of exemplary embodiments on the basis of the drawing, and from the drawing itself. Here, all features described and/or depicted, on their own or in any desired combination, constitute the subject matter of the present invention, irrespective of their subsumption in the claims or their dependency reference.

[0091] In the drawing: [0092] FIG. 1 shows a schematic sequence of the individual stages of the method of the invention, [0093] FIG. 2 shows a schematic representation of a system of the invention and of the sequence of the method of the invention in one method step, [0094] FIG. 3 shows a schematic representation of a system of the invention and of the sequence of the method of the invention in a further method step, and [0095] FIG. 4 shows a schematic representation of a system of the invention and of the sequence of the method of the invention in a further method step.

[0096] In FIG. 1 there is a schematic representation of a sequence of the method of the invention in a system 1 of the invention. In this connection it should be pointed out that the sequence scheme shown is one method possible according to the invention, but individual method steps may also be omitted or provided in a different order from that represented and subsequently described. Further method steps may be provided as well. In any case, not all of the method stages need in principle be provided in one centralized system 1. The decentralized realization of individual method stages is also possible.

[0097] In the sequence scheme represented in FIG. 1, stage A identifies the supplying and the deposition of automotive components 2 for galvanization at a connection point. In the present example, the automotive components 2 have already been mechanically surface-treated, more particularly sandblasted. This is a possibility but not a necessity.

[0098] In stage B, the automotive components 2 are joined with a goods carrier 7 of a conveying device 3 to form a group of automotive components 2. In some cases, the automotive components 2 are also joined to one another and hence only indirectly to the goods carrier 7. It is also possible for the goods carrier 7 to comprise a basket, a rack or the like into which the automotive components 2 are placed.

[0099] In stage C, the automotive components 2 are degreased. This is done using alkaline or acidic degreasing agents 11, in order to eliminate residues of greases and oils on the components 2.

[0100] In stage D, the degreased automotive components 2 are rinsed, in particular with water. This washes off the residues of degreasing agent 11 from the automotive components 2.

[0101] In the method step E, the surfaces of the automotive components 2 undergo pickling, i.e. wet-chemical surface treatment. Pickling takes place customarily in dilute hydrochloric acid.

[0102] Stage E is followed by stage F, which is again a rinsing stage, in particular with water, in order to prevent the pickling agent being carried into the downstream method stages.

[0103] Then the correspondingly cleaned and pickled automotive components 2still assembled as a group on the goods carrier 4for galvanizing are fluxed, i.e. subjected to a flux treatment. The flux treatment in stage H likewise takes place presently in an aqueous flux solution. After a sufficient residence time in the flux 23, the to goods carrier 7 with the automotive component 2 is passed on for drying in stage I in order to generate a solid flux film on the surface of the automotive components 2 and to remove adhering water.

[0104] In process step J, the automotive components 2, previously assembled as a group are separated and singled out, in other words taken from the group, and then further treated in the separated and singled out state. Separation and singling here may be accomplished by removing the automotive components 2 individually from the goods carrier 7 or else by the goods carrier 7 first depositing the group of automotive components 2 and then the automotive components 2 being taken individually from the group.

[0105] Following the separation and singling in step J, the automotive components 2 are then hot dip galvanized in the stage K. For this purpose, the automotive components 2 each individually are immersed into a galvanizing bath 28 and, after a specified residence time, emersed (removed) again.

[0106] The galvanizing in method step K is followed by dropping of the still liquid zinc in stage L. The dropping is for example accomplished by moving the automotive component 2, galvanized in the separated and singled out condition, along one or more strippers of a stripping device, or by specified pivoting and rotating movements of the automotive component 2, leading either to the dripping off or else to the uniform spreading of the zinc on the automotive component surface.

[0107] The galvanized automotive component is subsequently quenched in step M.

[0108] The quenching in method step M is followed by an aftertreatment in stage N, this aftertreatment possibly, for example, being a passivation, sealing, or organic or inorganic coating of the galvanized automotive component 2. The aftertreatment, however, also includes any afterwork possibly to be performed on the automotive component 2.

[0109] It should expressly be pointed out that in the case of exemplary embodiments not shown it is readily possible for the above-described method also to be carried out in such a way that a separated and singled out automotive component 2 or a small group in the form of a few automotive components, e.g., two or three automotive components, runs through the entire operation in the separated and singled out state, without any grouping or grouped treatment of automotive components during the operation. Hence it is possible for the automotive component 2 at the start of the method to be picked up by the conveying device 3 and guided through the individual method stages until it is taken over by a handling device 31 and supplied to the hot dip galvanizing stage. After the hot dip galvanizing, the galvanized automotive component can be supplied by the handling device 31 or else again by the conveying device 3 to the cooling device 29 and/or to the aftertreating device 30.

[0110] An alternative possibility is that, at the start of the overall operational sequence, a group of automotive components 2 is first transported via the conveying device 3 and separated and singled out after the degreasing and associated rinsing and/or after the surface treating and associated rinsing, after which the automotive components 2 in the separated and singled out state are then guided through the ongoing operation at least up to and including the hot dip galvanizing. Subsequently the automotive component 2, then galvanized, can be worked on further in the separated and singled out state or else grouped again and worked on further in the grouped state.

[0111] In FIGS. 2 to 4, an exemplary embodiment of a system 1 of the invention is represented schematically.

[0112] In FIGS. 2 to 4, in a schematic representation, one embodiment is depicted of a system 1 of the invention for the hot dip galvanizing of automotive components 2. The system 1 is intended for hot dip galvanizing a multiplicity of identical automotive components 2 in discontinuous operation, referred to as batch galvanizing. In particular, the system 1 is designed and suitable for the hot dip galvanizing of automotive components 2 in large-scale production. Large-scale galvanizing refers to galvanizing wherein more than 100, more particularly more than 1000, and preferably more than 10 000 identical automotive components 2 are galvanized in succession without interim galvanizing of automotive components 2 of different shape and size.

[0113] The system 1 comprises a conveying device 3 for conveying and/or for simultaneously transporting a plurality of automotive components 2 which are assembled to form a group. The conveying device 3 presently comprises a crane track with a rail guide 4, on which a trolley 5 with a lifting mechanism can be driven. A goods carrier 7 is connected to the trolley 5 via a lifting cable 6. The purpose of the goods carrier 7 is to hold and fasten the automotive components 2. The automotive components 2 are customarily joined to the goods carrier 7 at a connection point 8 in the system, at which the automotive components 2 are grouped for joining to the goods carrier 7.

[0114] The connection point 8 is followed by a degreasing device 9. The degreasing device 9 comprises a degreasing tank 10 in which there is a degreasing agent 11. The degreasing agent 11 may be acidic or basic. The degreasing device 9 is followed by a rinsing device 12, comprising a rinsing tank 13 with rinsing agent 14 located therein. The rinsing agent 14 presently is water. After the rinsing device 12, in other words downstream thereof in the process direction, is a surface treatment device configured as a pickling device 15 for the wet-chemical surface treatment of the automotive components 2. The pickling device 15 comprises pickling tank 16 with a pickling agent 17 located therein. The pickling agent 17, presently, is diluted hydrochloric acid.

[0115] Subsequent to the pickling device 15 there is, again, a rinsing device, 18, with rinsing tank 19 and rinsing agent 20 located therein. The rinsing agent 20 is again water.

[0116] Downstream of the rinsing device 18 in the process direction is a flux application device 21 comprising a flux tank 22 and flux 23 located therein. In a preferred embodiment, the flux comprises zinc chloride (ZnCl.sub.2) in an amount of 58 to 80 wt % and also ammonium chloride (NH.sub.4Cl) in the amount of 7 to 42 wt %. Furthermore, in a small amount, there may optionally be alkali metal salts and/or alkaline earth metal salts and also, optionally, in a comparatively further reduced amount, a heavy metal chloride. Additionally there may optionally be a wetting agent in small amounts. It is understood that the aforesaid weight figures are based on the flux 23 and make up 100 wt % in the sum total of all constituents of the composition. Moreover, the flux 23 is present in aqueous solution, specifically at a concentration in the range from 500 to 550 g/l.

[0117] It should be pointed out that the aforesaid devices 9, 12, 15, 18, and 21 may in principle each have a plurality of tanks. These individual tanks, but also the tanks described previously, are disposed one after another in cascade fashion.

[0118] The flux application device 21 is followed by a drying device 24, for removal of adhering water from the film of flux located on the surface of the automotive components 2.

[0119] Furthermore, the system 1 comprises a hot dip galvanizing device 25, in which the automotive components 2 are hot dip galvanized. The hot dip galvanizing device 25 comprises a galvanizing tank 26, optionally with a housing 27 provided at the top. In the galvanizing tank 26 there is a galvanizing bath 28 comprising a zinc/aluminum alloy. Specifically, the galvanizing bath comprises 60 to 98 wt % of zinc and 2 to 40 wt % of aluminum. Furthermore, optionally, small amounts of silicon and, optionally in further-reduced proportions, a small amount of alkali metals and/or alkaline earth metals and also heavy metals are provided. It is understood here that the aforesaid weight figures are based on the galvanizing bath 28 and in total make up 100 wt % of all constituents of the composition.

[0120] Located after the hot dip galvanizing device 25 in the process direction is a cooling device 29 which is provided for quenching the automotive components 2 after the hot dip galvanizing. Finally, after the cooling device 29, an aftertreating device 30 is provided, in which the hot dip galvanized automotive components 2 can be aftertreated and/or afterworked.

[0121] Located between the drying device 24 and the hot dip galvanizing device 25 is a handling device 31, which is provided for the automated supplying, immersion, and emersion of an automotive component 2, separated and singled out from the goods carrier 7, into and from the galvanizing bath 28 of the hot dip galvanizing device 25. In the exemplary embodiment shown, the handling device 31 comprises a handling means 32 which is provided for the handling of the automotive components 2, specifically for removing an automotive component 2 from the group of automotive components 2 and/or for taking off the grouped automotive components 2 from the goods carrier 7, and also for the supplying, immersing, and emersing (removing) of the separated and singled out automotive component 2 into and from the galvanizing bath 28.

[0122] For the separation and singling, there is a transfer point 33 located between the handling means 32 and the drying device 24, and at this point 33 the automotive components 2 either are put down or else, in particular in the hanging condition, can be removed and/or can be separated and singled out from the goods carrier 7 and hence from the group. For this purpose, the handling means 32 is preferably configured such that it can be moved in the direction of and away from the transfer point 33 and/or can be moved in the direction of and away from the galvanizing device 25.

[0123] Moreover, the handling means 32 is configured such that it moves an automotive component 2, immersed separately into the galvanizing bath 28, from the immersion region to an adjacent emersion region and subsequently emerses it in the emersion region. The immersion region and the emersion region here are spaced apart from one another, i.e., do not correspond to one another. In particular, the two regions also do not overlap. The movement from the immersion region to the emersion region here takes place only after a specified period of time has expired, namely after the end of the reaction time of the flux 23 with the surface of the respective automotive components 2 for galvanizing.

[0124] Moreover, the handling device 31 centrally, and/or the handling means 32 locally, possess/possesses a control device, whereby the handling means 32 is moved such that all of the components 2 separated and singled out from the goods carrier 7 are guided through the galvanizing bath 28 with identical movement in identical arrangement, and with identical time.

[0125] Not depicted is the presence, above the galvanizing bath 28 and still within the housing 27, of a stripper of a stripping device (not shown), this stripper being intended for the stripping of liquid zinc. Moreover, the handling means 32 may also be controlled, via the assigned control device, in such a way that an automotive component 2 which has already been galvanized is moved, still within the housing 27, for example, by corresponding rotational movements, in such a way that excess zinc drips off and/or, alternatively, is spread uniformly over the automotive component surface.

[0126] FIGS. 2 to 4 then represent different conditions during operation of the system 1. FIG. 2 shows a condition wherein a multiplicity of automotive components 2 for galvanizing are deposited at the connection point 8. Above the group of automotive components 2 there is the goods carrier 7. After the goods carrier 7 has been lowered, the automotive components 2 are attached on the goods carrier 7. In the exemplary embodiment shown, the automotive components 2 are disposed in layers. In this case, all of the automotive components 7 may each be joined to the goods carrier 7. It is, however, also possible for only the upper layer of automotive components 2 to be joined to the goods carrier 7, while the following layer is joined to the layer above it. Another possibility is for the group of automotive components 2 to be disposed in a basketlike rack or the like.

[0127] In FIG. 3, the group of automotive components 2 is located above the pickling device 15. Stages C and D, namely the degreasing and rinsing, have already been performed.

[0128] In FIG. 4, the group of automotive components 2 has been deposited at the transfer point 33. The trolley 5 is on the way back to the connection point 8, at which there are already automotive components 2 present, as a group, to be newly galvanized. Of the group of automotive components 2 deposited at the transfer point 33, the handling means 32 has already withdrawn one automotive component 2, which is about to be supplied to the hot dip galvanizing device 25.

LIST OF REFERENCE SYMBOLS

[0129]

TABLE-US-00001 1 System 2 Automotive component 3 Conveying device 4 Rail guide 5 Trolley 6 Lifting cable 7 Goods carrier 8 Connection point 9 Degreasing device 10 Degreasing tank 11 Degreasing agent 12 Rinsing device 13 Rinsing tank 14 Rinsing agent 15 Pickling device 16 Pickling tank 17 Pickling agent 18 Rinsing device 19 Rinsing tank 20 Rinsing agent 21 Flux application device 22 Flux tank 23 Flux 24 Drying device 25 Hot dip galvanizing device 26 Galvanizing tank 27 Housing 28 Galvanizing bath 29 Cooling device 30 Aftertreating device 31 Handling device 32 Handling means 33 Transfer point