Casting parts with anti-corrosion layer structure

Abstract

To provide a cast component that can be manufactured at a comparatively low cost and exhibits high corrosion resistance to a liquid metal cast melt, particularly an aluminum melt.SOLUTION: A cast component comprises a metal body (1) having an anticorrosion-layered structure (3) constituted by one or more superposition layers in a melt contact-surface area (2). In a component according to the present invention, the anticorrosion-layered structure (3) includes, as one layer or one out of a plurality of layers, a protection woven-fabric body (5) preformed as a flexible woven-fabric body from a woven fabric material having at-cast thermal resistance, a nonwoven-fabric protection layer (6) preformed as a soft nonwoven-fabric layer from a fibrous nonwoven-fabric material or fibrous paper material having at-cast thermal resistance, or a protection formed body preformed as a rigid formed body from a material having at-cast thermal resistance. For example, it is used in a thermal-pressurizing casting machine for pressure casting of aluminum and aluminum alloy.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cast part for an apparatus for casting or processing a metal melt, the cast part comprising a metal body having a corrosion protection layer structure consisting of one or more superimposed layers in the melt-contacting surface area. [Background technology]

[0002] Such cast parts are employed in metal casting techniques, such as hot and cold pressure casting machines, and are used in various forms, such as casting fittings, casting vessels, melting furnaces, melt transport units, and molds, as well as parts of these metal casting components. Ferrous materials, i.e., iron-based materials, typically steel materials such as cast steel materials, are usually employed for the metal body, as such components have a good cost / utility ratio. For the purposes of the present invention, melt-contact surface area is understood to mean the area of ​​the surface of the metal body of the cast part that is continuously exposed to the metal melt, or at least for some time, during the casting operation, i.e., that comes into contact with the metal melt.

[0003] It has been found that cast parts having a body made of steel can be chemically attacked by the liquid metal melt, i.e., are susceptible to corrosion, in their melt-contact surface areas, i.e., the areas where the component comes into contact with the hot metal melt during the casting operation. Thus, for example, significant corrosive attack by aluminum melt in aluminum pressure casting is observed on the steel surfaces of cast parts that come into contact with these melts.

[0004] A known solution for casting piston / cast cylinder units for metal pressure casting machines is to make the entire cast piston and cast cylinder out of ceramic or sintered materials, such as sintered titanium diboride (TiB2). However, the mechanical strength, heat resistance, and impact strength often remain insufficient.

[0005] Similarly, US Pat. No. 5,629,999 proposes producing cast pistons and cylinders from sintered components of a mixture of two or more materials from the group consisting of carbides, borides, and nitrides, with a specific mixture of boron carbide (BC) with one or more of TiB2, zirconium diboride (ZiB2), and boron nitride (BN) being mentioned.

[0006] Patent Document 2 states that this and other sintered materials tested remain insufficient, and proposes hot-pressed, ultrahard silicon nitride or sialon materials with high densities as replacements for cast cylinders and pistons. For cast iron crucibles, a corrosion- and oxidation-protective coating is disclosed, consisting of oxides such as Ca, Al2O3, or Al2O3-TiO2, or TiB2, ZrB2, CaB2, or other pure or mixed borides, or AlN, Si3N4, BN, sialon, or other nitrides, applied, for example, by emulsion or thermal spraying. The manufacture of conical plugs for closing accessible holes for riser channels and other parts of casting fittings from such corrosion- and erosion-resistant materials is also proposed. For parts of the mold exposed to the metal melt only at relatively low temperatures, a coating consisting of a dense material containing Si3N4, AlN, sialon, BN, graphite, or pyrolytic carbon, or their alloys, is proposed.

[0007] Patent document 3 discloses a cast part of the above-mentioned type, in which the corrosion-resistant layer structure is formed by a corrosion-resistant layer configured as a sol-gel layer having an average particle size of one or more substances in the range of 50 nm to 50 μm as fillers, the substances being selected from the group consisting of borides and carbides of transition metals and their alloys, and boron and silicon, the sol-gel layer containing a zirconium-based or silicon-based gel former, and at least one sublayer not containing fine particles and / or nanoparticles, and formed by a plurality of gel sublayers forming outer sublayers of the sol-gel layer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] German Patent Application Publication No. 2364809(A1) [Patent Document 2] U.S. Patent No. 4,556,098(A) [Patent Document 3] European Patent No. 2723916(B1) Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention addresses the technical problem of providing a cast component of the type described above, where the cast component can be produced at a relatively low cost and displays high corrosion resistance to liquid metal casting melts, particularly aluminum melts. [Means for solving the problem]

[0010] The present invention solves this problem by providing a cast part having the features of claim 1. Advantageous developments of the invention that contribute to solving this and further problems are set out in the dependent claims, the content of which includes all combinations of features indicated by reference in the claims and is fully incorporated herein by reference.

[0011] According to the present invention, the corrosion protection layer structure includes, as a single layer in the case of a single-layer configuration, or as one of multiple layers in the case of a multi-layer configuration, a protective woven fabric body pre-formed as a flexible woven fabric body from a woven fabric material having heat resistance during casting, or a nonwoven protective layer as a flexible nonwoven fabric layer pre-formed from a fibrous nonwoven fabric material or fibrous paper material having heat resistance during casting, or a protective molded body as a rigid molded body pre-formed from a molded body material having heat resistance during casting.

[0012] The fibrous nonwoven material or fibrous paper material for the nonwoven protective layer is made of relatively short fibers, while the flexible woven body for the protective woven body is made of long fibers with relatively high tensile strength. In both cases, fibrous or woven materials that are stable at casting temperatures, as known per se for casting applications, such as aluminum casting, are used for this purpose. As the fibrous nonwoven material, it is possible to use, in particular, conventional nonwoven materials commercially available under the name ceramic nonwoven. As the fibrous paper material, it is possible to use, in particular, conventional paper materials commercially available under the name ceramic paper. For the present purpose, for simplicity, the terms nonwoven woven layer or nonwoven woven protective layer encompass both the corresponding layer of ceramic nonwoven woven material and the corresponding layer of ceramic paper material, and these layers can be used interchangeably or interchangeably herein.

[0013] When a protective fabric body is used, it is preferably applied as a tailored coating on the melt-contact surface area. It can be firmly positioned against the melt-contact surface area of ​​the metal body under the liquid pressure of the molten material, displacing any entrapped air. During operation of the cast part, the protective fabric body prevents the intrusion of molten material into the metal body and, during use, for example, after several days or weeks, undergoes a sintering process due to contact with the hot melt material, resulting in the protective fabric body being transformed from a flexible, preformed fabric body into a brittle fabric body.

[0014] As with the flexible prefabricated protective woven fabric body, the prefabricated nonwoven protective layer, which is a flexible nonwoven fabric layer, can also function as an inert barrier to the metal melt, thus protecting the metal body from corrosion by the metal melt.

[0015] If a protective molding is used, it forms an impermeable lining from the outside to the inside for the melt-contact surface area of ​​the metal body of the cast part. In particular, it can be prefabricated as a tailored, one-piece rigid molding or as a molding consisting of several rigid plate components. In the latter case, the plate components can be prefabricated and individually placed on the melt-contact surface area of ​​the metal body of the cast part, or alternatively, they can be configured to form a molding and then placed together as a molding on the melt-contact surface area. If necessary, lateral joints or transition areas between adjacent plate components can be closed with a heat-resistant ceramic adhesive material. For this purpose, it is again possible to use ceramic adhesive materials that are sufficiently heat-resistant to the casting temperature, i.e., the typical operating temperature at which casting is performed, such as, for example, aluminum oxide-based materials, as is well known to those skilled in the art, particularly ceramic adhesive materials that can be heated to high temperatures.

[0016] The term "casting temperature resistance" here, as the term suggests, refers to the material's resistance to the casting temperatures it is exposed to during the casting process. The casting temperatures naturally depend on the molten material being cast in each case. Since the latter is a metal melt, these temperatures are generally very high, exceeding 500°C and well above 1000°C. Corresponding high-temperature-resistant raw materials must be sufficiently physically and chemically resistant at these temperatures, even during prolonged operational use. Such materials for use in specific casting temperature ranges are known to those skilled in the art, and therefore no further explanation is necessary at this point. For simplicity's sake, such casting temperature-resistant molding materials include corresponding plate materials known to those skilled in the art, for example, from furnace construction.

[0017] In the case of a multi-layer construction, one or more additional layers may optionally serve to provide improved bonding of the corrosion protection layer structure to the surface of the metal body and / or to provide an additional inert barrier to protect the metal body from corrosion by the metal melt.

[0018] It has been found that the metal body of the casting of the present invention can be very reliably protected against corrosion phenomena that may occur due to contact with the molten material, either by this single-layer, i.e. single layer, or by this multi-layer, i.e. layer structure consisting of several superposed layers, in its melt-contact surface area, which during operation may come into contact with the molten metal used in casting, such as aluminum or aluminum alloys or other non-ferrous metals.

[0019] In the case of the corrosion protection layer structure according to the invention, there is no adhesive bonding or positive locking over the entire surface area to the metal body to be protected. This makes the corrosion protection layer structure less sensitive to mechanical damage compared to conventional adhesively bonded or positively locked coatings, and any damage can also remain to a greater extent locally limited. Furthermore, the corrosion protection layer structure therefore has significantly better thermal expansion tolerances. That is, the occurrence of mechanical stresses in the corrosion protection layer structure caused by the thermal expansion of the metal body can be avoided or, in any case, significantly reduced compared to conventional adhesive bonding or positively locked coatings.

[0020] At the same time, this corrosion protection layer structure can be implemented relatively inexpensively, for which purpose protective woven and / or nonwoven protective layers and / or protective moldings consisting of corresponding woven fabric materials, fibrous nonwoven / fibrous paper materials, or prefabricated rigid plate / molding materials are applied to the melt-contacting surface area of ​​the body of the cast part to be protected.

[0021] It has now been found that a corrosion protection layer structure comprising a protective woven or nonwoven protective layer or protective molding can provide very long-term corrosion protection, even for cast parts whose metal bodies are made of steel, for many weeks. This corrosion protection is reliably maintained for a long period of time, even when the melt-contact surface area of ​​the metal body continues to be in contact with the molten metal being cast. This results in a longer operating life for the cast parts protected from the corrosive effects of the molten material.

[0022] Furthermore, this implementation of the corrosion protection layer structure allows for relatively simple restoration, and thus subsequent renewed use, of the cast part, if necessary. For this purpose, the layer in the form of a protective woven or nonwoven fabric layer or protective molding can be removed relatively easily, which is generally not possible with conventional protective coatings deposited by thin-layer technology on the metal body of the cast part. Likewise, if necessary in this case, any further layers of the corrosion protection layer structure can be removed again from the metal body. The metal body of the cast part can then be provided with a new corrosion protection layer structure on its melt-contact surface area.

[0023] It goes without saying that, if necessary, one or more further layers not having a corrosion protection function can be provided outside the outermost layer of the corrosion protection layer structure, and / or internally between the surface of the body and the innermost layer of the corrosion protection layer structure, and / or between two layers of the corrosion protection layer structure.

[0024] In a corresponding development of the invention, the woven fabric material with casting heat resistance is an aluminum oxide (Al2O3)-based material, and / or the fibrous nonwoven or paper material with casting heat resistance is an Al2O3-based material, and / or the molded body material with casting heat resistance is an Al2O3-based material. Components formed thereon are also referred to as Al2O3-protected woven fabric bodies, Al2O3-nonwoven protective layers, or Al2O3-protected molded bodies in this case. This material selection has been found to be particularly advantageous with regard to both physical and chemical resistance at typical casting temperatures, as well as technical and economic feasibility, including for use in aluminum casting. It goes without saying that such Al2O3-based materials generally do not necessarily have to consist exclusively of Al2O3, but rather can contain minor amounts of additional materials.

[0025] In a further development of the present invention, the corrosion protection layer structure is a multilayer structure that, in addition to the first-mentioned layer, includes at least one additional layer selected from the group consisting of a protective woven fabric body, a nonwoven protective layer, a protective molding, and a heat-resistant ceramic adhesive layer. This multilayer structure can, if necessary, particularly effectively improve the bonding of the corrosion protection layer structure to the surface of the metal body and / or provide at least one additional inert barrier layer to protect the metal body from corrosion by the metal melt. The heat-resistant ceramic adhesive layer can be a ceramic adhesive material (including those based on Al2O3) that is sufficiently heat-resistant at typical casting temperatures, as is well known to those skilled in the art. In an alternative single-layer configuration, the corrosion protection layer structure does not have such additional layers and consists only of the first-mentioned layer, optionally with one or more layers of a different type.

[0026] In one embodiment of the present invention, the corrosion resistant layer structure is multi-layered with a ceramic adhesion layer as the innermost layer, i.e., the layer adjacent to the metal body. The ceramic adhesion layer can, in appropriate applications, improve the bonding of the corrosion resistant layer structure to the melt-contacting surface area of ​​the metal body. In an alternative embodiment, the corrosion resistant layer structure does not have such an innermost ceramic adhesion layer.

[0027] In one embodiment of the present invention, the corrosion protection layer structure is multilayered and includes a protective woven fabric body as an outer layer and a nonwoven protective layer as an inner layer. This arrangement of the nonwoven protective layer closer to the body than the protective woven fabric body means that the nonwoven protective layer does not necessarily have to be the innermost layer and / or protective woven fabric body, and the nonwoven protective layer and the protective woven fabric body do not necessarily have to be the outer layers of the layer structure, and the nonwoven protective layer and the protective woven fabric body do not necessarily have to be two directly adjacent layers of the layer structure. This allows for a good combination of the good corrosion protection properties and other chemical and physical properties of the protective woven fabric body and the nonwoven protective layer, so that the outer protective woven fabric body can protect the inner nonwoven protective layer from mechanical effects such as impacts. In an advantageous embodiment, a ceramic adhesive layer is present as the innermost layer of the corrosion protection layer structure between the nonwoven protective layer and the metal body of the cast part, which can improve the bonding of the corrosion protection layer structure, especially in the melt-contact surface area of ​​the body.

[0028] In one embodiment of the present invention, the corrosion protection layer structure is at least three-layered, with a ceramic adhesive layer as the innermost layer, a protective molding as the outer layer, and a nonwoven protective layer formed as an intermediate layer between the ceramic adhesive layer and the protective molding. This embodiment combines the advantageous properties of the impermeable outer protective molding with the advantages of the ceramic adhesive layer regarding good bonding of the corrosion protection layer structure to the melt-contacting surface area of ​​the metal body of the cast part, and the advantages of the intermediate nonwoven protective layer, including thickness equalization ability and yielding ability under compressive stress. In an alternative embodiment, the intermediate nonwoven protective layer or the inner ceramic adhesive layer is not present.

[0029] In one embodiment of the present invention, the ceramic adhesive layer is made of a heat-resistant, particularly highly heat-resistant, ceramic adhesive based on Al2O3. This represents a particularly good material choice for the ceramic adhesive layer for this purpose. Alternatively, a ceramic adhesive layer made of a different heat-resistant ceramic adhesive can be used.

[0030] In a further development of the invention, the protective fabric body has a thickness in the range of 0.8 mm to 3 mm. This thickness range has been found to be optimal for the protective fabric body in terms of implementation costs, sufficient corrosion protection, and a very limited permanent increase in the dimensions of the cast part due to the corrosion protection layer structure. For specific applications, the thickness of the Al2O3 protective fabric body can be selected outside this range.

[0031] In the development of the present invention, the nonwoven protective layer has a thickness in the range of 0.5 mm to 5 mm. This thickness range has been found to be optimal for the nonwoven protective layer in terms of implementation costs, sufficient corrosion protection, and very limited permanent increase in the dimensions of the cast part due to the corrosion protection layer structure. For specific applications, the thickness of the nonwoven protective layer can be selected outside this range.

[0032] In a further development of the invention, the protective molding has a thickness in the range of 2 mm to 25 mm. This thickness range has been found to be optimal for the protective molding in terms of implementation costs, sufficient corrosion protection, and a very limited permanent increase in the dimensions of the cast part due to the corrosion protection layer structure. For specific applications, the thickness of the protective molding can be selected outside this range.

[0033] In a development of the present invention, the metal body is made of an iron-based material, in particular a cast steel material. This combines the advantages of the inventive corrosion protection layer structure with the known advantages of selecting an iron-based material for the metal body of the cast part. Alternatively, the body of the cast part can be made of another metal material.

[0034] In a development of the invention, the cast part can be a component for a metal pressure casting machine, for example a hot pressure casting machine. In particular, it can be a casting fitting, a casting vessel, a melting furnace component, a melt transport component, a mold component or a part of these components of a metal pressure casting machine that are in contact with the melt. Due to their specific corrosion protection layer structure, the cast part is particularly well suited for these purposes and has a relatively long useful life.

[0035] Advantageous embodiments of the invention are shown in the drawings. These and further embodiments of the invention are explained in more detail below. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 shows a schematic cross-section of a cast part having a partial outer three-layer corrosion protection layer structure. [Figure 2] FIG. 2 is a schematic cross-sectional view of a casting vessel as a casting part having the partially outer anticorrosion layer structure of FIG. [Figure 3] FIG. 3 shows a cross-sectional view of FIG. 1 for a single layer instead of triple layer sacrificial layer structure. [Figure 4] FIG. 4 is a cross-sectional view of FIG. 1 for a two layer instead of three layer corrosion protection layer structure variation. DETAILED DESCRIPTION OF THE INVENTION

[0037] Figures 1, 3 and 4 show, purely diagrammatically together with the components of interest here, a cast part for an apparatus for casting or processing metal melts, which cast part comprises a metal body 1 provided in its melt-contact surface area 2 with a corrosion protection layer structure 3. Figures 1, 3 and 4 show, by way of example, various embodiments for the corrosion protection layer structure 3 as further possible embodiments.

[0038] In the embodiment shown in Figure 1, the corrosion protection layer structure 3 has a protective woven fabric body 5 pre-fabricated as a flexible woven fabric body from a woven fabric material having casting heat resistance as the outermost layer 4, i.e., the layer 4 facing away from the surface of the metal body 1. Furthermore, the corrosion protection layer structure 3 in the example of Figure 1 includes a ceramic adhesive layer 8 having casting heat resistance as the innermost layer 9, and a nonwoven fabric protective layer 6 pre-fabricated as a flexible nonwoven fabric layer from a fibrous nonwoven fabric or fibrous paper material having casting heat resistance as the middle layer 10 of a three-layer structure, i.e., a layer structure including three layers.

[0039] In an advantageous embodiment, the protective fabric body 5 is prefabricated from a nonwoven material based on Al2O3 that is resistant to casting temperatures, i.e., in this case, it forms an Al2O3 protective fabric body. In an advantageous embodiment, the nonwoven protective layer 6 is prefabricated from a fibrous nonwoven or fibrous paper material based on Al2O3 that is resistant to casting temperatures, i.e., in this case, it forms an Al2O3 nonwoven protective layer. In alternative embodiments, other materials that are resistant to casting temperatures, such as zirconium oxide-based materials or oxide ceramic composites, including fiber-reinforced composites known to those skilled in the art for use in casting technology and other high-temperature applications, are used for the associated layered structural components. The nonwoven protective layer 6 preferably has a thickness in the range of 0.5 mm to 5 mm. The fibrous nonwoven or fibrous paper material for the nonwoven protective layer 6 has a high tensile strength and consists of shorter fibers than the fibers from which the flexible fabric body for the protective fabric body 5 is made.

[0040] 2 shows in particular the case where the casting part having the corrosion protection layer structure 3 in the example of FIG. 1 is a casting vessel, as is customary, for example, in metal pressure casting machines, more particularly in pressure casting machines for the casting of aluminum or aluminum alloys or other non-ferrous casting metals. The casting vessel of FIG. 2 is of a structure known per se, as disclosed, for example, in the above-mentioned EP 2723916 B1. In an alternative embodiment, the casting part constitutes a casting fitting, a casting vessel, a melting furnace component, a melt transport component, a mold component, or one of these pressure casting machine components. To better illustrate the layer arrangement of the corrosion protection layer structure 3 in this exemplary case, the involved layers are shown cut at different heights of the casting vessel so that each layer is visible, at least in areas.

[0041] In another embodiment, only the ceramic adhesive layer 8 or only the nonwoven protective layer 6 is provided as the outermost layer 4 of the two-layer configuration of the corrosion protection layer structure 3, and as the innermost layer 9 between the metal body 1 and the protective woven fabric body 5.

[0042] In the embodiment shown in Figure 3, the corrosion protection layer structure 3 is a single layer, i.e., it consists of only a single layer 11, formed in this example by the protective woven fabric body 5. The protective woven fabric body or Al2O3 protective woven fabric body 5 preferably has a thickness of 0.8 mm to 3 mm, here and in other multilayer embodiments of the corrosion protection layer structure 3 in which it is used. In another embodiment, the single layer 11 of the single-layer corrosion protection layer structure 3 consists of the nonwoven protective fabric layer or Al2O3 nonwoven protective fabric layer 6. The ceramic adhesive layer 8 can also be limited to a relatively small surface or transition area and used as a single-layer adhesive coating for the corrosion protection layer structure 3.

[0043] In the embodiment shown in Figure 4, the corrosion protection layer structure 3 is two-layered, with a ceramic adhesive layer 8 as the inner or innermost layer 9 and a protective molding 7 preformed as a rigid molding from a molding material that is refractory to casting as the outer or outermost layer 4. In an advantageous embodiment, the protective molding 7 is prefabricated from an Al2O3-based molding material that is refractory to casting, i.e., in this case forming an Al2O3 protective molding. In alternative embodiments, other materials that are refractory to casting, such as zirconium oxide-based materials or oxide ceramic composites, including fiber-reinforced composites, are used for the protective molding.

[0044] In an alternative embodiment, the corrosion protection layer structure 3 is three-layered, i.e., includes a protective molding 7 as the outermost layer 4, a ceramic adhesive layer 8 as the innermost layer 9, and a nonwoven protective layer 6 or protective woven fabric body 5 as an intermediate layer between the ceramic adhesive layer 8 and the protective molding 7.

[0045] In the corresponding case of at least a three-layer configuration of the corrosion protection layer structure 3, when the nonwoven protective layer 6 is used as the intermediate layer 10, it can act as an additional inert barrier against the molten material, thereby reliably protecting the metal body 1 from corrosion even if the outer protective woven body 5 or the outer protective molding 7 is damaged or penetrated.

[0046] Similar additional safety against corrosion is provided by other possible multi-layer embodiments of the corrosion protection layer structure 3, since in these multi-layer embodiments of the corrosion protection layer structure 3 it is highly unlikely that a metal melt will come into direct contact with the metal body 1, for example as a result of mechanical damage to one of the layers, in particular the outermost layer 4, but one or more further layers of the corrosion protection layer structure 3 still remain and can take on the corrosion protection function at the local point of damage to the damaged layer.

[0047] In a further alternative embodiment, the corrosion protection layer structure 3 comprises four or more superimposed layers, each of which is selected from the group consisting of a layer provided by a protective woven body 5, a layer provided by a nonwoven protective layer 6, a layer provided by a protective molding 7, and a layer provided by a ceramic adhesive layer 8, at least two of which are different from each other.

[0048] The ceramic adhesive layer 8 preferably consists of a heat-resistant ceramic adhesive material based on Al2O3; therefore, corresponding conventional ceramic adhesive materials of this type can be used. The ceramic adhesive layer 8 can be applied to part or the entire area of ​​the metal body 1 within the melt-contact surface area 2 of the metal body 1, as required. When used in conjunction with the protective molding 7, the ceramic adhesive material of the ceramic adhesive layer 8 preferably has a very large thermal expansion coefficient corresponding to that of the metallic material of the metal body 1. This minimizes thermal stresses between the metal body 1 and the surrounding protective molding 7 in the melt-contact surface area 2. For smaller surface areas or transitions, the ceramic adhesive layer 8 can also be used as a single coating or filler over the entire area.

[0049] The metal body 1 preferably consists of an iron-based material, in particular a cast steel material known for metal bodies of cast parts, i.e. it is possible to use customary iron-based or steel-based metal materials for this purpose.

[0050] Depending on the requirements and specific application, the protective molding 7 can be prefabricated as a custom, one-piece, rigid molding from a suitable molding material. This can be done by placing the protective molding 7 directly on the metal body 1 of the cast part, or alternatively by forming multiple prefabricated rigid plate components, each of which is first configured to provide a molding and then placed together as a uniform molding on the melt-contact surface area 2 of the metal body 1. Any joint gaps or interfaces and / or transitions between the plate components can be closed or sealed, for example, using the same ceramic adhesive material as the ceramic adhesive layer 8 or a separate, heat-resistant ceramic adhesive material. In a typical application, the protective molding 7 has a thickness ranging from 2 mm to 25 mm.

[0051] If a protective fabric body 5 is used, it is preferably manufactured in advance as a flexible fabric body from a conventional nonwoven material that is resistant to casting temperatures, such as an Al2O3 nonwoven material, in a custom-made manner and placed on the metal body 1 at its melt-contact surface area 2. As soon as the flexible fabric body comes into contact with the metal melt, for example when the metal body 1 is immersed in the metal melt, the pressure of the molten material presses the flexible fabric body against the melt-contact surface area 2, displacing the trapped air. The protective fabric body or Al2O3 protective fabric body 5 prevents the metal melt from penetrating the metal body 1 and, over the course of further use, typically after several days or weeks of contact with the melt, transforms from a flexible and elastic fabric body when first used into a brittle fabric body due to a sintering effect.

[0052] When the nonwoven protective layer 6 is used as an inner layer within the protective molding 7 as an outer layer, the soft and elastic nonwoven protective layer 6 can be incorporated into the corrosion protection layer structure 3 with varying thicknesses as required, thereby compensating for the different thermal expansion of the metal body 1 compared to the hard, dense and rather brittle lining formed by the outer protective molding 7.

[0053] Since the corrosion protection layer structure 3 is not adhesively bonded or securely fixed over the entire area to the metal body 1 to be protected, it is relatively insensitive to mechanical damage compared to conventional adhesively bonded or firmly fixed coatings, and any damage can be easily maintained locally. In addition, for this reason, the corrosion protection layer structure 3 is significantly less susceptible to thermal expansion differences, i.e., the occurrence of mechanical stresses in the corrosion protection layer structure 3 due to the thermal expansion of the metal body 1 can be avoided or, in any case, significantly reduced compared to conventional adhesively bonded or positively locked coatings.

[0054] It should be noted that in the illustrated working example, the metal body 1 is provided with the corrosion protection layer structure 3 only partially and on the outside, but in other embodiments, if necessary, the metal body 1 can be provided with the corrosion protection layer structure 3 not only partially but over its entire outside area and / or partially or entirely on the internal surface area that comes into contact with the molten material.

Claims

1. 1. A cast part for an apparatus for casting or processing metal melts, comprising: The cast part has a metal body (1) which includes a melt-contact surface area (2) having a corrosion protection layer structure (3) consisting of one or more superimposed layers, The corrosion protection layer structure (3) is multi-layered, and has, as one layer of a plurality of laminated layers, a protective woven fabric body (5) as a flexible woven fabric body preformed from a woven fabric material having heat resistance during casting, or a nonwoven fabric protective layer (6) as a soft nonwoven fabric layer preformed from a fibrous nonwoven fabric material or a fibrous paper material having heat resistance during casting, or a protective molded body (7) preformed as a rigid molded body from a molded body material having heat resistance during casting, and at least one additional layer different from the one layer, selected from the group consisting of the protective woven fabric body (5), the nonwoven fabric protective layer (6), the protective molded body (7), and a ceramic adhesive layer (8) having heat resistance during casting, The corrosion protection layer structure (3) has the protective woven fabric body (5) as an outer layer and the nonwoven fabric protective layer (6) as an inner layer, or The corrosion protection layer structure (3) has at least three layers, and includes the protective molding (7) or the protective woven fabric body (5) as an outer layer, the ceramic adhesive layer (8) as an innermost layer, and the nonwoven fabric protective layer (6) as an intermediate layer between the ceramic adhesive layer (8) and the protective molding (7) or the protective woven fabric body (5). A cast part characterized by:

2. The woven fabric material having heat resistance during casting is Al ２ O ３ and / or The fibrous nonwoven material or fibrous paper material having heat resistance during casting is Al ２ O ３ and / or The molding material having heat resistance during casting is Al ２ O ３ 10. The cast component of claim 1 further characterized in that it is a .alpha.-based material.

3. 3. A cast part according to claim 1 or 2, further characterized in that the corrosion protection layer structure (3) comprises the ceramic adhesive layer (8) as the innermost layer (9).

4. The ceramic adhesive layer (8) is Al ２ O ３ 4. A cast part according to claim 1, further comprising a ceramic adhesive material based on SiO 2 and SiO 2 that is resistant to the casting heat.

5. 5. The cast part according to any one of claims 1 to 4, further characterized in that the protective woven fabric body (5) has a thickness in the range of 0.8 mm to 3 mm, and / or the nonwoven protective layer (6) has a thickness in the range of 0.5 mm to 5 mm, and / or the protective molding (7) has a thickness in the range of 2 mm to 25 mm.

6. The cast part according to any one of claims 1 to 5, further characterized in that the metal body (1) is made of an iron-based material.

7. A cast part as described in claim 6, further characterized in that the metal body (1) is made of cast steel material.

8. The cast component of any one of claims 1 to 7 further characterized in that it is a component of a metal pressure casting machine.

9. The cast part of claim 8, further characterized in that the metal pressure casting machine part is a casting fitting, a casting vessel, a melting furnace component, a melt transport component, a mold component, or one of these pressure casting machine components.

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