Foundry Component Having an Anticorrosion Layer Structure

Abstract

A foundry component for an apparatus for casting or handling a metal melt includes a metallic main body which is provided in a melt-contact surface region with an anticorrosion layer structure composed of one or more superposed layers. The anticorrosion layer structure has, as a sole layer or as one of a plurality of layers, a protective woven fabric body prefabricated as flexible woven fabric body from a woven fabric material which is casting temperature resistant or a nonwoven protective layer prefabricated as pliable nonwoven layer from a fiber nonwoven material or fiber paper material which is casting temperature resistant or a protective shaped body prefabricated as rigid shaped body from a material which is casting temperature resistant.

Claims

1. A foundry component for an apparatus for casting or handling a metal melt, the foundry component comprising: a metallic main body which is provided in a melt-contact surface region with an anticorrosion layer structure composed of one or more superposed layers, wherein the anticorrosion layer structure comprises, as a sole layer or as one of a plurality of layers, a protective woven fabric body prefabricated as a flexible woven fabric body from a woven fabric material which is casting temperature resistant or a nonwoven protective layer prefabricated as a pliable nonwoven layer from a fiber nonwoven material or a fiber paper material which is casting temperature resistant or a protective shaped body prefabricated as a rigid shaped body from a shaped body material which is casting temperature resistant.

2. The foundry component according to claim 1, wherein the woven fabric material which is casting temperature resistant is a material based on Al.sub.2O.sub.3.

3. The foundry component according to claim 1, wherein the fiber nonwoven or fiber paper material which is casting temperature resistant is a material based on Al.sub.2O.sub.3.

4. The foundry component according to claim 1, wherein the shaped body material which is casting temperature resistant is a material based on Al.sub.2O.sub.3.

5. The foundry component according to claim 1, wherein the anticorrosion layer structure is multi-ply and comprises at least one further layer which differs from the first-named layer and is selected from the group consisting of: the protective woven fabric body, the nonwoven protective layer, the protective shaped body and a ceramic adhesive layer which is casting temperature resistant.

6. The foundry component according to claim 5, wherein the anticorrosion layer structure has the ceramic adhesive layer as an innermost layer.

7. The foundry component according to claim 5, wherein the anticorrosion layer structure has the protective woven fabric body as an outer layer and the nonwoven protective layer as an inner layer.

8. The foundry component according to claim 5, wherein the anticorrosion layer structure is at least three-ply and has the protective shaped body or the protective woven fabric body as an outer layer, the ceramic adhesive layer as an innermost layer and the nonwoven protective layer as an intermediate layer between the ceramic adhesive layer and the protective shaped body or the protective woven fabric body.

9. The foundry component according to claim 5, wherein the ceramic adhesive layer is made of a ceramic adhesive material which is based on Al.sub.2O.sub.3 and is casting temperature resistant.

10. The foundry component according to claim 1, wherein the protective woven fabric body has a thickness in the range from 0.8 mm to 3 mm.

11. The foundry component according to claim 1, wherein the nonwoven protective layer has a thickness in the range from 0.5 mm to 5 mm.

12. The foundry component according to claim 1, wherein the protective shaped body has a thickness in the range from 2 mm to 25 mm.

13. The foundry component according to claim 1, wherein the main body is made of an iron-based material.

14. The foundry component according to claim 13, wherein the main body is made of a cast steel material.

15. The foundry component according to claim 1, wherein the component is a component for a metal pressure casting machine.

16. The foundry component according to claim 15, wherein the component is a casting fitting, a casting vessel, a melt furnace component, a melt transport component, a casting mould component, or a part of one of these pressure casting machine components.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 is a schematic sectional view of a foundry component with a partial outer, three-ply anticorrosion layer structure;

[0037] FIG. 2 is a schematic sectional view of a casting vessel as foundry component with the partial outer anticorrosion layer structure of FIG. 1;

[0038] FIG. 3 is the sectional depiction of FIG. 1 for a variant having a one-ply instead of three-ply anticorrosion layer structure; and

[0039] FIG. 4 is the sectional depiction of FIG. 1 for a variant having a two-ply instead of three-ply anticorrosion layer structure.

DETAILED DESCRIPTION OF THE DRAWINGS

[0040] FIGS. 1, 3 and 4 show, purely schematically with the constituents thereof which are of interest here, a foundry component for an apparatus for casting or handling a metal melt, which comprises a metallic main body 1 which is provided in a melt-contact surface region 2 with an anticorrosion layer structure 3. FIGS. 1, 3 and 4 show by way of example and as representative of further possible realisations, various realisation examples for the anticorrosion layer structure 3.

[0041] In the embodiment shown in FIG. 1, the anticorrosion layer structure 3 comprises a protective woven fabric body 5 prefabricated as flexible woven fabric body from a woven fabric material which is casting temperature resistant as an outermost layer 4, i.e. layer 4 facing away from the surface of the metallic main body 1. Furthermore, the anticorrosion layer structure 3 in the working example of FIG. 1 comprises a ceramic adhesive layer 8 which is casting temperature resistant as an innermost layer 9, and a nonwoven protective layer 6 prefabricated as pliable nonwoven layer from a fiber nonwoven or fiber paper material which is casting temperature resistant as an intermediate layer 10 of the thus three-ply layer structure, i.e. layer structure comprising three layers.

[0042] The protective woven fabric body 5 is, in an advantageous realisation, prefabricated from a woven fabric material based on Al.sub.2O.sub.3 which is casting temperature resistant, i.e. it in this case forms an Al.sub.2O.sub.3 protective woven fabric body. The nonwoven protective layer 6 is, in an advantageous realisation, prefabricated from a fiber nonwoven or fiber paper material based on Al.sub.2O.sub.3 which is casting temperature resistant, i.e. it in this case forms an Al.sub.2O.sub.3 nonwoven protective layer. In alternative realisations, other materials which are casting temperature resistant are used for the layer structure components concerned, e.g. materials based on zirconium oxide or oxide-ceramic composite materials including fiber-reinforced composite materials as are known per se to a person skilled in the art for use in casting technology and other high-temperature applications. The nonwoven protective layer 6 preferably has a thickness in the range from 0.5 mm to 5 mm. The fiber nonwoven or fiber paper material for the nonwoven protective layer 6 consists of fibers which are shorter than fibers which have a high tensile strength and of which the flexible woven fabric body for the protective woven fabric body 5 is made.

[0043] FIG. 2 specifically shows a case in which the foundry component having the anticorrosion layer structure 3 in the realisation of FIG. 1 is a casting vessel as is customary, for example, in a metal pressure casting machine and more specifically in a hot chamber pressure casting machine for the casting of aluminium or aluminium alloys or other nonferrous casting metals. The casting vessel of FIG. 2 is of a construction known per se, as is disclosed, for example, in the above-mentioned patent publication EP 2 723 916 B1. In alternative embodiments, the foundry component forms a casting fitting, a casting vessel, a melt furnace component, a melt transport component, a casting mould component or a part of one of these pressure casting machine components. To give a better picture of the layer sequence of the anticorrosion layer structure 3 in this illustrative case, the participating layers are shown cut to different heights of the casting vessel, so that each layer can be seen at least in regions.

[0044] In alternative embodiments, only the ceramic adhesive layer 8 or only the nonwoven protective layer 6 is provided as innermost layer 9 between the metallic main body 1 and the protective woven fabric body 5 as outermost layer 4 in a two-ply configuration of the anticorrosion layer structure 3.

[0045] In the embodiment shown in FIG. 3, the anticorrosion layer structure 3 is one-ply, i.e. it consists only of a single protective layer 11 which in this example is formed by the protective woven fabric body 5. The protective woven fabric body or Al.sub.2O.sub.3 protective woven fabric body 5 here and in other multilayer realisations of the anticorrosion layer structure 3 in which it is used preferably has a thickness in the range from 0.8 mm to 3 mm. In an alternative embodiment, the single layer 11 of the anticorrosion layer structure 3 in a one-ply configuration consists of the nonwoven protective layer or Al.sub.2O.sub.3 nonwoven protective layer 6. Restricted to relatively small surface regions or transition regions, the ceramic adhesive layer 8 can also be used as one-layer adhesive coating for the anticorrosion layer structure 3.

[0046] In the embodiment shown in FIG. 4, the anticorrosion layer structure 3 is two-ply with the ceramic adhesive layer 8 as inner or innermost layer 9 and a protective shaped body 7 prefabricated as rigid shaped body from a shaped body material which is casting temperature resistant as outer or outermost layer 4. The protective shaped body 7 is, in an advantageous realisation, prefabricated from a shaped body material based on Al.sub.2O.sub.3 which is casting temperature resistant, i.e. it in this case forms an Al.sub.2O.sub.3 protective shaped body. In alternative realisations, other materials which are casting temperature resistant are used for the protective shaped body, e.g. once again materials based on zirconium oxide or oxide-ceramic composite materials including fiber-reinforced composite materials.

[0047] In alternative embodiments, the anticorrosion layer structure 3 is three-ply, i.e. comprises three layers, with the protective shaped body 7 as the outermost layer 4, the ceramic adhesive layer 8 as the innermost layer 9 and the nonwoven protective layer 6 or the protective woven fabric body 5 as intermediate layer between the ceramic adhesive layer 8 and the protective shaped body 7.

[0048] When the nonwoven protective layer 6 is used as intermediate layer 10 in the corresponding cases of an at least three-ply configuration of the anticorrosion layer structure 3, this can serve as further inert barrier against the melt material and thereby reliably protect the metallic main body 1 against corrosion even when the outer protective woven fabric body 5 or the outer protective shaped body 7 has been damaged or penetrated.

[0049] An analogous additional security against corrosion is offered by the other possible multi-ply embodiments of the anticorrosion layer structure 3. In these multilayer embodiments of the anticorrosion layer structure 3, it is extremely improbable that the metal melt can come into direct contact with the metallic main body 1 as a result of, for example, mechanical damage to one of the plurality of layers, in particular the outermost layer 4, since one or more further layers of the anticorrosion layer structure 3 still remain and can take on the anticorrosion function at the local point of damage of the damaged layer.

[0050] In further alternative embodiments, the anticorrosion layer structure 3 comprises four or more superposed layers, each of which is selected from the group consisting of the layer provided by the protective woven fabric body 5, the layer provided by the nonwoven protective layer 6, the layer provided by the protective shaped body 7 and the layer provided by the ceramic adhesive layer 8 and of which at least two are different from one another.

[0051] The ceramic adhesive layer 8 preferably consists of a heat-resistant ceramic adhesive material based on Al.sub.2O.sub.3, for which purpose it is possible to use a corresponding conventional ceramic adhesive material of this type. The ceramic adhesive layer 8 can, depending on requirements, be applied over part or the full area of the metallic main body 1 in the melt-contact surface region 2 thereof. The ceramic adhesive material of the ceramic adhesive layer 8 preferably has, when used with the protective shaped body 7, a coefficient of thermal expansion which corresponds very largely to that of the metal material of the main body 1. Thermal stresses between the metallic main body 1 and the protective shaped body 7 surrounding this in the melt-contact surface region 2 can thus be minimized. On smaller surface regions or transitions, the ceramic adhesive layer 8 can also be used as sole coating or filling over the full area.

[0052] The main body 1 preferably consists of an iron-based material, in particular a cast steel material as is known per se for metallic main bodys of foundry components, i.e. it is possible to use an iron-based or steel-based metal material customary for this purpose.

[0053] The protective shaped body 7 can, depending on requirement and the particular use, be prefabricated as tailored, one-piece, rigid shaped body from suitable shaped body material by being formed by a plurality of rigid, prefabricated plate elements which consist of a plate material suitable for the present purpose and are directly arranged on the main body 1 of the foundry component or, as an alternative, firstly assembled to give the shaped body and then arranged jointly as uniform shaped body on the melt-contact surface region 2 of the main body 1. Any joint gaps or interfaces and/or transitions between the plate elements can be closed or sealed using, for example, the same ceramic adhesive material as that of the ceramic adhesive layer 8, or as an alternative using a different heat-resistant ceramic adhesive material. The protective shaped body 7 has, in typical working examples, a thickness in the range from 2 mm to 25 mm.

[0054] When using the protective woven fabric body 5, this is preferably prefabricated in a tailored manner as flexible woven fabric body from the respective conventional woven fabric material which is casting temperature resistant, e.g. an Al.sub.2O.sub.3 woven fabric material, and placed on the main body 1 in the melt-contact surface region 2 thereof. As soon as the flexible woven fabric body comes into contact with the metal melt, e.g. when the main body 1 is dipped into the metal melt, it is pressed against the melt-contact surface region 2 by the pressure of the melt material and any enclosed air is displaced. The protective woven fabric body or Al.sub.2O.sub.3 protective woven fabric body 5 prevents penetration of the metal melt through to the metallic main body 1 and over the course of further use, typically after some days or weeks of contact with the melt material, transforms from the woven fabric body which is flexible and elastic when initially used into a brittle woven fabric body by a sintering effect.

[0055] When the nonwoven protective layer 6 is used as inner layer within the protective shaped body 7 as outer layer 4, the nonwoven protective layer 6, which is a soft and elastic layer, can if required be introduced with variable thickness into the anticorrosion layer structure 3. This makes it possible to compensate for different thermal expansion of the metallic main body 1 compared to the rigid, dense and rather brittle lining which is formed by the outer protective shaped body 7.

[0056] The anticorrosion layer structure 3 is, due to the fact that it is not adhesively bonded or positively locked over the entire area to the metallic main body 1 to be protected, relatively insensitive to mechanical damage compared to conventional adhesively bonded or positively locked coatings, and any damage can readily be kept local. In addition, the anticorrosion layer structure 3 has, for this reason, a significantly better thermal expansion tolerance, i.e. the occurrence of mechanical stresses in the anticorrosion layer structure 3 due to thermal expansion effects of the metallic main body 1 can be avoided or in any case significantly reduced compared to conventional adhesively bonded or positively locked coatings.

[0057] Even though the metallic main body 1 is provided only partially and on the outside with the anticorrosion layer structure 3 in the working examples shown, it goes without saying that in other embodiments the metallic main body 1 can, if required, be provided not only partially but over the full area on its total outer side and/or partially or completely on interior surface regions which come into contact with the melt material with the anticorrosion layer structure 3.