Production method, casting moulds, cores or feeders and kit and method for production of a metallic casting

Abstract

The invention relates to a method of producing an article selected from the group consisting of casting mold, core, feeder and molding compound for production of part of a casting mold, core or feeder, comprising the following steps: (S1) producing or providing in the foundry: a first component (A), comprising a first binder component (b1) of a binder system and an amount of a first mold base material and, spatially separated therefrom, a second component (B), comprising a second binder component (b2) of the binder system and an amount of a second mold base material wherein the first binder component (b1) and the second binder component (b2) are suitable for chemical reaction with one another and for curing of a mixture of the first component (A) and the second component (B), (S2) mixing by contacting the first component (A) and the second component (B) in a particular mass ratio, so as to result in a self-curing molding compound.

Claims

1. A method of producing an article selected from the group consisting of casting mold, core and feeder, by repair or completion of a corresponding defective or incomplete article, having at least the following steps: (S1) producing or providing in a foundry: a first component (A), comprising a first binder component (b1) of a binder system and an amount of a first mold base material and, spatially separated therefrom, a second component (B), comprising a second binder component (b2) of the binder system and an amount of a second mold base material wherein the first binder component (b1) and the second binder component (b2) are suitable for chemical reaction with one another and for curing of a mixture of the first component (A) and the second component (B), wherein the first binder component (b1) and the second binder component (b2) are each present as constituents of the first component (A) or the second component (B) in spatially separate containers, (S2) mixing by contacting at least the first component (A) and the second component (B) that has been produced or provided spatially separately therefrom in a particular mass ratio, so as to result in a self-curing molding compound, (S3) shaping and curing the self-curing molding compound that arises in step (S2), so as to result in a cured molded product of the first component (A) and of the second component (B), which forms a region of the article on conclusion of the production method.

2. The method as claimed in claim 1, wherein the self-curing molding compound that arises in step (S2) is kneaded in one or more subsequent steps by machine or manually.

3. The method as claimed in claim 1, wherein the article, for bounding of at least sections of a cavity to accommodate cast metal, has a first boundary region (12) and an adjacent, second boundary region (14) of different composition, wherein the first boundary region is formed from the cured shaped product of the first component (A) and the second component (B).

4. The method as claimed in claim 3 wherein the shaping in step (S3) is manual or automated, and/or the producing of the second boundary region (14) involves shaping a molding material using an automated shaping system.

5. The method as claimed in claim 3, wherein the first boundary region (12) of the article is first shaped and then the second boundary region (14) is shaped onto the first boundary region, wherein the first boundary region is shaped onto a shaping model (4) or the second boundary region of the article is first shaped and then the first boundary region is shaped onto the second boundary region.

6. The method as claimed in claim 1, wherein the first component (A) and/or the second component (B) comprise constituents present at least in the cured shaped product after step (S3) or in the article after conclusion of the production method such that they can be made to react with one another in a thermite reaction by heating.

7. The method as claimed in claim 1, wherein the mixing by contacting of the first component (A) and the second component (B) in step (S2) is at least partly manual, orat least partly without electrical assistance of the mixing operation.

8. The method as claimed in claim 1, having the following step: filling an intended or unintended recess in a surface region of a mold part, with the self-curing molding compound that arises in step (S2).

9. The method as claimed claim 1, wherein a constituent of the mold base material used in step (S1), in the first component (A) and/or the second component (B) is a refractory mold base material designated as refractory according to DIN 51060, and/or a constituent of the mold base material used in step (S1), in the first component (A) and/or the second component (B) is a thermally insulating filler, preferably and/or the first component (A) comprising binder component (b1) and/or the second component (B) comprising binder component (b2) additionally comprise(s) one, two, three or more further ingredients independently selected from the group consisting of: metallic materials selected from the group consisting of aluminum, magnesium, silicon, titanium, alloys thereof and mixtures thereof with one another or with other metallic materials, metal oxide, lithium silicate, cordierite, and alkali metal nitrate.

10. The method as claimed in claim 1, wherein the binder system is selected from the group consisting of: (G1) polyurethane no-bake systems, (G2) acid-curing cold resins, (G3) inorganic binder systems, and (G4) epoxy resins.

11. The method as claimed in claim 1, wherein the self-curing molding compound that arises in step (S2) comprises: 82% to 98% by weight, where the percentages by weight are based on the total mass of the self-curing molding compound.

12. The method as claimed in claim 1, wherein the first mold base material and the second mold base material have an identical chemical composition or have a different chemical composition.

13. The method as claimed in claim 1, wherein, in the contacting operation in step (S2), the temperature of the first component (A) and of the second component (B) are each within a range from 5 to 40? C.

14. The method as claimed in claim 1, wherein the cured molding compound has a flexural strength of more than 100 N/cm.sup.2, determined by means of a +GF+test bar and by means of a Multiserw flexural strength tester from MOREK, and/or the shaping and curing of the self-curing molding compound that arises in step (S2),in step (S3), is effected within a period of 1 to 60 minutes.

15. The method as claimed in claim 1, having the following steps after the mixing by contacting of the first component (A) and the second component (B) in step (S2): placing the self-curing molding compound that arises in step (S2) in a molding chamber or a molding box, then, during the curing or after the curing of the self-curing molding compound that arises in step (S2), introducing a molding material into the molding chamber or the molding box.

16. The method as claimed in claim 15, wherein the placing of the self-curing molding compound in the molding chamber or the molding box comprises the step(s) of: shaping the self-curing molding compound onto a model plate that bounds the molding chamber and/or onto a shaping model that forms the mold cavity of the article to be produced, and/or a casting mold with a feeder or core placed therein is produced by placing a feeder or core within the molding chamber or molding box, where a region of the feeder and/or of the core is a cured shaped product of the first component (A) and the second component (B).

17. The method as claimed in claim 15, wherein the article produced is separated from the model plate or the shaping model.

18. The method as claimed in claim 1, wherein the method is conducted in such a way that the curing of the self-curing molding compound that arises in step (S2) is not effected in the presence of gaseous catalysts and/or not in the presence of gaseous co-reactants.

19. A method for producing a metallic casting by metal casting in a casting mold, comprising the steps of: producing an article selected from the group consisting of casting mold, core and feeder by a method as claimed in claim 1, and inserting the article for bounding of at least sections of a cavity to accommodate cast metal, wherein the article has a first boundary region (12) and an adjacent, second boundary region (14) of different composition, wherein the first boundary region is formed from the cured shaped product of the first component (A) and the second component (B), contacting the casting metal at least with the first boundary region of the article produced during the casting.

Description

(1) The invention is described in detail hereinafter with reference to a preferred working example of a method of producing an article or a casting with reference to the appended schematics figures. These show:

(2) FIG. 1: a view of a model plate provided and of a shaping model disposed thereon;

(3) FIG. 2: a view of the model plate and other model with a self-curing molding compound shaped onto a critical region for metal casting on the shaping model;

(4) FIG. 3: a view of a detail from a molding chamber or molding box in which the model plate and the shaping model with the self-curing molding compound are disposed, wherein the molding chamber is filled with molding material;

(5) FIG. 4: at least a partial view of the article produced, especially of a mold part of a casting mold created;

(6) FIG. 5: a view of a casting mold which is composed of two mold parts and has a cured molding compound disposed in the cavity of the casting mold, wherein the casting mold is filled with casting metal; and

(7) FIG. 6: a view of a finished casting demolded from the casting mold.

(8) FIG. 1 depicts a model plate 2 with a shaping model 4 disposed thereon, which is used in a method of producing an inventive article 1 (FIG. 4), preferably a casting mold, more preferably a first mold part 10 of a casting mold (FIG. 4).

(9) The mold plate 2, in the case of customary use with the shaping model 4 disposed thereon, may be used, for example, in a molding box (not shown in detail), or forms a constituent of a molding chamber in the form of a mobile press plate (not shown in detail) of an automated shaping system. With the aid of the model plate 2, at least regions of the molding box or of the molding chamber of the shaping system are bounded.

(10) According to FIG. 2, a self-curing molding compound 6 is disposed in, especially shaped onto, a critical region of the shaping model 4, wherein the molding compound 6 is preferably shaped by manual kneading. The molding compound has been produced by a method of the invention from a first component (A) and a second component (B) (reference is made to the remarks further up). The critical region refers to a region of the shaping model in the proximity of which material defects, especially cavities within the casting metal, can arise in particular in the solidification of the casting metal on account of insufficient further feeding. The shaping model corresponds essentially to the shape of the later casting, with the shaping model, taking account of the degree of shrinkage, possibly being correspondingly oversized relative to the finished casting. The molding compound 6 formed from a first component (A) and a second component (B), in accordance with a preferred configuration of the invention, comprises constituents that can be made to react with one another in a thermite reaction; these constituents were previously present in the first component (A) and/or the second component (B).

(11) The molding compound 6 is preferably shaped by manual kneading onto the critical region of the shaping model 4 and cured thereon. In a configuration of the method of the invention which is not shown in detail, it is possible to arrange multiple amounts of such molding compounds 6 in uniform distribution around the circumference of the shaping model, in order thus to form a plurality of exothermic centers.

(12) In a further embodiment, not shown in detail, the molding compound may take the form of a prefabricated contour pad. Rather than being arbitrarily shaped manually as a molding compound, the self-curing molding compound in this case is preferably shaped beforehand in a mold intended for the purpose to give a contour pad of predefined shape. Such a prefabricated and typically already cured contour pad has a shape matched to the respective region of the shaping model 4 on which the contour pad is to be placed. The contour pad is set or placed on the regions of the shaping model intended for the purpose and optionally fixed thereon.

(13) FIG. 3 shows the result of a subsequent step of the method of the invention, in which a molding material 8 comprising a binder and a mold base material, for example a natural sand, semisynthetic molding sand or a synthetic mold base material, is introduced into the shaping box (not depicted in detail) or the molding chamber. After the molding material 8 has been introduced into the shaping chamber or the shaping box, it is compressed. The compression is effected by exerting a compressive force that acts on the molding material 8. The compressing and any associated curing process endows the molding material 8 with its necessary strength to form the article 1 of the invention, in the present context a mold part 10 of a casting mold, together with the molding compound 6.

(14) As apparent from FIG. 3, the molding material 8 here surrounds the molding compound 6 shaped onto the shaping model 4. Compressing of the molding material 8 embeds the molding compound 6 into the molding material 8, such that a firm bond is established between the molding compound 6 and the molding material 8.

(15) In a next step of the method that is preferred in accordance with the invention, the model plate 2 together with the shaping model 4 is separated from the mold part 10 produced. Beforehand, together with the separating or after the separating operation, the mold part 10 (including molding compound 6) is removed from the molding box (not shown) or the molding chamber. FIG. 4 shows the mold part 10 with the embedded molding compound 6 after performance of these measures.

(16) As further illustrated by FIG. 4, the molding compound 6 formed especially from the first component (A) and the second component (B) forms a first boundary region 12 of the article 1, which bounds a section of a cavity 16 for accommodation of casting metal. The molding material 8 forms a second boundary region 14 which is adjacent to and preferably adjoins the first boundary region 12. The second boundary region 14 of the article 1, which likewise bounds a section of the cavity 16 for accommodation of casting metal, has a different composition than the boundary region 12 (and, for example, is not capable of a thermite reaction). Removal of the shaping model 4 from the mold part 10 produced has given rise to a mold cavity 16 that corresponds to at least a portion of a casting 24 to be produced (FIG. 6).

(17) In a next step, the first mold part 10 (including the molding compound 6 that defines the first boundary region) as inventive article 1 is joined to a further mold part 18 to give a complete casting mold. After the joining, wherein the mold parts 10 and 18 are juxtaposed with sealing, the two mold parts 10 and 18 in the execution shown of the method of the invention are rotated by 180?. Thus, the mold part 18 now forms the top side of the article 1. Subsequently, a casting metal 22 is introduced via a mouth 20 that has been formed in the mold part 18 or produced subsequently in the mold part 18 into the cavity 16 of the article 1 which is preferably in the form of a casting mold, and this completely fills the cavity 16 and rises into the mouth 22. If the casting metal 22 comes into contact with the molding compound 6 that forms the first boundary region 12 of the cavity 16, the molding compound is heated to such an extent that an exothermic reaction, especially a thermite reaction, proceeds in the molding compound 6. As a result, the casting metal 22 in this region of the casting mold is kept in the liquid state for a prolonged period, which has an advantageous effect on the continued feeding process in the casting 24 to be produced. The result of this step is shown in FIG. 5.

(18) After the conclusion of the casting operation and the solidifying of the casting metal 22 and the at least partial cooling of the casting 24 produced, the latter is removed from the casting mold and any casting residues present are removed. On conclusion of these measures, the finished casting 24 shown in FIG. 6 has then been produced.

LIST OF REFERENCE NUMERALS

(19) 1 article/casting mold 2 model plate 4 shaping model 6 molding compound 8 molding material 10 mold part 12 boundary region 14 boundary region 16 cavity 18 mold part 20 casting metal 22 mouth 24 casting