EP0019015A1 - Foundry core for producing hardly accessible hollow cavities in casting pieces, and process for its manufacture - Google Patents

Foundry core for producing hardly accessible hollow cavities in casting pieces, and process for its manufacture Download PDF

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Publication number
EP0019015A1
EP0019015A1 EP79105250A EP79105250A EP0019015A1 EP 0019015 A1 EP0019015 A1 EP 0019015A1 EP 79105250 A EP79105250 A EP 79105250A EP 79105250 A EP79105250 A EP 79105250A EP 0019015 A1 EP0019015 A1 EP 0019015A1
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EP
European Patent Office
Prior art keywords
sugar
casting core
binder
basic substance
casting
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Granted
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EP79105250A
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German (de)
French (fr)
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EP0019015B1 (en
Inventor
Wolfram Dipl.-Ing. Wischnack
Alfred Dobner
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Alcan Aluminiumwerk Nuernberg GmbH
Novelis Deutschland GmbH
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Alcan Aluminiumwerk Nuernberg GmbH
Alcan Aluminiumwerke GmbH
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Publication of EP0019015A1 publication Critical patent/EP0019015A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
    • B22C1/26—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of carbohydrates; of distillation residues therefrom
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/105—Salt cores

Definitions

  • the invention relates to casting cores for producing cavities which are difficult to access in castings made of aluminum or one of its alloys, from a basic substance and a hardened organic binder, and to processes for producing such casting cores.
  • the synthetic F resin or synthetic resin of DE-OS 17 83 004 are those of the urea-formaldehyde type, phenol-formaldehyde type, melamine-formaldehyde type, urea furfuryl type, phenol furfuryl type or of the sugar or Glycose-based type or compatible compositions of such resins.
  • K resin-bound salt cores have the disadvantage that when used under the influence of the casting temperature, large amounts of gas can be released from the binder. To avoid porosity in the casting, these gases must be removed quickly and completely. Due to the mostly narrow cross sections, which are given by the geometry of the cast parts, blockages can easily occur in the outflow channels due to the condensation of resinous products. The result is an uncontrolled escape of the gases from the entire core surface with the known disadvantageous consequences for the casting.
  • the invention is therefore based on the object of creating casting cores and processes for their production, from which, under the action of the temperatures when casting light metal, in particular aluminum and its alloys, only Small amounts of gas, if any, are released, the type of reaction products should be such that gas can also be removed through thin channels without condensation products leading to blockages in these channels.
  • the core material should be easy to remove from the cavity from possibly very narrow openings, either by dissolving the base substance or by disintegrating the binder, in which the base substance becomes free-flowing again.
  • This object is achieved by creating a casting core of the type mentioned at the outset, which is characterized in that the binder used to bind the base substance is sugar or a sugar derivative.
  • the disadvantages mentioned above can be avoided by using sugar or natural sugar derivatives as binders. It is particularly advantageous here that the casting cores according to the invention release only very small amounts of combustion gases from the binder at the casting temperatures, it not forming pasty condensates through which the outflow channels could be restricted or blocked.
  • the binder used according to the invention is particularly advantageously sugar color.
  • Sugar color which is also called caramel
  • caramel is usually a more or less dark-colored mass which is produced when cane sugar, beet sugar or glucose - to a certain extent with the addition of a little alkali - to higher temperatures heated.
  • the (monomolecular) starting sugar as add such the basic substance and in the course of creation of the core H caramel to produce or already from the beginning, the basic substance having already panoramicen- the caramel to be provided.
  • the selected base substance which is bound with sugar (couleur) or a natural sugar derivative, is in granular form.
  • sugar couleur
  • a natural sugar derivative is in granular form.
  • Such a configuration generally facilitates the dissolution or removal of the basic substance.
  • a water-soluble salt, sands, e.g. quartz sand, metal granules, alone or in a mixture, are used as the basic substance. Particularly favorable results are obtained for some applications when water-soluble salt is combined with sugar color.
  • the amount of binder used can vary widely depending on the type of basic substance to be bound. Usually, the proportion of the binder, based on the total weight of the casting core, about 0.3 1 5 wt.%.
  • metal tubes are inserted into the cores bound with sugar or a sugar derivative, in particular based on salt, during their manufacture, e.g. by pressing that they can later be used both for fastening the cores in the casting mold and for removing the reaction gases during the casting process.
  • the tubes used in this way can be flanged in the manner of hollow rivets, slotted on the side or perforated, on the one hand in order to ensure a firm fit in the core material and on the other hand in order to easily remove the gases.
  • tubes e.g. Made of metal, which are designed such that they offer the possibility of connection to a suction line outside the mold.
  • the casting cores are produced in accordance with a method according to the invention in such a way that the selected basic substance is mixed with sugar or a derivative thereof in aqueous, organic or mixed aqueous-organic solution, pressed into molds and baked at elevated temperature.
  • the proportion of the solvent used can vary within wide limits, particularly favorable results have been obtained with a weight ratio of solvent to organic binder of about 1: 1 to 1:10.
  • the base substance is kept at a slightly higher temperature than the room temperature when it is coated with the binder.
  • the basic substance in the coating with the binder can have a temperature between 20 and 180 ° C., the mixing process required for the coating then being continued until a dry, free-flowing mixture has formed.
  • the subsequent pressing process can also take place at elevated temperatures, which can be set depending on the type of sugar or sugar derivative selected. Press temperatures in the range between 50 and 200 ° C. are preferred.
  • the baking that usually follows the pressing is also carried out at an elevated temperature. Temperatures between 150 and 300 ° C have proven to be favorable.
  • the time required for the baking depends on the type of sugar selected and the baking temperature, and it can usually comprise periods of about 10 minutes to about 2 hours for the baking temperatures indicated above.
  • drying or removal of the solvent can be accelerated or promoted by increasing the temperature by introducing warm dry air.
  • the casting cores according to the invention are illustrated schematically in a preferred embodiment in the attached figure.
  • a cooling channel ring core 1 which is used to produce a cooling channel in the piston of an internal combustion engine, is shown in the casting core.
  • the molded tubes 2 are used for fastening in the core receptacles 3 of the casting mold and at the same time for gas discharge.
  • the casting cores according to the invention have particular advantages. This allows the cores to be washed out of the finished castings without any effort, for example by adding water.
  • a further advantage of the casting cores according to the invention, but also of the process for their production, is that neither in the production of the cores nor during the casting process or during subsequent washing out of the core residues from the casting do gases or vapors or waste materials arise or be released which are present in any one would be environmentally harmful. Apart from this, as already stated above, the amount of gas released is relatively small.
  • the binder based on sugar or a derivative thereof has excellent disintegration properties, since its binding power is largely destroyed when the casting is poured. Therefore, not only water-soluble base substance, e.g. Salts are used, but also other non-soluble base substance, such as sand, metal granules in granular or "mobile” form.
  • the basic substance which is largely in the form of a pour after the casting has cooled, can then be easily removed from the resulting cavity by simply shaking it out or by rinsing.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Molecular Biology (AREA)
  • Mold Materials And Core Materials (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)

Abstract

Ein Gießkern (1) zur Erzeugung schwer zugänglicher Hohlräume in Gußstücken aus Aluminium oder aus einer seiner Legierungen aus einer Grundsubstanz, und einem gehärteten organischen Bindemittel, wobei das zur Bindung der Grundsubstanz eingesetzte Bindemittel Zucker oder ein Zuckerderivat ist, sowie Verfahren zur Herstellung eines solchen Gießkerns. Hierbei wird die Grundsubstanz mit Zucker oder einem Derivat hiervon in wässriger oder organischer Lösung vermischt, in Formen verpreßt und bei erhöhter Temperatur ausgebacken.A casting core (1) for creating cavities in castings made of aluminum or one of its alloys from a base substance, and a hardened organic binder, the binder used for binding the base substance being sugar or a sugar derivative, and method for producing such a casting core . Here, the basic substance is mixed with sugar or a derivative thereof in aqueous or organic solution, pressed into molds and baked at an elevated temperature.

Description

Die Erfindung betrifft Giesskerne zur Erzeugung schwer zugängliher Hohlräume in Gussstücken aus Aluminium oder aus einer seiner Legierungen, aus einer Grundsubstanz und einem ausgehärteten organischen Bindemittel, sowie Verfahren zur Herstellung solcher Giesskerne.The invention relates to casting cores for producing cavities which are difficult to access in castings made of aluminum or one of its alloys, from a basic substance and a hardened organic binder, and to processes for producing such casting cores.

Giesskerne für die Herstellung komplizierter oder schwer zugänglicher Hohlräume mit engen Querschnitten in methallgussteilen, die wasserlösliche Kerne darstellen, sind bereits bekannt. In der DE-PS 13 02 940 sind bereits gesinterte Salzkerne beschrieben worden. Nach einer Weiterentwicklung gemäss DE-PS 17 83 004 wird das wasserlösliche Kernmaterial mit einem synthetischen Harz bzw. Kunstharz gebunden. Als synthetisches F Harz bzw. Kunstharz der DE-OS 17 83 004 dienen solche vom Harnstoff-Formaldehyd-Typ, Phenol-Formaldehyd-Typ, MelaminFormaldehyd-Typ, Harnstoff-Furfuryl-Typ, Phenol-Furfuryl-Typ oder vom auf Zucker- oder Glykosebasis aufgebauten Typ bzw. verträgliche Zusammensetzungen solcher Harze.Casting cores for the production of complicated or difficult to access cavities with narrow cross sections in metal castings, which are water-soluble cores, are already known. Sintered salt cores have already been described in DE-PS 13 02 940. According to a further development according to DE-PS 17 83 004, the water-soluble core material with a synthetic resin or synthetic resin bound. The synthetic F resin or synthetic resin of DE-OS 17 83 004 are those of the urea-formaldehyde type, phenol-formaldehyde type, melamine-formaldehyde type, urea furfuryl type, phenol furfuryl type or of the sugar or Glycose-based type or compatible compositions of such resins.

Die vorbekannten Giesskerne vermögen jedoch in ihren Eigenschaften noch nicht vollständig zu befriedigen, da sowohl die gesinterteten Salzkerne wie auch solche mit Kunstharzbindung bei vielen Anwendungszwecken noch Nachteile aufweisen. So ist die Herstellung gesinterter Salzkerne relativ aufwendig und diese sind auch für einige Anwendungszwecke zu spröde. Weiterhin lassen sie sich nach dem Umgiessen mit dem Metall nur relativ schwierig aus dem Gussstück herauslösen.However, the properties of the previously known casting cores are still not entirely satisfactory, since both the sintered salt cores and those with a synthetic resin bond still have disadvantages in many applications. The production of sintered salt cores is relatively complex and they are too brittle for some applications. Furthermore, it is relatively difficult to remove them from the casting after the metal has been cast around them.

Kunstharzgebundene Salzkerne haben dagegen den Nachteil, dass bei ihrer Anwendung unter Einwirkung der Giesstemperatur grosse Gasmengen aus dem Bindemittel freigesetzt werden können. Zur Vermeidung einer Porosität im Gussstück müssen diese Gase schnell und vollständig abgeführt werden. Aufgrund der zumeist engen Querschnitte, die durch die Geometrie der Gussteile gegeben sind, kann es aber in den Abströmkanälen leicht zu Verstopfungen durch Kondensation harzartiger Produkte kommen. Als Folge ergibt sich dann ein unkontrolliertes Austreten der Gase aus der gesamten Kernoberfläche mit den bekannten nachteiligen Folgen für das Gussstück. K resin-bound salt cores, on the other hand, have the disadvantage that when used under the influence of the casting temperature, large amounts of gas can be released from the binder. To avoid porosity in the casting, these gases must be removed quickly and completely. Due to the mostly narrow cross sections, which are given by the geometry of the cast parts, blockages can easily occur in the outflow channels due to the condensation of resinous products. The result is an uncontrolled escape of the gases from the entire core surface with the known disadvantageous consequences for the casting.

Der Erfindung liegt daher die Aufgabe zugrunde, Giesskerne und·Verfahren zu deren Herstellung zu schaffen, aus denen unter Einwirkung der Temperaturen beim Giessen von Leichtmetall, insbesondere Aluminium und dessen Legierungen, nur geringe Mengen an Gas, sofern überhaupt, freigesetzt werden, wobei die Art der Reaktionsprodukte so sein soll, dass auch die Gasabführung durch dünne Kanäle möglich ist, ohne dass Kondensationsprodukte in diesen Kanälen zu Verstopfungen führen. Insbesondere soll sich das Kernmaterial leicht aus eventuell sehr engen Öffnungen aus dem Hohlraum, sei es durch Auflösung der Grundsubstanz, sei es durch Zerfall des Bindemittels, bei dem die Grundsubstanz wieder rieselfähig wird, entfernen lassen.The invention is therefore based on the object of creating casting cores and processes for their production, from which, under the action of the temperatures when casting light metal, in particular aluminum and its alloys, only Small amounts of gas, if any, are released, the type of reaction products should be such that gas can also be removed through thin channels without condensation products leading to blockages in these channels. In particular, the core material should be easy to remove from the cavity from possibly very narrow openings, either by dissolving the base substance or by disintegrating the binder, in which the base substance becomes free-flowing again.

Diese Aufgabe wird durch die Schaffung eines Giesskernes der eingangs genannten Art gelöst, der dadurch gekennzeichnet ist, dass das zur Bindung der Grundsubstanz eingesetzte Bindemittel Zucker oder ein Zuckerderivat ist.This object is achieved by creating a casting core of the type mentioned at the outset, which is characterized in that the binder used to bind the base substance is sugar or a sugar derivative.

Im Rahmen der Erfindung ist überraschenderweise gefunden worden, dass durch den Einsatz von Zucker oder natürlichen Zuckerderivaten als Bindemittel die vorstehend erwähnten Nachteile vermieden werden können. Hierbei ist insbesondere vorteilhaft, dass die erfindungsgemässen Giesskerne bei den Giesstemperaturen nur sehr geringe Mengen an Verbrennungsgasen aus dem Bindemittel freisetzen, wobei es nicht zur Bildung pastöser Kondensate kommt, durch die die Abströmkanäle eingeengt bzw. verstopft werden könnten.It has surprisingly been found in the context of the invention that the disadvantages mentioned above can be avoided by using sugar or natural sugar derivatives as binders. It is particularly advantageous here that the casting cores according to the invention release only very small amounts of combustion gases from the binder at the casting temperatures, it not forming pasty condensates through which the outflow channels could be restricted or blocked.

Das erfindungsgemäss eingesetzte Bindemittel stellt mit besonderem Vorteil Zuckercouleur dar. Zuckercouleur, das auch Karamel genannt wird, ist üblicherweise eine mehr oder weniger dunkel gefärbte Masse, die entsteht, wenn man Rohrzucker, Rübenzucker oder Traubenzucker - gegebenenfalls unter Zusatz von etwas Alkali - auf höhere Temperaturen erhitzt. Je nach Anwendungszweck kann es daher möglich sein, den gewählten (monomolekularen) Ausgangszucker als solchen der Grundsubstanz zuzufügen und im Verlauf der Herstellung des Giesskerns Zuckercouleur zu erzeugen oder bereits von Anfang an die Grundsubstanz mit bereits vorliegen- dem Zuckercouleur zu versehen.The binder used according to the invention is particularly advantageously sugar color. Sugar color, which is also called caramel, is usually a more or less dark-colored mass which is produced when cane sugar, beet sugar or glucose - to a certain extent with the addition of a little alkali - to higher temperatures heated. Depending on the application, it may therefore be possible to choose the (monomolecular) starting sugar as add such the basic substance and in the course of creation of the core H caramel to produce or already from the beginning, the basic substance having already vorliegen- the caramel to be provided.

Nach einer Ausführungsform der Erfindung liegt die gewählte Grundsubstanz, die mit Zucker (couleur) oder einem natürlichen Zuckerderivat gebunden wird, in körniger Form vor. Durch eine derartige Konfiguration wird die Auflösung bzw. Entfernung der Grundsubstanz im Regelfall erleichtert. Als Grundsubstanz werden ein wasserlösliches Salz, Sande, z.B.Quarzsand, Metallgranulat allein oder im jeweiligen Gemisch eingesetzt. Für manche Anwendungszwecke besonders günstige Ergebnisse werden bei der Kombination wasserlöslichen Salzes mit Zuckercouleur erhalten.According to one embodiment of the invention, the selected base substance, which is bound with sugar (couleur) or a natural sugar derivative, is in granular form. Such a configuration generally facilitates the dissolution or removal of the basic substance. A water-soluble salt, sands, e.g. quartz sand, metal granules, alone or in a mixture, are used as the basic substance. Particularly favorable results are obtained for some applications when water-soluble salt is combined with sugar color.

Der Mengenanteil des eingesetzten Bindemittels kann, je nach Art der zu bindenden Grundsubstanz, in weiten Mengen variieren. Üblicherweise beträgt der Mengenanteil des Bindemittels, bezogen auf das Gesamtgewicht des Giesskernes, etwa 0,3-15 Gew.%.The amount of binder used can vary widely depending on the type of basic substance to be bound. Usually, the proportion of the binder, based on the total weight of the casting core, about 0.3 1 5 wt.%.

Nach einer bevorzugten Ausführungsform der Erfindung werden in die mit Zucker oder einem Zuckerderivat gebundenen Kerne, insbesondere auf Basis von Salz, bei deren Herstellung Metallröhrchen derart mit eingeführt, z.B. durch Verpressen, dass sie später sowohl zur Befestigung der Kerne in der Giessform als auch zur Abführung der Reaktionsgase während des Giessvorganges dienen können. Die derart eingesetzten Röhr- , chen können, einerseits um einen festen Sitz im Kernmaterial und andererseits um eine leichte Abführung der Gase zu erreichen, in der Art von Hohlnieten umgebördelt, seitlich geschlitzt oder perforiert sein.According to a preferred embodiment of the invention, metal tubes are inserted into the cores bound with sugar or a sugar derivative, in particular based on salt, during their manufacture, e.g. by pressing that they can later be used both for fastening the cores in the casting mold and for removing the reaction gases during the casting process. The tubes used in this way can be flanged in the manner of hollow rivets, slotted on the side or perforated, on the one hand in order to ensure a firm fit in the core material and on the other hand in order to easily remove the gases.

Zur Befestigung der Kerne in der-Giessform können ebenfalls Röhrchen, z.B. aus-Metall, vorgesehen sein, die derart ausgebildet sind, dass sie ausserhalb der Giessform die Möglichkeit des Anschlusses an eine Saugleitung bieten.To fix the cores in the mold, tubes, e.g. Made of metal, can be provided, which are designed such that they offer the possibility of connection to a suction line outside the mold.

Die Giesskerne werden nach einem Verfahren gemäss der Erfindung derart hergestellt, dass die gewählte Grundsubstanz mit Zucker oder einem Derivat hiervon in wässriger, organischer oder gemischt wässrig-organischer Lösung vermischt, in Formen verpresst und bei erhöhter Temperatur ausgebacken wird. Wenngleich der Anteil des eingesetzten Lösungsmittels in weiten Grenzen schwanken kann, wurden doch besonders günstige Ergebnisse bei einem Gewichtsverhältnis von Lösungsmittel zu organischem Bindemittel von etwa 1:1 bis 1:10 erhalten.The casting cores are produced in accordance with a method according to the invention in such a way that the selected basic substance is mixed with sugar or a derivative thereof in aqueous, organic or mixed aqueous-organic solution, pressed into molds and baked at elevated temperature. Although the proportion of the solvent used can vary within wide limits, particularly favorable results have been obtained with a weight ratio of solvent to organic binder of about 1: 1 to 1:10.

Für die Herstellung von Giesskernen für bestimmte Anwendungszwecke kann es günstig sein, wenn die Grundsubstanz bei der Umhüllung mit dem Bindemittel auf einer gegenüber der Raumtemperatur etwas erhöhten Temperatur gehalten wird. So kann die Grundsubstanz bei der Umhüllung mit dem Bindemittel beispielsweise eine Temperatur zwischen 20 und 180°C aufweisen, wobei der für die Umhüllung erforderliche Mischvorgang dann solange fortgesetzt wird, bis ein trockenes rieselfähiges Gemisch entstanden ist.For the production of casting cores for certain applications, it can be advantageous if the base substance is kept at a slightly higher temperature than the room temperature when it is coated with the binder. For example, the basic substance in the coating with the binder can have a temperature between 20 and 180 ° C., the mixing process required for the coating then being continued until a dry, free-flowing mixture has formed.

Der nachfolgende Verpressungsvorgang kann ebenfalls bei erhöhten Temperaturen erfolgen, die je nach Art des gewählten Zuckers oder Zuckerderivates eingestellt werden können. Hierbei sind Presstemperaturen im Bereich zwischen 50 und 200°C bevorzugt.The subsequent pressing process can also take place at elevated temperatures, which can be set depending on the type of sugar or sugar derivative selected. Press temperatures in the range between 50 and 200 ° C. are preferred.

Das Ausbacken, das üblicherweise auf die Verpressung folgt, wird ebenfalls bei erhöhter Temperatur vorgenommen. Hierbei haben sich Temperaturen zwischen 150 und 300°C als günstig erwiesen. Die für das Ausbacken erforderliche Zeit richtet sich nach der Art des gewählten Zuckers und der Ausbacktemperatur, wobei sie für die vorstehend angegebenen Ausbacktemperaturen üblicherweise Zeiträume von etwa 10 Minuten bis etwa 2 Stunden umfassen kann.The baking that usually follows the pressing is also carried out at an elevated temperature. Temperatures between 150 and 300 ° C have proven to be favorable. The time required for the baking depends on the type of sugar selected and the baking temperature, and it can usually comprise periods of about 10 minutes to about 2 hours for the baking temperatures indicated above.

Bei der Herstellung des erfindungsgemässen Giesskernes kann die Trocknung bzw. die Entfernung des Lösungsmittels durch Temperaturerhöhung durch Einleiten warmer trockener Luft beschleunigt bzw. begünstigt werden.In the production of the casting core according to the invention, drying or removal of the solvent can be accelerated or promoted by increasing the temperature by introducing warm dry air.

Die erfindungsgemässen Giesskerne sind in der beigefügten Figur in einer bevorzugten Ausführungsform schematisch veranschaulicht. In der Figur ist bei dem Giesskern ein Kühlkanal-Ringkern 1, der zur Herstellung eines Kühlkanals im Kolben einer Brennkraftmaschine dient, gezeigt. Die eingeformten Röhrchen 2 dienen zur Befestigung in den Kernaufnahmen 3 der Giessform und zugleich zur Gasableitung.The casting cores according to the invention are illustrated schematically in a preferred embodiment in the attached figure. In the figure, a cooling channel ring core 1, which is used to produce a cooling channel in the piston of an internal combustion engine, is shown in the casting core. The molded tubes 2 are used for fastening in the core receptacles 3 of the casting mold and at the same time for gas discharge.

Die erfindungsgemässen Giesskerne weisen besondere Vorteile auf. So lassen sich die Kerne aus den fertigen Gussteilen ohne jegliche Mühe,beispielsweise durch Wasserzufuhr, auswaschen. Ein weiterer Vorteil der erfindungsgemässen Giesskerne aber auch des Verfahrens zu deren Herstellung besteht darin, dass weder bei der Herstellung der Kerne noch während des Giessvorganges oder beim späteren Auswaschen der Kernreste aus dem Gusstück Gase, Dämpfe oder Abfallstoffe entstehen bzw. frcigesetzt werden, die in irgendeiner Weise umweltschädlich wären. Abgesehen davon ist, wie bereits vorstehend ausgeführt wurde, die Menge an freigesetztem Gas relativ gering.The casting cores according to the invention have particular advantages. This allows the cores to be washed out of the finished castings without any effort, for example by adding water. A further advantage of the casting cores according to the invention, but also of the process for their production, is that neither in the production of the cores nor during the casting process or during subsequent washing out of the core residues from the casting do gases or vapors or waste materials arise or be released which are present in any one Would be environmentally harmful. Apart from this, as already stated above, the amount of gas released is relatively small.

Schliesslich ist zu erwähnen, dass das Bindemittel auf der Basis von Zucker bzw. eines Derivates hiervon ausgezeichnete Zerfallseigenschaften aufweist, da seine Bindekraft beim Giessen des Gussstückes weitgehend zerstört wird. Es kann daher für entsprechend geeignete Anwendungsfälle nicht nur wasserlösliche Grundsubstanz, z.B. Salze, eingesetzt werden, sondern auch andere nicht lösliche Grundsubstanz, wie Sand, Metallgranulat in körniger bzw. "beweglicher" Form. Die Grundsubstanz, die nach dem Erkalten des Gussstückes in weitgehend rieselförmiger Form vorliegt, lässt sich dann durch einfaches Ausrütteln oder aber durch Spülen aus dem entstandenen Hohlraum leicht entfernen.Finally, it should be mentioned that the binder based on sugar or a derivative thereof has excellent disintegration properties, since its binding power is largely destroyed when the casting is poured. Therefore, not only water-soluble base substance, e.g. Salts are used, but also other non-soluble base substance, such as sand, metal granules in granular or "mobile" form. The basic substance, which is largely in the form of a pour after the casting has cooled, can then be easily removed from the resulting cavity by simply shaking it out or by rinsing.

Die Herstellung des erfindungsgemässen Giesskernes wird nachstehend in einem Ausführungsbeispiel erläutert, das nicht als Einschränkung aufzufassen ist.The production of the casting core according to the invention is explained below in an exemplary embodiment, which should not be interpreted as a restriction.

Beispielexample

Zur Herstellung von 100 kg Kernmaterial wurden 2,7 kg Zuckercouleur mit 0,3 kg Alkohol verdünnt und in dieser Form einer Menge von 97 kg NaCl bei einer Temperatur von 120°C zugegeben und einem schonend arbeitenden Mischer zugeführt. Bereits nach kurzer Zeit waren die Salzkörner vom Bindematerial umhüllt und konnten durch Einleiten warmer Luft getrocknet werden. Sobald die Mischung wieder rieselfähig war, wurde sie in ein Pressgesenk der gewünschten Form gebracht und dort verdichtet, wobei des Verdichtungsverhältnis 1,4:1 betrug. Das Pressgesenk selbst wurde dabei auf einer Temperatur von 140°C gehalten. Es enthielt in einer entsprechenden Halterung die seitlich geschlitzten und in Form einer Hohlniete ausgebildeten Röhrchen. Der so hergestellte Kern wurde dem Pressgesenk mit hilfe einer entsprechenden Vorrichtung entnommen und anschliessend auf einer, der Kernform angepassten Unterlage während 60 Minuten bei 220°C ausgebacken.To produce 100 kg of core material, 2.7 kg of sugar color were diluted with 0.3 kg of alcohol and, in this form, an amount of 97 kg of NaCl was added at a temperature of 120 ° C. and fed to a gentle mixer. After a short time, the salt grains were enveloped by the binding material and could be dried by introducing warm air. As soon as the mixture was free-flowing again, it was brought into a press die of the desired shape and compacted there, the compression ratio being 1.4: 1. The die itself was kept at a temperature of 140 ° C. In a suitable holder, it contained the laterally slotted tubes, which were designed in the form of hollow rivets. The core produced in this way became the press die removed with the help of an appropriate device and then baked on a base adapted to the core shape for 60 minutes at 220 ° C.

Es hat sich gezeigt, dass die Verwendung eines anderen Zuckers oder Zuckerderivates oder die Verwendung von Wasser zur Einstellung der geeigneten Viskosität des Binders in gleicher Weise möglich ist.It has been shown that the use of another sugar or sugar derivative or the use of water to adjust the suitable viscosity of the binder is equally possible.

Claims (12)

1. Giesskern zur Erzeugung schwer zugänglicher Hohlräume in Gussstücken aus Aluminium oder aus einer seiner Legierungen, aus einer Grundsubstanz und einem gehärteten organischen Bindemittel, dadurch gekennzeichnet , dass das zur Bindung der Grundsubstanz eingesetzte Bindemittel Zucker oder ein Zuckerderivat ist.1. Casting core for the production of hard-to-reach cavities in castings made of aluminum or one of its alloys, of a basic substance and a hardened organic binder, characterized in that the binder used to bind the basic substance is sugar or a sugar derivative. 2. Giesskern nach Anspruch 1, dadurch gekennzeichnet , dass als Bindemittel Zuckercoleur verwendet wird.2. Casting core according to claim 1, characterized in that sugar cereal is used as the binder. 3. Giesskern nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet , dass die Grundsubstanz in körniger Form vorliegt.3. Casting core according to one of claims 1 or 2, characterized in that the basic substance is in granular form. 4. Giesskern nach einem oder mehreren der Ansprüche 1 bis 3, dadurch gekennzeichnet , dass die Grundsubstanz ein wasserlösliches Salz, Quarzsand, ein Metallgranulat allein oder im jeweiligen Gemisch darstellt.4. Casting core according to one or more of claims 1 to 3, characterized in that the basic substance is a water-soluble salt, quartz sand, a metal granulate alone or in the respective mixture. 5. Giesskern nach einem oder mehreren der Ansprüche 1 bis 4, dadurch gekennzeichnet , dass der Mengenanteil des Bindemittels,bezogen auf das Gesamtgewicht des Giesskernes, 0,3 bis 15 Gew.% beträgt.5. Casting core according to one or more of claims 1 to 4, characterized in that the proportion of binder, based on the total weight of the casting core, is 0.3 to 15% by weight. 6. Giesskern nach einem oder mehreren der Ansprüche 1 bis 5, dadurch gekennzeichnet , dass im Kern mindestens ein eingepresstes Röhrchen enthalten ist.6. Casting core according to one or more of claims 1 to 5, characterized in that at least one pressed-in tube is contained in the core. 7. Verfahren zur Herstellung eines Giesskernes nach den Ansprüchen 1 bis 6, dadurch gekennzeichnet , dass die Grundsubstanz mit Zucker oder einem Derivat hiervon in wässriger oder organischer Lösung vermischt, in Formen verpresst und bei erhöhter Temperatur ausgebacken wird.7. Process for producing a casting core according to the Claims 1 to 6, characterized in that the basic substance is mixed with sugar or a derivative thereof in aqueous or organic solution, pressed into molds and baked at an elevated temperature. 8. Verfahren nach Anspruch 7, dadurch gekennzeichnet , dass der Anteil des Wassers und/ oder des organischen Lösungsmittels etwa das 0,1- bis 1-fache des Gewichtes des organischen Bindemittels beträgt.8. The method according to claim 7, characterized in that the proportion of water and / or the organic solvent is about 0.1 to 1 times the weight of the organic binder. 9. Verfahren nach einem oder beiden Ansprüchen 7 und 8, dadurch gekennzeichnet , dass die Grundsubstanz bei der Umhüllung mit dem Bindemittel eine Temperatur zwischen 20 und 180°C aufweist und der für die Umhüllung erforderliche Mischvorgang so lange fortgesetzt wird, bis ein trockenes, rieselfähiges Gemisch entstanden ist.9. The method according to one or both claims 7 and 8, characterized in that the basic substance in the coating with the binder has a temperature between 20 and 180 ° C and the mixing process required for the coating is continued until a dry, free-flowing Mixture has arisen. 10. Verfahren nach einem oder mehreren der Ansprüche 7 bis 9, dadurch gekennzeichnet , dass das Pressen bei Temperaturen zwischen 50 und 200°C stattfindet.10. The method according to one or more of claims 7 to 9, characterized in that the pressing takes place at temperatures between 50 and 200 ° C. 11. Verfahren nach einem oder mehreren der Ansprüche 7 bis 10, dadurch gekennzeichnet , dass das Ausbacken bei Temperaturen zwischen 150 und 3000C über einen Zeitraum von 10-120 Minuten durchgeführt wird.11. The method according to one or more of claims 7 to 10, characterized in that the baking is carried out at temperatures between 150 and 300 0 C over a period of 10-120 minutes. 12. Verfahren nach einem oder mehreren der Ansprüche 7 bis 11, dadurch gekennzeichnet , dass das Trocknen durch Einleiten warmer, trockener Luft beschleunigt wird.12. The method according to one or more of claims 7 to 11, characterized in that the drying is accelerated by introducing warm, dry air.
EP79105250A 1979-04-27 1979-12-18 Foundry core for producing hardly accessible hollow cavities in casting pieces, and process for its manufacture Expired EP0019015B1 (en)

Applications Claiming Priority (2)

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DE19792917208 DE2917208A1 (en) 1979-04-27 1979-04-27 CASTING CORE FOR GENERATING HARD ACCESSIBLE CAVES IN CASTING PIECES, AND METHOD FOR THE PRODUCTION THEREOF
DE2917208 1979-04-27

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EP0019015A1 true EP0019015A1 (en) 1980-11-26
EP0019015B1 EP0019015B1 (en) 1983-04-27

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US (1) US4361181A (en)
EP (1) EP0019015B1 (en)
JP (1) JPS55144352A (en)
BR (1) BR8000487A (en)
CA (1) CA1158014A (en)
DE (1) DE2917208A1 (en)
ES (2) ES8104929A1 (en)
PT (1) PT70731A (en)

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WO2004082866A2 (en) * 2003-03-21 2004-09-30 Emil Müller GmbH Water-soluble salt cores and method for producing water-soluble salt cores
WO2008003518A1 (en) 2006-07-07 2008-01-10 Emil Müller GmbH Salt cores for plastic (injection) molding
WO2008003517A1 (en) 2006-07-07 2008-01-10 Emil Müller GmbH Water-soluble salt core comprising functional component

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US7013948B1 (en) 2004-12-01 2006-03-21 Brunswick Corporation Disintegrative core for use in die casting of metallic components
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US8426494B2 (en) * 2009-10-06 2013-04-23 Amcol International Corp. Lignite urethane based resins for enhanced foundry sand performance
JP6565011B2 (en) * 2015-05-29 2019-08-28 リグナイト株式会社 Mold manufacturing method
WO2018138210A1 (en) 2017-01-25 2018-08-02 Technische Universität Bergakademie Freiberg Method for producing high temperature-resistant objects with improved thermomechanical properties
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WO2008003518A1 (en) 2006-07-07 2008-01-10 Emil Müller GmbH Salt cores for plastic (injection) molding
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BR8000487A (en) 1980-12-30
CA1158014A (en) 1983-12-06
JPS55144352A (en) 1980-11-11
ES495002A0 (en) 1981-06-16
ES488019A0 (en) 1981-05-16
EP0019015B1 (en) 1983-04-27
US4361181A (en) 1982-11-30
ES8104929A1 (en) 1981-05-16
ES8105595A1 (en) 1981-06-16
PT70731A (en) 1980-02-01
DE2917208A1 (en) 1980-12-04

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