EP0648560A1 - Method for the production of ceramic cores for casting - Google Patents

Method for the production of ceramic cores for casting Download PDF

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Publication number
EP0648560A1
EP0648560A1 EP94402286A EP94402286A EP0648560A1 EP 0648560 A1 EP0648560 A1 EP 0648560A1 EP 94402286 A EP94402286 A EP 94402286A EP 94402286 A EP94402286 A EP 94402286A EP 0648560 A1 EP0648560 A1 EP 0648560A1
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Prior art keywords
core
ceramic cores
manufacturing ceramic
cores according
heat treatment
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German (de)
French (fr)
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EP0648560B1 (en
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Thierry Alain Bardot
Chantal Sylvette Marie Noelle Langlois
Nadine Burkarth
Nicolas Lequeux
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Safran Aircraft Engines SAS
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Societe Nationale dEtude et de Construction de Moteurs dAviation SNECMA
SNECMA SAS
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/12—Treating moulds or cores, e.g. drying, hardening

Definitions

  • the present invention relates to a process for manufacturing ceramic cores for foundries from a thermoplastic paste.
  • foundry cores of a so-called "ceramic” type is known in particular in certain applications which require obtaining a set of characteristics and strict quality criteria such as resistance to high temperatures, lack of reactivity , dimensional stability and good mechanical properties.
  • these applications presenting such requirements mention will be made in particular of aeronautical applications and, for example, the obtaining in the foundry of turbine blades for turbojet engines.
  • the improvement of foundry processes evolving from equiax foundry to foundry by directed solidification or monocrystalline, has further increased these requirements concerning cores whose use and complexity are imposed by the search for high performance for the parts to be obtained, as is the case for example for hollow blades with internal cooling.
  • These fields of application relate to precision foundry processes, in particular to the process known as the lost wax foundry. In all cases the use of the core intervenes for the manufacture of hollow parts.
  • a ceramic material core is used which is held in the mold during the casting of metal, the outer surface of the core forming the inner surface of an internal cavity of the finished product obtained from this way. Precision and dimensional stability of the core are therefore essential to meet the thicknesses targeted on cast metal parts.
  • compositions intended for the preparation of such cores are given by FR-A 2,371,257 and essentially comprise molten silica, zircon flour and cristobalite which is a form of crystallized silica, a silicone resin being used as a binder and additional elements in small quantities such as lubricant and catalyst being added.
  • FR-A 2,371,257 essentially comprise molten silica, zircon flour and cristobalite which is a form of crystallized silica, a silicone resin being used as a binder and additional elements in small quantities such as lubricant and catalyst being added.
  • FR-A 2,371,257 examples of known composition intended for the preparation of such cores are given by FR-A 2,371,257 and essentially comprise molten silica, zircon flour and cristobalite which is a form of crystallized silica, a silicone resin being used as a binder and additional elements in small quantities such as lubricant and catalyst being
  • the cores used to cast the parts and blades are composed of ceramic with a generally porous structure: these cores are produced from a mixture consisting of a refractory fraction (in the form of particles) and an organic fraction more or less complex.
  • a refractory fraction in the form of particles
  • an organic fraction more or less complex is described by EP-A 0 328 452.
  • the shaping of the foundry cores in particular from thermoplastic pastes, can be done by molding using for example a press injection. This shaping is followed by a debinding operation during which the organic fraction of the nucleus is eliminated by various known means such as sublimation or thermal degradation, depending on the materials used.
  • a porous structure results.
  • a heat treatment for baking the core to consolidate the porous structure is then applied to the refractory fraction.
  • This treatment introduces a dimensional modification, in the form of a withdrawal which is often non-isotropic in the volume of the nucleus, compared to the initial form. At this stage, it may be necessary to strengthen the core so that it is not damaged in the cycle following use. It is known in this case in particular to carry out an impregnation by means of an organic resin.
  • the cores must have good mechanical strength and sufficient strength to withstand the mechanical and thermomechanical stresses during the stages of the lost wax process: injection of the wax model around the core, thermomechanical stresses between the core and the shell during dewaxing , burning, sintering and during the casting of the alloy around the core.
  • the properties of the core result from cooking, but according to known methods, the consolidation of the structure of the refractory core fraction is accompanied by shrinkage. This phenomenon leads to difficulties in developing core shaping products and materials such as the injection mold and has repercussions on the quality of the cores, the amplitude of the withdrawal anisotropies being added dimensional dispersions.
  • the invention aims to improve the process for manufacturing ceramic cores by reducing these dimensional changes while tightening the dimensional dispersions and retaining adequate mechanical strength.
  • an additional heat treatment may be necessary after impregnation to ensure dilatometric stability of the product. It follows from the process according to the invention that the dry residues of the impregnation products form particles which partially fill the porosity of the core and have the effect of reinforcing the mechanical resistance of the core by consolidating it and blocking at a low level the removal, without significant modification during subsequent heat treatments.
  • a first composition I comprises a ceramic mineral filler based on fused silica mixed with zircon flour and a waxy organic binder based on synthetic wax.
  • a second composition II in addition to the components of the first composition described above, further comprises in the mineral filler a small fraction of crystallized silica and an inorganic release agent.
  • the parts obtained are then unbound by heating to 200 ° C, as is known per se.
  • a heat treatment is then applied to the parts. Satisfactory results are obtained after treatment at 1100 ° C for 5 hours. Pre-sintering is thus obtained without resulting in significant shrinkage and resistance Acceptable mechanical properties are obtained in such a way as to allow manipulation of the cores without risk of deterioration. At least 30% of open porosity is observed.
  • the heat treatment temperature is between 1000 ° C and 1150 ° C and the duration between 1 and 5 hours.
  • Product A is an aqueous colloidal suspension of silica particles having 40% by mass of silica. After 24 hours of impregnation, approximately 90% of the open porosity is impregnated. After drying in an oven at 70 ° C for 24 hours, a gain in mass of the parts of between 8.7% and 9.5% is observed. A clear improvement in mechanical strength is noted. Drying can be done under vacuum A second product B was tested consisting of a colloidal suspension at 10% by mass of alumina, obtained by dispersing boehmite / AlOOH powder in a solution of acetic acid at 0.7%. Impregnation of 90% of the open pores is also obtained after 24 hours. After drying and high-temperature decomposition of the boehmite into alumina, a mass gain of 3% of the parts is obtained.
  • a mullite formation reaction occurs as follows: 3 Al2 O3 + 2 SiO2 ⁇ 3 Al2 O3.2SiO2
  • a third product C is obtained by mixing the previous two A and B. To obtain it, colloidal silica is added to the boehmite solution in acetic acid at 0.7%. The impregnation in this case makes it possible to fill 80 to 90% of the porosity opened in 24 hours and the mass gain of the parts is 3 to 3.5% after heat treatment.
  • a fourth used sol D is obtained by mixing colloidal silica (product A above) and a solution of aluminum nitrate.
  • the mixtures are produced so as to obtain, after drying, a mixture of alumina and silica in the stoichiometric proportion of the mullite.
  • the soil obtained is loaded with 8% Al2 O3 and 3.1% SiO2.
  • the very low viscosity solution allows in this case a pore impregnation close to 100%
  • a mass gain of 2.6% is observed.
  • the core can be subjected to preheating, in particular at a temperature between 1000 ° C and 1100 ° C and for a period between 1 and 4 hours.
  • the tests carried out corresponding to the implementation of the process for manufacturing ceramic cores according to the invention made it possible to record significant and advantageous results.
  • the process according to the invention avoids excessive brittleness of the cores. Impregnation after sintering using an organic resin of the "glue" type previously applied and which causes drawbacks in deformation of the cores during their use can thus be avoided. Satisfactory mechanical properties of resistance of the cores are obtained by the process according to the invention, in particular as regards resistance to thermal shock and mechanical resistance to heat, in particular in bending which is increased from 170% to 230%, depending on the impregnator used.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Mold Materials And Core Materials (AREA)
  • Producing Shaped Articles From Materials (AREA)

Abstract

A method for the production of ceramic cores for casting includes the following stages: - hot-injection of a thermoplastic paste based on a refractory ceramic composition and an organic fraction, - removal of the organic fraction by heat treatment, - heat treatment limited to a minimum consolidation, - impregnation of the porous structure of the core using a solution including a colloid of a simple oxide based on silica or alumina, - removal of the liquid part of the impregnation product.

Description

La présente invention concerne un procédé de fabrication de noyaux céramiques pour fonderie à partir d'une pâte thermoplastique.The present invention relates to a process for manufacturing ceramic cores for foundries from a thermoplastic paste.

L'utilisation de noyaux de fonderie d'un type dits "céramiques" est notamment connue dans certaines applications qui imposent l'obtention d'un ensemble de caractéristiques et de critères sévères de qualité comme la tenue aux hautes températures, l'absence de réactivité, la stabilité dimensionnelle et de bonnes caractéristiques mécaniques. Parmi ces applications présentant de telles exigences, on citera notamment les applications aéronautiques et par exemple, l'obtention en fonderie d'aubes de turbine pour turboréacteurs. Le perfectionnement des procédés de fonderie, évoluant de la fonderie équiaxe à la fonderie par solidification dirigée ou monocristalline, a encore accru ces exigences concernant les noyaux dont l'utilisation et la complexité sont imposées par la recherche des hautes performances pour les pièces à obtenir, comme c'est le cas par exemple pour les aubes creuses à refroidissement interne. Ces domaines d'application se rattachent aux procédés de fonderie de précision, notamment au procédé connu sous la désignation de fonderie à la cire perdue. Dans tous les cas l'utilisation du noyau intervient pour la fabrication de pièces creuses.The use of foundry cores of a so-called "ceramic" type is known in particular in certain applications which require obtaining a set of characteristics and strict quality criteria such as resistance to high temperatures, lack of reactivity , dimensional stability and good mechanical properties. Among these applications presenting such requirements, mention will be made in particular of aeronautical applications and, for example, the obtaining in the foundry of turbine blades for turbojet engines. The improvement of foundry processes, evolving from equiax foundry to foundry by directed solidification or monocrystalline, has further increased these requirements concerning cores whose use and complexity are imposed by the search for high performance for the parts to be obtained, as is the case for example for hollow blades with internal cooling. These fields of application relate to precision foundry processes, in particular to the process known as the lost wax foundry. In all cases the use of the core intervenes for the manufacture of hollow parts.

Dans la méthode de fonderie dite à la cire perdue, on utilise un noyau en matériau céramique qui est tenu dans le moule lors de la coulée de métal, la surface extérieure du noyau formant la surface intérieure d'une cavité interne du produit fini obtenu de cette façon. La précision et la stabilité dimensionnelle du noyau sont donc essentielles pour satisfaire aux épaisseurs visées sur pièces métalliques coulées.In the lost wax foundry method, a ceramic material core is used which is held in the mold during the casting of metal, the outer surface of the core forming the inner surface of an internal cavity of the finished product obtained from this way. Precision and dimensional stability of the core are therefore essential to meet the thicknesses targeted on cast metal parts.

Des exemples de composition connues destinées à la préparation de tels noyaux sont donnés par FR-A 2.371.257 et comportent essentiellement de la silice fondue, de la farine de zircon et de la cristobalite qui est une forme de silice cristallisée, une résine de silicone étant utilisée comme liant et des éléments additionnels en faibles quantités tels que lubrifiant et catalyseur étant ajoutés. Le procédé de préparation est également décrit.Examples of known composition intended for the preparation of such cores are given by FR-A 2,371,257 and essentially comprise molten silica, zircon flour and cristobalite which is a form of crystallized silica, a silicone resin being used as a binder and additional elements in small quantities such as lubricant and catalyst being added. The preparation process is also described.

De manière générale, les noyaux utilisés pour couler les pièces et aubes sont composés de céramique à structure généralement poreuse : ces noyaux sont réalisés à partir d'un mélange constitué d'une fraction réfractaire (sous forme de particules) et d'une fraction organique plus ou moins complexe. Un autre exemple est décrit par EP-A 0 328 452.
De manière connue en soi, la mise en forme des noyaux de fonderie, notamment à partir de pâtes thermoplastiques, peut se faire par moulage en utilisant par exemple une injection à la presse. Cette mise en forme est suivie d'une opération de déliantage au cours de laquelle la fraction organique du noyau est éliminée par divers moyens connus tels que sublimation ou dégradation thermique, suivant les matériaux utilisés. Une structure poreuse en résulte. Un traitement thermique de cuisson du noyau permettant de consolider la structure poreuse est alors appliqué à la fraction réfractaire. Ce traitement introduit une modification dimensionnelle, sous forme d'un retrait qui est souvent non isotrope dans le volume du noyau, par rapport à la forme initiale.
A ce stade, il peut être nécessaire de renforcer le noyau afin qu'il ne soit pas endommagé dans le cycle suivant l'utilisation. Il est connu dans ce cas notamment d'effectuer une imprégnation au moyen d'une résine organique.In general, the cores used to cast the parts and blades are composed of ceramic with a generally porous structure: these cores are produced from a mixture consisting of a refractory fraction (in the form of particles) and an organic fraction more or less complex. Another example is described by EP-A 0 328 452.
In a manner known per se, the shaping of the foundry cores, in particular from thermoplastic pastes, can be done by molding using for example a press injection. This shaping is followed by a debinding operation during which the organic fraction of the nucleus is eliminated by various known means such as sublimation or thermal degradation, depending on the materials used. A porous structure results. A heat treatment for baking the core to consolidate the porous structure is then applied to the refractory fraction. This treatment introduces a dimensional modification, in the form of a withdrawal which is often non-isotropic in the volume of the nucleus, compared to the initial form.
At this stage, it may be necessary to strengthen the core so that it is not damaged in the cycle following use. It is known in this case in particular to carry out an impregnation by means of an organic resin.

A ce stade le noyau est prêt pour être utilisé c'est à dire qu'il doit supporter le cycle de fabrication dit à la cire perdue suivant :

  • injection du modèle cire autour du noyau
  • réalisation du moule carapace
  • élimination du modèle cire
  • divers traitements thermiques : brûlage des résidus cire, frittage du moule carapace, préchauffage, coulée de l'alliage, refroidissement de l'alliage
  • élimination du noyau.
At this stage the kernel is ready to be used, that is to say it must endure the wax-making cycle. lost following:
  • injection of the wax model around the nucleus
  • shell mold creation
  • elimination of the wax model
  • various heat treatments: burning of wax residues, sintering of the shell mold, preheating, casting of the alloy, cooling of the alloy
  • removal of the nucleus.

Dans la mise en oeuvre de ces procédés connus des difficultés subsistent et les résultats obtenus ne sont pas totalement satisfaisants. Des dispersions sur la géométrie du noyau se répercutent sur la pièce terminée alors qu'une tolérance dimensionnelle de l'ordre de ± 0,1 mm peut être exigée. Une amélioration des résultats impose d'obtenir une stabilité dimensionnelle des noyaux qui reste délicate à maîtriser car la structure du matériau évolue au cours des traitements thermiques successifs précédemment indiqués : cuisson du noyau, échanges thermiques dans le moule carapace de fonderie.In the implementation of these known methods, difficulties remain and the results obtained are not completely satisfactory. Dispersions on the geometry of the core affect the finished part, while a dimensional tolerance of the order of ± 0.1 mm may be required. An improvement in the results requires obtaining a dimensional stability of the cores which remains difficult to control because the structure of the material changes during the successive heat treatments previously indicated: firing of the core, heat exchanges in the foundry shell mold.

En outre, les noyaux doivent présenter une bonne tenue mécanique et une résistance suffisante pour supporter les contraintes mécaniques et thermomécaniques lors des étapes du procédé à la cire perdue : injection du modèle cire autour du noyau, contraintes thermomécaniques entre noyau et carapace au cours du décirage, brûlage, frittage et lors de la coulée de l'alliage autour du noyau.In addition, the cores must have good mechanical strength and sufficient strength to withstand the mechanical and thermomechanical stresses during the stages of the lost wax process: injection of the wax model around the core, thermomechanical stresses between the core and the shell during dewaxing , burning, sintering and during the casting of the alloy around the core.

Les propriétés du noyau résultent de la cuisson mais selon les procédés connus, la consolidation de la structure de la fraction réfractaire de noyau s'accompagne d'un retrait. Ce phénomène entraîne les difficultés de mise au point des produits et matériels de mise en forme du noyau tels que le moule d'injection et a des répercussions sur la qualité des noyaux, l'amplitude des anisotropies de retrait s'ajoutant aux dispersions dimensionnelles. L'invention vise à améliorer le procédé de fabrication des noyaux céramiques en réduisant ces modifications dimensionnelles tout en en resserrant les dispersions dimensionnelles et en conservant une tenue i mécanique adéquate.The properties of the core result from cooking, but according to known methods, the consolidation of the structure of the refractory core fraction is accompanied by shrinkage. This phenomenon leads to difficulties in developing core shaping products and materials such as the injection mold and has repercussions on the quality of the cores, the amplitude of the withdrawal anisotropies being added dimensional dispersions. The invention aims to improve the process for manufacturing ceramic cores by reducing these dimensional changes while tightening the dimensional dispersions and retaining adequate mechanical strength.

Ces résultats améliorés sont obtenus grâce à un procédé de fabrication de noyaux céramiques comportant les étapes connues en soi de mise en forme puis d'élimination de la fraction organique du noyau, caractérisé en ce que le traitement thermique est limité à une consolidation minimale de la structure de la fraction céramique du noyau, procurant une résistance mécanique juste suffisante pour la manipulation des noyaux et de manière à limiter le retrait à une valeur minimale et est suivi d'une étape d'imprégnation de la structure poreuse du noyau au moyen d'une solution constituée d'au moins un colloïde simple pris dans le groupe silice et alumine colloïdales et d'ajouts éventuels comportant plusieurs sols en mélanges ou des mélanges de sols et de sels, puis d'une étape d'élimination de la partie liquide du produit d'imprégnation.
L'élimination de la partie liquide du produit d'imprégnation peut être obtenue notamment par séchage.
Dans certains cas, un traitement thermique complémentaire peut être nécessaire après l'imprégnation pour assurer une stabilité dilatométrique du produit.
Il résulte du procédé conforme à l'invention que les résidus secs des produits d'imprégnation forment des particules qui comblent partiellement la porosité du noyau et ont pour effet de renforcer la résistance mécanique du noyau en le consolidant et de bloquer à un faible niveau le retrait, sans modification notable lors des traitements thermiques ultérieurs.These improved results are obtained thanks to a process for manufacturing ceramic cores comprising the steps known per se of shaping and then elimination of the organic fraction of the core, characterized in that the heat treatment is limited to a minimum consolidation of the structure of the ceramic fraction of the core, providing a mechanical resistance just sufficient for handling the cores and so as to limit the shrinkage to a minimum value and is followed by a step of impregnating the porous structure of the core by means of a solution consisting of at least one simple colloid taken from the colloidal silica and alumina group and possible additions comprising several mixed soils or mixtures of soils and salts, then a step of eliminating the liquid part of the impregnation product.
The elimination of the liquid part of the impregnation product can be obtained in particular by drying.
In some cases, an additional heat treatment may be necessary after impregnation to ensure dilatometric stability of the product.
It follows from the process according to the invention that the dry residues of the impregnation products form particles which partially fill the porosity of the core and have the effect of reinforcing the mechanical resistance of the core by consolidating it and blocking at a low level the removal, without significant modification during subsequent heat treatments.

D'autres caractéristiques et avantages de l'invention seront mieux compris à la lecture de la description qui va suivre d'exemples de modes de réalisation de l'invention, en référence aux dessins annexés sur lesquels :

  • la figure 1 représente les courbes de variation de températures lors d'essais de pièces représentatives des noyaux de fonderie obtenus par un procédé conforme à l'invention,
  • la figure 2 représente une courbe de variation des retraits en pourcentages en fonction d'un cycle de température pour une pièce obtenue selon un procédé antérieur connu,
  • la figure 3 représente les courbes de variation comparative des retraits en pourcentages en fonction de la température pour diverses variantes du procédé de fabrication.
Other characteristics and advantages of the invention will be better understood on reading the following description of examples of embodiments of the invention, with reference to the accompanying drawings in which:
  • FIG. 1 represents the temperature variation curves during tests of parts representative of the foundry cores obtained by a process in accordance with the invention,
  • FIG. 2 represents a curve of variation of the withdrawals in percentages as a function of a temperature cycle for a part obtained according to a known prior process,
  • FIG. 3 represents the curves of comparative variation of the withdrawals in percentages as a function of the temperature for various variants of the manufacturing process.

La mise au point du procédé de fabrication de noyaux céramiques pour fonderie de précision a été effectuée à partir de tests expérimentaux. Des pièces représentatives de noyaux sont ainsi réalisées suivant des techniques connues d'injection d'une pâte céramique thermoplastique. Une première composition I comporte une charge minérale céramique à base de silice fondue mélangée à de la farine de zircon et un liant organique cireux à base de cire de synthèse.The development of the process for manufacturing ceramic cores for precision foundries was carried out using experimental tests. Representative pieces of cores are thus produced according to known techniques for injecting a thermoplastic ceramic paste. A first composition I comprises a ceramic mineral filler based on fused silica mixed with zircon flour and a waxy organic binder based on synthetic wax.

Une deuxième composition II en plus des composants de la première composition décrits ci-dessus, comporte en outre dans la charge minérale une faible fraction de silice cristallisée et un agent démoulant minéral.A second composition II, in addition to the components of the first composition described above, further comprises in the mineral filler a small fraction of crystallized silica and an inorganic release agent.

Les pièces obtenues sont alors déliantées par chauffage vers 200°C, comme il est connu en soi.The parts obtained are then unbound by heating to 200 ° C, as is known per se.

Un traitement thermique est ensuite appliqué aux pièces. Des résultats satisfaisants sont obtenus après un traitement à 1100°C pendant 5 heures. Un préfrittage est ainsi obtenu sans qu'il en résulte un retrait significatif et une tenue mécanique acceptable est obtenue de manière à permettre une manipulation des noyaux sans risque de détérioration. Au moins 30 % de porosité ouverte est observée. Selon les applications, la température de traitement thermique est comprise entre 1000°C et 1150°C et la durée comprise entre 1 et 5 heures.A heat treatment is then applied to the parts. Satisfactory results are obtained after treatment at 1100 ° C for 5 hours. Pre-sintering is thus obtained without resulting in significant shrinkage and resistance Acceptable mechanical properties are obtained in such a way as to allow manipulation of the cores without risk of deterioration. At least 30% of open porosity is observed. Depending on the applications, the heat treatment temperature is between 1000 ° C and 1150 ° C and the duration between 1 and 5 hours.

Pour réaliser l'imprégnation des pièces, plusieurs compositions ont été testées. Un produit A est une suspension colloïdale aqueuse de particules de silice présentant 40 % en masse de silice. Après 24 heures d'imprégnation, environ 90 % de la porosité ouverte est imprégnée. Après séchage en étuve à 70°C pendant 24 heures, un gain en masse des pièces compris entre 8,7 % et 9,5% est observé. Une nette amélioration de la tenue mécanique est constatée. Le séchage peut être effectué sous vide
Un second produit B a été testé consistant en une suspension colloïdale à 10 % en masse d'alumine, obtenue en dispersant de la poudre de boehmite/AlOOH dans une solution d'acide acétique à 0,7 %. Une imprégnation de 90 % des pores ouvertes est également obtenue au bout de 24 heures. Après séchage et décomposition à haute température de la boehmite en alumine, un gain de masse de 3% des pièces est obtenu.In order to impregnate the pieces, several compositions were tested. Product A is an aqueous colloidal suspension of silica particles having 40% by mass of silica. After 24 hours of impregnation, approximately 90% of the open porosity is impregnated. After drying in an oven at 70 ° C for 24 hours, a gain in mass of the parts of between 8.7% and 9.5% is observed. A clear improvement in mechanical strength is noted. Drying can be done under vacuum
A second product B was tested consisting of a colloidal suspension at 10% by mass of alumina, obtained by dispersing boehmite / AlOOH powder in a solution of acetic acid at 0.7%. Impregnation of 90% of the open pores is also obtained after 24 hours. After drying and high-temperature decomposition of the boehmite into alumina, a mass gain of 3% of the parts is obtained.

Une réaction de formation de mullite se produit suivant : 3 Al₂ O₃ + 2 SiO₂ → 3 Al₂ O₃.2SiO₂

Figure imgb0001
A mullite formation reaction occurs as follows: 3 Al₂ O₃ + 2 SiO₂ → 3 Al₂ O₃.2SiO₂
Figure imgb0001

Un troisième produit C est obtenu par mélange des deux précédents A et B. Pour l'obtenir, la silice colloïdale est ajoutée dans la solution de boehmite dans l'acide acétique à 0,7 %. L'imprégnation permet dans ce cas de remplir 80 à 90 % de la porosité ouverte en 24 heures et le gain en masse des pièces est de 3 à 3,5 % après traitement thermique.A third product C is obtained by mixing the previous two A and B. To obtain it, colloidal silica is added to the boehmite solution in acetic acid at 0.7%. The impregnation in this case makes it possible to fill 80 to 90% of the porosity opened in 24 hours and the mass gain of the parts is 3 to 3.5% after heat treatment.

Un quatrième sol utilisé D est obtenu par mélange de silice colloïdale (produit A ci-dessus) et d'une solution de nitrate d'aluminium.A fourth used sol D is obtained by mixing colloidal silica (product A above) and a solution of aluminum nitrate.

Pour le produit D, comme pour le produit C, les mélanges sont réalisés de manière à obtenir après séchage un mélange d'alumine et de silice dans la proportion stoechiométrique de la mullite. le sol obtenu est chargé à 8 % de Al₂ O₃ et 3,1 % de SiO₂. La solution très peu visqueuse permet dans ce cas une imprégnation des pores proche de 100 % Après traitement thermique des pièces, effectué à 1150°C pendant 1 heure, un gain en masse de 2,6 % est observé.
Selon les applications, avant coulée du métal, le noyau peut être soumis à un préchauffage, notamment à une température comprise entre 1000°C et 1100°C et pendant une durée comprise entre 1 et 4 heures.
Les tests effectués correspondant à la mise en oeuvre du procédé de fabrication de noyaux céramiques conforme à l'invention ont permis d'enregistrer des résultats significatifs et avantageux.For product D, as for product C, the mixtures are produced so as to obtain, after drying, a mixture of alumina and silica in the stoichiometric proportion of the mullite. the soil obtained is loaded with 8% Al₂ O₃ and 3.1% SiO₂. The very low viscosity solution allows in this case a pore impregnation close to 100% After heat treatment of the parts, carried out at 1150 ° C. for 1 hour, a mass gain of 2.6% is observed.
Depending on the applications, before casting the metal, the core can be subjected to preheating, in particular at a temperature between 1000 ° C and 1100 ° C and for a period between 1 and 4 hours.
The tests carried out corresponding to the implementation of the process for manufacturing ceramic cores according to the invention made it possible to record significant and advantageous results.

Des mesures par dilatomètrie au moyen d'un dilatomètre absolu permettent notamment de relever le retrait des pièces en fonction de la température correspondant aux variations dimensionnelles des pièces qui représentent un critère important de qualité dans l'utilisation des noyaux en fonderie de précision.
Ainsi des pièces suivant la deuxième composition II précédemment décrite ont été soumises soit à un cycle thermique de montée en température à 1500°C qui correspond à la température atteinte par les noyaux lors de la coulée de super-alliages, comme représenté par la courbe 1 de la figure 1, soit à un cycle thermique comportant un palier intermédiaire de 5 heures à 1200°C, comme représenté par la courbe 2 de la figure 1 qui représente la température en degrés en ordonnées et le temps en minutes en abscisses.Measurements by dilatometry using an absolute dilatometer make it possible in particular to record the shrinkage of the parts as a function of the temperature corresponding to the dimensional variations of the parts which represent an important quality criterion in the use of cores in precision foundry.
Thus, parts according to the second composition II previously described were subjected either to a thermal cycle of temperature rise to 1500 ° C. which corresponds to the temperature reached by the cores during the casting of superalloys, as represented by curve 1 of Figure 1, or a thermal cycle comprising an intermediate level of 5 hours at 1200 ° C, as shown by curve 2 of Figure 1 which represents the temperature in degrees on the ordinate and the time in minutes on the abscissa.

La variation correspondante des retraits représentés en pourcentage en ordonnées est montrée par la courbe 3 de la figure 2 pour une pièce de composition II obtenue suivant un procédé antérieur connu et soumise au cycle de la courbe 1 de la figure 1.
Les courbes de la figure 3 montrent les variations de retraits comparatives suivant les imprégnations réalisées pour des pièces de composition II :

  • la courbe 4, sans infiltration
  • la courbe 5 avec une infiltration par le produit A
  • la courbe 6 avec une infiltration par le produit B
  • la courbe 7 avec une infiltration par le produit D.
The corresponding variation in shrinkage represented as a percentage on the ordinate is shown by curve 3 in FIG. 2 for a piece of composition II obtained according to a known prior process and subjected to the cycle of curve 1 in FIG. 1.
The curves in Figure 3 show the variations in comparative withdrawals according to the impregnations carried out for pieces of composition II:
  • curve 4, without infiltration
  • curve 5 with infiltration by product A
  • curve 6 with infiltration by product B
  • curve 7 with infiltration by product D.

Les tests effectués et les résultats observés montrent que l'opération d'imprégnation des pièces de compositions utilisées pour la fabrication de noyaux céramiques pour fonderie de précision au moyen d'oxydes colloïdaux du type précurseurs de silice, d'alumine ou de mullite assure un retrait mesuré sur les pièces 2 à 7 fois plus faible à l'issue d'un traitement thermique à 1500°C que le résultat obtenu pour des pièces non imprégnées suivant le procédé antérieur. Le support imprégné voit sa tenue mécanique en flexion à froid augmentée de 50 à 70%, suivant l'imprégnant utilisé.The tests carried out and the results observed show that the operation of impregnating the parts of compositions used for the manufacture of ceramic cores for precision foundry using colloidal oxides of the precursor type of silica, alumina or mullite ensures shrinkage measured on the parts 2 to 7 times lower after a heat treatment at 1500 ° C than the result obtained for parts not impregnated according to the previous process. The impregnated support sees its mechanical resistance in cold bending increased by 50 to 70%, depending on the impregnator used.

En outre, le procédé conforme à l'invention évite une fragilité trop importante des noyaux. L'imprégnation après frittage au moyen d'une résine organique de type "colle" antérieurement appliquée et qui entraîne des inconvénients de déformation des noyaux lors de leur utilisation peut ainsi être évitée. Des propriétés mécaniques satisfaisantes de tenue des noyaux sont obtenues grâce au procédé conforme à l'invention, notamment en ce qui concerne une tenue aux chocs thermiques et la tenue mécanique à chaud, notamment en flexion qui se trouve augmentée de 170% à 230%, suivant l'imprégnant utilisé.In addition, the process according to the invention avoids excessive brittleness of the cores. Impregnation after sintering using an organic resin of the "glue" type previously applied and which causes drawbacks in deformation of the cores during their use can thus be avoided. Satisfactory mechanical properties of resistance of the cores are obtained by the process according to the invention, in particular as regards resistance to thermal shock and mechanical resistance to heat, in particular in bending which is increased from 170% to 230%, depending on the impregnator used.

Claims (10)

Procédé de fabrication de noyaux céramiques pour fonderie de précision comportant une étape connue en soi de mise en forme telle que par injection à chaud d'une pâte thermoplastique composée d'une fraction céramique réfractaire et d'une fraction organique dans un moule métallique, suivie d'une opération de déliantage au cours de laquelle la fraction organique du noyau est éliminée dans des conditions connues en soi telles que par sublimation ou dégradation thermique caractérisé en ce que le traitement thermique subséquent est limité à une consolidation minimale de la structure de la fraction céramique réfractaire du noyau, procurant une résistance mécanique juste suffisante pour la manipulation du noyau et de manière à limiter le retrait à une valeur minimale et est suivi d'une étape d'imprégnation de la structure poreuse du noyau au moyen d'une solution constituée d'au moins un colloïde d'oxyde simple pris dans le groupe silice et alumine colloïdales et d'ajouts éventuels comportant plusieurs sols en mélanges ou des mélanges de sols et de sels, puis d'une étape d'élimination de la partie liquide du produit d'imprégnation.Method for manufacturing ceramic cores for precision foundries comprising a step known per se of shaping such as by hot injection of a thermoplastic paste composed of a refractory ceramic fraction and an organic fraction in a metal mold, followed a debinding operation during which the organic fraction of the nucleus is eliminated under conditions known per se such as by sublimation or thermal degradation characterized in that the subsequent heat treatment is limited to a minimum consolidation of the structure of the fraction refractory ceramic of the core, providing a mechanical resistance just sufficient for the manipulation of the core and so as to limit the shrinkage to a minimum value and is followed by a step of impregnating the porous structure of the core by means of a constituted solution at least one simple oxide colloid taken from the colloidal silica and alumina group e t possible additions comprising several mixed soils or mixtures of soils and salts, then a step of eliminating the liquid part of the impregnation product. Procédé de fabrication de noyaux céramiques selon la revendication 1 dans lequel ladite opération de déliantage est séparée du traitement thermique de consolidation.A method of manufacturing ceramic cores according to claim 1 wherein said debinding operation is separated from the consolidation heat treatment. Procédé de fabrication de noyaux céramiques selon la revendication 1 dans lequel le déliantage ou élimination de la fraction organique du noyau est obtenu au cours dudit traitement thermique.A method of manufacturing ceramic cores according to claim 1 wherein the debinding or elimination of the organic fraction of the core is obtained during said heat treatment. Procédé de fabrication de noyaux céramiques selon l'une quelconque des revendications 1 à 3 dans lequel l'élimination de la partie liquide du produit d'imprégnation est effectué par séchage.A method of manufacturing ceramic cores according to any one of claims 1 to 3 wherein the removal of the liquid part of the impregnation product is carried out by drying. Procédé de fabrication de noyaux céramiques selon la revendication 4 dans lequel ledit séchage est effectué sous vide.A method of manufacturing ceramic cores according to claim 4 wherein said drying is carried out under vacuum. Procédé de fabrication de noyaux céramiques selon la revendication 4 dans lequel le séchage est effectué en étuve, à 70°C, pendant 24 heures.A method of manufacturing ceramic cores according to claim 4 wherein the drying is carried out in an oven, at 70 ° C, for 24 hours. Procédé de fabrication de noyaux céramiques selon l'une quelconque des revendications 1 à 6 dans lequel le traitement thermique est effectué à une température comprise entre 1000°C et 1150°C, pendant une durée comprise entre 1 et 5 heures.A method of manufacturing ceramic cores according to any one of claims 1 to 6 wherein the heat treatment is carried out at a temperature between 1000 ° C and 1150 ° C, for a period between 1 and 5 hours. Procédé de fabrication de noyaux céramiques selon l'une quelconque des revendications 1 à 7 dans lequel la solution d'imprégnation utilisée est de la bochmite colloïdale et la durée de l'imprégnation est de 24 heures.Process for manufacturing ceramic cores according to any one of Claims 1 to 7, in which the impregnation solution used is colloidal bochmite and the duration of the impregnation is 24 hours. Procédé de fabrication de noyaux céramiques selon l'une quelconque des revendications 1 à 8 dans lequel avant coulée du métal, le noyau est soumis à un préchauffage, ledit traitement thermique assurant une réaction entre les résidus d'imprégnation et la partie céramique réfractaire du noyau de manière à renforcer le noyau et à assurer une bonne tenu mécanique aux hautes températures de coulée.Process for manufacturing ceramic cores according to any one of Claims 1 to 8, in which before casting the metal, the core is subjected to preheating, said heat treatment ensuring a reaction between the impregnation residues and the refractory ceramic part of the core so as to strengthen the core and ensure good mechanical strength at high casting temperatures. Procédé de fabrication de noyau céramiques selon la revendication 9 dans lequel le préchauffage est effectué à une température comprise entre 1000°C et 1100°C, pendant une durée comprise entre 1 et 4 heures.Process for manufacturing ceramic cores according to claim 9, in which the preheating is carried out at a temperature between 1000 ° C and 1100 ° C, for a time between 1 and 4 hours.
EP94402286A 1993-10-13 1994-10-12 Method for the production of ceramic cores for casting Expired - Lifetime EP0648560B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2785836A1 (en) * 1998-11-12 2000-05-19 Snecma Thin ceramic core, for precision casting e.g. of internally cooled aircraft turbo-jet blades, is produced by casting a core-making mixture strip, shaping, curing and impregnating with resin or organic polymer

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6029736A (en) * 1997-08-29 2000-02-29 Howmet Research Corporation Reinforced quartz cores for directional solidification casting processes
US6588484B1 (en) 2000-06-20 2003-07-08 Howmet Research Corporation Ceramic casting cores with controlled surface texture
US6808010B2 (en) 2001-03-13 2004-10-26 Howmet Research Corporation Method for treating ceramic cores
US6494250B1 (en) 2001-05-14 2002-12-17 Howmet Research Corporation Impregnated alumina-based core and method
CN102489670B (en) * 2011-12-13 2013-04-03 丹阳市精密合金厂有限公司 Ceramic core for molding of support plate and preparation method thereof
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JP6374752B2 (en) * 2014-10-08 2018-08-15 株式会社ノリタケカンパニーリミテド Refractory and its manufacturing method
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CN110465627B (en) * 2019-09-16 2021-02-02 郑州航空工业管理学院 Method for manufacturing surface-layer compact internal loose ceramic core for precision casting of hollow turbine blade
CN112222362B (en) * 2020-09-10 2021-10-29 中国科学院金属研究所 Silicon-based ceramic core resistant to cold and hot impact, high-temperature creep and easy to remove and preparation process thereof

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1187768B (en) * 1959-04-13 1965-02-25 Howe Sound Co Process for the production of foundry mold masks
JPS5029241A (en) * 1973-07-19 1975-03-25
DD127213A1 (en) * 1976-08-27 1977-09-14
JPS53212A (en) * 1976-06-24 1978-01-05 Toyota Motor Co Ltd Manufacture of ceramic products
FR2371257A1 (en) * 1976-11-17 1978-06-16 Howmet Turbine Components CERAMIC CORES FOR THE PREPARATION OF HOLLOW CASINGS
JPS5370030A (en) * 1976-12-03 1978-06-22 Taiyou Butsusan Kk Rapid molding method of investment mold
JPS5550947A (en) * 1978-10-12 1980-04-14 Hitachi Metal Precision:Kk Ceramic core for precision casting
US4685503A (en) * 1983-09-12 1987-08-11 Aisin Seiki Kabushiki Kaisha Method of manufacturing a disintegratable core for casting
EP0328452A1 (en) * 1988-02-10 1989-08-16 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Process for manufacturing ceramic foundry cores
US5067548A (en) * 1991-03-19 1991-11-26 Certech Incorporated Method of forming a ceramic mold for metal casting

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3686006A (en) * 1970-12-02 1972-08-22 Precision Metalsmiths Inc Refractory cores and methods of making the same
US3688832A (en) * 1971-02-22 1972-09-05 Precision Metalsmiths Inc Refractory cores
JPS5131009B2 (en) * 1973-05-09 1976-09-04

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1187768B (en) * 1959-04-13 1965-02-25 Howe Sound Co Process for the production of foundry mold masks
JPS5029241A (en) * 1973-07-19 1975-03-25
JPS53212A (en) * 1976-06-24 1978-01-05 Toyota Motor Co Ltd Manufacture of ceramic products
DD127213A1 (en) * 1976-08-27 1977-09-14
FR2371257A1 (en) * 1976-11-17 1978-06-16 Howmet Turbine Components CERAMIC CORES FOR THE PREPARATION OF HOLLOW CASINGS
JPS5370030A (en) * 1976-12-03 1978-06-22 Taiyou Butsusan Kk Rapid molding method of investment mold
JPS5550947A (en) * 1978-10-12 1980-04-14 Hitachi Metal Precision:Kk Ceramic core for precision casting
US4685503A (en) * 1983-09-12 1987-08-11 Aisin Seiki Kabushiki Kaisha Method of manufacturing a disintegratable core for casting
EP0328452A1 (en) * 1988-02-10 1989-08-16 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Process for manufacturing ceramic foundry cores
US5067548A (en) * 1991-03-19 1991-11-26 Certech Incorporated Method of forming a ceramic mold for metal casting

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 7631, Derwent World Patents Index; AN 76-58291X Ÿ31! *
DATABASE WPI Week 7751, Derwent World Patents Index; AN 77-90192 Ÿ51! *
DATABASE WPI Week 7807, Derwent World Patents Index; AN 78-13185A Ÿ07! *
DATABASE WPI Week 7830, Derwent World Patents Index; AN 78-54451A Ÿ30! *
PATENT ABSTRACTS OF JAPAN vol. 4, no. 92 (M - 018) 3 July 1980 (1980-07-03) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2785836A1 (en) * 1998-11-12 2000-05-19 Snecma Thin ceramic core, for precision casting e.g. of internally cooled aircraft turbo-jet blades, is produced by casting a core-making mixture strip, shaping, curing and impregnating with resin or organic polymer
EP1013360A1 (en) * 1998-11-12 2000-06-28 SOCIETE NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION -Snecma Method for producing thin ceramic foundry cores
US6286582B1 (en) 1998-11-12 2001-09-11 Societe Nationale d'Etude et de Construction de Moteurs d'Aviation “SNECMA” Process for the manufacture of thin ceramic cores for use in precision casting

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FR2711082A1 (en) 1995-04-21
JPH07232236A (en) 1995-09-05
DE69414974T2 (en) 1999-06-02
FR2711082B1 (en) 1995-12-01
US5697418A (en) 1997-12-16
DE69414974D1 (en) 1999-01-14
ZA947978B (en) 1995-06-15
JP3540842B2 (en) 2004-07-07

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