WO2010057464A2 - Mélange de matière de moulage et masselotte pour coulage d'aluminium - Google Patents

Mélange de matière de moulage et masselotte pour coulage d'aluminium Download PDF

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Publication number
WO2010057464A2
WO2010057464A2 PCT/DE2009/001602 DE2009001602W WO2010057464A2 WO 2010057464 A2 WO2010057464 A2 WO 2010057464A2 DE 2009001602 W DE2009001602 W DE 2009001602W WO 2010057464 A2 WO2010057464 A2 WO 2010057464A2
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WO
WIPO (PCT)
Prior art keywords
feeder
molding material
material mixture
aluminum
exothermic
Prior art date
Application number
PCT/DE2009/001602
Other languages
German (de)
English (en)
Other versions
WO2010057464A3 (fr
Inventor
Andre Gerhards
Udo Skerdi
Josef Kroth
Henning Rehse
Original Assignee
AS Lüngen GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AS Lüngen GmbH filed Critical AS Lüngen GmbH
Priority to CN200980153599XA priority Critical patent/CN102271836A/zh
Priority to EA201170690A priority patent/EA201170690A1/ru
Priority to BRPI0921527A priority patent/BRPI0921527A2/pt
Priority to JP2011536736A priority patent/JP2012509182A/ja
Priority to US13/130,134 priority patent/US20110220314A1/en
Priority to MX2011005223A priority patent/MX2011005223A/es
Priority to EP09801919A priority patent/EP2349609A2/fr
Publication of WO2010057464A2 publication Critical patent/WO2010057464A2/fr
Publication of WO2010057464A3 publication Critical patent/WO2010057464A3/fr
Priority to ZA2011/03298A priority patent/ZA201103298B/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D7/00—Casting ingots, e.g. from ferrous metals
    • B22D7/06—Ingot moulds or their manufacture
    • B22D7/10—Hot tops therefor
    • B22D7/104—Hot tops therefor from exothermic material only
    • 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
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
    • B22C1/04—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives for protection of the casting, e.g. against decarbonisation
    • B22C1/06—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives for protection of the casting, e.g. against decarbonisation for casting extremely oxidisable metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
    • B22C9/088—Feeder heads

Definitions

  • the invention relates to an exothermic Formstoffxnischung for the production of feeders for aluminum casting, a prepared from the molding material feeder for aluminum casting and its use for aluminum casting.
  • feeders are regularly used in or on the casting mold in order to compensate for the volume deficit on solidification of the casting and to prevent voids formation in the casting.
  • the feeders are connected to the casting or vulnerable casting area and are usually located above or on the side of the mold cavity. They include .one. Aus.gle.ichshohlraum ,. which is connected to the Eormhohlraum__der mold and initially receives liquid metal. At a later date, at which the metal in the mold cavity solidified, the liquid metal is again released from the compensation cavity to compensate for the volume deficit of the casting.
  • a model is first produced that substantially corresponds in shape to the metal casting to be produced. Feeders and feeders are attached to this model. Subsequently, the model is surrounded in a molding box with molding sand. The molding sand is compacted and then cured. After curing, the mold is removed from the molding box.
  • the mold has a mold cavity or, if the mold is made up of a plurality of sections, a part of the mold cavity, which substantially corresponds to a negative mold of the metal cast piece to be produced.
  • liquid metal is introduced into the mold cavity of the casting mold. In this case, the compensation cavity of the feeder is at least partially filled with liquid metal.
  • the inflowing liquid metal displaces the air from the mold cavity or the compensation cavity.
  • the air escapes through openings provided in the mold or through porous sections of the mold, for example through the wall of a feeder.
  • the feeders therefore preferably have a sufficient porosity, so that on the one hand during the filling of the liquid metal, the air is displaced from the feeder and the metal can flow into the feeder and on the other hand during cooling and solidification of the metal in the mold cavity of the mold, the still liquid metal the balancing cavity of the feeder can flow into the mold cavity of the casting mold, without a negative pressure, .in the Ausretehlraum d_e_s feeder., Generated, is.
  • the metal contained in the compensation cavity of the feeder In order for the metal from the compensation cavity to flow back into the mold cavity, the metal contained in the compensation cavity of the feeder must solidify at a later time than the metal in the mold cavity of the mold.
  • the solidification of the metal is determined by the heat loss experienced by the liquid metal.
  • the liquid metal contained in the compensation cavity To achieve that the liquid metal contained in the compensation cavity solidifies at a later time than the liquid metal in the mold cavity, the liquid metal contained in the compensation cavity must experience less heat loss than the metal in the mold cavity.
  • the heat loss is first determined by the ratio of the surface area of the shaped body, via which heat can be released, to its volume. For a given volume, the liquid metal will first solidify on the one having the larger surface area. The compensation cavity of the feeder or the used feeder volume is therefore made as compact as possible.
  • the heat loss is controlled by the insulating effect of the material surrounding the liquid metal, that is, the material of the mold or the feeder.
  • Feeders are therefore preferably made of a material which has a sufficiently high insulating effect, so that the metal remains sufficiently liquid in the compensation cavity.
  • the feeder can be made of a material which has a higher insulating effect than the material of the casting mold, so that the heat loss at the liquid metal contained in the compensation cavity of the feeder fails less than the heat loss during the metal contained in the mold cavity of the casting mold.
  • a material may, for example, be a refractory material containing aluminum silicate microbubbles. Due to the gas enclosed in the hollow microspheres, such a material has a highly insulating effect.
  • the feeder is produced from a molding material mixture which, in addition to the refractory material and the binder, also contains a combustible metal, for example aluminum semolina, and a suitable oxidizing agent, for example sodium nitrate.
  • a combustible metal for example aluminum semolina
  • a suitable oxidizing agent for example sodium nitrate.
  • the mixture ignites and releases the heat released during the oxidation of the metal to the liquid metal contained in the compensation cavity.
  • the compensation cavity or the feeder volume can therefore be chosen very small in exothermic feeders.
  • a suitable feeder must be selected in such a way that the feeder is not sucked out during feeding, ie the feeder volume is large enough so that sufficient liquid metal is still available for meals at the end of the feeding process. Too small a feeder volume leads to the formation of so-called Primärlunker. But the feeder must also be selected so that the liquid metal of the feeder volume solidifies later than the metal in the mold cavity of the mold. If the metal in the compensation cavity solidifies sooner than the metal in the mold cavity, metal can no longer pass from the compensation cavity into the mold cavity, the casting. So no longer be fed. This leads to the formation of so-called Sekundmaschinelunker.
  • the solidification of the liquid metal can be described approximately via the module of the casting or the feed volume.
  • a module is understood to mean the ratio of volume to heat-emitting surface.
  • K is a characteristic of the casting material used constant. As a first approximation, therefore, bodies with the same modulus solidify at the same speed. If the modulus of the observed body doubles, the solidification time quadruples.
  • the Absaugles the feeder is about 15%. So there are 15% of the originally filled in the compensation cavity feeder volume for dining the casting available.
  • the feeder volume may therefore be greater than the volume of the casting or the portion of the casting fed by the feeder.
  • the Absaug zucchini insulating feeders When using insulating feeders increases for a given feeder volume because of the lower heat dissipation of the module or can be reduced in specified by the casting module, the feeder volume. In insulating feeders, therefore, a higher Absaug Kings can be realized compared to natural feeders.
  • the Absaug Kings insulating feeders is usually selected in the range of about 25% of the originally available feeder volume.
  • EP 0 888 199 B1 describes feeders which may have exothermic properties or insulating properties and which are obtained by a cold-box process.
  • a feeder mixture is poured into a feeder mold.
  • the feeder mixture comprises an oxidizable metal and an oxidizing agent or an insulating refractory material or mixtures of these materials and an effective binding amount of a chemically reactive cold box binder.
  • the feeder mixture is formed into an uncured feeder which is then contacted with a vaporous curing catalyst.
  • the hardened feeder can then be removed from the mold. Hollow aluminum silicate microspheres may be used as the insulating refractory material.
  • the feeders receive a low thermal conductivity and thus a very pronounced insulating effect. Furthermore, these feeders have a very low weight, so that they can be easily handled and transported on the one hand and on the other not so easy to fall off the model when this is tilted, for example.
  • EP 0 913 215 B1 describes a method for producing feeders and other feed and feed elements for casting molds.
  • a composition comprising hollow aluminosilicate microspheres having an alumina content of less than 38% by weight, a binder for cold box curing, and optionally a filler, wherein the filler is not in fibrous form, is formed by blowing into a mold box shaped uncured molded product.
  • This uncured molded product is treated with a suitable catalyst. brought into contact, wherein the Forinkohl hardens. The cured molded product can then be removed from the molding box.
  • the feeders obtained by this method also have a pronounced insulating effect and a low weight.
  • an exothermic feeder composition which contains aluminum and magnesium, at least one oxidizing agent, a filler containing SiO 2 and an alkali metal silicate as binder. Further, the feeder mass contains about 2.5 to 20% by weight of a reactive alumina having a specific surface area of at least about 0.5 m 2 / g and an average particle diameter (D 50 ) of about 0.5 to 8 ⁇ m.
  • the feeder mass is practically free of fluoride-containing fluxes.
  • the exothermic feeder In order to prevent the formation of voids in the casting during metal casting, the exothermic feeder must reliably ignite on contact with the liquid hot metal and then controlled and burned off evenly. This is now reliably mastered with feeders that were developed for iron or steel casting. In iron or steel casting temperatures are in the range between about 1300 and 1600 0 C, so that the liquid metal is sufficiently hot to ignite the feeder. In addition, sufficiently high amounts of oxidizable metal and oxidizing agent can be added to the molding material mixture for producing the feeder, that upon contact with the liquid hot metal reliable ignition of the feeder takes place and the oxidation proceeds sufficiently vigorously, so that a temperature is reached at which the im Balancing cavity of the feeder contained metal remains in the liquid phase. customarily Example, such feeders contain between 20 and 33 wt .-% oxidizable metal and between 5 and 25 wt .-% oxidizing agent, based on the weight of the material from which the feeder is made.
  • the feeder no longer ignites reliably or does not burn uniformly and reliably after ignition has taken place so that it is not ensured that a sufficient amount of heat is reproducibly provided in order to obtain the aluminum contained in the compensation cavity in the liquid state.
  • the invention was therefore an object of the invention to provide a molding material mixture for the production of feeders are available, from which feeders can be produced, which enable a reliable feeding of a casting, especially in aluminum casting.
  • the feeder reaches a maximum temperature below 1250 0 C, preferably less than 1150 0 C, can be further preferably maintained below 1050 ° C. At such a temperature, there is no need to fear that aluminum will be heated above its boiling point, causing gas pockets and microstructural defects in the casting.
  • the temperature inside the feeder can be determined, for example, with a thermocouple, which is placed in the center of the balancing cavity of the feeder. If the feeder is ignited in air, slightly higher temperatures result compared to a feeder, which is integrated in a casting mold, ie surrounded by sand. The inventors believe that this is due to the better access of air.
  • the measured temperature when burning in air is about 50 to 100 0 C higher than a feeder, which is integrated in a mold. Even with a combustion in air, however, the measured maximum temperature remains in the specified range.
  • the oxidation of the metal is compensated by the added in deficit amount of the oxidizing agent more a fuming than a burning. Nevertheless, the feeder can be ignited reproducible and the oxidation of the feeder runs evenly through the body of the feeder, without the oxidation extinguished prematurely or form individual local temperature maxima within the feeder body.
  • the oxidizable metal is activated.
  • the oxidizable metal is passivated by a thin oxide layer that forms on the surface.
  • the ignition means for example, the oxide layer can be at least partially etched and thus destroyed, so that the bare metal is exposed on the surface. This bare metal is very easily oxidized, so that the oxidation of the oxidizable metal starts and the feeder ignites.
  • the ignition means ignites itself, thereby initiating the oxidation of the oxidizable metal.
  • the aluminum Due to the uniform heat generation of the feeder on a relatively low, suitable for the aluminum casting temperature level, the aluminum can be kept in the compensation cavity of the feeder long in a liquid state.
  • the aluminum can therefore flow from the balancing cavity of the feeder into the mold cavity of the mold, while the aluminum solidifies in the mold cavity.
  • the formation of the voids during the solidification of the aluminum in the compensation cavity is controlled at a remote for connection between the compensation cavity and mold cavity, so that casting errors can be reliably avoided.
  • the feeder or the compensation cavity Due to the exothermicity of the oxidation and the consequent possibility to obtain the aluminum in the compensation cavity in the liquid state, the feeder or the compensation cavity can be significantly reduced compared to the usual nature feeders.
  • an exothermic molding material mixture is made available for the production of feeders for cast aluminum, which contains at least:
  • an amount of an oxidizable metal of 5 to 18 wt .-%;
  • an oxidizing agent in an amount, based on the amount of the oxidizing agent required for complete oxidation of the oxidizable metal, of from 10 to 50%;
  • an initiator for the oxidation of the oxidizable metal in an amount, based on the amount of the oxidizable metal, of 1 to 50 wt .-%.
  • materials are used, as they are already known for the production of feeders.
  • the materials are, however, used in a specially tuned proportion, so that the oxidation or heat generation can be controlled and maintained at a very low level.
  • the molding material mixture initially comprises a refractory molding material.
  • the refractory molding base material has a melting point which is significantly above the temperature which is reached by an oil feedstock produced from the molding material mixture according to the invention after the ignition.
  • the melting point is reached.
  • the melting point of the refractory molding base preferably at least 200 0 C, preferably at least 500 0 C above the maximum temperature of the feeder.
  • the refractory mold raw material has a melting point of at least 1300 0 C, preferably at least 1 500 0 C.
  • a refractory molding material is used, which has a melting point of less than 3000 0 C, according to another embodiment of less than 2700 0 C.
  • Suitable refractory mold bases are, for example, quartz, aluminum silicates or zirconia sand. Furthermore, synthetically prepared refractory fillers may also be used, such as mullite (AlaSiO 5 ).
  • the refractory molding base should have sufficient particle size so that a feeder made of the molding material mixture has a sufficiently high porosity to allow escape of volatile compounds during the casting process.
  • at least 70% by weight, in particular preferably at least 80% by weight, of the refractory molding base material has a particle size ⁇ 100 ⁇ m.
  • the average particle size D 50 of the refractory base molding material should preferably be between 100 and 350 ⁇ m. The particle size can be determined, for example, by sieve analysis.
  • the proportion of the refractory molding material to the molding material mixture is preferably selected in the range of 10 to 75 wt .-%, preferably 40 to 70 wt .-%.
  • the novel molding material mixture comprises a binder with which the molding material mixture can be solidified after shaping by producing a firm cohesion between the grains of the refractory molding base material.
  • the amount of binder is chosen to be high enough to ensure sufficient dimensional stability of a feeder produced from the molding material mixture can. It can at all the binders are used, which are common in the production of feeders.
  • both organic and inorganic binders can be used in the molding material mixture according to the invention, whose curing can be carried out by cold or hot process.
  • Cold processes are processes which are carried out essentially at room temperature without heating the molding material mixture.
  • the curing is usually carried out by a chemical reaction, which can be triggered, for example, by passing a gaseous catalyst through the molding material mixture to be cured, or by adding a liquid catalyst to the molding material mixture.
  • hot processes the molding material mixture is heated to a sufficiently high temperature after molding to drive off, for example, the solvent contained in the binder, or to initiate a chemical reaction by which the binder is cured by crosslinking.
  • a binder which is cured by cold processes by adding a catalyst this is preferably selected from the group of phenol-urethane resins which are activated by amines, epoxy-acrylic resins, which can be activated by SO 2 , alkaline phenolic resins, which can be activated by CO 2 or methyl formate, and water glass, which can be activated by CO 2 .
  • phenol-urethane resins which are activated by amines
  • epoxy-acrylic resins which can be activated by SO 2
  • alkaline phenolic resins which can be activated by CO 2 or methyl formate
  • water glass which can be activated by CO 2 .
  • the person skilled in the art is aware of such cold-box binders.
  • Such binder systems are described for example in US 3,409,579 or US 4,526,219.
  • other binders can also be used, for example dextrin, sulfite waste liquor or salt binders.
  • Polyurethanes based on polyurethanes are generally composed of two components, a first component containing a phenolic resin and a second component containing a polyisocyanate. These two components will be. mixed with the refractory molding green material and the molding material mixture by ramming, blowing, shooting or other process in a mold, compacted and then cured. Depending on the process with which the catalyst is introduced into the molding material mixture, a distinction is made between the "polyurethane no-bake process” and the "polyurethane cold-box process".
  • a liquid catalyst generally a liquid tertiary amine
  • phenolic resin, polyisocyanate and curing catalyst are mixed with the refractory molding material.
  • the refractory molding base material is first coated with a component of the binder, and then the other component is added.
  • the curing catalyst is added to one of the components.
  • the ready-made molding material mixture must have a sufficiently long processing time, so that the molding material mixture can be plastically deformed for a sufficient time and processed into a feeder.
  • the polymerization must be correspondingly slow, so that not already in the storage tanks or supply lines, a curing of the molding material mixture. On the other hand, the curing must not be too slow to achieve a sufficiently high throughput in the production of feeders.
  • the processing time can be influenced for example by adding retarders, which slow down the curing of the molding material mixture.
  • a suitable retarder is, for example, phosphorus oxychloride.
  • the molding material mixture prepared from refractory molding base material, polyol component, polyisocyanate component and, if appropriate, additives is initially devoid of brought into a form.
  • a gaseous tertiary amine which may optionally be mixed with an inert carrier gas, is then passed through the molding material mixture formed into a feeder.
  • the binder On contact with the gaseous catalyst, the binder binds very quickly, so that a high throughput in the production of feeders is achieved.
  • Inorganic binders are preferably used in the molding material mixture according to the invention.
  • water glass is used as a binder in the exothermic molding material mixture.
  • the use of water glass as a binder has the advantage that when burned the feeder less smoke occurs than when using organic binder. As a result, the burden of harmful compounds that are released during the casting, as well as the odor nuisance decreases.
  • Conventional water glasses can be used as the water glass, as they are already used as binders in molding mixtures for the foundry industry. These water glasses contain dissolved sodium or potassium silicates and can be prepared by dissolving glassy potassium and sodium silicates in water.
  • the water glass preferably has a modulus M2 ⁇ / SiC> 2 in the range of 2.0 to 3.5, where M is sodium and / or potassium.
  • the water glasses preferably have a solids content in the range of 20 to 50 wt .-%. Furthermore, solid water glass can also be used for the production of the feeder. For the proportions of the molding material for the production of the feeder only the solids content of the water glass are considered in each case.
  • the proportion of the binder, calculated in the dry state, ie without consideration of solvents for diluting the binder, and based on the dry molding material mixture, is preferably between 5 and 50 wt .-%, particularly preferred between 8 and 40 wt .-% and particularly preferably selected in the range of 10 to 20 wt .-%.
  • the molding material mixture according to the invention comprises an oxidizable metal.
  • all oxidizable metals can be used as they are already used for the production of exothermic feeders.
  • the metals should have sufficient reactivity to react with an oxidizing agent so that the feeder can be reliably ignited on contact with molten aluminum.
  • the proportion of the oxidizable metal in the molding material mixture is kept relatively low, so that compared to feeders for iron and steel casting only a relatively low heat development takes place and produced from the molding material feeder only up to a temperature of preferably less than 1250 0 C heated.
  • the proportion of oxidizable metal in the molding material mixture is only 5 to 18 wt .-%, preferably 8 to 15 wt .-%, preferably 9 to 14 wt .-%, based on the weight of the molding material mixture. This is very low compared to feeders for iron and steel casting.
  • Such feeders for iron and steel casting have a content of oxidizable metal in the range of 20 to 33 wt .-% on.
  • the percentage figures relate to the molding material mixture without proportions of solvent, which are introduced for example via the solvent of the binder in the molding material mixture.
  • the molding material mixture contains an oxidizing agent with which the oxidizable metal is oxidized after ignition of the feeder.
  • the oxidizing agent for example, iron oxide and / or an alkali nitrate such as sodium or potassium nitrate can be used.
  • the oxidizing agent is used in a strong deficit.
  • the proportion of the oxidizing agent is selected in a range of 10 to 50%, preferably 15 to 35%, particularly preferably 20 to 30%, based on the amount of the oxidizing agent used for the complete oxidation of the oxidizable metal.
  • the proportion depends on the oxidant used.
  • the proportion of the oxidizing agent in the molding material mixture in the range of 3 to 20 wt .-%, preferably 5 to 18 wt .-%, particularly preferably 7 to 15 wt .-% is selected.
  • the molding material mixture according to the invention contains an ignition agent for the oxidation of the oxidizable metal.
  • the inventors started from the idea that the grains of the oxidizable metal are passivated by a thin oxide layer.
  • any material that can overcome the passivation experienced by the oxidized metal through the oxide layer formed on its surface is suitable as the ignition means.
  • the ignition means thus causes the passivating oxide layer to break through, so that the bare oxidizable metal is exposed.
  • the igniter can react with the thin oxide layer, whereby it is reduced, for example, or converted into a compound which does not cause continuous passivation of the oxidisable metal or which is impermeable to the oxidant JJCOOCU-d.
  • an ignition means By means of such an ignition means, it is thus possible for the passivation layer present on the oxidizable metal be etched.
  • Such an ignition means may for example be a halogen, such as bromine or iodine, which reacts with the passivating layer of the oxidisable metal, for example aluminum.
  • the igniter may also be a material that is more easily oxidized than the oxidisable metal and exhibits sufficiently high levels of heat generation during the oxidation that the oxidisable metal is melted, at least in portions, whereby the passivating layer can be ruptured.
  • the ignition agent is used in a proportion of 15 to 50 wt .-%, preferably 25 to 40 wt .-%, preferably 30 to 35 wt .-%.
  • the proportion of the ignition agent is preferably greater than 1 wt .-%, preferably greater than 2 wt .-%, more preferably greater than 3 wt .-% and according to another embodiment greater than 4 wt .-% selected. In order to achieve an activation of the oxidizable metal, it is sufficient according to one embodiment if the proportion of the ignition agent is less than 15 wt .-%, preferably less than 12 wt .-%, preferably less than 9 wt .-% is selected.
  • feeders can be produced which produce a temperature profile reproducible after ignition, which has a maximum temperature of preferably less than 1250 0 C, more preferably less than 1150 0 C, wherein the burn-off proceeds evenly and controlled , On the other hand reaches the feeder during combustion a temperature of preferably more than 600 0 C, preferably more than 700 0 C, so that the aluminum is maintained in the feeder cavity in the liquid phase, until the aluminum has solidified in the mold cavity of an associated mold.
  • the aluminum contained in the compensation cavity of a feeder produced from the molding material mixture according to the invention can be reliably kept in a liquid state, so that feeding the casting under controlled and reproducible conditions.
  • So feeders can be produced from the molding material mixture according to the invention which, for a given feeder volume, have a higher modulus than natural feeders or insulating feeders, or which have a smaller feeder volume for a given module.
  • the oxidizing metal oxidizing agent is an etchant which can etch the passivated surface of the oxidizable metal.
  • an etchant is meant a compound which can react with the passivating layer of the oxidisable metal, generally an oxide film, so that the passivating layer is broken up and the reactivity or ignitability of the oxidisable metal is increased.
  • a fluorine-containing flux is used as the ignition.
  • the proportion of the fluorine-containing flux is calculated as sodium hexafluoroaluminate.
  • fluorine-containing fluxes which are already used in the production of exothermic feeders can be used per se.
  • Suitable fluorine-containing fluxes are, for example, sodium hexafluoroaluminate, potassium hexafluoroaluminate, sodium fluoride and potassium fluoride. Due to the high proportion of the fluorine-containing flux, a low ignition temperature and a uniform burnup of the exothermic molding material mixture according to the invention is achieved.
  • magnesium is used as the ignition agent.
  • Magnesium metal is relatively easy to ignite and shows a high level of heat during oxidation.
  • the proportion of magnesium in the exothermic molding material mixture is preferably at least 3, based on the molding material mixture Wt .-%, more preferably at least 5 wt .-%. At too low a proportion of magnesium of the impact on the inflammable ⁇ bility of the mixture is low.
  • the magnesium metal can be used in any form per se. Preferably, the magnesium is used in the form of a fine semolina, since it can be distributed very homogeneously in the molding material mixture.
  • the magnesium metal can be used in pure form. However, it is also possible to use the magnesium in the form of an alloy, for example in the form of an alloy with the oxidizable metal, for example an aluminum-magnesium alloy. Due to the fine distribution of magnesium in the alloy, the ignition temperature of the alloy can be reduced, so that a controlled ignition of the molding material mixture or the feeder produced therefrom is achieved as the liquid aluminum flows into the compensation cavity of the feeder.
  • the proportion of magnesium in the alloy is preferably greater than 30 wt .-%, preferably greater than 40 wt .-%, more preferably selected in the range of 50 to 80 wt .-%.
  • the oxidizable metal used in the molding material mixture according to the invention is preferably selected from the group of aluminum, magnesium and silicon, and their alloys.
  • the metals or alloys mentioned can each be used alone or as a mixture.
  • both the oxidizable metal and the ignition agent may be formed by magnesium.
  • magnesium is more difficult to access than, for example, aluminum
  • aluminum is preferably chosen as the oxidizable metal.
  • Magnesium is preferably used as an ignition agent and less preferably as an oxidizable metal.
  • the oxidizable metal should preferably be distributed homogeneously in the exothermic molding material mixture, so that after ignition a uniform heating of the feeder takes place.
  • the oxidizable metal is therefore preferably incorporated into the molding material mixture in the form of a powder or fine granules or semolina.
  • the oxidizable metal should also not be present in too finely distributed form, since otherwise the metal particles can be given too much reactivity and the oxidation of the oxidizable metal proceeds too rapidly.
  • the particle size of the oxidisable metal is preferably chosen to be greater than 0.05 .mu.m, particularly preferably greater than 0.1 .mu.m.
  • the grain size should preferably not be too large, since then a uniform heat generation of the feeder beyond the casting process is no longer ensured.
  • the particle size of the oxidisable metal is preferably chosen to be less than 1 mm, preferably less than 0.8 mm, particularly preferably less than 0.5 mm.
  • the grain size of the oxidizable metal can be determined by conventional means, for example by sieve analysis.
  • the grain size of the magnesium semolina is selected in ranges as indicated above for the oxidizable metal.
  • the feeder is preferably designed so that the molding material mixture has a heat-insulating effect.
  • the refractory molding base material is at least partially formed by an insulating refractory material.
  • An insulating refractory material is understood to be a refractory molding material which has a lower thermal conductivity than quartz sand. Suitable insulating refractories are, for example pumice, hollow glass beads, chamotte, light spheres, ⁇ mica, clays, fly ash, geBANumte_ materials, open-pore ceramic and similar materials.
  • the thermal conductivity of the insulating refractory material is preferably 0.04-0.25 W / mK, preferably 0.07-0.2 W / mK.
  • the thermal conductivity can be determined with conventional equipment, for example a TCT 426 thermal conductivity tester according to the T (R) method according to ASTM-C-I113.
  • the refractory molding base material of the exothermic molding material mixture according to the invention therefore preferably comprises at least a portion of an insulating refractory material which has cavities and which is highly heat-insulating by the gas enclosed in the cavities.
  • the exothermic molding material mixture comprises as a refractory insulating material a proportion of refractory hollow microspheres. These hollow microspheres have a continuous outer shell enclosing a gas-filled cavity.
  • the shell is preferably constructed of an aluminum silicate.
  • the hollow microspheres have a diameter of preferably less than 3 mm, particularly preferably less than 1 mm.
  • the wall thickness of the hollow microspheres is preferably 5 to 20% of the diameter of the hollow microspheres.
  • Such microspheres can be obtained, for example, from fly ash, which is separated from combustion exhaust gases in industrial plants.
  • the composition of the aluminum silicate microbubbles may vary within wide ranges.
  • the aluminum content calculated as Al 2 O 3 and based on the weight of the hollow microspheres, is between 20 and 75%, preferably 25 and 40%.
  • the fraction of hollow microspheres on the refractory base molding material is preferably greater than 30%, preferably greater than 40%, more preferably in the range of 60 to 9% to 5%, and in particular of the range of 5 to 90% by weight. selected.
  • Glass hollow spheres with an Alummium content of 0 to 25% can also be used.
  • the molding material mixture according to the invention comprises at least partially as a refractory insulating material a porous refractory material having an open-pored structure. Due to the open-pore structure of the feeder receives a very good gas permeability, so that the air in the compensating cavity during penetration of the liquid aluminum can escape largely unhindered or if the liquid aluminum flows back from the compensating cavity when dining again, can flow largely unhindered back into the compensation cavity.
  • a refractory material Under a porous refractory material, which has a continuously open pore structure, a refractory material is understood with a sponge-like structure, which extends through the entire volume of the grain.
  • Such an open-pored structure can be recognized, for example, on a micrograph of a grain, possibly under microscopic magnification. While in the above-mentioned microballoons each a single "pore" is surrounded by a largely gas-tight envelope and therefore no simple gas exchange between the cavity of the hollow microspheres and the environment is possible, the open-pored porous refractory material is traversed by passages, which gas exchange of the individual pores enable with the environment.
  • the proportion of pores in the entire volume of the porous open-celled substance is preferably very high.
  • the porous refractory material has a pore volume of at least 50%, preferably at least 60%, in particular at least 65%, based on the total volume of the porous refractory.
  • the pore volume can be determined, for example, by mercury intrusion.
  • Suitable porous refractory materials are, for example, pumice stone, expanded slate, perlite, vermiculite, boiler sand, foam lava, porous glass beads or expanded concrete, and mixtures thereof.
  • the porous refractory materials having an open-pore structure contained in the inventive exothermic molding material according to one embodiment preferably have a density of less than 0.5 g / ml, preferably less than 0.4 g / ml, particularly preferably 0.05 to 0.4 g / ml up. Density is understood to mean the bulk density.
  • the feeders produced from the exothermic molding material mixture according to the invention which comprise a proportion of an insulating refractory material, therefore advantageously have a low weight. For example, the feeders can be plugged onto a model and, because of their low weight, do not fall off when the model or mold is turned.
  • the refractory molding base may be wholly or partly formed by the insulating refractory. Also for cost reasons, mixtures of insulating refractory material and other refractory molding base materials, which have a lower insulating effect, are preferably used. Exemplary less insulating refractory mold bases have already been mentioned. An example of a suitable refractory base stock that can be mixed with the insulating refractory is quartz sand. The proportion of the insulating refractory material on the refractory molding base material is preferably greater than 20% by weight, preferably greater than 30% by weight, in particular greater than 40% by weight.
  • a sufficient insulating effect is already achieved if the proportion of the insulating refractory material on the refractory molding base material is preferably less than 80 wt .-%, preferably less than 70 wt .-%, more preferably less than 60 wt .-%.
  • the exothermic molding material mixture according to the invention preferably has a viscosity of at least 150, preferably more than 200, in particular more than 300.
  • the gas permeability number is a characteristic customary in the foundry industry. great for the porosity of moldings or molding sands. It is determined on a test piece, which has a certain shape, with devices from Georg Fischer AG, Schaffhausen, Switzerland. The determination of gas permeability is described in the examples.
  • pumice is used as a porous refractory material with an open-pore structure.
  • Pumice is a naturally occurring rock glass, ie it has essentially an amorphous structure without recognizable crystals.
  • Pumice has a low specific gravity of up to about 0.3 g / cm 3 . It has a very high pore volume of up to 85%. Due to its high porosity, the pumice has a very high gas permeability.
  • the pumice it is preferable to use a material from a natural source ground to a suitable grain size.
  • the grain size of the ground pumice is preferably less than 1.5 mm, more preferably less than 1 mm.
  • the grain size can be adjusted, for example, by sieving or air classification.
  • Another suitable insulating refractory material are porous glass beads.
  • the grain size is preferably 0.1 to 1 mm.
  • the bulk density is preferably in the range of 200 to 500 kg / m 3 .
  • the exothermic molding material mixture may contain a proportion of a reactive aluminum oxide.
  • the reactive aluminum oxide preferably has the following properties: Al 2 O 3 -Ge-IaIt> 90%
  • the strength of a feeder produced from the molding material mixture can be improved.
  • the reactive aluminum oxide is preferably, based on the weight of the exothermic molding material mixture in a proportion of more than 2 wt .-%, preferably more than 5 wt .-% in the molding material mixture according to the invention.
  • the exothermic molding material mixture can also comprise a refractory filler, which preferably has a relatively low SiO 2 content.
  • the refractory filler has a SiO 2 content of less than 60% by weight, preferably less than 50% by weight, particularly preferably less than 40% by weight. Due to the low proportion of SiO 2 , the risk of vitrification is counteracted, as a result of which casting defects can be avoided.
  • the exothermic molding material mixture according to the invention contains no SiO 2 as a mixture component, that is, it is free of quartz sand, for example.
  • the SiO 2 content contained in the molding material mixture is therefore preferably present in bound form as aluminum silicate.
  • the refractory filler is at least partially formed from chamotte.
  • Fireclay is understood to mean a highly fired (double-fired) clay, which is a Dimensional stability up to a temperature of about 1500 ° C.
  • chamotte may contain the crystalline phases mullite (3Al 2 O 3 .2SiO 2 ) and cristobalite (SiO 2 ).
  • the chamotte is also preferably ground to a particle size of less than 1.5 mm, preferably less than 1 mm.
  • the chamotte gives the feeders produced from the exothermic molding material mixture according to the invention a very high temperature resistance and strength.
  • the proportion of fireclay on the refractory filler is preferably chosen to be high.
  • the proportion of chamotte based on the weight of the refractory filler, at least 50 wt .-%, more preferably at least 60 wt .-%, and most preferably at least 70 wt .-%.
  • the refractory filler is formed essentially only of chamotte.
  • the chamotte is preferably contained in ground form in the exothermic molding material mixture.
  • the particle size here is preferably less than 1.5 mm, particularly preferably less than 1 mm.
  • the chamotte preferably has a high proportion of aluminum oxide.
  • the chamotte preferably contains at least 30% by weight of aluminum oxide, particularly preferably at least 35% by weight and very particularly preferably at least 40% by weight.
  • the alumina is preferably in the form of aluminum silicates.
  • the fraction of the refractory filler is preferably between 5 and 60% by weight, particularly preferably 8 to 50% by weight.
  • the fractions of the refractory filler do not include the proportions of pumice and reactive alumina.
  • the constituent molding material mixture may also contain other constituents in customary amounts.
  • an organic material be included, such as wood flour.
  • the organic material is in a form in which it does not absorb any liquid components, such as water glass.
  • the wood meal may first be sealed with a suitable material, such as water glass, so that the pores are closed. The presence of the organic material further reduces the cooling of the liquid aluminum on initial contact with the wall of the balance cavity.
  • an organic material such as wood flour
  • this is preferably present in a proportion of 5 to 20% by weight, preferably 8 to 12% by weight, based on the exothermic molding material mixture.
  • a feeder made of the above-described exothermic molding material mixture is particularly suitable for aluminum casting, since it shows only a relatively small amount of heat after ignition and therefore does not heat the liquid aluminum arranged in a balancing cavity of such a feeder to a high temperature so that boiling of the aluminum is prevented. This effectively restricts gas pockets in the casting and disturbances in the crystal structure of the casting.
  • the invention therefore also relates to a feeder for the aluminum casting, prepared from an exothermic molding material mixture as described above.
  • the feeder reaches a burnup temperature of less than 1250 0 C, preferably less than 1150 0 C, preferably less than 1050 0 C.
  • the feeder during Burning preferably a temperature of more than 600 0 C, preferably more than 700 0 C.
  • the exothermic feeder according to the invention for aluminum casting comprises a compensation cavity and a feeder wall surrounding the compensation cavity, wherein the feeder wall is constructed from a material which contains at least:
  • an oxidizable metal in a proportion of 5 to 18 wt .-%, based on the weight of the feeder wall;
  • an oxidizing agent in an amount, based on the amount of the oxidizing agent required for complete oxidation of the oxidizable metal, of from 10 to 50%;
  • an ignition agent for the oxidation of the oxidizable metal in an amount, based on the amount of the oxidizable metal, of 15 to 50 wt .-%.
  • the exothermic feeder according to the invention for aluminum casting can in itself take any known form for feeder.
  • the term "feeder”, as used here, for example, includes feeder sleeves, so approximately cylindrical tubes that are open on both sides, caps, so approximately cylindrical tubes that are closed on one side, as well as feeder in the usual sense.
  • the feeders can be inserted into a casting mold or molded into the casting mold. Under a feeder in the context of the invention, therefore, a molded body is understood with a feeder wall, which encloses a compensation cavity, wherein the compensation cavity on one side oaer aucn be two-sided georrnet.
  • the Ausg ⁇ excnsnon ⁇ - takes space during the metal casting liquid metal and gives this at least partially during the solidification of the casting Piece off again.
  • a residual feeder is understood as meaning the solidified metal which, after the casting process, remains in the compensation cavity of the feeder and solidifies and is connected to the casting.
  • the exothermic feeder according to the invention for aluminum casting can in itself take on any desired shape, as is known for metal casting, for example cast iron or steel.
  • the feeder can be made in one or more parts, wherein the entire feeder can be made from the exothermic molding material mixture according to the invention, or only parts of the feeder.
  • the feeder may comprise a feeder head made of the exothermic molding material mixture, wherein in the feeder head, a slidable sleeve may be inserted, which establishes the connection between a compensating cavity contained in the feeder head and the mold cavity of the mold.
  • the feeder can be designed in a form so that it can be placed directly on a model. But it is also possible to provide a receptacle for a spring mandrel on which the feeder according to the invention is then plugged.
  • the feeder according to the invention can be made in any size and with any wall thickness. The dimensions listed below are therefore exemplary.
  • the volume of the balance cavity is selected depending on the size of the casting to be produced and the shrinkage experienced by the casting during the solidification of the aluminum. According to one embodiment, the volume of the compensation cavity is less than 2000 cm 3 , according to another embodiment, less than 1500 cm 3 , and chosen according to another embodiment less than 500 cm 3 . But it is also possible to provide feeders with a compensation cavity whose volume is greater than 2000 cm 3 . According to one embodiment, the volume of the compensation cavity is chosen to be greater than 100 cm 3 .
  • the wall thickness of the feeder or the outer volume of the feeder can be selected smaller than in the usual feeders for aluminum casting.
  • the outer volume of the feeder is less than 3000 cm 3 , according to a further embodiment less than 2500 cm 3 , and according to further embodiment less than 1000 cm 3 .
  • the outer volume of the feeder is selected to be greater than 250 cm 3 .
  • the maximum wall thickness of the feeder according to the invention is less than 15 cm according to one embodiment, less than 8 cm according to another embodiment and less than 4 cm according to another embodiment. However, it is also possible to provide feeders according to the invention, which have a maximum Wall thickness, which is more than 15 cm. According to one embodiment, the maximum wall thickness is greater than 0.5 cm, chosen according to a further embodiment greater than 1 cm. The maximum wall thickness corresponds to the thickest point of the balancing cavity surrounding feeder wall, in each case the shortest distance between the outer and inner wall is measured.
  • Feeders made from a standard refractory base material, such as silica sand can reduce the amount of aluminum consumed in the balancing cavity of the feeder to feed the casting by up to 80%.
  • the feeder according to the invention is in itself prepared by conventional methods.
  • This exothermic molding material mixture is processed into a blank by the exothermic molding material mixture is shot, for example, in a nuclear shooter by means of compressed air into a suitable shape.
  • Preferred refractory mold raw materials and further constituents of the exothermic molding material mixture have already been explained in connection with the description of the exothermic molding material mixture according to the invention.
  • Suitable binders have also been explained in the description of the exothermic molding material mixture.
  • Particularly preferably, water glass is used as the binder.
  • the curing of the exothermic molding material mixture by conventional methods. Curing can be achieved by conduct carbon dioxide through the blank of the feeder, wherein the curing is preferably carried out at room temperature. But it is also possible to heat the blank of the feeder, for example, to temperatures of 120 to 200 0 C. To accelerate the curing, hot air can be passed through the blank of the feeder. The temperature of the injected air is preferably 100 ° C. to 180 ° C., particularly preferably 120 ° C. to 150 ° C. After the first curing, the feeder can still be dried, for example in an oven or by irradiation with microwaves.
  • binders for example organic binders
  • the curing of the exothermic molding material mixture after shaping of the feeder is likewise carried out by customary methods.
  • a gaseous tertiary amine may be passed through the exothermic molding material mixture formed into a feeder in a conventional manner.
  • the feeder can be removed from the mold.
  • the curing can be complete or only partially carried out, so that after the removal of a post-curing, for example by heat, is performed.
  • the feeder according to the invention is suitable for aluminum casting.
  • the invention therefore further relates to the use of the feeder for aluminum casting described above.
  • the feeder is attached in the usual way to the mold or introduced into this. After production of the mold, the aluminum casting is carried out in a conventional manner.
  • the exothermic bpexser rur ⁇ en aluminum casting according to the invention is used in such a way that initially a casting mold is provided with a mold cavity.
  • the mold comprises at least one feeder, as described above, and which comprises a compensation cavity.
  • liquid aluminum is filled into the mold, so that at least the mold cavity of the mold and a feeder volume of the feeder are filled with the liquid aluminum.
  • the feeder volume is at most equal to the volume of the compensating cavity of the feeder and corresponds to the amount of aluminum provided at the beginning of feeding in the compensating cavity.
  • the feeder volume is chosen to be smaller than the volume of the compensation cavity, preferably less than 95%, preferably less than 90%, of the volume of the compensation cavity.
  • at least 50% of the volume of the compensation cavity is used as feeder volume.
  • the feeder By flowing into the compensation cavity of the feeder liquid aluminum, the feeder is ignited.
  • liquid aluminum is allowed to solidify, with the aluminum initially solidifying in the mold cavity of the mold. In this case, to compensate for the shrinkage occurring during solidification liquid aluminum is sucked from the compensation cavity of the feeder in the mold cavity of the mold.
  • the volume of the compensation cavity can be chosen relatively small, with a high proportion of the feeder volume can be used for dining.
  • preferably at least 25%, preferably at least 30%, particularly preferably at least 40%, particularly preferably at least 50% of the feeder volume is used to feed the casting, ie the corresponding amount of liquid aluminum from the compensating cavity of the feeder into the feeder Mold cavity transferred to the mold.
  • the entire volume of the compensation cavity can not be used for dining. so that a residual feeder remains on the casting.
  • less than 90% of the feeder volume is used for dinning.
  • FIG. 1 shows a longitudinal section through a feeder according to the invention
  • FIG. 2 shows a longitudinal section through a further embodiment of the feeder according to the invention.
  • Fig. 1 shows a longitudinal section through a feeder according to the invention.
  • the feeder 1 has a tubular shape.
  • the feeder wall 2 is constructed of a refractory molding material mixture, which is characterized by a very small proportion of an oxidizable metal, a selected in comparison to the amount of oxidizable metal subset of oxidizing agent and by a relatively high proportion of a fluorine-containing flux.
  • the feeder wall 2 surrounds a compensation cavity 3, which is open to one side by a compensation opening 4 to the environment. Via the compensation opening 4, a connection to a mold cavity of a casting mold (not shown) is produced. At the opposite end of the compensation opening 4 there is a ventilation opening 5.
  • the diameter of the compensation opening 4 in the illustrated embodiment of the feeder is chosen to be larger than the diameter of the ventilation opening 5, so that the feeder has a conical shape. However, it is also possible to make the diameter of the compensation opening 4 and the ventilation opening 5 the same, so that the feeder annimmif the shape of a tube.
  • the inner diameter of such a feeder for example, 8 cm and the wall thickness of the feeder wall 3 cm at a height of the feeder of 15 cm.
  • the feeder 6 comprises a compensation cavity 3, which is surrounded by the feeder wall 7, so that the compensation cavity 3 is closed at the top, in order to reduce heat losses of the liquid aluminum.
  • the feeder 6 has a two-part construction and comprises a feeder base 8 and a feeder cover 9.
  • the feeder base 8 and feeder cover 9 together form a feeder wall which surrounds the compensation hollow space 3.
  • a recess 10 for receiving the tip of a spring mandrel 11 is provided in the center of the feeder cover 9, a recess 10 for receiving the tip of a spring mandrel 11 is provided.
  • a compensation opening 4 is provided, which is the connection from the compensation cavity 3 is made to a mold cavity, not shown, of a mold.
  • Both the feeder base 8 and the feeder cover 9 are made from the molding material mixture according to the invention, which is characterized by a low content of oxidizable metal, an oxidizing agent used in the undershot compared to the complete oxidation of the metal and by a high proportion of a fluorine-containing flux.
  • the diameter of the feeder shown in Figure 2 is at its widest point about 15 cm.
  • the height is about 20 cm.
  • the wall thickness of the feeder cover 9 is about 2 cm.
  • the BET surface area is determined on a fully automatic nitrogen porosimeter from the company Micromeritics, type ASAP 2010, in accordance with DIN 66131.
  • the mean particle diameter was determined by laser diffraction on a Mastersizer S, Malvern Instruments GmbH,dorfberg, DE according to the manufacturer.
  • the analysis is based on a total analysis of the materials. After dissolution of the solids, the individual components are treated with conventionally specific analytical methods, e.g. ICP analyzed and quantified.
  • the powdery porous refractory material is charged in one go into a previously weighed 1000 ml glass cylinder which has been cut off at the 1000 ml mark. After the material has been scraped off and removed from the outside of the cylinder, the cylinder is weighed again. The weight gain corresponds to the density.
  • the gas permeability test is carried out with a type PDU permeability testing apparatus from Georg Fischer Aktiengesellschaft, 8201 Schaffhausen, Switzerland.
  • the test specimen prepared as described under (a) is inserted into the precision test specimen tube of the apparatus and the gap between specimen and test specimen tube is sealed.
  • the test specimen tube is inserted into the test apparatus and determines the gas permeability Gd.
  • the gas permeability number Gd indicates how much cm 3 of air passes through a cube or cylinder of 1 cm 2 cross-section in one minute at a pressure of 1 cm water column.
  • the gas permeability is calculated as follows:
  • F cross-sectional area of the test piece (19.63 cm 3 ); p: pressure in cm water column; t: flow-through time for 2000 cm 3 of air in minutes. p and t are determined; all other values are constants set by the tester.
  • Example 1
  • Tubular feeders were produced from a molding material mixture of the following formulations:
  • Solids content 50% by weight, modulus: 2.2
  • the molding material mixtures were shot into a mold at room temperature and cured there for 90 seconds by passing carbon dioxide through. Subsequently, the feeder blanks for 5 hours in an oven at 180 0 C were dried. Tubular feeders having a length of 150 mm, an outer diameter of 59 mm and an inner diameter of 40 mm were obtained.
  • One of the feeders was ignited at its lower end by being briefly placed on a hot plate. After ignition, the feeder was placed on a clay plate. The oxidation front moved evenly from bottom to top through the feeder. After the oxidation front had migrated through the feeder, the temperature in the interior of the compensation cavity was determined to be about 1150 ° C.
  • the feeders were each installed in a mold and made an aluminum casting.
  • As aluminum casting was a Cube made with an edge length of 15 cm. After the casting had cooled, the casting mold was removed and the remainder was knocked off. The fracture site was reworked by grinding. The casting was X-rayed. No voids were found in the casting. Furthermore, the feed point on the casting was examined microscopically. No crystalline dislocations or cast inclusions were detected.

Abstract

L'invention concerne un mélange de matière de moulage exothermique pour la réalisation de masselottes de coulée d'aluminium, ledit mélange contenant au moins : une matière de base réfractaire pour moulage, un liant, une part de métal oxydable de 5 à 18 % en poids par rapport au poids du mélange de matière de moulage, une part d'oxydant représentant de 10 à 50 % de la quantité d'oxydant nécessaire pour l'oxydation complète du métal oxydable, et une part de 15 à 50 % en poids par rapport au poids de métal oxydable d'un amorceur de l'oxydation du métal oxydable. Une masselotte réalisée avec ledit mélange de matériau de moulage exothermique est amorcée de manière fiable même à des températures peu élevées, et se caractérise par des pertes de chaleur réduites. Elle se prête par conséquent particulièrement au coulage d'aluminium.
PCT/DE2009/001602 2008-11-20 2009-11-16 Mélange de matière de moulage et masselotte pour coulage d'aluminium WO2010057464A2 (fr)

Priority Applications (8)

Application Number Priority Date Filing Date Title
CN200980153599XA CN102271836A (zh) 2008-11-20 2009-11-16 造型材料混合物和铸造铝的冒口
EA201170690A EA201170690A1 (ru) 2008-11-20 2009-11-16 Формовочная смесь и прибыль для литья алюминия
BRPI0921527A BRPI0921527A2 (pt) 2008-11-20 2009-11-16 mistura de material de moldagem exotérmica, alimentador exotérmico para fundir alumínio e respectivo uso
JP2011536736A JP2012509182A (ja) 2008-11-20 2009-11-16 アルミニウム鋳造用成形材料混合物およびフィーダ
US13/130,134 US20110220314A1 (en) 2008-11-20 2009-11-16 Molding material mixture and feeder for casting aluminum
MX2011005223A MX2011005223A (es) 2008-11-20 2009-11-16 Mezcla de materiales de moldeo y alimentador para fundir aluminio.
EP09801919A EP2349609A2 (fr) 2008-11-20 2009-11-16 Mélange de matière de moulage et masselotte pour coulage d'aluminium
ZA2011/03298A ZA201103298B (en) 2008-11-20 2011-05-06 Molding material mixture and feeder for casting aluminium

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DE102008058205A DE102008058205A1 (de) 2008-11-20 2008-11-20 Formstoffmischung und Speiser für den Aluminiumguss
DE102008058205.0 2008-11-20

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WO2010057464A2 true WO2010057464A2 (fr) 2010-05-27
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DE (1) DE102008058205A1 (fr)
EA (1) EA201170690A1 (fr)
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CN105414486A (zh) * 2016-01-12 2016-03-23 哈尔滨理工大学 铸造镁合金用发热保温冒口材料及制备方法
CN105817603A (zh) * 2016-04-26 2016-08-03 安徽纯启动力机械有限公司 一种防缩孔压铸模具
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CN107649651A (zh) * 2017-11-01 2018-02-02 江苏丹耐刚玉材料有限公司 一种铸造用高效发热保温冒口
CN110919818A (zh) * 2019-11-29 2020-03-27 王海江 一种生产铸造浇冒口系统的半固态浆料低温成型方法
CN110899628A (zh) * 2019-12-25 2020-03-24 银峰铸造（芜湖）有限公司 三乙胺法冷芯盒制芯方法以及铸造砂芯
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KR20110086635A (ko) 2011-07-28
CN102271836A (zh) 2011-12-07
JP2012509182A (ja) 2012-04-19
ZA201103298B (en) 2011-12-28
US20110220314A1 (en) 2011-09-15
EP2349609A2 (fr) 2011-08-03
EA201170690A1 (ru) 2012-01-30
DE102008058205A1 (de) 2010-07-22
WO2010057464A3 (fr) 2010-10-21
MX2011005223A (es) 2011-09-06

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