US20140255601A1 - Coating compositions for inorganic casting molds and cores and use thereof and method for sizing - Google Patents

Coating compositions for inorganic casting molds and cores and use thereof and method for sizing Download PDF

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Publication number
US20140255601A1
US20140255601A1 US14/348,232 US201214348232A US2014255601A1 US 20140255601 A1 US20140255601 A1 US 20140255601A1 US 201214348232 A US201214348232 A US 201214348232A US 2014255601 A1 US2014255601 A1 US 2014255601A1
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Prior art keywords
sizing composition
weight
sizing
composition according
solids content
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Michael Kloskowski
Peter Wachtarczyk
Carolin Wallenhorst
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ASK Chemicals GmbH
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ASK Chemicals GmbH
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22CFOUNDRY MOULDING
    • B22C3/00Selection of compositions for coating the surfaces of moulds, cores, or patterns
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22CFOUNDRY MOULDING
    • B22C1/00Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/18Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents
    • B22C1/186Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents contaming ammonium or metal silicates, silica sols
    • B22C1/188Alkali metal silicates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22CFOUNDRY MOULDING
    • B22C9/00Moulds or cores; Moulding processes
    • B22C9/02Sand moulds or like moulds for shaped castings
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22CFOUNDRY MOULDING
    • B22C9/00Moulds or cores; Moulding processes
    • B22C9/18Finishing

Definitions

  • the invention relates to a coating composition for casting molds and the use thereof.
  • the coating composition is suitable for casting molds and cores, in particular those that are produced using water glass as a binder.
  • the coating composition comprises certain clay materials.
  • a sizing method is also claimed.
  • Casting molds can be produced from a refractory material, for example quartz sand, by shaping into a casting mold and binding using a suitable binder to guarantee adequate mechanical strength.
  • casting molds are produced using a refractory basic material and a suitable binder.
  • the refractory basic mold material is preferably present in free-flowing form, so that it can be packed into a suitable hollow mold and compacted there.
  • the binder produces firm cohesion between the particles of the basic mold material, so that the mold form achieves the necessary mechanical stability.
  • Both organic and inorganic binders can be used for producing casting molds, and they can be cured by cold or hot processes.
  • Cold processes are those that are essentially performed at room temperature without heating the casting molds.
  • the curing is usually performed by a chemical reaction, initiated, for example, by passing a gas as a catalyst through the mold to be cured.
  • hot processes the molding mixture, after forming, can be heated to a temperature high enough, for example, to expel the solvent present in the binder or to initiate a chemical reaction by which the binder is cured, for example by cross-linking.
  • binders may be used which are based on inorganic materials or which contain a very small fraction of organic compounds. Such binder systems have long been known.
  • Binder systems have been developed which can be cured by passing gases into them.
  • a system of this type is described, for example, in GB 782205, in which an alkali water glass is used as the binder and can be cured by passing in CO 2 .
  • U.S. Pat. No. 6,972,059 B1 an exothermic feeder mass containing an alkali silicate as binder is described.
  • binder systems that are self-curing at room temperature have been developed.
  • One such system based on phosphoric acid and metal oxides, is described for example in U.S. Pat. No. 5,582,232.
  • inorganic binder systems that are cured at higher temperatures, for example in a hot tool are also known.
  • Such hot-curing binder systems are known, for example, from U.S. Pat. No. 5,474,606, in which a binder system consisting of alkali water glass and aluminum silicate is described.
  • a binder system for molding sands for producing cores is described.
  • the binder system based on water glass, consists of an aqueous alkali silicate solution and a hygroscopic base, for example sodium hydroxide, which is added in a ratio of 1:4 to 1:6.
  • the water glass has a SiO 2 /M 2 O modulus of 2.5 to 3.5 and a solids fraction of 20 to 40%.
  • the binder system also contains a surface-active material, such as silicone oil, which has a boiling point ⁇ 250° C.
  • the binder system is mixed with a suitable refractory material, such as quartz sand, and can then be shot into a core box using a core shooting machine.
  • a suitable refractory material such as quartz sand
  • the curing of the molding material mixture is accomplished by withdrawing the remaining water.
  • the drying or curing of the casting mold can also take place with the aid of microwaves.
  • inorganic binders also have drawbacks compared with organic binders; for example, the known inorganic binders result in low stability of the casting molds produced by using them toward high atmospheric humidity and toward water. Thus storage of the moldings over a long period of time, as is customary with organic binders, is not definitely possible.
  • a molding mixture is suggested which in addition to a refractory basic mold material contains a water glass-based binder.
  • a fraction of a particulate metal oxide is added to the mold material mixture.
  • precipitated silica or pyrogenic silica is used as the particulate metal oxide.
  • the methods described for producing casting molds and cores generally also include the application of a refractory mold coating, also known as sizing agent, at least to the surfaces of the basic mold that come into contact with the cast metal.
  • a refractory mold coating also known as sizing agent
  • the mold coatings are primarily intended to influence the surface of the molded parts, to improve the appearance of the casting, to influence the casting metallurgically, and/or to prevent casting defects.
  • the sizing agents generally used contain as their basic materials, for example, clays, quartz, diatomaceous earth, crystobalite, tridymite, aluminum silicate, zirconium silicate, mica, fireclay and also coke and graphite. These basic materials are the defining parts of the sizing agent, which cover the mold surface and close the pores against the penetration of the casting metal.
  • the surface of the casting mold can be modified and tailored to the properties of the metal being processed.
  • the sizing agent can improve the appearance of the casting by producing a smooth surface, since the sizing agent smooths out irregularities caused by the [different] sizes of the granules of the molding material.
  • the sizing agent can metallurgically influence the casting in that, for example, through the sizing agent, additives at the surface of the casting are selectively transferred into the casting, improving the surface properties of the casting.
  • the sizing agents form a layer that chemically isolates the casting mold during the casting of liquid metal. In this way, any adhesion between the casting and the casting mold is prevented, so that the casting can be removed from the casting mold without problems.
  • the sizing agent can also be used to control the heat transfer between liquid metal and casting mold, in order for example to accomplish the formation of a certain metal microstructure via the cooling rate.
  • the invention was based on the task of suggesting a sizing agent through which the most defect-free possible coating, especially of inorganic cores and molds, can be assured, without negatively impacting the stability of the cores or molds and thus their processing and storage.
  • the sizing composition according to the invention is prepared in the form of a paste or a suspension.
  • the sizing composition contains a carrier fluid.
  • sizing agents with an unusually high solids content can be produced, the viscosity of which is nevertheless comparable to that of commercial ready-to-use sizing agents such as Trioflex WK-LS-1.
  • the quality of cores and molds coated with these sizing agents and bonded with inorganic binders is lastingly improved by the combination of clays according to the invention and, for example, in this way several days' storage stability of the cores and molds can be achieved.
  • the viscosity of the sizing agent is in the customary range for sizing agents with substantially lower solids contents.
  • the sizing agents can be brought into the ready-to-use condition without the use of special additives or large amounts of water.
  • the clay material used was a combination of
  • the total content of the above-mentioned clays in the sizing agent amounts to 0.1 to 4.0% by weight, preferably 0.5 to 3.0% by weight, and particularly preferably 1.0 to 2.0% by weight.
  • Palygorskite is a magnesium-aluminum hydrosilicate listed under CAS No. 8031-18-3. Palygorskite is a constituent of commercial products sold as attapulgite. Attapulgite does contain palygorskite, but should not be used because of other interfering constituents and the absence of rod-shaped crystals.
  • Palygorskite exists in the form of rod-shaped crystals.
  • the particles have the following dimensions: 1 to 3 ⁇ m, especially 1.5 to 2 ⁇ m in length at a diameter of 1 to 5 nm, especially about 3 nm.
  • Palygorskite has different properties from attapulgite. Palygorskite does not swell or shrink, is shear-stable, and in a slurry with water or water-based liquids with A(2) or A(3), e.g., at low addition rates such as 0.01 to 3% by weight, produces a structurally viscous or thixotropic fluid. Once the shear effect ceases, the higher initial viscosity is rapidly restored. The viscosity is low in the presence of shear. Attapulgite contains smectite, SiO 2 , and/or CaCO 3 and other contaminants.
  • the product Acti-Gel® 208 from the “Active Minerals” company can be used as the palygorskite.
  • Bentone CT from the “Elementis” company can be used as the hectorite.
  • Volclay from the “Südchemie” company can be used as the sodium bentonite.
  • This natural raw material consists primarily (>80%) of montmorillonite; accompanying minerals can be quartzite, calcite, feldspar and mica.
  • the sizing composition e.g., as a base coat or top coat, and the desired layer thickness of the coating produced from the sizing composition, additional characteristic parameters of the sizing composition can be set.
  • the carrier fluid may be partially or completely composed of water.
  • the carrier fluid is the component that can be evaporated at 160° C. and normal pressure and in this sense, by definition, is primarily the component that is not the solids content.
  • the carrier fluid contains water to the extent of more than 50% by weight, preferably 75% by weight, especially more than 80% by weight, and optionally greater than 95% by weight of water.
  • the additional constituents in the carrier fluid may be organic solvents.
  • Suitable solvents are alcohols, including polyalcohols and polyether alcohols. Examples of alcohols are ethanol, n-propanol, isopropanol, butanol and glycol.
  • the solids content of the ready-to-use sizing composition is preferably adjusted to the range of 10 to 90% by weight, especially more than 80% by weight to 85% by weight.
  • the sizing agent according to the invention can contain additional constituents customary for sizing agents.
  • the sizing composition according to the invention contains at least one powdered refractory material.
  • This refractory material serves to block the pores in a casting mold against the penetration of the liquid metal.
  • the refractory material achieves thermal insulation between the casting mold and the liquid metal.
  • Suitable refractory materials are quartz, aluminum oxide, zirconium oxide, aluminum silicates such as pyropillite, kyanite, andalusite or fireclay, zirconium sands, ziconium silicates, olivine, talc, mica, graphite, coke, feldspar, diatomite, kaolins, calcined kaolins, kaolinite, metakaolinite, iron oxide and/or bauxite.
  • quartz aluminum oxide
  • zirconium oxide aluminum silicates such as pyropillite, kyanite, andalusite or fireclay
  • zirconium sands zirconium sands
  • ziconium silicates olivine, talc, mica, graphite, coke, feldspar, diatomite, kaolins, calcined kaolins, kaolinite, metakaolinite, iron oxide and/or bauxite.
  • the refractory material is prepared in powdered form.
  • the particle size is selected such that a stable structure is formed in the coating and that the sizing agent preferably can be distributed without problems on the wall of the casting mold using a spray device.
  • the refractory material has a mean particle size (measured by light scattering according to DIN/ISO 13320) in the range of 0.1 to 500 ⁇ m, particularly preferably in the range of 1 to 200 ⁇ m.
  • Particularly suitable as refractory materials are those that have a melting point that is at least 200° C. above the temperature of the liquid metal and independently of this, do not react with the metal.
  • the fraction of the refractory material (in each case contributing only to the solids content), e.g., in the commercial form of a paste, relative to the solids fraction of the sizing material composition, is advantageously more than 70% by weight, preferably more than 80% by weight, and particularly preferably more than 85% by weight.
  • the fraction of the refractory material for the case of application following dilution (e.g., of the paste) with water is selected to be less than 80% by weight, according to an additional embodiment less than 70% by weight and according to a further embodiment less than 60% by weight.
  • the sizing material according to the invention may contain at least one suspending agent.
  • the suspending agent brings about an increase in the viscosity of the sizing agent, so that the solid constituents of the sizing agent do not drop to the bottom in the suspension, or do so to only a slight degree.
  • Organic or inorganic materials or mixtures thereof can be used to increase the viscosity.
  • Suitable inorganic suspending agents are, for example, strongly swelling clays, such as sodium bentonite.
  • the suspending agent may also include organic thickeners, since after application of the protective coating, these can be dried to such an extent that they scarcely release any water after application of the protective coating.
  • organic suspending agents are, for example, swellable polymers such as carboxymethyl-, methyl-, ethyl-, hydroxyethyl- and hydroxypropylcelluloses, plant mucilages, polyvinyl alcohols, polyvinylpyrrolidone, pectin, gelatin, agar-agar, polypeptides and/or alginates.
  • the fraction of the suspending agent, based on the total sizing composition is advantageously selected as 0.1 to 5% by weight, preferably 0.5 to 3% by weight, particularly preferably 1 to 2% by weight.
  • the sizing agent according to the invention contains at least one binder as an additional component.
  • the binder makes possible better fixation of the sizing agent or the protective coating made from the sizing agent onto the wall of the casting mold.
  • the binder increases the mechanical stability of the protective coating, so that less erosion is observed under the influence of the liquid metal.
  • the binder cures irreversibly, so that an abrasion-resistant coating is obtained.
  • Particularly preferred are binders that do not soften again under contact with atmospheric humidity. Fundamentally any binder used in sizing agents may be present. Both inorganic and organic binders may be used. Suitable binders for use include, for example, clays, especially bentonite.
  • the fraction of the binder is preferably selected in the range of 0.1 to 20% by weight, particularly preferably 0.5 to 5% by weight, based on the solids content of the sizing composition.
  • the sizing agent contains a graphite fraction. This supports the formation of lamellar carbon at the interface between casting and casting mold.
  • the fraction of the graphite is preferably selected in the range of 1 to 30% by weight, especially preferably 5 to 15% by weight, based on the solids content of the sizing agent. In iron casting, graphite has a beneficial effect on the surface quality of the casting.
  • the sizing composition according to the invention may contain other constituents customary in sizing agents, for example wetting agents, defoamers, pigments, colorants or biocides.
  • the fraction of these additional constituents in the ready-to-use coating composition is advantageously less than 10% by weight, preferably less than 5% by weight and particularly preferably less than 1% by weight.
  • wetting agents may include anionic and non-anionic surfactants, especially those with an HSB value of at least 7.
  • a wetting agent is disodium dioctylsulfosuccinate.
  • the wetting agent is preferably used in a quantity of 0.01 to 1% by weight, preferably 0.05 to 0.3% by weight, based on the ready-to-use sizing composition.
  • Defoamers also known as antifoamers, can be used to prevent foam formation during the production or application of the sizing composition. Foam formation during application of the sizing composition can lead to lack of uniformity in the layer thickness and to holes in the coating.
  • silicone oil or mineral oil may be used as defoamers.
  • the defoamer is advantageously present in a quantity of 0.01 to 1% by weight, preferably of 0.05 to 3% by weight, based on the ready-to-use sizing composition.
  • the usual pigments and colorants may be used if desired. These are added to achieve contrast, e.g., between different sizing agents, or to create a stronger separating effect of the sizing agent from the casting.
  • pigments are red and yellow iron oxide and graphite.
  • colorants are commercial colorants such as the Luconyl® colorant series from BASF AG, Ludwigshafen, DE.
  • the colorants and pigments are preferably present in a quantity of 0.01 to 10% by weight, preferably of 0.1 to 5% by weight, based on the solids content of the sizing composition.
  • the sizing composition contains a biocide to prevent bacterial attack and thus avoid a negative effect on the rheology and the binding strength of the binder.
  • a biocide to prevent bacterial attack and thus avoid a negative effect on the rheology and the binding strength of the binder.
  • the carrier fluid contained in the sizing composition is made up essentially (on a weight basis) of water, and thus the sizing agent according to the invention is supplied in the form of a so-called aqueous sizing agent.
  • suitable biocides are formaldehyde, 2-ethyl-4-isothiazolin-3-one (MIT), 5-chloro-2-methyl-4-isothiazolin-3-one (CIT) and 1,2-benzisothiazolin-3-one (BIT).
  • MIT, BIT or a mixture thereof is used.
  • the biocides are usually used in a quantity of 10 to 1000 ppm, preferably of 50 to 500 ppm, based on the weight of the ready
  • the sizing composition according to the invention may be made by the usual methods.
  • a sizing composition according to the invention can be prepared by initially taking water and then dispersing clay, acting as a suspension agent, in it using a high-shear agitator. Then the refractory components, pigments and colorants, as well as the metal additive are mixed in until a homogeneous mixture forms. Finally, wetting agents, antifoamers, biocides and binders are mixed in.
  • the sizing composition according to the invention can be prepared and sold as a ready-to-use formulated sizing agent.
  • the sizing agent can also be prepared and sold in concentrated form. In this case, to produce a ready-to-use sizing agent, the quantity of the carrier fluid needed to establish the desired viscosity and density of the sizing agent is added.
  • the sizing agent according to the invention can also be prepared and sold in the form of a kit, wherein for example the solid component(s) and the solvent component(s) are present side by side in separate containers.
  • the solid component(s) can be supplied as a powdered solids mixture in a separate container. Additional liquid component(s) optionally to be used, for example binders, surfactants, wetting agents/defoamers, pigments, colorants and biocides, can also be present in this kit, once again in a separate container.
  • the solvent component(s) can either include the optional additional components for use, e.g., in a single container, or they can be present separate from other optional components in a separate container. To produce a ready-to-use sizing agent, the suitable quantities of the solids components, the optional additional components and the solvent components are mixed together.
  • the sizing compositions according to the invention are suitable for coating casting molds.
  • casting mold used here includes all types of solid bodies needed for producing a casting, e.g., cores, molds and dies.
  • the use of the sizing agent according to the invention also includes partial coating of casting molds.
  • the sizing agents are used for casting molds for metal processing, obtainable from inorganic molding material mixtures containing at least one refractory basic mold material, a water glass-based binder and preferably a fraction of a metal oxide selected from the group of silicon dioxide, especially amorphous silicon dioxide, aluminum oxide, titanium oxide or zinc oxide and mixtures thereof, wherein this is preferably present in particulate form and especially has particle sizes of less than 300 ⁇ m (screen analysis).
  • amorphous silicon dioxide can be obtained through precipitation processes starting from water glass, which can be obtained by solubilizing quartz said with sodium carbonate or potassium carbonate.
  • SiO 2 obtained in this way is called precipitated silica.
  • Another important manufacturing variant is the production of so-called pyrogenic SiO 2 in an oxyhydrogen gas flame, starting from liquid chlorosilanes such as silicon tetrachloride.
  • casting molds to be coated typically comprise
  • the invention relates to a method for producing sized casting molds for metal processing with application of sizing agents to the above-mentioned, partially or completely cured inorganic molding material mixtures.
  • the application or preparation of the sizing agents can take place as follows:
  • the casting mold in the mold cavity of which a base coat of sizing agent has been applied, is dipped for about 2 seconds to 2 minutes in a container that is filled with a ready-to-use sizing composition according to the invention.
  • the casting mold is then removed from the sizing composition and excess sizing composition is allowed to run out of the casting mold.
  • the time taken for the excess sizing composition to run out after dipping depends on the run-off behavior of the sizing composition used.
  • the sizing composition in a diluted state, is filled into a spray tank.
  • the sizing agent can be forced into a spray gun, where it is sprayed with the aid of separately controllable atomizing air.
  • the conditions are advantageously selected such that the pressure for the sizing composition and atomizing air are selected on the spray gun is set so that the sizing composition that is sprayed atomizing air strikes the mold or the core while said sizing composition is still wet, but results in a uniform application.
  • the casting mold optionally with a base coat applied in the mold cavity, is covered with a ready-to-use sizing composition with the aid of a tube, a lance or similar instruments.
  • the casting mold is covered completely with the sizing composition and the excess sizing composition runs out of the casting mold.
  • the time taken for the excess sizing composition to run off after flow coating depends on the flow behavior of the sizing composition used.
  • the sizing agent can also be applied by painting.
  • the carrier fluid contained in the sizing agent is then evaporated, so that a dry sizing agent layer is obtained.
  • Drying methods used may include all conventional drying methods, for example allowing to dry in air, drying with dehumidified air, drying with microwave or infrared radiation, drying in a convection oven and comparable methods.
  • the coated casting mold is dried in a convection oven at 20 to 250° C., preferably 50 to 180° C.
  • the sizing composition according to the invention is preferably dried by burning off the alcohol or the alcohol mixture.
  • the coated casting mold is additionally heated by the heat of combustion.
  • the coated casting mold is dried in air without further treatment or using microwaves.
  • the sizing agent can be applied in the form of a single layer or in the form of several layers arranged one on top of the other.
  • the individual layers may be the same or different in terms of their composition.
  • a base coat can be produced from a conventional commercial sizing agent that contains no metal additive according to the invention.
  • water-based sizing agents or alcohol-based sizing agents may be used. It is also possible to prepare all layers from the sizing composition according to the invention. The layer that will later come into contact with the liquid metal, however, is always produced from the sizing agent according to the invention.
  • each individual layer may be dried completely or partially after application.
  • the coating prepared from the sizing composition advantageously has a dry layer thickness of at least 0.1 mm, preferably at least 0.2 mm, particularly preferably at least 0.45 mm, especially preferably at least 0.55 mm.
  • the thickness of the coating is selected to be less than 1.5 mm.
  • the thickness of the dry layer in this case is the layer thickness of the dried coating obtained by essentially completely removing the solvent component and optionally curing subsequently.
  • the dry layer thickness of the base coat and the top coat are preferably determined by measuring with the wet layer thickness comb.
  • the casting mold can then be assembled completely if desired.
  • the casing is advantageously performed to make iron and steel castings.
  • the core sizing agents 1 and 2 have the compositions and physical properties indicated in Tables 1 and 2.
  • composition of sizing agents Sizing agent 1 Sizing agent 2 Name, company (designation) % by weight % by weight Water 15.0 21.0 Attagel 40; Solvadis (attapulgite) — 1.2 Actigel 208; Active Minerals (palygorskite 0.3 — Bentone CT, Elementis (hectorite) 0.4 — Volclay, Südchemie (sodium bentonite) 0.6 0.6 Zircon flour 45 ⁇ m 30.5 24 Zircon flour 75 ⁇ m 51 51 PVA solution (25%) 1.2 1.2 1.2Surfynol ® SEF (wetting agent 1) 0.2 0.2 D0.2ynol ® 604 (wetting agent 2) 0.05 0.05 Foamstar ® MF 324 (defoamer)0.05 0.2 0.2 Acticide ® F(N) (preservative 1) 0.4 0.4 Acticide ® MBS (preservative 2) 0.15 0.15
  • the mold casting sizing agent was produced as follows: water is placed in a vessel and the clay(s) broken up using a high-shear unit and a chopper disk for at least 15 minutes. Then the refractory components, pigments and colorants are mixed in for at least 15 minutes until a homogeneous mixture forms. Finally, additives such as wetting agents, defoamers and preservatives as well as the binder are mixed in for 5 minutes.
  • the sizing agents were adjusted to a viscosity in the range of 0.6 Pas, suitable for application.
  • the adjustment was done by adding appropriate amounts of water to the original composition and then homogenizing.
  • the main characteristic in this case is the viscosity, measured with a Brookfield viscometer (DIN EN ISO 2555) and with a DIN 4 mm viscosity flow cup (DIN EN ISO 2431), at 20° C. in each case.
  • Georg Fischer test bar illustrates the behavior of the sized test pieces on thicker core geometries
  • long cores illustrates the behavior of the sized test pieces on thin geometries.
  • Georg Fischer test bars are defined as rectangular test bars with dimensions of 150 mm ⁇ 22.36 mm ⁇ 22.36 mm.
  • the long cores have dimensions of 13 mm ⁇ 20 mm ⁇ 235 mm.
  • the composition of the molding material mixture is shown in Table 3.
  • the quartz sand was placed in a vessel and the water glass was added while stirring.
  • a sodium water glass containing some potassium was used as the water glass.
  • the SiO 2 :M 2 O modulus of the water glass was about 2.2, wherein M is the sum of sodium and potassium.
  • amorphous silicon dioxide was optionally added under further agitation.
  • the amorphous silicon dioxide is pyrogenic silica from the RW Silicium company. Then the mixture was agitated for an additional minute.
  • the molding composition mixture was transferred to the storage bunker, an H 2.5 Hot Box core shooting machine from the Röperwerk-Giessmaschinen GmbH, Viersen, DE, the molding tool of which was heated to 180° C.
  • the molding composition mixture was introduced into the molding tool using compressed air (5 bar) and remained in the molding tool for an additional 35 seconds.
  • compressed air 5 bar
  • hot air 2 bar, 150° C. upon entry into the tool
  • the molding tool was opened and the test bar removed.
  • the coating compositions were applied to the test bar by dipping; the application parameters are listed in Table 2.
  • the test bars were coated either immediately after removal from the molding tool or after a 30 min cooling time.
  • the coated test bars were held in a drying oven for 30 min at 150° C.
  • test bars were placed in a Georg Fischer strength testing apparatus equipped with a 3-point bending device (DISA Industrie AG, Schaffhausen, CH) and the force resulting in breakage of the test bar was measured.
  • the uncoated bending strengths were measured according to the following plan:
  • the quality of the inorganic cores and molds coated with these sizing agents is lastingly improved, and thus for example, storage stability of the cores and molds for several days can be achieved. It should be mentioned in particular that despite the unusually high solids content, the viscosity of the sizing agents lies in a customary range for sizing agents. The agents can be brought into the condition suitable for application without using special additives or large amounts of water.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
  • Paints Or Removers (AREA)
  • Silicates, Zeolites, And Molecular Sieves (AREA)
US14/348,232 2011-09-30 2012-10-01 Coating compositions for inorganic casting molds and cores and use thereof and method for sizing Abandoned US20140255601A1 (en)

Applications Claiming Priority (3)

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DE102011114626.5 2011-09-30
DE102011114626A DE102011114626A1 (de) 2011-09-30 2011-09-30 Beschichtungsmassen für anorganische Giessformen und Kerne und deren Verwendung
PCT/DE2012/000952 WO2013044904A1 (de) 2011-09-30 2012-10-01 Beschichtungsmassen für anorganische giessformen und kerne und deren verwendung und verfahren zum schlichten

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CN114226637A (zh) * 2021-11-29 2022-03-25 武汉纺织大学 一种湿型砂铸钢用环保型低成本醇基涂料及其制备方法
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US11858030B2 (en) 2018-07-20 2024-01-02 Ask Chemicals Gmbh Sizing composition for casting molds for metal casting, method for producing the casting molds, and casting molds provided with the sizing composition
CN113149602A (zh) * 2021-05-07 2021-07-23 徐金花 一种强度高可塑性强综合性能优异的新型釉面瓷砖
CN114226637A (zh) * 2021-11-29 2022-03-25 武汉纺织大学 一种湿型砂铸钢用环保型低成本醇基涂料及其制备方法

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IN2014KN00901A (pt) 2015-10-09
DE102011114626A1 (de) 2013-04-04
RU2014117287A (ru) 2015-11-10
ZA201401614B (en) 2015-01-28
EP2760607A1 (de) 2014-08-06
KR20140071439A (ko) 2014-06-11
BR112014007623A2 (pt) 2017-04-18
EP2760607B1 (de) 2015-12-30
MX2014003804A (es) 2014-07-22
WO2013044904A1 (de) 2013-04-04
JP2014527915A (ja) 2014-10-23
CN103826775A (zh) 2014-05-28

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