US20130266476A1 - Anti-veining additive for the production of casting molds and cores - Google Patents

Anti-veining additive for the production of casting molds and cores Download PDF

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US20130266476A1
US20130266476A1 US13/993,484 US201013993484A US2013266476A1 US 20130266476 A1 US20130266476 A1 US 20130266476A1 US 201013993484 A US201013993484 A US 201013993484A US 2013266476 A1 US2013266476 A1 US 2013266476A1
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additive
core
sand
mold
cores
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Santiago Prat Urreiztieta
Marco Antonio Mendizábal Castellanos
Maria José Puertollano Abascal
Jesús Reina Rivero
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ASK CHEMICALS ESPANA SA
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ASK CHEMICALS ESPANA SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/02—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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
    • B22C1/22—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B26/00—Compositions of mortars, concrete or artificial stone, containing only organic binders, e.g. polymer or resin concrete
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
    • C04B35/18—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay rich in aluminium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/653—Processes involving a melting step
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00939—Uses not provided for elsewhere in C04B2111/00 for the fabrication of moulds or cores
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3201—Alkali metal oxides or oxide-forming salts thereof
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3201—Alkali metal oxides or oxide-forming salts thereof
    • C04B2235/3203—Lithium oxide or oxide-forming salts thereof
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
    • C04B2235/3206—Magnesium oxides or oxide-forming salts thereof
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
    • C04B2235/3208—Calcium oxide or oxide-forming salts thereof, e.g. lime
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
    • C04B2235/3213—Strontium oxides or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
    • C04B2235/3232—Titanium oxides or titanates, e.g. rutile or anatase
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/327—Iron group oxides, their mixed metal oxides, or oxide-forming salts thereof
    • C04B2235/3272—Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/44—Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
    • C04B2235/442—Carbonates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/528—Spheres
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/72—Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics

Definitions

  • the present invention belongs to the field of additives for molding sands used in the manufacture of casting molds and cores. More specifically, the present invention relates to an additive to prevent veining in the manufacture of metal parts, to a molding sand comprising said additive, to a core or mold prepared from said molding sand and to a metal part prepared by means of using one of said cores or molds.
  • the castings obtained using cores and molds manufactured with molding sands generally have a series of shape defects that must be later machined to obtaining a dimensionally suitable part. These defects occur because the core or mold experiences heating due to the effect of the molten metal which is poured therein, which causes its expansion and, as a consequence, the occurrence of cracks on its surface. The molten metal penetrates into these cracks, thus forming a type of partitions or lamellas on the surface of the part obtained. This unwanted effect is known as veining or “rat tail”.
  • Cores or molds are manufactured today by mixing sands with gas-cured or heat-cured resins, or with self-setting resins, a series of additives intended for improving the features of the final part obtained further being used.
  • Several solutions are known to control or reduce veining.
  • iron oxides as an additive in the preparation of molding sands.
  • the iron oxides are intended for minimizing problems created by the expansion of the silica contained in the sands, red, black or yellow iron oxides or iron oxides from Sierra Leone, incorporated into the mixture in percentages ranging between 1 and 3%, being used for that purpose.
  • These oxides act as a fayalite forming factor, such that during the formation of the crack in the core, viscous fayalite fills in the cracks thus minimizing veining.
  • this technique has the drawbacks of the iron oxide reducing the mechanical strength of the core and, furthermore, the formation of fayalite increases the tendency of penetration causing the outer surface of the part obtained to have irregularities which must be later treated.
  • Patent WO 2009155242 describes an anti-veining additive based on the use of iron oxide to which a glass component has been added. Said glass component forms a molten glass among the grains of sand which increases plasticity, reducing the breakage of the cores and, therefore, the occurrence of veining. The problem again is the reduction of the mechanical strength of the core.
  • Another existing solution consists of using wood flours and carbon dust as an additive.
  • the wood dust or coal is added to the molding sand in proportions ranging between 1 and 3%.
  • This flour burns during melting, leaving empty cavities distributed throughout the entire volume of the core which allow the expansion of the silica to occur in those cavities without needing to increase their outer size, thereby preventing the occurrence of cracks which cause veining.
  • the main drawback of this technique is that since the flour burns, a large amount of gas is produced which, when diffuse, can lead to dimensional problems in the obtained parts. With additives of this type of additives, the mechanical strength of the cores is likewise reduced.
  • U.S. Pat. No. 4,735,973 describes the use of titanium oxide additives.
  • the additive is present in a percentage ranging between 0.5 and 5% of the total sand and this additive containing between 15 and 95% titanium oxide.
  • EP0891954 Another solution for controlling veining in the preparation of metal parts is described in patent EP0891954 and in ES2116245, closely related to the former.
  • the solution of these patents comprises the use of hollow alumina silicate microspheres as an anti-veining additive.
  • EP0891954 describes the use of hollow alumina silicate microspheres which are added to the sand in a percentage by weight of 1 to 30%.
  • the microspheres must contain between 20-35% of alumina.
  • an additive is achieved which allows lowering the amount of microspheres in the sand mixture to less than 10%. This allows obtaining molds and cores having suitable mechanical characteristics but which surprisingly further allow the complete lack of veining in the final metal parts.
  • the use of the additive of the invention also allows obtaining metal parts with a smooth surface or skin.
  • FIG. 1 shows an image of a metal part where the veining defect caused by the use of a core made up of 100% sand can be seen.
  • FIG. 2 shows a graph depicting the shrinkage percentage of the different microspheres depending on the temperature. The final shrinkage temperature of each type of microsphere is indicated.
  • FIG. 3 shows a graph depicting the shrinkage percentage of the different microspheres depending on the temperature and in the presence of 6% lithium carbonate and a 6% strontium carbonate.
  • FIG. 4 shows an image of a metal part of obtained by means of using a core prepared with the additive of the invention where the absence of veining is seen.
  • FIG. 5 shows a graph depicting gas production during the preparation of a metal part with different cores prepared without additives, with different commercial additives and with the additive of the invention.
  • FIG. 6 shows a graph depicting the tensile strength of the cores with different percentages of the additive of the invention (sample 5 94%+6% CO 3 Li 2 ) upon coming out of the box, at 24 hours and at 24 hours with 100% relative humidity.
  • FIG. 7 shows a graph depicting the abrasion resistance of the cores with different percentages of the additive of the invention (sample 5 94%+6% CO 3 Li 2 ) upon coming out of the box, at 24 hours and at 24 hours with 100% relative humidity.
  • the main object of the present invention consists of an additive for molding sands comprising hollow alumina silicate microspheres between 90-99% of the total weight of the additive and a flux between 1-10% of the total weight of the additive.
  • the additive comprises between 94-97% hollow alumina silicate microspheres and between 3-6% flux.
  • additive of the invention is used mixed with the sands to prepare casting molds and cores.
  • the additive surprisingly reduces the occurrence of cracks in molds and cores during the casting and molding of the metal part, in most cases preventing the occurrence thereof. Veining in the final metal parts is thus prevented.
  • the hollow alumina silicate microspheres are the first component of the additive of the invention. As previously discussed, these microspheres have the capacity to absorb the expansion of the silica when the core or mold is heated upon contact with the molten metal. Any type of hollow alumina silicate microsphere can be used in the preparation of the additive of the invention, including those with a high alumina content.
  • the microspheres of the additive of the invention can have an alumina content of between 15-45% by weight.
  • the preferred embodiment contemplates the use of microspheres with an alumina content of between 18-40%.
  • the hollow microspheres can contain other minor elements or components in their composition besides alumina silicate such as Fe 2 O 3 , CaO, MgO, Na 2 O, K 2 O or TiO 2 , which can slightly alter the thermal behavior of the microspheres, but in any case the presence of these elements will not affect the anti-veining capacity of the additive of the invention.
  • alumina silicate such as Fe 2 O 3 , CaO, MgO, Na 2 O, K 2 O or TiO 2 , which can slightly alter the thermal behavior of the microspheres, but in any case the presence of these elements will not affect the anti-veining capacity of the additive of the invention.
  • the other component of the additive of the invention is the flux.
  • the inventors have observed that it has the capacity to alter the thermal properties of the microspheres.
  • the flux has the effect of lowering the melting point of the microspheres, making them soften and collapse (break) sooner. This allows optimizing the effect of absorbing the expansion of the sand.
  • the inventors have also observed that the presence of the flux allows working with hollow alumina silicate microspheres of any type.
  • the preferred embodiment of the invention contemplates the use of an alkaline or alkaline-earth element carbonate as a flux. More preferably, said carbonates can be lithium carbonate and/or strontium carbonate.
  • the additive of the invention is used mixed with sands.
  • Said sands called molding sands are used to prepare casting molds and cores.
  • Another object of the present invention is, therefore, a molding sand comprising between 90% and 99% by weight of sand and between 1-10% by weight of the additive of the invention.
  • the molding sand of the invention preferably comprises between 94-97% of sand and 3-6% of the additive of the invention.
  • any commonly used type of sand can be used in the preparation of casting molds and cores.
  • sands for producing casting cores and molds with a silica content greater than 95% and with different grain-size distributions from AFA 40 to AFA 120 can be used.
  • the molding sand of the invention can also contain other conventional components, such as casting aggregates, binders and other optional components used in this field of the art.
  • Another object of the invention is the use of the molding sand of the invention for preparing casting molds and cores. More specifically, an object of the present invention is a method for preparing a casting mold or core which comprises:
  • Step a) comprises the mixture and homogenization of the molding sand, which includes in its composition the sand and the additive of the invention, with a binding resin. After the resins are cured, they favor the binding and cohesion of the particles and the hardening of the mold or core.
  • any type of resin commonly used in the preparation of casting cores and molds can be used in step a).
  • the invention contemplates the use of phenolic-urethane resins gassed with amine; acrylic-epoxy resins gassed with SO 2 : phenolic-alkaline resins gassed with methyl formate or CO 2 ; furan resins, phenol resins, hot-box urea-formol resins or the combinations thereof; hot-box INOTEC inorganic system, or also sands pre-coated with Novolac resins, for example.
  • the molding sand is mixed with the resin, the mixture is introduced in a mold to provide the sand mold or core with the final shape it must adopt. The shape it acquires will determine the shape of the final metal part.
  • a curing catalyst which accelerates the polymerization of the resin is applied in step c).
  • Any catalyst commonly used in this technical field is suitable for the purposes of the invention, gaseous catalysts such as amines, SO 2 , methyl formate or CO 2 are normally used.
  • the sand mold or core is separated from the mold used to give it shape and it is ready for use in the manufacture of the metal part.
  • Another object of the present invention is a mold or core comprising a molding sand according to the invention, i.e., a molding sand comprising the additive of the invention.
  • the cores and molds of the invention have a mechanical performance substantially identical to that of the cores and molds produced only with sand but with the advantage that veining is altogether prevented.
  • Another advantage of the cores and molds of the invention resides in the gas given off in the produced part. The amount of gas is not only significantly reduced (see FIG. 5 ) but furthermore gas production stabilizes after 20 minutes similarly to other commercial anti-veining additives.
  • Another object of the invention is a method for preparing metal castings which comprises:
  • the cores or molds of the invention allow obtaining according to the method herein described parts from different metals and/or alloys such as ferric metals, such as grey, nodular cast iron and steel, or non-ferric metals such as copper, bronze and tin.
  • ferric metals such as grey, nodular cast iron and steel
  • non-ferric metals such as copper, bronze and tin.
  • a final object of the present invention is precisely a metal part obtained according to the previously described method.
  • the metal parts of the invention are free of veining and have a substantially smooth surface or skin, lacking roughnesses.
  • Said metal parts can be of ferric metals such as grey, nodular cast iron and steel or non-ferric metals such as copper, bronze and tin.
  • the melting test was carried out in a MISURA hot-stage microscope.
  • the hot-stage microscope is an equipment which allows observing a sample when it is subjected to a heating cycle. At the same time it allows recording the outline of the sample throughout the melting test in a data carrier. The evolution of the shrinkage of the sample depending on the temperature was determined from the recorded images by means of image analysis equipment.
  • a cylindrical button 3 mm in diameter and 3 mm in height was formed with each sample by pressing and was placed on a support.
  • the latter was housed in the sample holder of the hot-stage microscope, where it was subjected to a heating cycle with a rate of 25° C./min up to the maximum temperature of 1550° C.
  • Cores were prepared from 94% Echave C-70 sand, 1% ISOCURE FOCUS® 418/618 phenolic-urethane resin, and 5% of the additive (94% of the microsphere sample+6% Co3Li).
  • the 3 components were mixed in a grinder and the mixture was introduced in the in the hopper of a core shooting machine. The mixture was shot into the core box to obtain the shape of the core and it was gassed with amine. The cured cores were extracted with their final shape.
  • the use of 6% lithium carbonate as a component of the anti-veining additive provides metal parts without veining, regardless of the microsphere sample used.
  • the parts also have a skin without defects worth reporting.
  • both the parts obtained by molding from cores without an additive (100% sand) or only with microspheres as the additive (100% sample 5) provided considerable veining defects of 10 and 7, respectively (on a veining scale of 0-10).
  • a test was carried out to determine the abrasion resistance and the tensile strength of a core obtained from sand and a variable amount of additive (94% of microspheres sample 5+ 6% of lithium carbonate).

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US13/993,484 2010-12-30 2010-12-30 Anti-veining additive for the production of casting molds and cores Abandoned US20130266476A1 (en)

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PCT/ES2010/070876 WO2012089856A1 (es) 2010-12-30 2010-12-30 Aditivo antiveining para la preparación de moldes y machos de fundición

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CN104493075B (zh) * 2014-12-04 2016-05-11 宁夏共享化工有限公司 一种铸造专用无机防脉纹添加剂的制备方法
CN105195670B (zh) * 2015-10-09 2017-09-22 宁夏共享化工有限公司 一种防止脉纹缺陷的水基流涂涂料的生产方法
CN110000328A (zh) * 2019-03-05 2019-07-12 宁夏共享化工有限公司 一种铸造用防脉纹添加剂及其制备方法
CN110465621A (zh) * 2019-09-17 2019-11-19 马鞍山市三川机械制造有限公司 一种自剥落水基抗脉纹铸铁涂料的制备方法
CN110722093A (zh) * 2019-10-16 2020-01-24 沈阳大学 一种动物胶改性制备的铸造型砂添加剂

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5911269A (en) * 1992-11-16 1999-06-15 Industrial Gypsum Co., Inc. Method of making silica sand molds and cores for metal founding
US6598654B2 (en) * 1996-12-27 2003-07-29 Iberia Ashland Chemical, S.A. Molding sand appropriate for the fabrication of cores and molds

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1096706A (en) * 1965-08-11 1967-12-29 Foseco Int Production of steel ingots
US4735973A (en) 1985-11-15 1988-04-05 Brander John J Additive for sand based molding aggregates
US4874726A (en) * 1987-11-18 1989-10-17 Dresser Industries, Inc. Lightweight fused silica refractory compositions
GB9308363D0 (en) * 1993-04-22 1993-06-09 Foseco Int Refractory compositions for use in the casting of metals
ES2115563B1 (es) * 1996-12-27 1999-04-01 Iberica Ashalnd Chemical S A Arena de moldeo adecuada para fabricar machos y moldes de fundicion.
US20020165292A1 (en) * 2001-05-01 2002-11-07 Baker Stephen G. Casting sand cores and expansion control methods therefor
DE102004042535B4 (de) * 2004-09-02 2019-05-29 Ask Chemicals Gmbh Formstoffmischung zur Herstellung von Gießformen für die Metallverarbeitung, Verfahren und Verwendung
WO2008046651A1 (de) * 2006-10-19 2008-04-24 Ashland-Südchemie-Kernfest GmbH Kohlenhydrathaltige formstoffmischung
WO2009046128A1 (en) 2007-10-03 2009-04-09 Igc Technologies, Llc Material used to combat thermal expansion related defects in the metal casting process
US20090114365A1 (en) 2007-11-07 2009-05-07 Igc Technologies, Llc Material used to combat thermal expansion related defects in high temperature casting processes
US7938169B2 (en) 2008-06-20 2011-05-10 Prince Minerals, Inc. Anti-veining agent for metal casting

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5911269A (en) * 1992-11-16 1999-06-15 Industrial Gypsum Co., Inc. Method of making silica sand molds and cores for metal founding
US6598654B2 (en) * 1996-12-27 2003-07-29 Iberia Ashland Chemical, S.A. Molding sand appropriate for the fabrication of cores and molds

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UA106559C2 (ru) 2014-09-10
MX2013006692A (es) 2013-12-02
BR112013016833A2 (pt) 2016-09-27
CN103384653A (zh) 2013-11-06
WO2012089856A1 (es) 2012-07-05
JP5801900B2 (ja) 2015-10-28
RU2570680C2 (ru) 2015-12-10
EP2660222A4 (en) 2017-01-11
AU2010366563A1 (en) 2013-07-11
RU2013127624A (ru) 2015-02-10
MX352826B (es) 2017-12-11
CA2822690A1 (en) 2012-07-05
EP2660222A1 (en) 2013-11-06
JP2014500150A (ja) 2014-01-09

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