US20170297087A1 - Composition and method to form displacements for use in metal casting - Google Patents

Composition and method to form displacements for use in metal casting Download PDF

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US20170297087A1
US20170297087A1 US15/132,031 US201615132031A US2017297087A1 US 20170297087 A1 US20170297087 A1 US 20170297087A1 US 201615132031 A US201615132031 A US 201615132031A US 2017297087 A1 US2017297087 A1 US 2017297087A1
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Prior art keywords
displacement
mold
ground
microns
applicants
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US15/132,031
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David A. Rohrbacker
Jon Chatwood
William Palmer
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Destech Corp
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Individual
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Priority to US15/132,031 priority Critical patent/US20170297087A1/en
Priority to CA3020767A priority patent/CA3020767C/en
Priority to PCT/US2017/028000 priority patent/WO2017184527A1/en
Priority to BR112018071431A priority patent/BR112018071431A2/pt
Priority to RU2018140459A priority patent/RU2725314C2/ru
Priority to CN201780024220.XA priority patent/CN109070192A/zh
Priority to EP17720923.6A priority patent/EP3445514B1/en
Publication of US20170297087A1 publication Critical patent/US20170297087A1/en
Priority to US16/157,941 priority patent/US10646916B2/en
Assigned to DESTECH CORPORATION reassignment DESTECH CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PALMER, WILLIAM, ROHRBACKER, DAVID A, CHATWOOD, Jon
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
    • C—CHEMISTRY; METALLURGY
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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
    • C04B35/01—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
    • C04B35/14—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 silica
    • C—CHEMISTRY; METALLURGY
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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
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
    • C04B35/524—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite obtained from polymer precursors, e.g. glass-like carbon material
    • C—CHEMISTRY; METALLURGY
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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
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63448—Polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63472—Condensation polymers of aldehydes or ketones
    • C04B35/63476—Phenol-formaldehyde condensation polymers
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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
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63448—Polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63472—Condensation polymers of aldehydes or ketones
    • C04B35/6348—Melamine-formaldehyde condensation polymers
    • C—CHEMISTRY; METALLURGY
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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
    • C04B35/71—Ceramic products containing macroscopic reinforcing agents
    • C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
    • C04B35/80—Fibres, filaments, whiskers, platelets, or the like
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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
    • C04B2235/42—Non metallic elements added as constituents or additives, e.g. sulfur, phosphor, selenium or tellurium
    • C04B2235/422—Carbon
    • C—CHEMISTRY; METALLURGY
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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
    • C04B2235/48—Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
    • 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
    • C04B2235/5208—Fibers
    • C04B2235/5216—Inorganic
    • 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
    • C04B2235/5208—Fibers
    • C04B2235/526—Fibers characterised by the length of the fibers
    • 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
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
    • 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
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    • C04B2235/5463—Particle size distributions
    • 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
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/616—Liquid infiltration of green bodies or pre-forms

Definitions

  • This invention relates to a composition and method to form one or more displacements for use in a metal, ceramic, or cermet casting process.
  • the invention is directed to a composition, and method using that composition, to form one or more displacements for use in a metal, ceramic, or cermet casting process.
  • Foundry work involves the introduction of molten metal into a mold, which is formed to contain a hollow cavity defining a desired shape.
  • Sand casting is one of the most popular and simplest types of casting because it allows for flexible sizes of batches and provides reasonable cost.
  • the first step in the sand casting process is to create the mold.
  • the sand is packed around the pattern to replicate the external shape of the casting.
  • the cavity that forms the casting remains when the pattern is removed. Lubrication is often applied to the surfaces of the mold cavity in order to facilitate removal of the casting.
  • internal features of the casting are defined by separate displacements which are prepared prior to molding process.
  • Applicants' disclosure provides a method to form a displacement for use in the metal casting process, wherein the method provides a plurality of ceramic particles and a plurality of resin particles.
  • the method further grinds the plurality of ceramic particles until those ceramic particles comprise a maximum dimension less than about 150 microns.
  • the method further grinds the plurality of resin particles until those resin particles comprise a maximum dimension less than about 100 microns.
  • the method subsequently forms a powder blend consisting of a mixture of the plurality of ground ceramic particles and the plurality of ground resin particles.
  • the powder blend comprises a plurality of ground ceramic particles, a plurality of ground resin particles, and a plurality of reinforcing fibers.
  • the powder blend comprises a plurality of ground ceramic particles, a plurality of ground resin particles, and a cylindrical graphite member.
  • Applicants' disclosure also provides further treatments of the displacement for use in the metal casting process. These additional treatments enhance the mechanical strength so that the displacement will better survive the molten metal molding process.
  • FIG. 1 illustrates a cross-sectional view of a metal casting mold
  • FIG. 2A shows a perspective view of a metal casting with displacement 110 A/ 110 B still inserted therein;
  • FIG. 2B shows a perspective view of metal molding 202 , wherein displacement 110 A/ 110 B have been removed;
  • FIG. 3 is a flow chart summarizing the steps of Applicants' method to form a casting displacement without glassy carbon moieties
  • FIG. 4 shows a flow chart summarizing the steps of Applicants' method to form a casting displacement comprising glassy carbon moieties.
  • casting metal mold 100 comprises displacement 110 , cavity 120 , chaplets 130 and 140 .
  • Displacement 110 is positioned within cavity 120 and fastened by chaplets 130 and 140 .
  • Liquid molten metal is then introduced into mold 100 .
  • Liquid molten metal is introduced into mold 100 to fill entire cavity 120 .
  • the molten metal that is poured into the mold then begins to cool and solidify.
  • FIG. 2A illustrates metal molding 200 , wherein a distal end 110 B of displacement 110 ( FIG. 1 ) extends outwardly from end 205 of molding 200 .
  • FIG. 2B illustrates metal molding 202 , wherein displacement portions 110 A and 110 B have been removed.
  • displacement portions 110 A and 110 B are removed using a water spray under pressure.
  • the displacement can be a complex displacement.
  • the complex displacement comprises a cylindrical body 204 formed to include an aperture 210 extending inwardly from distal end 205 , wherein cylindrical body comprises a first diameter, in combination with an integral annular lip 215 disposed around proximal end 207 of cylindrical body 204 , wherein annular ring 215 comprises a second diameter, wherein the second diameter is greater than the first diameter.
  • FIG. 3 summarizes the steps of Applicants' method to form displacements for metal casting process using Applicants' molding composition.
  • Applicants' method provides a ceramic powder.
  • that ceramic powder is selected from the group consisting of, but not limited to, silica, zirconia, olivine, magnesium oxide, silica carbide, aluminum oxide, and combinations thereof.
  • the ceramic powder is a mixture of silica and aluminum oxide. Applicants have found that if a molding composition comprises mostly silica, the molding composition does not have a sufficient compression strength and cracks when the molding composition is fired at 1000° C.
  • Step 320 further comprises providing a resin system.
  • the resin system of step 320 comprises a thermosetting adhesive composition.
  • the thermosetting resin system of step 310 is selected from the group consisting of a phenol-formaldehyde resin, a resorcinol-formaldehyde resin, a resol resin, a novalac resin, and a melamine resin.
  • melamine resins are formed by a reaction of dicyandiamide with formaldehyde.
  • phenolic resins, melamine resol resins, novalacs, and formaldehyde resins comprise strong bonds and exhibit good resistance to high temperatures.
  • Applicants' resin system comprises a one part system that cures with heat or heat and pressure.
  • Applicants' resin system comprises a resin, as described above, in combination with a hardener, wherein the resin system crosslinks, i.e. cures, with the application of heat.
  • Applicants' hardener comprises a diamine. In certain embodiments, Applicants' hardener comprises an aromatic diamine, such as and without limitation to luene diamine, diphenylmethane diamine, and the like. In certain embodiments, Applicants' hardener comprises an alkyl diamine, such as and without limitation, hexamethylene diamine.
  • step 330 Applicants' method grinds the ceramic powder of step 310 .
  • the ceramic powder must be ground to smaller than 100 microns.
  • Applicants have found that use of powders having particles with diameters larger than about 150 microns result in the formation of displacements that comprise insufficient mechanical properties during the high temperature metal casting process.
  • step 330 comprises grinding the ceramic powder of step 310 until the particles comprising that powder comprise diameters less than about 150 microns.
  • Applicant means plus or minus ten percent (10%).
  • step 330 comprises forming a ceramic powder comprising particles having maximum dimensions less than about 150 microns and greater than about 30 microns. In certain embodiments, the average particle maximum dimension is about 75 microns.
  • step 340 Applicants' method grinds the resin system of step 320 .
  • the resin system must be ground to smaller than 150 microns.
  • Applicants have found that use of resin systems comprising particles with a maximum dimension larger than about 150 microns result in the formation of displacements that comprise insufficient mechanical properties during the high temperature metal casting process.
  • step 340 comprises grinding the resin system of step 310 until the particles comprising that powder comprise maximum dimensions less than about 150 microns. In certain embodiments, step 340 comprises providing a resin system comprising particles having maximum dimensions less than about 150 microns and greater than about 30 microns. In certain embodiments, the average particle maximum dimension is about 75 microns.
  • step 350 Applicants' method determines if a fiber reinforcement will be used. In certain embodiments, Applicants' displacements for metal casting process are formed without a fiber reinforcement. On the other hand in certain embodiments, Applicants' displacements are formed using one or more fiber reinforcements. If Applicants' method elects not to use a fiber reinforcement, then the method transitions from step 350 to step 370 .
  • Applicants' method elects to use a fiber reinforcement, then the method transitions from step 350 to step 360 wherein the method provides a plurality of reinforcing fibers.
  • Applicants' reinforcement fiber comprises carbon fiber.
  • Applicants' reinforcement fiber comprises fiber glass. Applicants have found that fiber glass reinforcement fibers comprise a low coefficient of thermal expansion in combination with a high thermal conductivity. As a result, fiber glass reinforced displacements comprise a dimensionally stable material that more rapidly dissipates heat as compared to asbestos and organic fibers.
  • Applicants' fiber glass comprises a fiber glass mat. In certain embodiments, Applicants' fiber glass comprises a plurality of uncoated milled fibers comprising about a 200 micron length.
  • reinforcing fibers comprising a nominal length of about 200 microns imparts the optimal combination of mechanical strength and surface smoothness to the cured displacements. More specifically, Applicants have found that using displacements comprising reinforcing fibers comprising a nominal length of about 200 microns results in optimal cavity formation in the metal casting process. Applicants have further found that use of longer fibers results in only a minimal mechanical property enhancement but also further results in a much rougher surface.
  • step 370 comprises using a twin shell V blender for approximately 30 minutes using 1 ⁇ 8′′ alumina media to insure a nearly homogenous mixture.
  • Applicants' method transitions from step 370 to step 375 wherein the method loads this blended composition of step 370 into the mold provided in step 310 .
  • step 380 Applicants' method densifies the blended composition disposed in the mold.
  • step 380 includes using isostatic pressing to densify the blended ceramic, resin, and reinforcement. In certain embodiments, step 380 includes using uniaxial pressing to densify the blended ceramic, resin, and reinforcement. In certain embodiments, step 380 includes using vibration to densify the blended ceramic, resin, and reinforcement.
  • the blended composition of step 370 comprises between about 50 to about 95 weight percent ceramic powder, between about 5 to about 25 weight percent resin system, and between about 0 to about 25 weight percent reinforcing fiber.
  • “about” is used to mean that a difference in weight percentage is plus or minus ten percent (10%).
  • the weight percentage of resin system increases as the average particle dimension of the ceramic powder decreases.
  • the weight percentages of the ceramic powder, the resin system, and the reinforcing fiber are adjusted respectively to achieve a certain Grain Fineness Number (AFS 11-6-00-S) to ensure a particular particle size distribution in the molding composition.
  • GBN Grain Fineness Number
  • the optimal grain fineness number (GFN) in a system is determined by the type of metal poured, pouring temperatures, casting product mix (heavy vs. light castings) and required surface finish. After that optimal fineness level is determined, maintaining a consistent grain structure becomes a critical factor in the quality of the final castings.
  • GFN is a measure of the average size of the particles (or grains).
  • the grain fineness of molding sand is measured using a test called sieve analysis, which is performed as follows:
  • a representative sample of the sand is dried and weighed, then passed through a series of progressively finer sieves (screens) while they are agitated and tapped for a 15-minute test cycle.
  • the percentage of particles retained is then multiplied by a factor, or multiplier, for each particular screen (Table 1).
  • the factors reflect the fact that the sand retained on a particular sieve (e.g. 50 microns) is not all 50 microns in size, but rather smaller than 40 microns (i.e. it passed through a 40 micron screen) and larger than 50 microns (it won't pass through 50 micron screen). The result should be rounded to one decimal place.
  • This number is the weighted mathematical average of the particle size for that sand sample.
  • Many metal casting facilities have developed computer spread sheets to perform these calculations, limiting the potential for human error.
  • GFN does not identify a good molding material, or produce the qualities needed in a particular metal casting sand system. Because GFN represents an average fineness, particle blends comprising resin particles in combination with ceramic particles with very different grain size distribution may have similar GFN numbers. This being the case, the distribution of grains on the screens is another critical factor. The distribution refers to the quantity of particles retained on each individual sieve, rather than the average of all particles retained on all sieves.
  • U.S screens are manufactured using inches as the measurement for the screen openings (openings per linear inch), as designated in ASTM E-11. Some screen manufacturers in Europe and Asia may have metric screen size openings. AFS measurements using metric screens will not compare directly to U.S.-based screen measurements.
  • step 385 comprises heating the mold at a temperature of about 200° C. for about one hour. As described herein, “about” is used to mean that a difference in temperature or length of time is plus or minus ten percent (10%). In certain embodiments, step 385 comprises using a forced air oven. In certain embodiments, step 385 comprises disposing the mold onto a conveyor belt that transports the mold through an oven. In certain embodiments, step 385 comprises using infrared heating.
  • the mold of step 310 is formed using a UV transparent material
  • the binder of step 310 comprises a UV-curable binder, wherein in step 385 the mold is exposed to UV irradiation to effect the cure of the binder composition.
  • the displacements can be machined into a final desired shape if a secondary machining is required in step 390 .
  • the cured displacements from step 385 can be machined with high precision into casting products with different dimensions and requirements, such as threads. If a secondary machining is not required, the current method continues from step 390 to step 397 .
  • the formed displacements from step 385 or step 395 are further treated to enhance their mechanical properties in preparation for the metal casting process. If the formed displacements from step 385 or step 395 need to have further property enhancement, the current method transitions from step 397 to step 440 ( FIG. 4 ). To the contrary, if the formed displacements from step 385 or step 395 do not need further property enhancement, Applicants' method transitions from step 397 to step 399 and ends.
  • the Applicants' method eliminates any material(s) or additive(s) in the displacements that will volatize when molten metal is poured onto the displacements. As a result, violent vaporization and/or thermal decomposition of any material in the displacements will not take place. Therefore, the metal casting comprises a smooth surface.
  • displacements for metal casting need to have a sufficient compactability to avoid cuts and washes, friable broken edges, crushes, hard-to-lift pockets, penetration, and erosion scabbing. Also, the compactability cannot be too high to cause oversized castings.
  • displacements need to have a balanced compressive strength to be strong under the pouring pressure of the liquid molten to avoid formation of inclusions, erosions, friable broken edges, etc.
  • step 410 the method provides (N) displacement articles for use in a metal casting system.
  • one or more of the (N) displacements were previously formed.
  • step 420 the method sets (i) equal to 1.
  • step 430 the method determines if an (i)th displacement article comprises satisfactory properties. If the method determines in step 430 that the mechanical and thermal properties of an original (i)th displacement are sufficient, then the method transitions from step 430 to step 432 wherein the method determines if (i) equals (N), i.e. if each of the (N) displacements of step 410 have been evaluated. If the method determines in step 432 that (i) equals (N), then the method transitions from step 432 to step 490 and ends.
  • step 432 determines in step 432 that (i) does not equal (N)
  • step 434 wherein the method sets (i) equal to (i+1).
  • step 430 continues as described herein.
  • step 430 determines in step 430 that the mechanical and thermal properties of an original (i)th displacement are not sufficient, then the method transitions from step 430 to step 440 , wherein a previously-prepared (i)th displacement is immersed in a mixture comprising one or more polymer precursor compounds, such as and without limitation, carbon-containing resins.
  • step 450 the method heats at about 1000° C. an (i)th displacement impregnated with the one or more polymer precursors to form polymeric microstructures that are precursors to high-carbon solids, in combination with a conversion of these polymers to functional high-carbon solids, sometimes referred to as “glassy carbon.”
  • Glass-like carbon often called glassy carbon or vitreous carbon, is a non-graphitizing, or nongraphitizable, carbon which combines glassy and ceramic properties with those of graphite.
  • the most important properties are high temperature resistance, hardness (7 Mohs), low density, low electrical resistance, low friction, low thermal resistance, extreme resistance to chemical attack and impermeability to gases and liquids.
  • glassy carbon has long been a subject of debate. Early structural models assumed that both sp 2 - and sp 3 -bonded carbon atoms were present, but it is now known that glassy carbon is 100 percent sp 2 hybridized carbon.
  • the structure of glassy carbon consists of long, randomly oriented microfibrils (15-50 A° wide) that bend, twist, and interlock to form robust interfibrillar nodes. More recent research has suggested that glassy carbon comprises a fullerene-type structure 1.
  • Glassy (or vitreous) carbon is typically a hard solid prepared by heat treatment at elevated temperatures of polymer precursors such as copolymer resins of phenolformaldehyde or furfuryl alcohol-phenol.
  • the polymer precursor compound(s) of step 440 is selected from the group consisting of furfuryl alcohol, phenol formaldehyde oligomer, acetone-furfural, furfuryl alcohol-phenol oligomer, polyvinyl chloride oligomer, polyvinylidene chloride oligomer, polyacrylonitrile oligomer, cellulose, and any combinations thereof.
  • the displacement in step 440 is immersed in 10 percent by weight furfuryl alcohol 2 in chloroform, alcohol, benzene, ethanol, ethyl ether, water, acetone, or ethyl acetate, until a weight of the displacement stops increasing.
  • a catalyst is added to the furfuryl alcohol, such as a zinc chloride. In other embodiment, a catalyst is not added.
  • step 450 the displacement, after soaking, is fired at about 1000° C. with a temperature ramp rate of about 60° F./hour for about 24 hours under an inert atmosphere to first form polymeric material 3 between the ceramic powder (provided in step 310 ) particles, wherein polymer 3 reinforces the previously formed displacement.
  • polyunsaturated sequences are formed by successive hydride/proton abstractions from certain methylene groups in polymer 3 to form polymer 4 comprising only sp 2 hybridized carbon atoms.
  • step 450 polymer 3 and/or polymer 4 are continuously converted into the fullerene structure 1, thereby forming glassy carbon moieties within the original displacement to impart more desirable mechanical and electrical properties of the enhanced displacement.
  • step 460 the method determines if the mechanical and thermal properties of an (i)th displacement have been sufficiently enhanced. If the method determines in step 460 that the mechanical and/or electrical properties of the treated displacement of step 440 does not comprise a desired compactability level and/or compressive strength, then the method transitions from step 460 to step 440 , and continues as described herein.
  • step 460 determines in step 460 that the mechanical and thermal properties of an (i)th displacement have been sufficiently enhanced
  • step 470 the method determines if (i) equals (N), i.e. if each of the (N) displacements of step 410 have been treated. If the method determines in step 470 that (i) equals (N), then the method transitions from step 470 to step 490 and ends. Alternatively, if the method determines in step 470 that (i) does not equal (N), then the method transitions from step 470 to step 480 wherein the method sets (i) equal to (i+1). The method transitions from step 480 to step 440 and continues as described herein.

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  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Mold Materials And Core Materials (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
US15/132,031 2016-04-18 2016-04-18 Composition and method to form displacements for use in metal casting Abandoned US20170297087A1 (en)

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US15/132,031 US20170297087A1 (en) 2016-04-18 2016-04-18 Composition and method to form displacements for use in metal casting
CA3020767A CA3020767C (en) 2016-04-18 2017-04-17 Composition and method to form displacements for use in metal casting
PCT/US2017/028000 WO2017184527A1 (en) 2016-04-18 2017-04-17 Composition and method to form displacements for use in metal casting
BR112018071431A BR112018071431A2 (pt) 2016-04-18 2017-04-17 método para formação de um deslocamento para uma fundição metálica
RU2018140459A RU2725314C2 (ru) 2016-04-18 2017-04-17 Композиция и способ образования литейных стержней, предназначенных для применения при литье металла
CN201780024220.XA CN109070192A (zh) 2016-04-18 2017-04-17 形成用于金属铸造的置换件的组合物和方法
EP17720923.6A EP3445514B1 (en) 2016-04-18 2017-04-17 Composition and method to form displacements for use in metal casting
US16/157,941 US10646916B2 (en) 2016-04-18 2018-10-11 Composition and method to form displacements for use in metal casting

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WO2019118805A1 (en) * 2017-12-15 2019-06-20 Carbo Ceramics Inc. Foundry media formed from slurry droplets and methods of use

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WO2019118805A1 (en) * 2017-12-15 2019-06-20 Carbo Ceramics Inc. Foundry media formed from slurry droplets and methods of use
US10507517B2 (en) 2017-12-15 2019-12-17 Carbo Ceramics Inc. Foundry media formed from slurry droplets and methods of use

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CA3020767A1 (en) 2017-10-26
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RU2018140459A3 (zh) 2020-06-05
WO2017184527A1 (en) 2017-10-26
EP3445514A1 (en) 2019-02-27
EP3445514B1 (en) 2019-10-30
RU2725314C2 (ru) 2020-07-02
CA3020767C (en) 2019-03-26
US20190039122A1 (en) 2019-02-07
RU2018140459A (ru) 2020-05-19

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