Abstract: A powder binder product for use in making a slurry for investment casting molds comprising Nano-sized powders; and an organic polymer powder, wherein it does not require aqueous colloidal silica to produce slurries used to build investment casting molds. The Nano-sized powders comprise fumed alumina, boehmite, fumed silica, or fumed titanium oxide or combinations thereof. The coarse refractory powder, combined with the powder binder for mold manufacture, comprises milled zircon, tabular alumina or fused alumina, fused silica, alumino-silicate, zirconia, and yttria or combinations thereof. The organic polymer in a powder binder comprises a cellulose-based material. A powder investment casting binder, that once fired, consists of up to 96 weight percent aluminum oxide.

Abstract: A composition which comprises a soluble or partially soluble phosphate, a refractory material and less than 1% of an oxide or hydroxide of magnesium or calcium. The composition may be mixed with water to form an investment casting slurry into which a wax pattern may be dipped. Slurry coated onto the pattern may be set by applying a stucco composition which comprises an oxide or hydroxide of magnesium or calcium. Coats of set slurry may be built up on the pattern to form an investment casting shell.

Abstract: A method of removing a core of a cast component includes providing a casting that includes a silica based ceramic core in a temperature controlled closed volume; cycling temperature between a first temperature and a second temperature within the temperature controlled closed volume that repeatedly subjects the silica based ceramic core to a beta-to-alpha cristobalite transition that induces microfractures in the silica based ceramic core; and after the cycling temperature, chemically dissolving the silica based ceramic core from the casting.

Abstract: A method of forming cooling channels in a component is provided. The component has a substrate having outer and inner surfaces. The inner surface defines at least one interior space, and a core is disposed within each interior space. The method includes forming at least one access hole in the substrate, while the core is disposed within the respective interior space, removing the core from the respective interior space, and forming at least one groove in the outer substrate surface (before or after the core is removed). Each access hole connects the groove in fluid communication with the respective interior space. The method further includes disposing a coating over at least a portion of the outer substrate surface, where the coating includes at least a structural coating that extends over the groove(s), such that the groove(s) and the structural coating together define one or more channels configured to convey a coolant from the respective interior space(s) for cooling the component.

Abstract: A method of machining a component is provided. The component includes a substrate having an outer surface and an inner surface, where the inner surface defines at least one interior space. A core is disposed within each interior space. The method includes forming at least one hole in the substrate while the core is disposed within the respective interior space. Each hole extends through the substrate to provide fluid communication with the respective interior space. The method further includes removing the core from the respective interior space. The core may be a casting core or a subsequently formed core.

Abstract: The disclosure relates generally to mold compositions and methods of molding and the articles so molded. More specifically, the disclosure relates to silicon carbide-containing mold compositions, silicon carbide-containing intrinsic facecoat compositions, and methods for casting titanium-containing articles, and the titanium-containing articles so molded.

Abstract: A method and casting core for forming a landing for welding a baffle inserted into an airfoil are disclosed, wherein the baffle landing of the blade or vane is formed in investment casting by the casting core rather than by wax, reducing tolerances and variability in the location of the baffle inserted into the cooling cavity of airfoil when the baffle is welded to the baffle landing.

Abstract: The process for investment casting of complex shapes has historically had 6 basic steps in it. Depending upon the path taken, these discrete steps have been reduced to either 5 steps, or to 2 steps, discarding the unwanted steps. Instead of having to generate the shape of each sacrificial pattern, the process generates either (A) a male tree containing a plurality of sacrificial patterns, already on their runners, onto which a mold shell can be formed, or, (B) a female shell, made of a refractory material, and forming internally the outside surfaces of the plurality of patterns and runners. This process removes both capital expenditure for tooling and process time by up to 90%. By removing several lengthy, time-dependant steps from the process the part cost and lead time are reduced.

Abstract: A casting process for producing metal alloy castings, facecoats and apparatuses suitable for carrying out the process, and castings produced by the process. The casting process entails the use of a mold having a cavity with a continuous aluminum-containing solid facecoat on its surface. A molten quantity of a metal alloy is introduced into the mold cavity so that the molten alloy contacts the solid facecoat. The mold is then allowed to cool to solidify the molten alloy and form a cast product. During the casting process, aluminum in the solid facecoat diffuses into the cast product to form an aluminum-containing surface region at the casting surface. Following removal of the cast product from the mold, an alumina-containing scale grows on the casting surface as a result of oxidation of the casting surface region.

Abstract: The disclosure relates generally to mold compositions comprising calcium aluminate and calcium titanate. The disclosure also relates to methods of molding and the articles so molded using the mold compositions. More specifically, the disclosure relates to calcium aluminate/calcium titanate mold compositions and methods for casting titanium-containing articles, and the titanium-containing articles so molded.

Abstract: Methods for manufacturing cast titanium helmets include casting a helmet in an oversized mold. The resulting oversized cast helmet is then exposed to a hot isostatic press (HIP) process that applies heat and pressure for a predetermined period of time. The resulting oversized cast helmet is then exposed to an acid bath that chemically mills the helmet to a desired thickness and removes contaminants formed during casting of titanium.

Abstract: Casting molds suitable for directional solidification processes using a liquid cooling bath include a graded facecoat structure on a mold body. The graded facecoat structure includes an innermost layer and a delamination layer, wherein the delamination layer fractures upon cooling of the molten metal so as to separate the mold body from the innermost layer, which remains in contact with or in close proximity to the metal being cast. Also disclosed are directional solidification processes.

Abstract: A casting process and apparatus for producing directionally-solidified castings, and castings produced therewith. The process entails applying a facecoat slurry to a surface within a mold cavity to form a continuous solid facecoat on the surface, introducing a molten metal alloy into the mold cavity so that the molten metal alloy contacts the facecoat, and then immersing the mold in a liquid coolant to cool and solidify the molten metal alloy and form a casting of the metal alloy, during which an oxide layer forms on the casting surface. The facecoat is sufficiently adherent to the oxide layer such that at least a portion of the facecoat detaches from the mold surface and remains tightly adhered to the casting surface in the event the casting contracts during cooling. The facecoat contains at least 60 weight percent of a first phase of yttria, and the balance of the facecoat is a binder phase of an inorganic material.

Abstract: A slurry suitable for forming facecoats, facecoats formed by such a slurry, and processes using such facecoats. The slurry is formed of a particulate refractory material, an aqueous suspension containing a particulate inorganic binder, a thixotropic organic binder, a dispersant, and possibly optional constituents excluding particulate refractory materials and inorganic binders. The particulate refractory material constitutes at least about 60 weight percent of the slurry and consists essentially of yttria. The aqueous suspension containing the particulate inorganic binder constitutes at most about 35 weight percent of the facecoat slurry. The dispersant is present in the slurry in an amount sufficient to stabilize the slurry at a pH of up to about 10, and has the general formula Hx[N(CH2)yOH]z, where x has a value of 0, 1 or 2, y has a value of 1 to 8, and z=3?x.

Abstract: The invention relates to a method and to a device for sing out this method, during which the shell molds (3) are filled with a melt (11) in a clocked manner, the respectively required amount of melt being currently provided at the same time. The casting process ensues by marrying the crucible (6), which is filled with a melt (11), with a shell mold (3) so that the crucible (6) and shell mold (3) form a common cavity (10), and this arrangement is subsequently tilted 180°, so that the melt (11) falls into the shell mold (3).

Abstract: Shell molds and processes for making the shell molds that exhibit high emissivity in the red and infrared regions. In this manner, thermal resistance within a gap formed between solidifying cast metal and the interior mold surface is decreased. In one embodiment, the facecoat region is formed from a slurry composition comprising an aluminum oxide, a green chromium oxide and a silicon dioxide. In another embodiment, the facecoat region is formed from a slurry composition including zirconium silicate and silica with stucco layer of alumina is included.

Abstract: An investment casting method involves producing a casting shell by applying a hardenable slurry to a sacrificial pattern. To hasten the hardening of the slurry into the shell, a stucco coat including a desiccant material having a high surface area is subsequently applied to the slurry.

Abstract: Method for producing a mold for use in casting reactive metals comprising preparing a slurry of a yttria-based refractory composition and a binder, and using said slurry as a mold facecoat by applying said slurry onto a surface of a mold pattern, wherein said yttria-based refractory composition is obtainable by (a) mixing particles of a yttria-based ceramic material and a fluorine containing dopant, and (b) heating the resulting mixture to effect fluorine-doping of said yttria-based ceramic material.

Abstract: In a collapsible mold and a method of manufacturing the same, the collapsible mold has extremely low moisture-absorption properties, does not change in surface properties thereof due to absorption of moisture and swelling, and is storable for a long time without absorbing moisture and swelling. Specifically, the method manufactures a collapsible mold containing at least any of calcium oxide and magnesium oxide. The method includes a step of bringing the collapsible mold into contact with carbon dioxide immediately after a step of burning the collapsible mold or a step of casting the collapsible mold.

Abstract: A substrate is coated by applying an essentially pure aluminum first layer to a surface of the substrate. At least a first portion of the first layer is oxidized so as to provide a protective coating of desired properties. The substrate may be a refractory metal-based investment casting core.

Abstract: A rare earth-based core for use in the casting of a reactive metal is described. The core contains a ceramic composition which includes at least about 10% by weight of monoclinic rare earth aluminate (RE4Al2O9), wherein RE represents at least one rare earth element; and at least about 10% by weight of at least one free rare earth oxide. The ceramic phase of the composition may include a microstructure which comprises a multitude of substantially spherical pores which are formed as a result of the removal of aluminum metal from the core composition during a heat treatment step. Additional embodiments relate to a method for the fabrication of a ceramic core, employing a rare earth oxide, aluminum metal, and a binder. Methods for removing cores from a cast part are also described.

Abstract: An unfired ceramic base core having a first coefficient of thermal expansion is provided. A core element having a second coefficient of thermal expansion is positioned in an opening formed in the unfired ceramic base core. The opening in the unfired ceramic base core is filled with a filler material having a third coefficient of thermal expansion. The third coefficient of thermal expansion is greater than the first coefficient of thermal expansion and less than the second coefficient of thermal expansion. The ceramic base core is fired without cracking the base core and without cracking the filler material. The ceramic base core contains silica and zircon and has a silica content of 70% or less and a zircon content of 30% or more. The core element may be formed of a ceramic material or a refractory metal.

Abstract: Compositions suitable for use as cores and shell molds for casting of reactive metal alloys, and casting processes for producing components from such alloys. The composition contains a sintered particulate material of hafnia and at least one additional metal oxide in amounts to yield a ceramic composition containing up to 70 molar percent of hafnia, wherein the additional metal oxide is a rare-earth oxide, the sintered particulate material contains first and second phases, the first phase is the rare-earth oxide and hafnia in solid solution, the second phase is a compound of the rare-earth oxide and hafnia, and the second phase is less reactive with the reactive metal alloy than the first phase.

Abstract: A rare earth-based core for use in the casting of a reactive metal is described. The core contains a ceramic composition which includes at least about 10% by weight of monoclinic rare earth aluminate (RE4Al2O9), wherein RE represents at least one rare earth element; and at least about 10% by weight of at least one free rare earth oxide. The ceramic phase of the composition may include a microstructure which comprises a multitude of substantially spherical pores which are formed as a result of the removal of aluminum metal from the core composition during a heat treatment step. Additional embodiments relate to a method for the fabrication of a ceramic core, employing a rare earth oxide, aluminum metal, and a binder. Methods for removing cores from a cast part are also described.

Abstract: Shell molds and processes for making the shell molds that exhibit high emissivity in the red and infrared regions. In this manner, thermal resistance within a gap formed between solidifying cast metal and the interior mold surface is decreased. In one embodiment, the facecoat region is formed from a slurry composition comprising an aluminum oxide, a green chromium oxide and a silicon dioxide. In another embodiment, the facecoat region is formed from a slurry composition including zirconium silicate and silica with stucco layer of alumina is included.

Abstract: A method of fabricating a core for a ceramic shell mold is disclosed. A porous core body is formed from at least about 50% by weight of at least one rare earth metal oxide. The core body is heated under heating conditions sufficient to provide the core with a density of about 35% to about 80% of its theoretical density. The core body is then infiltrated with a liquid colloid or solution of at least one metal oxide compound, e.g., rare earth metal oxides; silica, aluminum oxide, transition metal oxides, and combinations thereof. The infiltrated core body is then heated to sinter the particles without substantially changing the dimensions of the core body. Mold-core assemblies which include such a core body are also described. A description of processes for casting a turbine component, using the core, is also set forth herein.

Abstract: A substrate is coated by applying a first layer atop the substrate and including, in major weight part, a non-refractory first metal. A second layer is applied atop the first layer and includes, in major weight part, a carbide and/or nitride of a second metal. A third layer is applied atop the second layer and comprises, in major weight part, a ceramic. The substrate may be a refractory metal-based investment casting core.

Abstract: A method for forming an article is described. The method includes the step of applying a precursor material to at least one surface of a mold structure for casting the article, and curing the applied precursor material. The precursor material includes facecoat-forming constituents which can be curably converted into a facecoat; and a protective coating-former for the article being cast. Molten material is then introduced into the mold structure, so as to come in contact with the facecoat formed from the cured precursor material. The molten material is cooled, to form the article. The cured precursor material, which is in contact with a surface of the cast article, is then reacted with the article, to form the protective coating on the surface of the article. Related mold structures are also described.

Abstract: A method of securing a precast refractory shape within a refractory structure, comprising the steps of forming a precast refractory shape by casting a refractory shape to have a plurality of spaced-apart cavities formed in an outer surface thereof; positioning the precast refractory within a refractory structure; and casting a refractory material around the precast refractory shape such that the refractory material covers the outer surface of the precast refractory and fills the cavities.

Abstract: A method of improving the removal of an investment casting shell surrounding a metallic article. The shell is made from the deposit of layers refractory slurry and stucco onto a pattern. The shell contains, after firing, an amount of an alkali metal oxide or an alkaline earth metal oxide sufficient to reduce the strength of the shell. By this invention, after firing of the shell and pouring of the molten metallic part into the shell, the shell is hydrated to further reduce the strength of the shell, to facilitate its removal from the metallic part.

Abstract: A slurry composition for a mold and method of use thereof. The slurry composition includes about 45-80% by weight alumina, about 10-30% by weight silicon carbide, and about 10-50% by weight colloidal silica. In one aspect, the alumina component comprises a material selected from the group consisting of brown fused alumina, white fused alumina, tabular alumina, calcined alumina, and mixtures thereof. In another aspect, the composition includes fumed silica at 2-5% by weight. The composition may also include a setting agent at 0.05-2% by weight.

Abstract: A tool and method for production of a cast component from molten titanium alloy. The tool includes a casting mold, wherein at least one mold wall area of the casting mold, which comes into contact with the molten titanium alloy, is made of yttrium oxide, magnesium oxide and calcium oxide. The casting mold includes at least first and second layers, the first layer forming a mold wall area which comes into contact with the molten titanium alloy and the second layer forming a backfilling stabilization area for the mold wall area. Both the first layer and the second layer is formed of yttrium oxide, magnesium oxide and calcium oxide. In addition, the second layer, which backfills the first layer, has less yttrium oxide and is more coarsely grained than the first layer.

Abstract: A method of manufacture of a multilayer ceramic shell mould whereof at least one contact layer out of a wax master pattern or a part to be manufactured, or other similar material, includes a step of preparing a first slip containing ceramic particles and a binder; a step of dipping the master pattern in a first slip; a step of forming the contact layer, and a step of depositing sand particles particles onto the layer and drying the contact layer. The ceramic particles of the slip are mullite particles and the slip includes a texturing agent.

Abstract: A method of manufacture of a multilayer ceramic shell mould out of a master pattern includes the steps of dipping the master pattern in a first slip containing ceramic particles and a binder, depositing sand particles to form a contact layer, dipping the master pattern in a second slip containing ceramic particles and a binder, depositing sand particles to form an intermediate layer, dipping the master pattern in at least a third slip containing ceramic particles to form a reinforcing layer. The ceramic particles of the slips includes mullite, alumina, or a mixture of the two, whereas no layer contains any zircon.

Abstract: In accordance with the present invention, a casting system is provided which broadly comprises a core and a wax die spaced from said core, a refractory metal core having a first end seated within a slot in the core and a second end contacting the wax die for positioning the core relative to the wax die, and the refractory metal core having at least one of a mechanism for providing spring loading when closed in the wax die and a mechanism for mechanically locking the wax die to the core.

Abstract: A shell mold for casting molten material to form an article is described. The mold includes a shell for containing the molten material, formed from at least one of yttrium silicates, zirconium silicates, hafnium silicates, and rare earth silicates. The mold also includes a facecoat disposed on an inner surface of the shell that contacts the molten material. The facecoat can be made from the materials described above. A method of casting a niobium-silicide article is also described, using the shell mold described herein. A method of making the ceramic shell mold is described as well, along with a slurry composition used in the manufacture of the shell mold.

Abstract: An investment casting method involves producing a casting shell by applying a hardenable moist mixture to a sacrificial pattern. To hasten the hardening of the moist mixture to create the shell, a stucco coat is subsequently applied to the mixture. In some cases, the stucco coat comprises a drier mixture of the elements used in the moist mixture. The drier mixture preferably includes a material that alters the alkalinity of the underlying moist mixture. In some cases, the stucco coat also includes an amorphous mineral silicate. Once the shell is created, a molten metal is introduced into the shell to replace the sacrificial pattern, thereby producing a metal cast item.

Abstract: Method and apparatus for prolonging the stability (working life) of a ceramic slurry and other aqueous mixture or dispersion containing a liquid silica-bearing or other component as well as the raw liquid silica-bearing component in ambient air over time by providing a gas blanket that reduces exposure to ambient air.

Abstract: The invention concerns a die for producing a casting, particularly a component for a motor or other engine, from a reactive molten non-ferrous metal charge using a casting mould and a method for manufacturing the die. The die consists of a casting mould which has a front layer area which comes into contact with the reactive non-ferrous molten metal charge and a top layer area mechanically stabilising the front layer area, the front layer area consisting of a minimum of one rare earth oxide and a minimum of one additional metal oxide, the minimum of one additional metal oxide being selected from the group of oxides of the following metals: titanium and nickel.

Abstract: The present invention consists of an investment casting process that makes use of a frangible low-strength investment material mold and a mold removal solution to facilitate the removal the investment material mold from the casting. The mold removal solution is a liquid that permeates the mold material and effervesces while inside the mold material, causing fracturing of the frangible investment material mold, and carrying away the resulting mold particles. The investment material compositions have the property of sufficiently decreasing in strength after cooling to facilitate the removal of the mold material by the removal solution. Two particular investment material compositions that possesses these properties are describe which contains powdered silica quartz, beta-hemi-hydrate calcium sulfate (gypsum), a hardening agent of potassium sulfate, and water. A mold removal solution composition is described that is composed of hydrogen peroxide solution in water.

Abstract: In accordance with the present invention, a casting system is provided which broadly comprises a core and a wax die spaced from said core, a refractory metal core having a first end seated within a slot in the core and a second end contacting the wax die for positioning the core relative to the wax die, and the refractory metal core having at least one of a mechanism for providing spring loading when closed in the wax die and a mechanism for mechanically locking the wax die to the core.

Abstract: An investment casting pattern is formed by forming a metallic first core element including at least one recess. The first core element is engaged to at least a mating one of an element of the die and a second core element. The recess serves to retain the first core element relative to the mating one. The die is assembled and a sacrificial material is introduced to the die to at least partially embed the first core element. The recess may be pre-formed prior to cutting the first core element from a larger sheet of material.

Abstract: A composition and method for forming investment casting shells includes using colloidal silica, zircon flour, and fused silica in a slurry which is applied to a pattern. After the slurry is applied to the pattern, it is allowed to partially or completely solidify. After the shell has solidified, the pattern may be melted or otherwise removed. A molten material is introduced into the shell and allowed to cool to form an article. Finally, the shell is broken away or otherwise removed from the article. The improved shell slurry composition and corresponding method minimizes pattern-to-pour cycle times and is environmentally friendly.

Abstract: The invention relates to a investment casting shell molds and their method of manufacture. The method entails mixing fiber and refractory filler to form a dry blend; mixing the dry blend with a binder sol to form a refractory slurry, and employing the refractory slurry to produce an investment casting shell mold.

Abstract: Incorporation of rice hull ash into investment casting shell molds improves the permeability, shell build thickness, and/or shell build uniformity of the molds. A method to make the molds entails mixing refractory filler, rice hull ash, and preferably a fiber to form a dry blend; mixing the dry blend with a binder sol to form a refractory slurry, and employing the refractory slurry to produce an investment casting shell mold.

Abstract: The invention relates to investment casting shell molds and their method of manufacture. The method entails mixing fiber such as ceramic refractory fiber and organic fiber with ceramic filler to form a dry blend. The dry blend is mixed with a binder sol such as colloidal silica sol to form slurry. An expendable preform is dipped into the slurry, stuccoed and dried. This step is repeated until a ceramic shell of a desired thickness is formed over the expendable preform. The expendable preform then is removed, and the green ceramic shell is fired. Molten metal then may be poured into the shell to form a metal casting.

Abstract: Embodiments of a method for increasing the lifetime of a casting slurry are described. One feature of the disclosed embodiments comprises processing refractory materials that are used to form casting slurries to provide a substantial increase in slurry lifetime for slurries made using such processed materials compared to slurries made using materials not processed as described herein. One embodiment of the method comprises heat processing at least one refractory powder. Without limiting the invention to a theory of operation, processing is continued for a period of time sufficient to reduce the amount of hydration from a first hydration level to a second hydration level. A slurry is formed using the refractory powder at a hydration level which provides an increased slurry lifetime relative to the same material without processing according to the disclosed embodiments.

Abstract: A method of making a ceramic shell mold comprises repeatedly coating a fugitive pattern of an article to be cast with a ceramic slurry layer and applying on the ceramic slurry layer a refractory stucco to form a plurality of ceramic slurry layers and stucco layers on the pattern wherein at least one of the stucco layers is formed by applying discontinuous stucco fiber bundles held together in the bundles by a fugitive binder, which is removed during subsequent firing of the shell mold at elevated temperature.

Abstract: Disclosed is a mold material for metal casting capable of suppressing the deterioration of cast metal. The mold material for metal casting contains hemihydrate gypsum and a heat resistant material, wherein an oxoacid salt of phosphorus, insoluble in water, is contained in the mold material.

Abstract: A corrosion resistant and durable forstner bit is formed from stainless steel using an investment casting process.