Abstract: In the art of investment casting, a refractory mold characterized by a casting system including a sprue passage, a cup at one end of the sprue passage, a runner extending from the cup and connecting to the sprue passage near its other end, at least one pattern cavity gated into the sprue passage between the ends of the runner, and a refractory wall in the cup dividing it into a pouring cup portion communicating with the runner and another portion communicating with the sprue passage. A pattern set-up designed to make the mold by the "lost pattern" process of investment casting.

Abstract: A method of manufacturing a mold adapted to be used for casting bodies of fiber-reinforced composites. A model of the body to be cast is prepared and coated with a one-piece dense shell of refractory metallic oxide deposited by plasma or flame spraying and the model is then separated from the shell by conventional physical or chemical treatment.

Abstract: A method of making a shell mold (6) includes alternately applying a ceramic coating composition (8) and a stucco composition (10) to an expendable pattern, the presence of graphite being substantially avoided therein, and applying a barrier coating (16) thereto including a ceramic powder, a binder, and a preselected amount of graphite. A preferred range of graphite of about 13 to 17 Wt. % in the barrier coating (16) minimizes decarburization of a ferrous article formed in the cavity of the shell mold (6).

Abstract: Method for making a novel shell mold for use in directional solidification and for casting alloys containing reacting components, wherein a binder comprising a non-fibrous aqueous acidic dispersion of alumina monohydrate and being essentially free of silica, is employed. The resultant shell mold is particularly suitable for the casting of nickel and cobalt based alloys containing relatively reactive constituents such as zirconium, aluminum and titanium.

Abstract: A fired alumina article having a core of material having from 20 to 65 percent continuous porosity by volume and desired crushability characteristics and an integral outer barrier layer consisting of porous alumina having a density gradient.

Abstract: A shell mold for producing directionally solidified single crystal metal castings in which use is made of a crystal selector of helical shape wound about a support of a non heat disposable material which eliminates the need for providing a crystal selector of sufficient dimension for self support or other supporting means which may form a part of the pattern assembly about which the shell mold is formed.

Abstract: A method for manufacturing a thermally highly stressed, cooled component, more particularly, a blade for turbine engines. A component of the above-mentioned type has a central supporting core formed of a solid material and has connected thereto several short, radially outwardly projecting ridges which, in turn, carry an outer shroud concentrically encompassing the supporting core, and which is made of a through-porous material, whereby the supporting core, ribs, and outer shroud are cast in a single piece.

Abstract: Gas permeable shell molds and methods of using them for vacuum/inert gas casting of metal are disclosed. The single or multiple cavity gas permeable shell mold described has a riser passage with an open lower end and one or more mold cavities connected to the riser passage by gate passages each having a novel stabilizing screen member with a multiplicity of openings therein extending across it. The screen is preferably in a slanted plane with the bottom portion thereof nearer to the mold cavity.

Abstract: A porous high-silica core is disclosed for use in directional solidification casting processes having exceptional thermal stability at temperatures above 1650.degree. C. and containing mineralizers which promote the formation of cristobalite. The cores may be made by mixing at least 75 parts of essentially pure fused silica particles with 1 to 25 parts of activating particles containing a mineralizer, such as an alkali metal or alkaline earth metal compound, may be fired at a temperature of 1000.degree. to 1300.degree. C. until they contain 35 percent or more of cristobalite and may then be cooled to room temperature. They may thereafter be incorporated in a shell mold in accordance with the "lost-wax" process and preheated with the shell mold at a temperature of 1300.degree. to 1600.degree. C. to provide a cristobalite content of 60 to 85 percent or more within a short period of time, such as 10 to 30 minutes, and before a molten superalloy is allowed to flow into the mold.

Abstract: An apparatus for producing directionally solidified castings wherein a mold having an open bottom is supported on a chill plate with metal poured into the mold initially solidifying adjacent the chill plate and thereafter progressively solidifying away from the chill plate. The chill plate is provided with a plug member, and the metal being cast initially solidifies around this plug member whereby the metal is securely held in intimate contact with the plug member and adjacent chill plate surfaces so that the withdrawal of heat from the casting through the chill plate is greatly facilitated.

Abstract: A stronger, thinner shell mold suitable for making cast metal parts comprises a base member of resin bonded sand and a second surfacing layer of a cured thermosetting binder material. Also disclosed is a method for forming the new shell mold.

Abstract: An improved method of forming a shell mold for casting having a shrink bob is provided. A tubular frusto-conical shrink bob, or riser, is first formed from sand and a plastic or resin binder such that both the apex and base of the riser are open. The riser is then inverted and positioned on a casting pattern with the apex of the riser abutting against the casting pattern. The entire pattern is then cast with a thermosetting material, such as sand and a binder, such that the thermosetting material bonds to both the pattern and the riser. After hardening, the thermosetting material with the attached riser forms a shell mold which is subsequently utilized in a foundry casting operation.

Abstract: A method of making investment shell molds by the lost pattern process characterized in that a strand such as wire or the like is wound circumferentially about a pattern assembly in at least one location before it is coated with refractory material to form a mold shell. Thereafter, the strand is unwound to separate the shell into segments, each of which is usable as a mold.

Abstract: The mold is preheated to a temperature above the maximum local casting temperature prior to casting of the melt and is also cooled to obtain a variation of temperatures throughout the mold. The resulting temperature gradient of the mold is intended to maintain the heat content per unit volume in the unsolidified melt portions greater than in the adjacent solidified melt portions to compensate for the latent heat of solidification in the melt and thus avoid shrinkholes and blowholes.

Abstract: The invention is an improvement in apparatus for growing crystalline bodies from the melt. The apparatus comprises a crucible and a novel die assembly in which the die assembly is made in two parts and essentially comprises inner and outer concentric members. The inner and outer members are spaced from one another to define an annular lower capillary section. One member is longer than the other and is shaped so that its upper end overhangs and engages the upper end of the other member. A plurality of upstanding dies are formed in the upper end of the longer member. Each of the dies has a top end surface and is slotted in a generally radial direction with the slots being deep enough to intersect the annular space between the two members. The slots in the dies serve as capillaries to provide communication between the lower capillary section and the top end surfaces of the dies.

Abstract: The device according to the invention is intended for making single-crystal products by the vertically-directed crystallization of molten metal on a seed and comprises a ceramic mould with a seed pocket in the bottom and a cooler with a flat face surface, installed under the mould and having an axial hole for accommodating the seed cooling unit interacting with the seed pocket and, according to the invention, installed with a provision for independent vertical movement relative to the cooler and seed pocket and made in the form of a tube embracing the seed pocket, said tube having an internal partition which divides the tube space into two compartments the lower of which is supplied with refrigerant and is made of a metal whose thermal conductivity ensures a maximum temperature gradient along the length of the seed for the initiation of a crystal.

Abstract: In an iron molding process and in a mold for carrying out the process, in which the mold is at least locally coated with tellurium or bismuth to promote the production of a white iron structure there is included in the coating a water-bearing substance in which the water is loosely chemically combined tightly enough so that it withstands the heat involved in drying of the mold but is liberated on contact with the molten iron.

Abstract: An investment shell mold inhibited against reaction with molten titanium, zirconium and other reactive and refractory metals cast therein is made by investing a pattern with successive dip coats and stucco coats. The first dip coat includes a tungsten and/or molybdenum compound inhibitor-former which is reducible by hydrogen to metallic tungsten or molybdenum. After removal of the pattern, the green mold is dried and then pyrolyzed in an atmosphere of hydrogen under conditions predetermined to convert the inhibitor-former to metallic condition. This creates on the mold interface a coating of metallic molybdenum or tungsten which serves as a physical barrier, inhibiting reaction of a molten reactive or refractory metal subsequently cast in the mold, with the mold material and binder particles of the latter.

Abstract: In the manufacture of hollow cast articles such as turbine blades or vanes, the article is cast in opposed halves on opposite sides of a "strong back" or mid-section, to which wax patterns are attached for the preparation of a shell mold around the strong back and patterns. The article halves, after removal from the mold, are bonded together.

Abstract: In making columnar grained castings the shell mold is spaced from the chill plate by a ceramic ring on which the mold is positioned, the ring being made thicker and/or of a different ceramic from the mold to withstand the thermal stress developing while the mold is being heated for pouring, so that the mold, not being subjected to such stresses at the base, may be made thinner for producing better castings. In this way the best mold material for the purpose may be selected, as, for example, a material to have no reaction with the alloy and, by lowering the thermal gradient decrease the likelihood of mold failure.

Abstract: A metal oxide barrier layer is provided at the interface between a refractory oxide-silica investment mold and a contained metal superalloy, allowing directional solidification of the contained superalloy at elevated temperatures without metal-mold reaction.

Abstract: In the manufacture of cast articles such as gas turbine blades and vanes from high temperature alloys or eutectics, the heating of the mold in readiness for pouring and the cooling of the mold after pouring are precisely controlled by mechanism responsive to thermocouples internal and external to the mold and moving with the mold and a thermocouple in fixed relation within the furnace. The mechanism is especially adapted for use with the withdrawal technique in which the mold when poured is withdrawn from within the heating furnace past a radiation baffle thereby maintaining a steep thermal gradient within the mold and moving relative to the mold to establish the rate of upward movement of the solidification front within the alloy.