DUAL VACUUM INDUCTION MELTING & CASTING

Abstract

A furnace system for melting and casting metals, alloys, and superalloys and a related method. A melt chamber of the furnace system is configured and arranged to include at least two melt boxes, thereby increasing the volume of alloy charge that can be rendered molten during a single furnace heating cycle. Accordingly, a number of ceramic casting molds equal to the number of melt boxes can be used to form castings following a single furnace heating cycle. The ceramic casting molds can be pre-heated in an external oven before being introduced to the mold or loading chamber of the furnace system. The throughput of the furnace system is increased by the ability to pour more than one casting per alloy charge melting cycle.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. Provisional Application No. 62/072,635 entitled “DUAL VACUUM INDUCTION MELTING & CASTING”, filed on Oct. 30, 2014, the disclosure of which is hereby incorporated by reference.

FIELD OF THE INVENTION

The present disclosure relates to a system, apparatus, and method of melting and casting metals in a controlled atmospheric environment, such as those that use vacuum induction melting. The system, apparatus, and method is particularly useful for high temperature metals, alloys, and superalloys, including alloys used in the aerospace industry such as nickel-chromium alloys.

BACKGROUND OF THE INVENTION

The casting of metal, alloy, and superalloy parts often requires a process with specific, controllable temperature and pressure requirements. Superalloys generally refer to group of alloys used in turbosuperchargers, aircraft turbine engines, gas turbines, rocket engines, chemical, and petroleum plants that require high performance retaining their structural strength at elevated temperatures (e.g. 650° C. and greater) over long exposure times. The versatility of superalloys stems from a combination of high strength with good low-temperature ductility and excellent surface stability. Apparatus for melting and casing metals, alloys, and superalloys into molds to thereby make corresponding parts can be complicated and therefore requires a minimum amount of time to accomplish the casting.

Typically in the industry, in order to increase throughput, doubling or further increasing casting throughput and capacity requires installation of a second complete furnace, which further requires its own support equipment including, but not limited to: decking, a melt chamber, a mold chamber, a vacuum system, a water cooling system, a control system, and the like. Further, and additional external mold handling pathway would be required for the second furnace. Accordingly, apparatus and processes for melting and casing metals, alloys, and superalloys as known in the industry can be limited in throughput and production volume, or can incur a greater cost and complexity related to the use of additional complete furnaces.

BRIEF SUMMARY OF THE INVENTION

The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.

For at least the reasons given above, it is desirable to design a melting and casing apparatus for metals, alloys, and superalloys having a throughput or production volume that is increased relative to known apparatus and processes. Further, it is desirable to control the heating of molten metal or alloys, as well as the heating of a mold, to make the overall melting and casing apparatus design more effective, feats which have heretofore not been accomplished with known hearths in the industry.

In embodiments, the present disclosure provides for a vacuum induction casting apparatus that can include a loading chamber configured to receive a casting mold; a melt chamber, configured to concurrently house a first melt box and a second melt box; an interlock mechanically coupled to both the loading chamber and the melt chamber; a loading mechanism, configured to move the casting mold into and out of the melt chamber through the interlock to a casting position; and a vacuum system coupled to both the melt chamber and to the loading chamber.

In some aspects, the loading mechanism can be a loading elevator configured to reciprocally move the casting mold vertically through the interlock. In other aspects, the loading mechanism can be a platen configured to reciprocally move the casting mold horizontally through the interlock. In further aspects, the vacuum induction casting apparatus further can include a charge temperature sensor system coupled with the melt chamber and configured to measure temperatures of one or more molten charges in either or both of the first melt box and the second melt box. In some implementations, the vacuum induction casting apparatus can further include a mold temperature sensor system coupled with the melt chamber and configured to measure a temperature of a mold within the casting mold. In some aspects, the vacuum system separately controls pressure within the melt chamber and the loading chamber. In other aspects, the vacuum system can further include a first vacuum system and a second vacuum system atmospherically separate from each other, where the first vacuum system is coupled to the melt chamber and where the second vacuum system is coupled to the loading chamber. In further aspects, the vacuum induction casting apparatus is further configured to allow for the melt chamber to load an alloy charge into either or both of the first melt box and the second melt box concurrent with the loading mechanism in a position outside of the melt chamber. In further embodiments, the vacuum induction casting apparatus can include a third melt box and/or a fourth melt box.

In embodiments, the present disclosure provides for a method of forming castings that includes: loading a first alloy charge into a first melt box and a second alloy charge into a second melt box within a melt chamber of a furnace system; melting the first and second alloy charges within the first melt box and the second melt box to be molten; pre-heating an initial casting mold and pre-heating a subsequent casting mold; loading the initial casting mold into a loading chamber of the furnace system; moving the initial casting mold to a casting position within the melt chamber, pouring the molten first alloy charge from the first melt box into the initial casting mold; moving the initial casting mold out of the melt chamber and removing the initial casting mold from the furnace system; loading the subsequent casting mold into the loading chamber of the furnace system; moving the subsequent casting mold to the casting position within the melt chamber; pouring the molten second alloy charge from the second melt box into the subsequent casting mold; and moving the subsequent casting mold out of the melt chamber and removing the subsequent casting mold from the furnace system.

In some implementations, the method further includes, reducing the pressure in the melt chamber and reducing the pressure in the loading chamber. In some specific aspects, the method can include reducing the pressure in the melt chamber to about 5 mTorr and reducing the pressure in the loading chamber to about 100 mTorr. In other implementations, the initial casting mold and the subsequent casting mold can each be pre-heated to a temperature of about 800° C. to about 1,000° C. In further implementations, the melt chamber can be raised to a temperature of about 1,300° C. to melt either or both of the first and second alloy charges within the first melt box and the second melt box. In some aspects, the casting mold can be removed from the furnace system and allowed to cool such that a casting in the casting mold has an equiaxed structure. In other aspects, the method can include reloading an alloy charge into either or both of the first melt box and the second melt box after either the initial casting mold or the subsequent casting mold is moved out of the melt chamber. In further embodiments, the method can include used of a third melt box and/or a fourth melt box in order to allow for casting of a third and/or fourth casting mold as part of a processing cycle.

For a more complete understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative aspects and embodiments are described in detail below with reference to the following drawing figures.

FIG. 1 is a flowchart illustrating a process for casting a metal or alloy mold in combination with a dual melt box melt chamber, in accordance with some embodiments of the present disclosure.

FIG. 2 is a schematic diagram of a connected mold chamber and melt chamber coupled with an atmospheric and vacuum control system, in accordance with some embodiments of the present disclosure.

FIG. 3 is a schematic diagram of a furnace system having a connected mold chamber and melt chamber, in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Throughout this description for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the many embodiments disclosed herein. It will be apparent, however, to one skilled in the art that the many embodiments may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in diagram or schematic form to avoid obscuring the underlying principles of the described embodiments.

Embodiments of the present disclosure provide for a vacuum induction melting and casting system and related method for efficiently and effectively casting metal, alloy, and superalloy parts. Vacuum induction casting (alternatively referred to as vacuum pressure casting) can be considered a subset of investment casting or lost-wax casting, where a ceramic mold (alternatively referred to as the investment, shell, or casting mold) produced by investment casting is placed within a melt chamber, the pressure in the chamber is reduced to vacuum (or a sufficiently low pressure), and metal or alloy is poured into the ceramic mold. By casting the metal or alloy at vacuum (or a sufficiently low pressure), the porosity of the casting can be reduced and the overall strength of the casting is improved. Once the casting of metal or alloy has cooled, the ceramic mold is released from the casting by direct physical force (e.g. hammering), media blasting, vibration, waterjet cutting, or chemical solvents. Any excess portions of the casting or sprue can be cut or otherwise removed from the casting.

Investment casting involves producing a master pattern, forming a master die (alternatively referred to as a mold or mould) based on the master pattern, producing a secondary pattern (which can be made of wax, polymers, frozen mercury, or other materials known in the industry) based on the master die. The secondary pattern, which can be combined with other secondary patterns, is then used as the base for an investment which is formed by coating, stuccoing, and hardening a ceramic around the secondary mold, thereby forming a ceramic mold. The coating, stuccoing, and hardening cycle is repeated as necessary until the ceramic mold is of desired dimensions. The ceramic mold can then be dried and/or heated to remove traces of the secondary pattern material remaining on the ceramic mold and to sinter the ceramic mold. The ceramic mold can then be used for casting according to the vacuum process disclosed herein.

Embodiments of the present disclosure can improve the throughput, production, and yield for casting metals, alloys, or superalloys in ceramic molds through a vacuum induction process. In particular, a vacuum induction process can use a furnace having a melt chamber with two (2) melt boxes. Furnace melt chambers as known in the industry typically have a single melt box per melt chamber, due to restrictions of size, melt box shape, and apparatus for tilting or moving the melt box within the melt chamber. In aspects, a furnace of the present disclosure utilizes two independent melt box and crucible tilt assemblies within a single melt chamber, where both melt boxes cast into molds received from a single mold loading chamber. This design can provide advantages including, but not limited to: providing flexibility and improvements of time cycle scheduling for mold castings; providing flexibility and improvements of time cycle scheduling for the furnace; reducing the overall facility footprint (i.e. reducing the number of furnaces needed to achieve a comparable throughput); providing flexibility for utilization of operators running the furnace; and decreasing the idle time of the furnace and any related subassemblies.

The configuration of a furnace having two melt boxes within a single melt chamber of the furnace increases the output of the furnace while retaining essentially the same footprint of space of the furnace. The melt chamber of the furnace is mechanically coupled to the loading chamber, with an isolation valve connecting the two chambers. In some embodiments, the melt chamber and loading chamber can be arranged vertically relative to each other, where an elevator within the loading chamber can lift or otherwise move a mold into a casting position below the melt boxes of the melt chamber. In other embodiments, the melt chamber and loading chamber can be arranged horizontally relative to each other, where a platen can shift, slide, or otherwise move a mold into a casting position below the melt boxes of the melt chamber. The throughput of the furnace is increased in part because the duration of time required to melt a charge of alloy is longer than the time required to load an investment in a loading chamber of the furnace, and longer than the time required to pour molten alloy into an investment. Accordingly, the amount of molten alloy available to pour for a given heating cycle is increased for any given casting, or in some aspects, for multiple castings.

Superalloys are generally based on Group VIIIB elements and usually consist of various combinations of iron (Fe), nickel (Ni), cobalt (Co), and chromium (Cr), as well as lesser amounts of tungsten (W), molybdenum (Mo), tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), or aluminum (Al). Additionally, other elements can be used in superalloys as grain boundary components, including boron (B), carbon (C), calcium (Ca), magnesium (Mg), and zirconium (Zr). The three major classes of superalloys are nickel-, iron-, and cobalt-based alloys. A furnace according to the present disclosure can cast components made of metals, alloys, or superalloys, where in some aspects the superalloys case can include, but are not limited to: nickel-chromium alloys, iron-based alloys, cobalt-based alloys, zirconium-doped alloys, magnesium-doped alloys, and the like.

Molds used in conjunction with the vacuum induction melting and casting system may have many different possible shapes depending upon the articles desired to be cast. The mold may be shaped for semi-continuous ingot production. In this case, the mold may have an open top and bottom. Any number of molds may be moved into and out of the casting position through a withdrawal port in a sequential fashion. Alternatively, any suitable closed- or open-bottom mold may be used. The mold may be shaped to create a specific part or parts or any preformed shape which can be converted into a part or parts. In such cases, the mold may have an open top and closed bottom.

FIG. 1 is a flowchart illustrating a process for casting a metal or alloy mold in combination with a dual melt box melt chamber. The flowchart represents a portion of an investment casting process, specifically a furnace casting cycle, during which a ceramic mold is used to cast an alloy in a controlled atmospheric environment, which in some aspects can be the casting of a superalloy. A control system can be coupled with the furnace, specifically in electronic communication with sensors (such as temperature sensors) and actuating elements (such as chamber doors, tilting assemblies, or elevators) located within the furnace. The control system can include a non-transitory computer-readable medium and microprocessors configured in part to receive and/or process data from sensors located within the furnace. In some aspects, the control system can further include a user interface to allow for an operator to monitor and/or alter the function of the furnace. In other aspects, the control systems can include computer-executable instructions or algorithms to actuate mechanical elements within the furnace to control a casting process. The control unit can further be electronically coupled to other, local or remote, non-transitory computer-readable mediums (not shown) to transmit or receive data or operational instructions.

In embodiments of the present disclosure, two ceramic casting molds are used for each furnace casting cycle, and while the two casting molds can be identical, for any given casting cycle the casting molds are referred to as an initial casting mold and a subsequent casting mold. At step 100, an initial casting mold is pre-heated in a preheating oven external to a furnace loading chamber. The initial casting mold can be formed by investment casting or by other means known in the industry. The initial casting mold can be pre-heated to a temperature of about 800° C. to about 1,000° C., preparing or heat-priming the ceramic mold to receive molten alloy at temperatures at or about 800° C. to about 1,000° C. or greater. In some aspects, heat-priming a ceramic mold can increase the structural quality of the casting ultimately formed from the molten alloy poured into the mold, in part due to a reduction in any thermal shock to the casting or formation effects potentially resulting from a relatively steep temperature gradient at the interface between the molten alloy and ceramic casting. At step 102, the initial casting mold is transferred to and placed within a loading chamber (also referred to as a mold chamber) of a furnace. At step 104, the pressure of the loading chamber is reduced from atmospheric pressure, which can be accomplished by either or both of a mechanical vacuum pump and a diffusion pump connected to the loading chamber. In some aspects, the loading chamber can have its internal pressure reduced to about one hundred millitorr (100 mTorr).

Concurrently, sequentially, or in parallel to loading a pre-heated casting mold into the loading chamber of the furnace, the melt chamber of the furnace can be prepared and an alloy can be melted for casting. At step 106, charges of one or more alloys are loaded into dual melt boxes of a melt chamber. The charges of alloys can be of the same alloy, of similar alloys with different ratios of component metals, or of different alloys. At step 108, the pressure of the melt chamber is reduced from atmospheric pressure, which can be accomplished by either or both of a diffusion pump and a mechanical vacuum pump connected to the melt chamber. In some aspects, the melt chamber can have its internal pressure reduced to about five millitorr (5 mTorr). At steps 110 and 110′, the temperature in the melt chamber is elevated such that the charges of alloy in both the first melt box and the second melt box within the melt chamber are rendered into molten alloy. The melt chamber can be elevated to any given temperature necessary to melt a given alloy. For example, to melt a charge of nickel-chromium alloy such as Inconel 718, the melt chamber can be elevated to a temperature of about 1,300° C. or greater. For many alloys, melting the charges of alloy in the melt chamber can take from about five to ten minutes (5-10 min). The charges of alloy are raised to a temperature above the melting temperature of the alloy, but not above the boiling temperature of the alloy. (In the industry, raising an alloy to such a temperature can be referred to as “superheating”; this is not an accurate usage of term according to the traditional physics definition of superheating as related to boiling retardation or boiling delay.)

Within the melt chamber, dual melt boxes can be arranged or oriented on opposing sides of the location where a casing mold can be positioned. In some aspects, each melt box can have an independent tilt assembly, which can operate independently of each other or in concert with each other. In other aspects, the melt boxes can share a single tilt assembly that can incline each melt box independently in an alternating or sequential order. The tilt assembly or tilt assemblies for each of the melt boxes can be positioned on the same side of the melt chamber, allowing for access to the tilt assembly or tilt assemblies in melt chamber from a single access point, and providing for efficient removal, replacement, or maintenance of the tilt assembly or tilt assemblies.

At step 112, an isolation valve (which in some aspects can be a flapper valve) is opened thereby placing the loading chamber and melt chamber in communication with each other. The pressure between the loading chamber and melt chamber can balance to an equilibrium. At step 114, the initial casting mold can be moved to a casting position by a loading mechanism. In some aspects, the melt chamber and loading chamber can be arranged vertically relative to each other, where the movement of the initial casting mold can be with an elevator mechanism, lifting the initial casting mold up into the melt chamber to a casting position, from the loading chamber. In other aspects, the melt chamber and loading chamber can be arranged horizontally relative to each other, where a platen mechanism can shift, slide, or otherwise move a mold into a casting position below the melt boxes of the melt chamber. Both the first melt box and the second melt box can be configured and arranged to tilt and pour at the same casting position. At step 116, molten alloy from one of the first melt box or the second melt box is poured into the initial casting mold. Each of the first melt box and the second melt box has an individual tilting crucible to accomplish the pouring action. In some aspects, the pouring of the molten alloy at step 116 can take from about two to three seconds (˜2-3 sec). In further aspects, the amount of time required to place a ceramic mold in the loading chamber (step 102), evacuate the loading chamber atmosphere (step 104), open the isolation valve (step 112), position the ceramic mold at the casting position (step 114), and pour the molten alloy into the ceramic mold (step 116) can take about forty-five seconds (˜45 sec).

At step 118, the initial casting mold, now holding the casting of molten alloy, is withdrawn from the casting position and withdrawn from the melt chamber. At step 120, the isolation valve between the melt chamber and the loading chamber is closed. At step 122, the loading chamber is returned to atmospheric pressure, which in some aspects can take about thirty seconds (30 sec). At step 124, the initial casting mold with the cast alloy is removed from the loading chamber. The casting is allowed to cool and solidify at atmospheric pressure. By allowing the casting to cool at atmospheric pressure, the casting can have an equiaxed grain structure, such that the grains of the metal can have an approximately equal size and be randomly oriented in all directions across and through the casting.

At decision step 126, a determination can be made if at least one of the melt boxes in the melt chamber still holds a charge of alloy, where the charge can be either in a molten or solid state. In at least one of the melt boxes in the melt chamber does still hold a charge of alloy, a second casting can be made before reloading the melt boxes and proceeding though a further melt chamber heating cycle. Accordingly, if at least one of the melt boxes in the melt chamber still holds a charge of alloy, the process returns to step 102, taking a subsequent pre-heated casting mold for use in the process. (Alternatively, the process can return to step 100 and pre-heat a new ceramic mold in the external pre-heating oven.) The subsequent casting mold is placed in the loading chamber at step 102, the loading chamber is again evacuated with a vacuum system at step 104, and, if needed, the charge of alloy remaining in the loading chamber is melted to a molten state. The isolation valve between the loading chamber and the melt chamber is again opened at step 112. The subsequent casting mold is moved to a casting position at step 114. At step 116, the molten alloy from whichever of the first melt box and the second melt box still holds molten alloy is poured into the subsequent casting mold.

At step 118, the subsequent casting mold, now holding the casting of molten alloy, is withdrawn from the casting position and withdrawn from the melt chamber. At step 120, the isolation valve between the melt chamber and the loading chamber is closed. At step 122, the loading chamber is returned to atmospheric pressure. At step 124, the subsequent casting mold with the cast alloy is removed from the loading chamber, and the casting is allowed to cool and solidify at atmospheric pressure.

In some implementations, during a casting cycle, after step 118 where a casting mold is withdrawn from the melt chamber, either or both of the melt boxes can be reloaded (or “recharged”) with an alloy charge. Allowing the system to recharge the melt boxes in the melt chamber as the casting within the loading chamber is returned to atmospheric pressure and/or removed from the loading chamber can further increase the efficiency and throughput of the overall system.

The selection of which melt box to use at step 116 for an initial casting mold can be based on a programmable selection process, operator control, or the sensed or calculated temperature at a region of the melt chamber. In some aspects, the melt box used for the initial casting mold can alternate between furnace casting cycles. In other aspects the same melt box can be used for each initial casting mold for each furnace casting cycle.

At decision step 126, if neither of the melt boxes in the melt chamber still holds a molten charge of alloy, the process proceeds to step 128, ending the furnace casting cycle. Continuing the production of castings with further furnace casting cycles requires reloading the melt boxes with alloy charges, and requires another duration of time to melt the alloy charges into molten form for pouring into further ceramic molds.

FIG. 2 is a schematic diagram of a connected mold chamber and melt chamber coupled with an atmospheric and vacuum control system. A melt chamber 202 is coupled to a mold chamber 204 (i.e. the loading chamber) via an isolation valve 206. The melt chamber has a door through which alloy charges can be loaded into one or more melt boxes within the melt chamber 202. Similarly, the mold chamber 204 has a door through which ceramic casting molds can be loaded. The melt chamber 202 is coupled to a first vacuum system which can include a poppet valve structure 208 and a diffusion pump 210, which when active operates to reduce the pressure in the melt chamber 202 below atmospheric pressure. The mold chamber 204 is coupled to a first vacuum system 212, which can include a dry pump and a blower, and when active operates to reduce the pressure in the mold chamber 204 below atmospheric pressure.

The melt chamber 202 can be further coupled to a first venting system 214, which can open and return the melt chamber 202 to atmosphere. Similarly, mold chamber 204 can be further coupled to a second venting system 216, which can open and return the mold chamber 204 to atmosphere. A holding pump 218 and a melt chamber pumping package 220 can be further coupled to the poppet valve structure 208 and diffusion pump 210. Either or both of the holding pump 218 and melt chamber pumping package 220 are arranged as backing, or upstream in series with, the diffusion pump 210. Accordingly, when the diffusion pump 210 is in operation, either or both of the holding pump 218 and melt chamber pumping package 220 can back-up, support, and/or maintain a desired pressure in the melt chamber 202 and overall system. In particular, during a melt cycle, the diffusion pump 210 is backed-up and/or supported by the melt chamber pumping package 220.

A horizontal bar feeder 222 can deliver alloy charges into the melt chamber 202, and in some embodiments more than one horizontal bar feeder 222 can be coupled to the melt chamber 202. A charge temperature sensor system 224 is coupled with the melt chamber 202 and configured to measure the temperatures of the molten charge in each melt box. A mold temperature sensor system 226 is coupled with the melt chamber 202 and configured to measure the temperature of the mold cast within the melt chamber. Both of the charge temperature sensor system 224 and mold temperature sensor system 226 can be electronically coupled with a control system to relay temperature data to an operator or processing device.

A control system 228 can be located proximate or remote to the overall mold chamber, melt chamber, and vacuum system apparatus. The control system 228 can be electronically and operationally coupled to the controllable systems of the apparatus, and further provide a user interface for control by an operator. As noted above, the control system 228 can include a non-transitory computer-readable medium and microprocessors configured in part to receive and/or process data from sensors located within the furnace.

FIG. 3 is a schematic diagram of a furnace system 300 having a connected melt chamber 302 and mold chamber 304. As illustrated, the melt chamber 302 is positioned above the mold chamber 304. Horizontal bar feeders 306, 306′ can couple and feed into the melt chamber 302, providing alloy charges to be loaded into the two melt boxes 308, 308′ within the melt chamber 302. In some aspects, isolation valves melt boxes 307, 307′ can be provided between the horizontal bar feeders 306, 306′ and the melt boxes 308, 308′, respectively. In many aspects, each of the melt boxes 308, 308′ have a tilting crucible aligned to pour molten alloy at a casting position 316.

A withdrawal assembly 310 can be positioned below a casting mold support 312, where the withdrawal assembly 310 is an elevator that can move the casting mold support 312 up through an isolation or flapper valve 314 into the melt chamber 302. The withdrawal assembly 310 can position the casting mold support 312 at a casting position 316 where both of the melt boxes 308, 308′ can pour into (at different times). Once a casting has been poured into a casting mold located at the casting position 316, the withdrawal assembly 310 can retract from the melt chamber 302 and through the isolation or flapper valve 314. The casting mold support 312 can be positioned next to a mold cooling port 318 where a casting and casting mold can be taken out of the mold chamber 304.

Additionally illustrated as offset in FIG. 3, the mold chamber 304′ is shown with the flapper valve 314′ in positions at and in between an open configuration and a closed configuration, and further illustrates a maximum size of mold 313 that that the mold chamber 304′ and flapper valve 314′ can accommodate. Further illustrated as offset is a poppet valve and diffusion pump assembly 322 (otherwise located in a position occluded by the furnace system 300 in FIG. 3), which is coupled to and in communication with the furnace system 300. As shown, the poppet valve and diffusion pump assembly 322 is presented to show the relative size of the poppet valve and diffusion pump assembly 322 as compared to the melt chamber 302 and connected operational components.

In further embodiments, three melt boxes can be arranged within a single melt chamber, further increasing the throughput of casting of the furnace system. In yet further embodiments, four or more melt boxes can be arranged within a single melt chamber, further increasing the throughput of casting of the furnace system.

As provided herein, the furnace system, including the temperature and atmospheric controls for both the melt chamber and the mold chamber can be electronically coupled with an instrumentation interface with sensors and gauges to measure sensory data in the furnace system. Such an instrumentation system and interface can be electrically coupled to a microprocessor (or other such non-transitory computer readable mediums) by wires or by wireless means, and thereby send imaging data signals to the microprocessor. The coupled microprocessor can collect sensory data from the furnace and can further relay collected information to other non-transitory computer readable mediums, and/or run calculations on collected data and relay the calculated result to a user-operable and/or user-readable display. The sensory data captured by the furnace system can be evaluated according to computer program instructions controlling the microprocessor (either through hardware or software) to analyze or base calculations on specific sensory data and in some aspects adjust the temperature or pressure controls according to processing parameters. In further aspects, an operator can monitor sensory data and manually adjust temperature or pressure controls according to processing parameters

The instrumentation which can include a microprocessor can further be a component of a processing device that controls operation of the instrumentation, in particular, the thermal or pressure set points for melting and casting parameters of the furnace. The processing device can be communicatively coupled to a non-volatile memory device via a bus. The non-volatile memory device may include any type of memory device that retains stored information when powered off. Non-limiting examples of the memory device include electrically erasable programmable read-only memory (“ROM”), flash memory, or any other type of non-volatile memory. In some aspects, at least some of the memory device can include a non-transitory medium or memory device from which the processing device can read instructions. A non-transitory computer-readable medium can include electronic, optical, magnetic, or other storage devices capable of providing the processing device with computer-readable instructions or other program code. Non-limiting examples of a non-transitory computer-readable medium include (but are not limited to) magnetic disk(s), memory chip(s), ROM, random-access memory (“RAM”), an ASIC, a configured processor, optical storage, and/or any other medium from which a computer processor can read instructions. The instructions may include processor-specific instructions generated by a compiler and/or an interpreter from code written in any suitable computer-programming language, including, for example, C, C++, C#, Java, Python, Perl, JavaScript, etc.

The above description is illustrative and is not restrictive, and as it will become apparent to those skilled in the art upon review of the disclosure, that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. For example, any of the aspects described above may be combined into one or several different configurations, each having a subset of aspects. Further, throughout the foregoing description, for the purposes of explanation, numerous specific details were set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to persons skilled in the art that these embodiments may be practiced without some of these specific details. These other embodiments are intended to be included within the spirit and scope of the present invention. Accordingly, the scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the following and pending claims along with their full scope of legal equivalents.

Claims

1. A vacuum induction casting apparatus, comprising:

a loading chamber, configured to receive a casting mold;

a melt chamber, configured to concurrently house a first melt box and a second melt box;

an interlock mechanically coupled to both the loading chamber and the melt chamber;

a loading mechanism, configured to move the casting mold into and out of the melt chamber through the interlock to a casting position; and

a vacuum system coupled to both the melt chamber and to the loading chamber.

2. The vacuum induction casting apparatus according to claim 1, wherein the loading mechanism is a loading elevator configured to reciprocally move the casting mold vertically through the interlock.

3. The vacuum induction casting apparatus according to claim 1, wherein the loading mechanism is a platen configured to reciprocally move the casting mold horizontally through the interlock.

4. The vacuum induction casting apparatus according to claim 1, further comprising a charge temperature sensor system coupled with the melt chamber and configured to measure temperatures of one or more molten charges in either or both of the first melt box and the second melt box.

5. The vacuum induction casting apparatus according to claim 1, further comprising a mold temperature sensor system coupled with the melt chamber and configured to measure a temperature of a mold within the casting mold.

6. The vacuum induction casting apparatus according to claim 1, wherein the vacuum system separately controls pressure within the melt chamber and the loading chamber.

7. The vacuum induction casting apparatus according to claim 1, wherein the vacuum system further comprises a first vacuum system and a second vacuum system atmospherically separate from each other, wherein the first vacuum system is coupled to the melt chamber and wherein the second vacuum system is coupled to the loading chamber.

8. The vacuum induction casting apparatus according to claim 1, wherein the apparatus is further configured to allow for the melt chamber to load an alloy charge into either or both of the first melt box and the second melt box concurrent with the loading mechanism in a position outside of the melt chamber.

9. The vacuum induction casting apparatus according to claim 1, further comprising a third melt box.

10. The vacuum induction casting apparatus according to claim 9, further comprising a fourth melt box.

11. A method of forming castings, comprising:

loading a first alloy charge into a first melt box and a second alloy charge into a second melt box within a melt chamber of a furnace system;

melting the first and second alloy charges within the first melt box and the second melt box to be molten;

pre-heating an initial casting mold and pre-heating a subsequent casting mold;

loading the initial casting mold into a loading chamber of the furnace system;

moving the initial casting mold to a casting position within the melt chamber;

pouring the molten first alloy charge from the first melt box into the initial casting mold;

moving the initial casting mold out of the melt chamber and removing the initial casting mold from the furnace system;

loading the subsequent casting mold into the loading chamber of the furnace system;

moving the subsequent casting mold to the casting position within the melt chamber;

pouring the molten second alloy charge from the second melt box into the subsequent casting mold; and

moving the subsequent casting mold out of the melt chamber and removing the subsequent casting mold from the furnace system.

12. The method according to claim 11, further comprising:

reducing the pressure in the melt chamber; and

reducing the pressure in the loading chamber.

13. The method according to claim 12, further comprising:

reducing the pressure in the melt chamber to about 5 mTorr; and

reducing the pressure in the loading chamber to about 100 mTorr.

14. The method according to claim 11, wherein the initial casting mold and the subsequent casting mold are each pre-heated to a temperature of about 800° C. to about 1,000° C.

15. The method according to claim 11, wherein the melt chamber is raised to a temperature of about 1,300° C. to melt either or both of the first and second alloy charges within the first melt box and the second melt box.

16. The method according to claim 11, wherein a casting mold removed from the furnace system is allowed to cool such that a casting in the casting mold has an equiaxed structure.

17. The method according to claim 11, further comprising reloading an alloy charge into either or both of the first melt box and the second melt box after either the initial casting mold or the subsequent casting mold is moved out of the melt chamber.

18. The method according to claim 11, further comprising:

loading a third alloy charge into a third melt box within the melt chamber of the furnace system;

melting the third alloy charge with the first and second alloy charges to be molten;

pre-heating a third casting mold;

following removal of the subsequent casting mold, loading the third casting mold into the loading chamber of the furnace system;

moving the third casting mold to a casting position within the melt chamber;

pouring the molten third alloy charge from the third melt box into the third casting mold;

moving the third casting mold out of the melt chamber and removing the third casting mold from the furnace system.

19. The method according to claim 18, further comprising:

loading a fourth alloy charge into a fourth melt box within the melt chamber of the furnace system;

melting the fourth alloy charge with the first and second alloy charges to be molten;

pre-heating a fourth casting mold;

following removal of the third casting mold, loading the fourth casting mold into the loading chamber of the furnace system;

moving the fourth casting mold to a casting position within the melt chamber;

pouring the molten third alloy charge from the fourth melt box into the fourth casting mold;

moving the fourth casting mold out of the melt chamber and removing the fourth casting mold from the furnace system.