JP2007167954A - Method for casting molten metallic material and casting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for casting titanium alloys, titanium aluminide or the like in an investment mold. <P>SOLUTION: The invention comprises the steps of disposing a non-metallic mold having one or more mold cavities in a container, holding the container with the mold therein relative to a platen of a casting machine such that the one or more mold cavities communicate to a shot sleeve to receive molten metallic material therefrom, flowing the molten metallic material in the shot sleeve under pressure into the one or more mold cavities of the mold while the container is held relative to the platen, and at least partially solidifying the metallic material in the one or more mold cavities. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to casting of metals and alloys, and more specifically, to a method and apparatus for casting (casting) metal or alloy under pressure into a non-metallic investment mold.

  Titanium-based alloys (eg Ti-6Al-4V) and intermetallic compounds (eg TiAl) are used as cast parts in the aerospace industry. Such cast parts are manufactured by the well-known investment gravity casting method in which a suitable molten metal is put into a preheated ceramic investment shell mold formed by the lost wax method.

  Investment castings of titanium-based material parts with complicated shapes are generally used, but they are relatively expensive and yield is low. The low casting output is due to several factors, such as insufficient filling of a given mold area, for example a thin wall (thin) mold cavity area. For example, filling a molten metal of titanium alloy or titanium aluminide into a thin wall mold cavity region of thickness less than 0.050 to 0.060 inches (0.127 to 0.1524 cm) Difficult due to low overheating and gas leakage problems.

Conventional casting methods include vacuum die casting with metal molds of oxygen-reactive alloys such as titanium alloys, nickel-base superalloys and cobalt-base superalloys.
In addition, conventional casting methods include casting with a reactive metal / alloy permanent mold such as titanium or titanium / nickel-based alloy using a reusable iron-based or titanium-based permanent mold consisting of composite parts. There is.
Further, some conventional casting methods cast aluminum, copper or iron castings using permanent molds.

US Pat. No. 6,070,643 US Pat. No. 5,287,910 US Pat. No. 5,119,865

  In attempts to improve the filling of ceramic investment shell molds, attempts have been made to increase the mold preheat temperature (eg, 700 degrees F. or more). However, this attempt is disadvantageous in that at such high temperatures, the molten titanium alloy or titanium aluminide reacts with the mold and a deleterious phase is formed on the surface of the casting produced in the shell mold. This phase must be removed by chemical treatment. Further, in order to satisfactorily fill the mold during casting, it is often necessary to increase the thickness of one or more thin-wall mold cavities when manufacturing the mold. As a result, the casting becomes larger than necessary, so that the dimensions of the casting must be reduced, and the specific part dimensions must be noted and mechanically and / or chemically processed.

  The disadvantages of using metal die casting molds are the high cost of metal die molds, and the presence of parting lines between metal dies, resulting in die mold cavities (and hence die cast castings). The complexity of the shape is limited. Another disadvantage of using a metal die when die casting a titanium aluminide material is that the molten metal in the metal mold rapidly solidifies, resulting in cracks in the casting.

  An object of the present invention is to provide a method and apparatus for casting a metal or alloy under pressure, particularly titanium alloy or titanium aluminide, etc., in an investment mold in order to overcome the above-mentioned drawbacks.

  The present invention includes a step of placing a non-metallic mold having one or more mold cavities in a container, and the one or more mold cavities communicate with the shot sleeve to introduce molten metal material from the shot sleeve. The step of holding the container against a platen of a casting machine with the mold placed therein, and melting the shot sleeve under pressure with the container held against the platen Introducing a metal material into one or more mold cavities of the mold, and at least partially solidifying molten metal in the one or more mold cavities.

  The present invention improves casting in the mold, can satisfy the filling of the mold during casting, does not limit the complexity of the shape of the die cavity, and causes cracks in the cast product. Can be prevented.

  The present invention includes placing the non-metallic mold into a container and placing the non-metallic mold in such that one or more mold cavities communicate with the shot sleeve and introduce molten metal material from the shot sleeve. Holding the container relative to the platen of the casting machine in the disposed state, and in a state where the container is held against the platen, the molten metal material in the shot sleeve subjected to pressure is supplied to one or more of the molds. The present invention provides a method and apparatus for casting a metal material comprising a step of flowing into a mold cavity and a step of at least partially solidifying molten metal in one or more mold cavities.

  In one embodiment of the present invention, the plunger within the shot sleeve moves in response to hydraulic fluid pressure and a predetermined distance before the plunger reaches the end of the injection stroke so as to reduce the likelihood of non-metallic mold breaking. To drain or return to the oil pan. In the container, a refractory particulate material is arranged around the mold in order to accommodate the metal material overflowing from the mold due to mold destruction.

  In one embodiment of the invention, the mold is a ceramic investment shell mold that is cast at ambient temperature. The mold cavity of this investment shell mold is evacuated to a sub-ambient pressure (eg 100 microns) and oxygen-reacted metal or alloy (eg titanium alloy, titanium aluminide, nickel-based superalloy, cobalt-based superalloy). Alloy die casting). The container includes a chamber in which an investment mold with a refractory particulate material disposed around is disposed. The mold includes an injection cup or other element secured to the container end closure. The mold also includes a gate passage for carrying the molten metal material between the injection cup and the one or more mold cavities.

  In one embodiment of the present invention, the container in which the investment mold is placed is held against a fixed (non-movable) platen of the die cast machine. In another embodiment of the present invention, the end of the container communicates with a base plate that communicates with the stationary platen of the die cast machine. Alternatively, the container is configured as part of a base plate that communicates with the stationary platen of the die cast machine. In yet another embodiment of the present invention, the movable second platen of the die caster can be moved to engage the opposite end of the container.

  Another embodiment of the present invention provides a container having a non-metallic mold therein and a caster platen for which one or more molds are introduced to introduce molten metal material from a shot sleeve. A casting apparatus is provided that holds a container so that a cavity communicates with a shot sleeve, and has means for introducing molten metal material in the shot sleeve under pressure into the one or more mold cavities. It is. The refractory particulate material is placed around a non-metallic mold in the container.

  INDUSTRIAL APPLICABILITY The present invention is useful for casting a molten metal / molten alloy (such as a titanium alloy or a titanium aluminide alloy), which is difficult to fill into a mold cavity region of a thin wall by a conventional investment casting method. For example, the present invention is a titanium alloy or titanium aluminide turbocharger having a plurality of thin foil (e.g., 0.025 to 0.200 inch (0.0635 to 0.508 cm)) airfoil vanes located around the hub. Useful for casting compressors and turbine wheels. Similarly, the present invention is useful for casting compressor blades having thin-wall (eg, 0.025 to 0.35 inch (0.0635 to 0.889 cm)) airfoil.

  Further, the present invention can be used for casting an investment mold having a complicated shape such as a back lock or an undercut, which cannot be cast by using a metal die. The practice of the present invention allows casting in complex shaped molds without the use of costly metal dies and without the need for chemical and / or mechanical rework on the die cast parts.

  Details and advantages of the present invention will become readily apparent from the detailed description taken in conjunction with the drawings.

  FIG. 1 shows a die cast casting machine 10 configured to carry out the present invention. For purposes of illustration and not limitation, the casting machine is configured to cast a molten metal material, including thixotropic metal material subjected to operating pressure, into an exhausted non-metallic investment shell mold 31. Has been. Such a casting metal material is a material that is difficult to fill a thin or narrow region of the investment shell mold cavity, such as a titanium alloy, a titanium aluminide alloy, a nickel-base superalloy, a cobalt-base superalloy, and / or the like. Including but not limited to oxygen reactive materials.

  Embodiments of the present invention are described below with respect to vacuum casting of a titanium alloy turbocharger wheel having a plurality of thin wall (thin) airfoil vanes located around the hub. The non-metallic investment shell mold 31 has first and second mold cavity forming regions 31a and 31b that form the shape of each turbocharger wheel therein.

  This die cast casting machine 10 has a reservoir (not shown) that stores hydraulic fluid used by the hydraulic actuator 12 to open and close the movable platen 16 relative to the fixed (stationary) platen 14 to open and close them. A base 11 is provided. The movable platen 16 is arranged to move on a stationary guide rod (bush) 18. A platen clamping link mechanism (not shown) communicates with the movable platen 16 in a conventional manner that does not constitute the present invention. The die-casting machine 10 has a tubular and horizontal shot sleeve 24. An intermediate portion of the shot sleeve 24 is a fixed platen 14 and a conventional bolt or clamp (not shown) on the fixed platen 14. It is inserted into the base plate 30 of the mold fixed in (1). The shot sleeve 24 extends into a vacuum (melting) chamber 40 where the metal or alloy to be die cast melts under high vacuum conditions (eg, less than 100 microns), eventually resulting in an oxygen reactive metal / alloy. (For example, a titanium alloy, a titanium aluminide alloy, a superalloy, etc.) will be die-cast.

  The vacuum chamber 40 is defined by a vacuum housing wall 42 that surrounds and extends around the fill side end 24a of the shot sleeve 24 and surrounds the periphery of a hydraulic actuator 25 '' having a movable ram 25a ''. Yes. The vacuum housing wall 42 is hermetically sealed by a stationary horizontal shot sleeve 24 and a plunger support member 44. The vacuum chamber 40 is evacuated by a conventional suction pump P in communication with the vacuum chamber 40. Base 11 and vacuum housing wall 42 are placed on a concrete floor or other suitable carrier.

  The cylindrical plunger 27 is inserted and disposed in the cylindrical bore of the shot sleeve 24, and the injection start position on the left side of the injection port (melting inlet) 50 shown in FIG. Move between the injection end positions. The injection port 50 has a melting receiving container 52 provided on the shot sleeve 24. The melting receiving container 52 is disposed under the melting crucible 54 so as to introduce molten metal or molten alloy for die casting. In the present invention, the means for introducing the molten metal material under the super ambient pressure into the investment shell mold 31 is not limited to the hydraulic plunger 27. For example, even if there is a plunger for introducing the molten metal material into the investment shell mold 31 by pressure, a gas pressure of super-ambient pressure may be applied to the end of the shot sleeve 24.

  The melting crucible 54 may be an induction skull crucible made of a copper segment in which a filler of a solid metal or solid alloy to be die-cast is melted. The solid metal or solid alloy is placed in the melting crucible 54 before suction in the vacuum chamber 40, and the suction coil 56 is energized and melted after the suction. Alternatively, the solid metal or solid alloy filling is filled in the melting crucible 54 of the vacuum chamber 40 evacuated by a decompression port (not shown), and then the induction coil 56 is energized and melted. In carrying out the present invention, known ceramic crucibles and refractory crucibles can also be used. For example, a method such as an arc melting method or an electron beam melting method can be used in the practice of the present invention. The melting crucible 54 is tilted so as to inject a molten metal / alloy filler into the molten receiving vessel 52 communicating with the shot sleeve 24 through the opening 58 in the shot sleeve wall. The molten metal / molten alloy filling is introduced into the shot sleeve 24 in front of the plunger 27 through the opening 58.

  The plunger 27 is moved from the injection start position to the injection end position by a conventional hydraulic actuator 25 ''. The radial clearance between the shot sleeve 24 and the plunger 27 is typically 0.001 to 0.008 inches (0.00254 to 0.02032 cm).

  A die-casting machine having such features is disclosed in commonly assigned US Pat. No. 6,070,643, the teachings of which are incorporated herein by reference.

  According to an embodiment of the present invention, the die-casting machine 10 is charged with a molten metal material subjected to a hydraulic pressure into an exhausted non-metallic (for example, ceramic) investment shell mold 31 manufactured by a known lost wax method. Configured to do. Such an investment shell mold 31 repeatedly immerses one or more transient patterns (eg, wax or plastic patterns) of parts to be cast as part of a pattern assembly in a ceramic powder slurry to remove excess ceramic slurry. Then, a rough ceramic octopus is applied to a wet ceramic slurry and dried until a shell mold having a wall with a desired thickness on the pattern is formed. The one or more patterns are then optionally removed by steam autoclaving, burr dewaxing, or other conventional pattern removal methods, wherein the ceramic has one or more cavities where one or more patterns previously existed. The shell mold remains. The ceramic shell mold is then subjected to a combustion treatment at a high temperature so as to have sufficient strength during casting. The production of ceramic shell molds using the lost wax process is disclosed in numerous specifications such as US Pat. Nos. 4,966,225, 5,983,982, and 6,749,006. For purposes of illustration and not limitation, the present invention can be practiced using conventional colloidal silica-bonded or sodium silicate-bonded investment shell templates, although other investment shell templates can also be used. .

  The specific ceramic powder and stucco material for manufacturing the investment shell mold 31 depend on the metal / alloy die cast with this mold and casting parameters (for example, heating, mold preheating temperature, etc.).

  1 to 5 show an investment shell mold 31 for casting two turbocharger wheels. The investment shell mold 31 includes a gate gate having an injection cup 33, a gate 32, and first and second gates 34 communicating with two turbocharger wheel-shaped mold cavities 31a and 31b. . The tubular ceramic sealing collar 38 is hermetically adhered, otherwise fixed in the vicinity of the injection cup 33, or constructed integrally with the injection cup 33. The sealing collar 38 is hermetically joined to the discharge end of the shot sleeve 24 as shown in FIG. The molten metal / molten alloy passes through the injection cup 33 and flows into the mold cavity 36 formed in the mold cavity forming regions 31 a and 31 b through the gate 32 and the passages of the respective runners 34. The turbocharger wheel shaped mold cavity 36 has a small dimension (thin thickness) airfoil or vane forming cavity region 36v that is spaced from the hub forming cavity region 36h. This airfoil or vane forming cavity region 36v forms a thin wall of the airfoil or vane on the die-cast turbocharger wheel hub so that its internal thickness is thin, typically 0.025-0. 100 inches (0.0635 to 0.254 cm).

  The present invention also envisages that ceramic cores (not shown) are provided in the mold cavity forming regions 31a and 31b of the turbocharger wheel shape in order to generate a cavity at a predetermined portion inside the cast turbocharger wheel. The ceramic core is formed to create a desired cavity inside a cast turbocharger wheel (or other cast product formed in other investment shell mold 31). The present invention also envisages providing a reinforcement, ie a porous or solid preform, that is placed in the mold cavity 36 and integrated with the cast part.

  As shown in FIGS. 1-5, according to one embodiment of the present invention, a metal (eg, steel) gas impermeable container 60 is provided to house an investment shell mold 31 when die casting is performed. It has been. The container 60 has a tubular main body 60a having a circular or square cross section. The container 60 includes end closing means 62 fixed by welding. The container 60 also includes removable end closure means 64 that are clamped to a welded annular flange 66 to form an internal container chamber 68. In this inner container chamber 68, the investment shell mold 31 is disposed, and the surrounding space is filled with a refractory particulate material 70.

  This detachable end closing means 64 is used to hermetically seal the end closing means 64 and the flange 66 of the container 60 when the fixture 67 is secured to the container (FIG. 4). Engages with ring seal seal S1 (FIGS. 2 and 4).

  An O-ring sealing seal S2 is provided between the end closing means 62 and the base plate 30 to hermetically seal the container 60 when the container 60 comes into contact with the base plate 30 (described below) ( FIG. 1). The container 60 is not permanently fastened to the base plate 30. The O-ring sealing seals S1 and S2 are Viton materials or other suitable high temperature sealing materials.

  The container end closing means 62 is provided with a passage 62p formed so as to be inserted through the shot sleeve 24 so as to be in a flow positional relationship with the injection cup 33 when the investment shell mold 31 is fixed at a predetermined position of the container 60. (Fig. 1). In particular, the container 60 is provided with a plurality of elongated clamp fingers 60f secured on the surface of the sealing collar 38 for clamping the investment shell mold 31 in the inner container chamber 68 to the end closure means 62. (FIGS. 1-2 and 4-5). The clamp finger 60f is fixed by inserting the fixture 70 'through the end closing means 62.

  Although the investment shell mold 31 is shown in which the runner 34 is oriented substantially horizontally and tightened with the container 60, the present invention is not so limited. Because the investment shell mold 31 can be oriented in any direction as appropriate, for example, the runner 34 may be in any orientation such as substantially vertical, substantially horizontal, or in the middle. is there.

  When so clamped, the mold injection cup 33 and gate 32 passages communicate with the shot sleeve 24 to introduce molten metal material from the shot sleeve 24 that is pushed out by the plunger 27. The shot sleeve 24 is hermetically inserted into the passage 62p. The sealing collar 38 seals against molten metal material leaking out of the shot sleeve and injection cup.

  The container 60 is provided with a supply port 60n for disposing flared (free flowing) refractory particulate material (such as ceramic support sand of alumina or zirconia) 70 around the investment shell mold 31 of the inner container chamber 68 of the container 60. I have. The supply port 60n is closed by a detachable vacuum coupler F for preventing the flapping fire-resistant particulate material 70 from falling. The container 60 also includes a lifting ring 60r, which allows the use of a conventional overhead hoist for lifting and moving the container for mold filling and removal.

  When carrying out the method according to the embodiment of the present invention, the melting crucible 54 of the vacuum chamber 40 is filled with a solid ingot of a die-cast metal material. The container 60 having the investment shell mold 31 therein is held between the base plate 30 and the movable platen 16 by the movement of the movable platen 16 with respect to the fixed platen 14. Before the container 60 is held at a predetermined position with respect to the fixed platen 14 by the movement of the movable platen 16, the container 60 is filled with the refractory particulate material 70 for supporting the material through the supply port 60n. The fluffy refractory particulate material 70 is manually or automatically introduced around the investment shell mold 31 of the internal container chamber 68 through the supply port 60n. The vacuum chamber 40 is then at a level suitable for melting a particular packing by the suction pump P (less than 100 microns for titanium alloys such as Ti-6Al-4V alloy and titanium aluminides such as TiAl). Exhaust. The container 60 held between the base plate 30 and the movable platen 16 and having the investment shell mold 31 therein is in communication with the vacuum chamber 40 through the shot sleeve 24, and also with O-ring seals S1 and S2. By being separated from the ambient air, it is simultaneously evacuated to a level similar to a vacuum.

  The investment shell mold 31 is usually at an ambient temperature (room temperature) when disposed in the container 60. Alternatively, the investment shell mold 31 can be preheated to an appropriate temperature using a cartridge or a resistance heater before being placed in the container 60 or when being placed in the container 60.

  The solid filling of metal / alloy disposed in the melting crucible 54 is melted by energizing the induction coil 56, and then this melt is poured under vacuum with the plunger 27 in the pouring start position shown in FIG. It is injected into the shot sleeve 24 through the inlet 50. This molten metal / molten alloy is injected into the shot sleeve 24, but stays there for a predetermined rest time so that the molten metal is not left behind the plunger 27. Molten metal / molten alloy is directly injected into the shot sleeve 24 from the melting crucible 54 through the injection port 50, thereby shortening the time before the injection starts and metal cooling.

  Then, the plunger 27 receives the hydraulic pressure and injects molten metal or molten alloy into the mold cavity 36 through the injection cup 33, the gate 32, and the runner 34, and therefore advances to the shot sleeve 24 side by the hydraulic actuator 25 ″. To do. In the case of a titanium alloy or a titanium aluminide, the molten metal or alloy is, for example, 10 to 120 inches (25.4 to 304.8 cm) / sec. Pressed against the mold cavity 36.

  Plunger 27 is advanced into shot sleeve 24 using the hydraulic system shown in FIG. The hydraulic system includes a supply assembly (supply manifold) 70 ′, an injection speed assembly 72 ′ that controls the plunger speed, an injection recovery assembly 74 ′ that controls the return of the plunger 27 to the injection start position, A pressure discharge assembly 76 ′ is provided for discharging the hydraulic pressure to the tank S ′ when the plunger 27 is at a predetermined distance from the injection end position, that is, returning it to the tank S ′. The hydraulic system is controlled by a programmable logic controller (not shown). However, the limit switch 80a fixed to the support frame of the hydraulic actuator (hydraulic cylinder) 25 ″ is in direct electrical communication with a relay (not shown). This relay is in direct electrical communication with the directional valve 27 'of the pressure exhaust assembly 76' in order to control the energization of the directional valve 27 '. As shown in FIG. 1, the switch trip element 80b is fixed to the movable ram 25a '' and interferes or activates the limit switch 80a when it moves with the ram. Before the limit switch 80a is obstructed, the directional valve 27 'is de-energized so as to keep the cartridge valve 28' closed (the directional valve 27 'is used unless the limit switch 80a is obstructed). (The power is always cut off.) If the limit switch 80a is obstructed, the directional valve 27 'is energized, causing the normally closed pressure maintaining cartridge valve 28' to be discharged to the tank S 'via line 81, and the cartridge valve 28' The downstream side of the hydraulic pressure passes through the opened valve 28 'and is discharged to the pipe 83 and the tank S'. The pressure discharge assembly 76 ′ functions to control the hydraulic pressure on the investment shell mold 31 so that the investment shell mold 31 is not destroyed when the molten metal material is injected under pressure. The position of the limit switch 80a (and thus a predetermined distance from the injection end position where the hydraulic pressure is discharged) is determined based on experience, and is adjusted to avoid mold destruction. The components of this hydraulic system are as follows.

The components of the hydraulic system shown in FIG.
1'-aggregate (manifold),
2'-SV310-00 115 AP directional valve (commercially available from Vickers Hydraulics; hereinafter referred to as Vickers),
3′-NS 800 S flow rate control valve (Parker Hannitin Corp., hereinafter referred to as Parker),
4′-CV5-10-P05 check valves (Vickers),
5′-PRV 1-10 SO 24 pressure regulator (Vickers),
6'-A9K2310D3KPN 10gal accumulator (Parker),
7′-A9675 3AA pressure switch (Barksdale Control Products, Barksdale, Inc.),
8'-pressure gauge (3000 psi),
9'-flow rate control (1/4 inch NPT),
10'-DG4S4 012A 50 directional valve (Vickers),
11'-SO63C 10 02 P cover (port. Oilear Company, hereinafter referred to as Oilear),
12'-SEO 63 10 K1 0001.5 / 3V5 insert (cartridge valve, Oilear),
13'-CV1 16 D11 2L 10 insert (cartridge valve, Vickers),
14'-CVCS 16A S2 10 cover (port, Vickers),
15'-DG4V 3S 2A MFW B60 directional valve (Vickers),
16'-CV1 40D1 2L10 cover (port, Vickers),
17'-CVCS 40D1 S2 10 cover (port, Vickers),
18'-A7K 1155 K3 K PL 5gal accumulator (Parker),
19'-aggregate,
20'-CVCS 16D1 S2 10 cover (port, Vickers),
21'-SE6310 K2 000 A1.5 / 3P insert (cartridge valve, Oilear),
22'-SO63 A10 P cover (port, Oilear),
23'-TDAD1097E40LAF proportional valve (Parker),
24'-WO 0179-1 63MM-40MM adapter (Parker),
25'-15 P1 10 B M 50 MM1 filter (Parker),
26'-aggregate,
27'-DG4S4 012A B 60 directional valve (Vickers),
28'-CVC 50 D2 S2 10 insert (cartridge valve, Vickers),
29'-Aggregates.

  After the molten metal or molten alloy is injected, the base plate 30 and the movable platen 16 are opened by moving the movable platen 16 away from the stationary platen 14 in, for example, 5 to 25 seconds, and then the molten metal or molten metal is melted. Allow sufficient time for the alloy to solidify at least on the surface of the cast part of the mold cavity 36. The container 60 is then removed from the base plate 30 and moved to the discharge station with the hoist engaged with the hoist ring 60r, where the supply port 60n is opened to remove the supporting refractory particulate material 70. Then, the end closing means 64 is removed, and the investment shell mold 31 filled with the melt is clamped and released from the container 60. The metal material that solidifies in the mold cavity 36 is substantially solidified when the investment shell mold 31 is removed from the container 60. The investment shell mold 31 then separates the die cast parts in a conventional manner (does not constitute the present invention). The cast product is visually inspected by a method according to the customer's request.

  In the die casting of titanium alloy, titanium aluminide, nickel-base superalloy, and cobalt-base superalloy, the shot sleeve 24 that comes into contact with the molten metal or molten alloy is made of an iron-based material such as H-13 tool steel, a Mo-based alloy Or a TZM alloy refractory material, a ceramic material such as alumina or graphite, or a combination thereof that is compatible with a metal or alloy that is melted and die-cast. The plunger tip 27a is constituted by a permanent or disposable tip, and in the case of disposable, the plunger tip 27a is discarded every time a filling of molten metal or molten alloy is injected into the investment shell mold 31. The plunger tip is a copper-based alloy such as a copper-beryllium alloy, or a suitable material such as steel or graphite.

  The specific casting parameters used for the die cast part will depend on several factors such as the size of the mold, the spout, the weight of the pouring cup, the fragility of the investment shell mold for the melt pouring pressure. The injection pressure is selected so as to hold the investment shell mold 31 intact (no damage to the mold due to pressure) while sufficiently filling the mold cavity region. The weight of the metal or alloy in the melting crucible 54 depends on the size of the mold and the number of parts die-cast with the mold.

The following specific examples illustrate the present invention more specifically without limiting it.
Specific Example 1.
In accordance with the present invention, the turbocharger wheel was successfully die cast with titanium alloy and titanium aluminide (TiAl) alloy by a conventional lost wax investment shell mold 31. Turbocharger wheels were manufactured with casting parameters generally in the following range. The melt injection pressure setting is 400 to 1800 psi (2.75 to 12.41 MPa), the melt injection speed (plunger speed) is 10 to 120 inches (25.4 to 304.8 cm) / sec, and the heating degree of the melt is 0 to 75 ° F. (0 to 41.7 ° C.), mold preheating temperature from room temperature to 600 ° F. (about 316 ° C.), lost wax investment shell mold 31 thickness is 0.20 to 1.0 inch (0 .508 to 2.54 cm), the length and diameter of the shot sleeve are 15 inches (38.1 cm) and 3 inches (7.62 cm), respectively. It was set so that the plunger hydraulic pressure was discharged when it was located at 1.27 cm).

  Although an investment shell mold 31 for manufacturing a turbocharger wheel has been disclosed as described above, the present invention is not so limited and may include other components such as internal combustion engine valves, automobile and truck turbochargers. It can be implemented to produce parts such as compressors, turbine wheels, gas turbine engine compressors and turbine blade vanes, or medical parts such as hip stems, acetabular knees, tibial trays, spine parts.

  Further, in the present invention, the container 60 is disclosed as being held between the base plate 30 and the movable platen 16, but the present invention is not so limited, and in another embodiment, the container It is assumed that 60 is attached to the base plate 30 and that the container 60 is formed integrally with the base plate 30.

  Although the present invention has been disclosed in terms of specific embodiments, it is not intended to be limited thereto, but only to the extent described in the claims.

  The present invention relates to a method and apparatus for casting a metal or alloy under pressure into a non-metallic investment mold, and is applied to casting an investment casting of a titanium base material part having a complicated shape. Can do.

1 is a schematic side view of a casting machine for performing a method according to an embodiment of the present invention, and is a cross-sectional view of a vacuum chamber. FIG. 6 is a front view of the container end with the rear closure means removed to show the mold. It is a perspective view of an investment shell mold. It is a perspective view which shows the investment shell mold fastened to the end closing means within the container. FIG. 3 is a perspective view of an investment shell mold with refractory particulate material disposed around the mold and clamped to the end closure means within the container. It is a hydraulic fluid system figure of a plunger.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Die-casting machine 12 Hydraulic actuator 14 Fixed platen 16 Movable platen 24 Shot sleeve 27 Plunger 31 Investment shell mold 36 Mold cavity 40 Vacuum chamber 54 Molten crucible 60 Container

Claims (33)

Placing a non-metallic mold having one or more mold cavities in a container;
Holding the container against a platen of a casting machine with the mold disposed therein such that one or more mold cavities communicate with the shot sleeve and introduce molten metal material from the shot sleeve; ,
Introducing molten metal material in the shot sleeve under pressure into the one or more mold cavities of the mold with the container held against the platen;
And at least partially solidifying the molten metal in one or more of the mold cavities.   The method of casting molten metal material according to claim 1, comprising placing a refractory particulate material around the mold of the container.   The method of casting molten metal material according to claim 1, wherein the molten metal material is introduced into the mold that is not heated before being placed in the container.   The method of casting molten metal material according to claim 1, comprising placing a ceramic investment shell mold in the container.   5. The molten metal material according to claim 4, wherein at least one of the one or more mold cavities has a cavity region having a thickness of 0.35 inches (0.889 cm) or less. Method.   The at least one of the mold cavities is configured as a turbocharger wheel-shaped cavity having a plurality of vane-shaped cavity regions of the thickness at positions spaced from the hub forming cavity region. A method for casting the molten metal material according to 1.   The method for casting molten metal material according to claim 1, wherein one or more of the one or more mold cavities are configured as an airfoil forming region having the thickness.   The container has a tubular body having end closing means, and the container has a chamber in which the mold is disposed and a refractory particulate material is disposed around the mold. Item 8. A method for casting the molten metal material according to Item 1.   9. The method for casting molten metal material according to claim 8, wherein the mold is fastened to one of the end closing means of the container.   The mold includes an injection cup that communicates with one or more of the mold cavities by a gate passage, the injection cup having the end so that the gate passage communicates with the shot sleeve for introducing molten metal material. 10. A method for casting molten metal material according to claim 9, characterized in that it is fastened to one of the closing means.   The method of casting molten metal material according to claim 1, comprising connecting the container to a base plate connected to a stationary platen.   The method of casting molten metal material according to claim 1, comprising the step of holding the container between a first platen and a second platen of a die-casting machine.   The method of casting molten metal material according to claim 1, comprising forming the container as a part of a base plate connected to the platen.   The method of casting molten metal material according to claim 1, comprising evacuating one or more mold cavities to below ambient pressure.   14. The method of casting molten metal material according to claim 13, wherein one or more mold cavities are evacuated through the shot sleeve communicating with the mold cavities.   The method of casting a molten metal material according to claim 12, wherein the pressure below the ambient pressure is 100 microns or less.   The method of casting molten metal material according to claim 1, comprising melting the metal material in a vacuum chamber in communication with the shot sleeve.   The method of casting a molten metal material according to claim 1, wherein the metal material is selected from the group consisting of a titanium alloy, a titanium aluminide, a nickel-base superalloy, and a cobalt-base superalloy.   2. The melting according to claim 1, wherein the plunger moves into the shot sleeve in accordance with the hydraulic pressure, and the hydraulic pressure is discharged to the oil receiver at a predetermined distance before the end of the injection stroke of the plunger. Method of casting metal material a) a container having disposed therein a non-metallic mold having one or more mold cavities;
b) a platen on which the container is held such that one or more mold cavities communicate with the shot sleeve and introduce molten metal;
c) a shot sleeve means for introducing metal material in the shot sleeve under pressure into the one or more mold cavities of the mold when the mold is placed in the container relative to the platen; Having casting equipment.   21. The casting apparatus according to claim 20, wherein the mold is a ceramic investment shell mold.   21. The casting apparatus of claim 20, wherein one or more of the one or more mold cavities have a cavity region having a thickness of 0.100 inches or less.   One or more of the one or more mold cavities are configured as a turbocharger wheel-shaped cavity having a plurality of vane-shaped cavity regions of the thickness at positions spaced from the hub forming cavity region. The casting apparatus according to claim 22,   23. The casting apparatus according to claim 22, wherein one or more of the one or more mold cavities are configured as an airfoil forming region having the thickness.   The container has a tubular body having end closing means, and the container has a chamber in which the mold is disposed and a refractory particulate material is disposed around the mold. The casting apparatus according to claim 20.   26. The casting apparatus according to claim 25, further comprising a clamping device for fastening the mold to one of the end closing means of the container.   The mold includes an injection cup that communicates with one or more mold cavities by a gate passage, the injection cup having the end so that the gate passage communicates with the outside of the can for introducing molten metal material. 27. A casting apparatus according to claim 26, wherein the casting apparatus is fastened to one of the closing means.   21. The casting apparatus according to claim 20, further comprising means for evacuating one or more mold cavities below ambient pressure.   The casting apparatus according to claim 28, wherein the exhaust means is a shot sleeve that is under a pressure equal to or lower than an ambient pressure and communicates with one or more mold cavities.   The casting apparatus according to claim 29, further comprising an airtight seal provided in the end closing means of the container.   21. The casting apparatus according to claim 20, wherein a base plate connected and fixed to the platen is provided, and the container is connected to the base plate.   The casting apparatus according to claim 20, wherein the container is held between a first platen and a second platen of a die cast casting machine.   21. The casting according to claim 20, wherein the plunger moves into the shot sleeve in accordance with the hydraulic pressure, and the hydraulic pressure is discharged to the oil receiver at a predetermined distance before the end of the injection stroke of the plunger. apparatus.

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