JP2007167955A - Method for casting metallic material and casting apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for casting a metallic material and a casting apparatus therefor where the complication in the shape of a mold cavity is not limited, and further, the generation of cracking in a casting is evaded. <P>SOLUTION: The method for casting a metallic material comprises the steps of providing a non-metallic mold in a mold-receiving chamber disposed in at least one of relatively movable first and second members, communicating a mold cavity in the mold to a gating passage disposed in at least one of the first and second metallic members, communicating the gating passage to a short sleeve, and flowing metallic material under pressure from the shot sleeve to the gating passage and into the non-metallic mold. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of casting a metal or alloy and a casting apparatus thereof, and more particularly to a method of casting (casting) a metal, alloy or intermetallic compound subjected to pressure into a non-metallic investment mold and a casting apparatus thereof. It is.

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 thin wall mold cavity region with a thickness of less than 0.050 to 0.060 inches (0.127 to 0.1524 cm) with a titanium alloy or titanium aluminide molten metal is Difficult due to low overheating and gas leakage problems.
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.

US Pat. No. 6,070,643 describes vacuum die casting with metal molds of oxygen-reactive alloys such as titanium alloys, nickel-base superalloys and cobalt-base superalloys.
Reactive metal / alloy permanent molds such as titanium and titanium / nickel based alloys using reusable iron-based or titanium-based permanent molds made of composite parts are disclosed in US Pat. No. 5,287,910 to Colvin. Is disclosed.
Aluminum, copper and iron castings using permanent molds are disclosed in US Pat. No. 5,119,865.
US Pat. No. 6,070,643 US Pat. No. 5,287,910 US Pat. No. 5,119,865

  By the way, conventionally, in the above-mentioned patent documents, the disadvantage of using a metal die-casting mold is that the metal die mold is expensive, and there is a parting line between the metal dies. The complexity of the shape of the part (and hence the die cast product) 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.

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

  The present invention includes a step of placing a non-metallic mold in a mold accommodating chamber provided in at least one of the first and second members that can move relative to each other, and the mold cavity portion in the mold and the first and second molds. A step of connecting a gate passage provided in at least one of the members, a step of connecting the gate passage and the shot sleeve, and a metal material under pressure from the shot sleeve through the gate passage. And a step of flowing into the mold.

  The method for casting a metal material and the casting apparatus thereof according to the present invention can prevent the complexity of the shape of the die cavity from being limited, and can prevent the casting from being cracked.

The present invention aims to prevent the shape complexity of the die-type cavity from being restricted, and to avoid the occurrence of cracks in the cast product, such as metals and alloys subjected to pressure, particularly titanium alloys and titanium aluminides. Is realized by casting it in an investment mold.
Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

  FIG. 1 shows a die casting machine 10 suitable for carrying out the present invention. For purposes of illustration and not limitation, the casting machine is subjected to hydraulic pressure to evacuate molten metal materials including metals, alloys, intermetallic compounds, and thixotropic metal materials. Investment shell mold 31 (four are shown). The number of investment shell molds 31 is selected according to the individual casting process. 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. Each non-metallic investment shell mold 31 has a mold cavity forming region 36 in which the shape of each turbocharger wheel is formed. Although only one mold cavity forming region 36 is shown, each investment shell mold 31 includes one or more mold cavity forming regions 36.

  This die-casting machine includes 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 stationary (stationary) platen. 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 cast casting machine has a tubular and horizontal shot sleeve 24, and an intermediate portion of the shot sleeve 24 is a mold accommodating member (fixed to the fixed platen 14 and the fixed platen extension 14a with bolts or clamps ( Plate) 30. 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 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 the plunger hydraulic actuator 25 '' having a ram 25a ''. ing. The vacuum housing wall 42 is hermetically sealed by a stationary horizontal shot sleeve 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 into the cylindrical bore of the shot sleeve 24, and is placed between the injection start position on the left side of the injection port (melting inlet) 50 shown in FIG. Move between 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 into the investment shell mold 31 by the superambient pressure is not limited to the hydraulic plunger. 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.

  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 manufactured by a known lost wax method and is melted by applying one or more non-metallic (for example, ceramic) investment shell molds 31 subjected to hydraulic pressure. Configured to input metal material. 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. Each of the investment shell molds 31 includes an injection cup 33, a gate 32, and a turbocharger wheel-shaped mold cavity forming region 36. The molten metal or molten alloy flows into the mold cavity forming region 36 through the pouring cup 33 and the pouring passage 32a of the pouring gate 32. The turbocharger wheel shaped mold cavity formation region 36 is spaced from the hub formation cavity region 36h and has a small dimension (thin) airfoil or vane formation cavity region 36v. 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). One skilled in the art will recognize that the investment shell mold 31 can be used as a set to use one pouring cup and a plurality of gates and runners, and the molten metal material can be supplied to the set of molds. The present invention is not limited to such non-metallic, refractory or ceramic molds.

  The injection cup 33 includes a first annular lip L1 and a second annular lip L2, which are formed as part of each mold and form a groove G positioned around the injection cup. The present invention also envisages providing a ceramic core (not shown) in the mold cavity forming region 36 in the shape of a turbocharger wheel in order to create a cavity at a predetermined site 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 to 4, according to one embodiment of the present invention, the mold accommodating member 30 is configured to be fitted with the mold accommodating member 29, and the mold accommodating members 29, 30 are vertically divided surfaces. , A chamber C for accommodating the investment shell mold 31 is formed and a mold gate system 35 is formed between them. The mold gate system includes gate inserts 40 and 42 that can be replaced by machining. The gate inserts 40 and 42 are accommodated in mold accommodating members 29 and 30, respectively. It is located on the same plane as the outer surface of. When the mold accommodating members 29 and 30 come into contact with each other on the dividing surface, the gate insert forms a gate system including a runner R communicating with the shared passage CP. The shared passage CP communicates with the end of the shot sleeve 24. Each runway R extends from the common passage CP to each investment shell mold 31. The mold housing members 29 and 30 and the gate inserts 40 and 42 are usually suitable permanent metals / alloys (metal materials) such as steel, and are placed on or connected to the platens 14 and 16 of the die-casting machine. Yes.

  The O-ring seal S1 is provided between the mold housing members 29 and 30 and tightly seals between them (FIG. 1). The O-ring seal S1 extends around the gate system 35 and surrounds it.

  The investment shell mold 31 is located in the chamber C. When the mold accommodating members 29 and 30 come into contact with each other at the dividing surface, the shelf or ledge 41 that forms the bottom wall of the chamber C (complementary cylindrical shape). An injection cup 33 is disposed in the recess 41a. 2 to 3, a half ledge (shelf) 41 formed on the mold housing member 30 side and each recess 41a are shown, and the other half is formed on the mold housing member 29 side. Thereby, the investment shell mold 31 is positioned in the vertical inversion such that the rear closed end 31e faces upward.

  As shown below, the end face of each injection cup 33 is sealingly engaged with the ledge 41 of the recess 41a, and the molten metal material leaks from the interface when the mold is clamped or pressed against the ledge. Can be prevented. For this purpose, a flat seal or gasket can optionally be used between the inlet cup end face and the ledge 41 if desired. The investment shell mold 31 is arranged with respect to the runner R using a fixed positioning plate 51 having a slot 51a formed between the finger portions 51b. Each investment shell mold 31 is inserted into each slot 51a with the adjacent finger 51b inserted into the mold positioning groove G. Then, half of each injection cup 33 is positioned so as to straddle each runner R to introduce the molten metal material. The positioning plate 51 is horizontally fixed and fixed to one of the mold housing members 29 and 30 so as to be housed in the ledge of the other mold housing member facing the finger portion 51b.

  In such a position, the injection cup 33 and the spout passage 32a of the investment shell mold 31 communicate with the shot sleeve 24 through the gate system, and when the plunger 27 is pressed, the molten metal material is introduced from the shot sleeve 24. The shot sleeve 24 is inserted into the mold housing member 30 in a sealed state.

  Each investment shell mold 31 is supported at a predetermined position in the chamber C against the upward force of the molten metal material introduced into the mold via the gate system. For example, the upward closed end of each investment shell mold 31 is in contact with the respective support plate 60. The support plate 60 communicates with a shaft 62 provided on the hinge 64, and after the mold is placed on the positioning plate 51, the support plate 60 is in a position where it abuts against the closed end 31e of the mold. By urging the main shaft 66 communicating with each hinge 64 and a pressure device (for example, a spring, a pneumatic cylinder, a hydraulic cylinder, and / or a mechanical clamp) 63 downward, the support plate 60 is gently moved toward the closed end of the mold. Pressed.

  The vacuum chamber 40 is then at an appropriate level 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). Exhausted. The investment shell mold 31 in the chamber C communicates with the vacuum chamber 40 through the shot sleeve 24, and is separated from the ambient air by an O-ring seal S1 between the mold housing members 29 and 30. The air is exhausted to the same level as the vacuum. The investment shell mold 31 can be evacuated using an arbitrarily independent suction path or a pipe line connected to the inside of the mold.

  The investment shell mold 31 is usually at an ambient temperature (room temperature) when placed in the chamber C. Alternatively, the investment shell mold 31 can be preheated to an appropriate temperature before being placed in the chamber C. Furthermore, a heater (not shown) can be provided in the chamber C to maintain the temperature of the investment shell mold 31.

  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 from the gate system into the mold cavity 36 through the injection cup 33, the gate 32, and the runner 34. Move forward. 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.

  The plunger 27 is advanced into the 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 or returning the hydraulic pressure to the tank S ′ when the plunger 27 is at a predetermined distance from the injection end position. 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 obstructs 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 mold receiving members 29 and 30 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 alloy. Allows sufficient time to solidify at least on the surface of the cast part of the mold cavity 36. The investment shell mold 31 is then removed from the chamber C and moved to a discharge station where the investment shell mold 31 and cast product are separated by conventional methods (not constituting the present invention). The metal material solidified in the mold cavity 36 is substantially solidified when the investment shell mold 31 is removed from the chamber C. The cast product is visually inspected by a method according to the customer's request.

  In 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, or a Mo-based alloy. Or a refractory material of a W-based alloy or a TZM-based alloy, a ceramic material such as alumina, 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 examples illustrate the invention more specifically without limiting it.

[Specific Examples of Examples]
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 17.38 inches (about 44.1 cm) and 2.8 inches (about 7.1 cm), respectively. It was set so that plunger hydraulic pressure was discharged when it was located at about 0.5 inch (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.

Although the embodiments of the present invention have been described above, the embodiments of the present invention will be described separately.
First, a method of casting a metal material according to the present invention includes a step of placing a non-metallic mold in a mold receiving chamber provided in at least one of the first and second members that can be relatively moved, and a mold cavity portion of the mold. 1. A step of communicating with a gate passage arranged in at least one of the second members, a step of connecting the gate passage and the shot sleeve, and a flow of metal material from the gate passage to the non-metallic mold under pressure from the shot sleeve Process.
In one embodiment of the present invention, the first member and the second member can be moved relative to each other by being arranged on each of the first platen and the second platen of the die-casting machine.
In another embodiment of the present invention, the movement of the shot sleeve plunger causes the metallic material to flow. The plunger moves according to the fluid pressure to cause the metal material to flow, and this fluid pressure is discharged to the oil receiver at a predetermined distance before the end of the plunger injection stroke.
A casting machine according to another embodiment of the present invention includes first and second members that can move relative to each other, and at least one of the first and second members includes a mold accommodating chamber, and the first and second members. At least one of the two members is provided with first and second members having a gate passage for introducing a metal material from the shot sleeve, and a non-metallic mold is provided at a place communicating with the gate passage in the mold receiving chamber, Means are provided in fluid communication with the sleeve for flowing the metallic material through the gate passageway to the non-metallic mold.
In yet another embodiment of the present invention, a ceramic investment shell mold is held in place in the mold containment chamber to communicate with the gate passage, which was introduced into the mold through the gate passage. It is held in the mold receiving chamber against the force of the molten metal material. For example, the support plate is in contact with the closed end of the mold and is biased against it. The mold communicates with the gate passage and has an open injection cup. The mold also has a gate passage for carrying the molten metal material between the injection cup and one or more mold cavities. The mold cavity of the shell mold is evacuated to below ambient pressure (for example, 100 microns), and die casting of a reaction metal or a reaction alloy (for example, titanium alloy, titanium aluminide, nickel base superalloy, cobalt base superalloy, etc.) is performed. . The mold includes an element such as an injection cup connected to the gate passage. The mold also includes a gate passage for carrying the molten metal material between the injection cup and the one or more mold cavities.
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.
Furthermore, the present invention can be used for casting an investment mold having a complicated shape such as a backlock or undercut, which cannot be cast using a metal die. The practice of the present invention allows casting in complex shaped molds without the need for chemical and / or mechanical rework on die cast parts.

  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 method of casting a titanium alloy, titanium aluminide, or the like in an investment mold can be applied to other castings.

1 is a schematic side view of a casting machine for carrying out a method according to an embodiment of the present invention, and is a sectional view of a vacuum chamber. It is a disassembled perspective view of a pair of mold accommodation member connected to the platen of the casting machine. It is a disassembled perspective view of a pair of mold housing members. It is a perspective view of an investment shell mold. It is a hydraulic fluid system figure of a plunger.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Die-cast casting machine 14 Fixed platen 16 Movable platen 24 Shot sleeve 27 Plunger 29, 30 Mold accommodation member (plate)
31 Investment shell mold 32 Sprue 33 Injection cup 36 Mold cavity 40 Vacuum (melting) chamber 50 Inlet 54 Melting crucible

Claims (35)

  Disposing a non-metallic mold in a mold housing chamber provided in at least one of the first and second members capable of relative movement; and a mold cavity in the mold and at least one of the first and second members. A step of communicating with the gate passage provided in the step, a step of contacting the gate passage and the shot sleeve, and a metal material under pressure is allowed to flow from the shot sleeve to the non-metallic mold through the gate passage. A method of casting a metal material comprising the steps of:   The method of casting metal material according to claim 1, further comprising the step of holding the mold in a predetermined position in the chamber so as to communicate with the gate passage.   3. The method for casting a metal material according to claim 2, wherein the mold is held by a plate inserted in a groove portion of the mold.   The method for casting a metal material according to claim 1, further comprising a step of holding the mold in a predetermined position in the chamber against a force of the metal material introduced into the mold through the gate passage.   The method of casting metal material according to claim 4, wherein the mold is brought into contact with a closed end of the mold by a support plate.   The method for casting a metal material according to claim 5, wherein the support plate is pressed toward the closed end of the mold.   The method of casting metal material according to claim 1, wherein the metal material is introduced into the mold that is not heated before being placed in the chamber.   The method of casting a metal material according to claim 1, comprising placing a ceramic investment shell mold in the chamber.   5. The method of casting a metal material according to claim 4, wherein the mold cavity has a cavity region having a thickness of 0.35 inches (0.889 cm) or less.   The said mold cavity part is comprised as a turbocharger wheel-shaped cavity provided with the several vane-shaped cavity area | region of the said thickness in the position spaced apart from the hub formation cavity area | region. A method of casting a metal material.   The method for casting a metal material according to claim 1, wherein the mold cavity is configured as an airfoil forming region having the thickness.   2. The metal material according to claim 1, wherein the first and second members are relatively movable by being attached to the first and second platens of the die-casting machine. How to cast   The method for casting a metal material according to claim 1, wherein the mold includes an injection cup connected to the mold cavity through a gate passage, and the injection cup communicates with the gate passage.   The method for casting a metal material according to claim 1, further comprising the step of evacuating the mold cavity to below ambient pressure.   15. The method of casting metal material according to claim 14, wherein the mold cavity is evacuated through the shot sleeve connected to the mold cavity.   The method of casting a metal material according to claim 15, wherein the pressure below the ambient pressure is 100 microns or less.   The method of casting metal material according to claim 1, comprising melting the metal material in a vacuum chamber in communication with the shot sleeve.   2. The method of casting a 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.   The plunger moves into the shot sleeve in accordance with the hydraulic pressure and the metal material flows, and the hydraulic pressure is discharged to the oil receiver at a predetermined distance before the end of the plunger injection stroke. A method for casting the metal material according to claim 1. a) First and second members which are relatively movable, at least one of the first and second members is provided with a mold accommodating chamber, and at least one of the first and second members is formed from a shot sleeve. First and second members having gate passages for introducing the metal material are provided,
b) providing a non-metallic mold where the molten metal is introduced from the gate passage in the mold accommodating chamber;
c) A casting apparatus, characterized in that means for communicating a metal material with the shot sleeve through the gate passage by pressure to the non-metallic mold is provided.   The casting apparatus according to claim 20, wherein the mold is a ceramic investment shell mold.   21. The casting apparatus according to claim 20, wherein the first and second members are respectively connected to first and second platens of a die-cast casting machine that can move relative to each other.   The casting apparatus according to claim 20, wherein the flow means is a plunger in the shot sleeve.   The plunger moves according to the hydraulic pressure, and the hydraulic pressure control system includes means for discharging the hydraulic pressure to the oil receiver at a predetermined distance before the end of the injection stroke of the plunger. The casting apparatus according to claim 23.   21. The casting apparatus according to claim 20, wherein the chamber includes a mold support member that holds the non-metallic mold in the predetermined position.   The casting apparatus according to claim 24, wherein the mold support member is a plate inserted into a groove of the mold.   21. The casting apparatus according to claim 20, further comprising a mold support member that holds the mold in the chamber against a force of a metal material introduced into the mold through the gate passage.   28. The casting apparatus according to claim 27, wherein the mold support member is a support plate that contacts the closed end of the mold.   The casting apparatus according to claim 28, wherein the mold support member is pressed toward the closed end of the mold.   21. The casting apparatus of claim 20, wherein the mold comprises one or more mold cavities having a cavity region with a thickness of 0.100 inches (0.254 cm) or less.   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 a hub-forming cavity region. 30. A casting apparatus according to 30.   The casting apparatus according to claim 30, wherein the one or more mold cavities are configured as an airfoil forming region having the thickness.   21. The casting apparatus according to claim 20, wherein the mold includes an injection cup that communicates with the mold cavity through a gate passage, and the injection cup communicates with the gate path.   21. The casting apparatus according to claim 20, further comprising an exhaust unit configured to make the inside of the mold have an ambient pressure or less.   35. The casting apparatus according to claim 34, wherein the exhaust means is a shot sleeve connected to the inside of the mold under a pressure equal to or lower than an ambient environment.

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