The present invention relates to a new and improved method and apparatus for use in casting nickel chrome super alloy articles.
During the casting of nickel chrome super alloy articles, such as turbine engine components, waste or scrap metal is formed. For example, this scrap metal can be formed in a gating system which is connected with the article mold cavities. Due to the relatively high cost of nickel chrome super alloy metals, this scrap metal is recast and subsequently used to charge a crucible during a casting of metal articles of many different types.
One known method of recasting scrap nickel chrome super alloy metal has been to melt the scrap metal and pour it into pipes. The ingot which is cast in a pipe may be forced from the pipe utilizing a hydraulic ram. During this casting process, there is usually a certain amount of waste of the scrap metal. Due to the high cost of the nickel chrome super alloy scrap metal, the elimination of even a small amount of waste is economically advantageous.
The present invention relates to a method of casting nickel chrome super alloy articles. A plurality of molds are disposed on a rotatable base. The base is rotated to move each of the molds, in turn, through a pouring station to an article removal station and back to the pouring station. A molten nickel chrome super alloy is poured into each of the molds in turn at the pouring station. Cast nickel chrome super alloy articles are removed from the molds at the article removal station.
The molds may be continuously rotated. Molten metal may be continuously poured into the molds as they are rotated. Deflectors may be associated with the molds to deflect molten metal during rotation of the molds and pouring of the molten metal. Alternatively, the molds may be intermittently rotated. If this is done, molten metal would be poured while the molds are stationary.
The present invention includes a plurality of features which may be utilized together in the manner described herein. These features may also be used separately and/or in combination with features from the prior art.
The foregoing and other features of the present invention will become more apparent upon a consideration of the following description taken in connection with the accompanying drawings wherein:
An apparatus 12 for use in casting nickel chrome super alloy articles is illustrated schematically in
The valves are operable to a first condition to connect the conduits 22 and 24 in fluid communication with the source of low pressure. The valves are also operable to a second condition to connect the conduits 22 and 24 with atmospheric or ambient pressure to vent the housing assembly 14. If desired, the conduits 22 and 24 may be connected with a source inert gas, such as argon rather than a source of low pressure (vacuum).
The housing assembly 14 has a known construction. The illustrated housing assembly 14 is similar to the housing assembly disclosed in U.S. Pat. No. 3,841,384. The disclosure in the aforementioned U.S. Pat. No. 3,841,384 is hereby incorporated herein in its entirety by this reference thereto. However, it should be understood that the housing assembly 14 may have a different construction if desired. For example, the housing assembly 14 may have a construction similar to the construction disclosed in U.S. Pat. No. 6,308,767.
The housing assembly 14 (
The lower housing 30 includes a door 34 which can be opened to have access to the casting apparatus 18. The casting apparatus 18 may be moved into and out of the housing assembly 14 through the door 34. The crucible 16 is a vessel which has a known construction and includes a cavity or chamber 35 which is charged with metal, specifically, nickel chrome super alloy. At least some of this metal may be scrap nickel chrome super alloy from past casting operations.
An induction coil 36 extends around the crucible 16 and is electrically energizable to melt the metal in the chamber 35 of the crucible 16. A pour stopper or valve 37 (
After the chamber 35 in the crucible 16 has been charged with pieces of metal (nickel chrome super alloy) and with the pour stopper 37 in the closed position illustrated schematically in
After the nickel chrome super alloy scrap metal with which the chamber 35 in the crucible 16 was initially charged has melted, the crucible will contain a molten nickel chrome super alloy 40. The molten nickel super chrome alloy 40 is poured from the crucible 16 to the casting apparatus 18 by raising the pour stopper 37. In order to prevent splashing of the molten nickel chrome super alloy as it is poured from the crucible 16 into the casting apparatus 18, a suitable conduit or trough may be provided to conduct the molten nickel chrome super alloy 40 from the opening 38 at the lower end portion of the crucible 16 to the casting apparatus 20.
The casting apparatus 20 includes a rotor 46 (
Rotation of the rotor 46 sequentially moves the molds 50-64 through a pouring station 74 (
In
During pouring of molten nickel chrome super alloy 40 from the crucible 16 (
Since the rotor 46 is being continuously rotated at a constant speed by an electric motor (not shown) in the support section 70, the molds 50-64 are continuously moving in a counterclockwise direction (as indicated by arrows 71 in
Deflectors 88 are provided between the molds to direct the continuous flow of the molten nickel chrome super alloy 40 to first one and then into a next succeeding adjacent one of the molds 50-64. The deflectors 88 are continuously rotated along a circular path, in a counterclockwise direction as viewed in
The deflectors 88 are disposed midway between adjacent molds and are rotated with the molds. Therefore, each deflector 88 is effective to first direct molten nickel chrome super alloy 40 into a leading mold and than into a trailing mold adjacent to the leading mold. The drive motor in the support section 70 rotates the deflectors 88 in the same direction and at the same speed as the molds 50-64. The deflectors 88 do not move relative to each other.
In the illustrated embodiment of the invention, there is a continuous pouring of molten metal that is the nickel chrome super alloy 40, from the crucible 16 into the molds 50-64. The molds 50-64 are continuously moved, at a constant speed, along circular path by a drive assembly disposed in the support section 70 of the casting apparatus 18. However, it should be understood that the flow of molten metal from the crucible 16 may be interrupted and/or the rotational movement of the rotor 46 interrupted.
If the rotational movement of the rotor 46 is to be interrupted, an intermittent drive mechanism may be provided in the support section 70. This intermittent drive mechanism may include a geneva drive or other known type of intermittent drive mechanism. Alternatively, a clutch and brake assembly may be utilized to connect the drive motor with the rotor 46. If this was done, the clutch would be periodically operated between the engaged and disengaged conditions.
It is also contemplated that rather than having a constant flow of molten nickel chrome super alloy 40 from the crucible 16 downward to the casting apparatus 18, the flow of molten metal may be periodically interrupted by moving the pour stopper 24 from an open position to a closed position in which the pour stopper blocks the opening 26 in the bottom of the crucible 16. If this is done, the pour stopper 37 would be in the closed position blocking the flow of molten metal when the rotor 46 is moving. The pour stopper 37 would be in the open position enabling a flow of molten metal when the rotor 46 is stationary. Rather than having a pour stopper to control a flow of molten metal through the opening 26 in the crucible 16, the crucible 16 may be tilted or rocked to pour molten metal.
The cast articles 80 are removed from the molds 50-64 and are dropped onto a receiving tray or bin 94 (
The illustrated casting apparatus 18 includes the rotor 46 having a plurality of solid metal support sections 100 (
Although the molds 50-64 are integrally formed as one piece with the metal support sections 100, it is contemplated that the molds 50-64 may be formed separately from the support sections 100. Thus, each mold 50-64 may be formed separately from the support sections 100. Once the separate molds 50-64 have been formed, they may be mounted on the support sections. This would enable the support sections 100 to be formed of one material, for example metal, and the molds 50-64 to be formed of another material, for example a ceramic. Heat would be transmitted from the molds 50-64 to the fluid cooled support sections 100 to promote solidification of molten metal 40 in the molds.
Although two molds are mounted on each of the support sections 100 in the embodiment of the invention illustrated in
Although the molds 50-64 may have a different construction, in the illustrated embodiment of the invention, each of the molds is integrally formed as one piece with a support section 100. Thus, the support section 100 is a piece of metal, that is, copper, in which one or more of the molds 50-64 is formed. By integrally forming each of the molds 50-64 as one piece with a support section 100, cooling of the molds by a flow of cooling fluid, such as water, through the metal support sections 100 is promoted. The metal support sections 100 provide for a high rate of heat transfer between the molten nickel chrome super alloy 40 in a mold and the cooling fluid being conducted through the support section for the mold. A greater or lesser number of support sections 100 may be provided in the casting apparatus 18.
The relationship between the mold 50, the support section 100 and a cooling fluid passage 104 is illustrated schematically in
Although only the cooling fluid passages 104 associated with the mold 50 have been illustrated schematically in
Although only two cooling fluid passages 104 have been illustrated in
The circular side surface 106 of the mold cavity 108 has a uniformly curving arcuate configuration throughout the extent of the side surface. The uniform radius of curvature of the side surface 106 is indicated schematically by arrows 112 and 114 in
By having the radius of curvature of the arcuate side surface 106 in the mold cavity 108 greater than the radius of the circular mold cavity 50, removal of a cast nickel chrome super alloy article 80 from the mold cavity 108 is facilitated. This is because an upper (as viewed in
In order to have clearance between the corner 126 of the cast nickel chrome super alloy article 80 and the arcuate side surface 106 of the mold cavity 108 increase as the cast nickel chrome super alloy article moves out of the mold under the influence of gravity, the center of curvature of the arcuate side surface 106 of the mold is disposed above (as viewed in
However, the arcuate side surface 106 of the mold cavity 108 can not be cylindrical and still have increasing clearance between the side surface of the mold and the side surface of the cast nickel chrome super alloy article 80 as the article moves out of the mold. Therefore, it is believed that it may be desired to have the arcuate side surface 106 of the mold cavity 108 formed with a radius of curvature which is the same as or greater than the diameter of the mold cavity. In addition, it is believed that the side surface 106 of the mold cavity 108 may advantageously have a center of curvature which is offset from the mold cavity in the direction of movement of the nickel chrome super alloy article 80 from the mold cavity.
The rotor 46 includes a generally X-shaped base 132 (
The drive assembly 140 (
The arcuately curving deflectors 88 rotate with the molds 50-64 at the same speed as the molds. Each of the deflectors 88 (
The support sections 100 are pivotal between the pouring position illustrated in
When the support section 100 for the molds 56 and 58 has moved into the article removal station 78 and pivoted to the orientation illustrated in
Each of the support sections 100 is supported in the pouring position illustrated in
In addition, the linkage assembly 150 includes a connector link 158. The connector link 158 has a lower end portion which is pivotally connected at 160 to the upper end portion of the main link 154. The connector link 158 has an upper end portion which is pivotally connected at 164 to one of the support sections 100.
The main link 154 has a lower end portion on which a circular cam follower 168 (
As the rotor 46 is rotated by the central shaft 134, the cam follower 168 moves into alignment with the cam section 174 in the lower track 172. The cam follower 168 is moved upwardly (as viewed in
The force resulting from the weight of the support section 100 and molds 56 and 58 is transmitted through the connector link 158 to the upper end portion of the main link 154. This force causes the upper end portion of the main link 154 to move inward toward the central shaft 134 (
Each of the support sections 100 is pivotally connected to a radially outer end portion of a horizontal arm of the base 132 by a pivot connection 180 (
In the embodiment of the invention illustrated in
In the illustrated embodiment of the invention, a plurality of deflectors are moved with the molds 50-64 during rotation of a rotor 46. However, it is contemplated that the deflectors may be mounted in a different manner. For example, a single deflector 88 may be provided in association with the pouring station 74. When a single deflector 88 is utilized, the deflector may be moved relative to the pouring station 74 between a retracted position in which the deflector is ineffective to deflect a flow of molten metal from the trough 84 and an extended position in which the deflector is effective to deflect the flow of molten metal from the trough 84. Although the deflectors 88 are fixedly connected to the support shafts 144, it is contemplated that the deflectors 88 may be movable axially along the support shafts between the extended position illustrated in
The illustrated deflectors 88 have a metal core which is formed as half of a cylinder. This core is lined with a semi circular layer of ceramic material which is engaged by the molten nickel chrome super alloy 40. Of course, the deflectors 88 may be constructed in a different manner if desired. For example, the deflectors 88 may be formed of a solid piece of ceramic material.
Although the drive assembly 140 is continuously operated to rotate the rotor 46 at a constant speed, it is contemplated that the drive assembly 140 may be intermittently operated. If this is done, operation of the drive assembly 140 and rotation of the rotor 46 would be interrupted each time one of the molds 50-64 moves into the pouring station 74. Operation of the drive assembly 140 would be interrupted long enough to allow one of the molds 50-64 as the pouring station 74 to be filled with molten metal 40. Operation of the drive assembly 140 would then be resumed to move the next succeeding mold to the pouring station 74. Operation of the drive assembly 140 would again be interrupted for a length of time sufficient to enable the next succeeding mold to be filled with molten metal 40.
If the drive assembly 140 is intermittently operated to intermittently rotate the rotor 46, molten nickel chrome super alloy 40 may be intermittently poured from the crucible 16. If this is done, the pouring of molten nickel chrome super alloy 40 from the crucible 16 would occur when rotation of the rotor 46 is interrupted by interrupting operation of the drive assembly 140. The pouring of molten nickel chrome super alloy 40 from the crucible 16 would be interrupted during rotation of the rotor 46. However, it should be understood that there may b a continuous pouring of nickel chrome super alloy 40 from the crucible 16 even though there is intermittent rotation of the rotor 46.
In the embodiment of the invention illustrated in
A casting apparatus 18a includes a base 132a which is rotatable about a horizontal axis. A plurality of molds 50a-64a are pivotally mounted on the base 132a. The base 132a is rotatable about a horizontal axis to sequentially move the molds in a counterclockwise direction (as viewed in
The molds 50a-64a are pivotal, about horizontal axes, relative to the base 132. The molds 50a-64a remain in an upright orientation as they move from the pouring station 74a to the article removal station 78a. Each mold 50a-64a is pivoted in turn at the article removal station remove a cast article 80a from the mold. The mold 64a is illustrated in
The molds 50a-64a may be sequentially pivoted at the article removal station 78a by a cam follower which is connected with the mold and engages a stationary cam track. Of course, the mold 64a may be pivoted at the article removal station 78a in a different manner if desired. As each of the molds 50a-64a moves through the article removal station 78a in turn, each of the molds is pivoted relative to the base 132a.
Although only a single base 132 is illustrated in
The molds 50a-64a are cooled by a flow of cooling fluid (water) through passages connected with the molds. The cooling fluid passages connected with the molds 50a-64a are connected with a source of cooling fluid through conduits which accommodate the pivotal movement of the molds. The cooling fluid conduit may include flexible sections and/or swivel connections which accommodate pivotal movement of the molds 50a-64a.
In the embodiments of the invention illustrated in
A casting apparatus 18b includes a metal rotor 46b in which molds 50b, 52b, 54b, 56b, 58b, 60b, 62b, and 64b are formed. The molds 50b-64b are sequentially filled with molten nickel chrome super alloy at a pouring station 74b. Cast metal articles, corresponding to the cast metal articles 80 of
Molten nickel chrome super alloy is conducted to the molds at the pouring station 74b through a conduit 84b. The conduit 84b may be a trough, corresponding to the trough 84 illustrated schematically in
The rotor 46b is formed as a single piece of metal in which the molds 64b are formed. The single piece of metal forming the rotor 46b is cooled to promote solidification of the molten nickel chrome super alloy in the molds 50b-64b. There are cooling fluid (water) flow passages formed in the rotor 46b. A plurality of deflectors, corresponding to the deflectors 88 of
The rotor 46b may be continuously or intermittently rotated. Similarly there may be continuous or intermittent pouring of molten nickel chrome super alloy. For example, if rotation of the rotor 46b is interrupted each time one of the molds 50b-64b is moved to the pouring station 74b, there may be with continuous or intermittent pouring of the molten nickel chrome super alloy. Assuming a continuous pouring of the molten nickel chrome super alloy, deflectors, corresponding to the deflectors 88, may be utilized in association with the molds 50b-64b.
The present invention relates to a method of casting nickel chrome super alloy articles 80. A plurality of molds 50-64 are disposed on a rotatable base 132. The base 132 is rotated to move each of the molds 50-64, in turn, through a pouring station 74 to an article removal station 78 and back to the pouring station. A molten nickel chrome super alloy 40 is poured into each of the molds 50-64 in turn at the pouring station 74. Cast nickel chrome super alloy articles 80 are removed from the molds 50-64 at the article removal station 78.
The molds 50-64 may be continuously rotated. Molten metal 40 may be continuously poured into the molds as they are rotated. Deflectors may be associated with the molds to deflect molten metal 40 during rotation of the molds and pouring of the molten metal. Alternatively, the molds 50-64 may be intermittently rotated. If this is done, molten metal 40 would be poured while the molds 50-64 are stationary.
The present invention includes a plurality of features which may be utilized together in a manner described herein. Alternatively, these features may be used separately and/or in combination with features from the prior art.