A forming device for nickel-based high-temperature alloy ring bodies with different chord lengths

Abstract

A molding device suitable for nickel-based high-temperature alloy ring bodies with different chord lengths, which relates to the technical field of gas turbine component casting. The present invention solves the problem that the existing pouring system cannot provide shrinkage compensation for the solidification part of the nickel-based high-temperature alloy casting. The two cavities of the present invention are respectively located on the left and right sides of the pouring system, and the pouring system is respectively connected to the upper and lower parts of the two cavities to achieve pouring; the pouring system includes a pouring cup, a sprue, a pouring nest, an upper pouring channel and a lower pouring channel, the upper pouring channel and the lower pouring channel are arranged in parallel up and down and are respectively connected to the upper and lower parts of the two cavities in a dispersed manner to compensate for shrinkage in the cavity, the sprue is vertically arranged at the geometric center of the upper pouring channel and the lower pouring channel, the sprue is connected to the contact part of the upper pouring channel and the lower pouring channel, and the pouring cup and the pouring nest are respectively installed at the upper and lower ends of the sprue. The present invention is used for casting the upper guard ring of a gas turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbine component casting, in particular to a molding device suitable for nickel-based high-temperature alloy ring bodies with different chord lengths, which is used for casting a retaining ring body of a steam turbine. Background Art

[0002] A gas turbine is an internal combustion engine that uses a continuously flowing gas as a working fluid to drive the high-speed rotation of an impeller, converting the fuel's energy into useful work. It is a type of rotating impeller heat engine. The massive gas turbine unit is composed of numerous structural components that work together to generate electricity.

[0003] The gas turbine retaining ring is a high-strength, non-magnetic, metal ring-shaped component used to protect and secure the rotor winding ends. It primarily prevents deformation, displacement, and eccentricity of the rotor components and excitation winding ends due to electromagnetic and high-speed centrifugal forces. It is a crucial component of a steam turbine generator.

[0004] This retaining ring features thin walls, variable cross-sections, and requires high-temperature resistance. Investment casting of the retaining ring body typically utilizes either a top-injection or bottom-injection gating system. Both top-injection and bottom-injection systems can result in casting defects such as shrinkage cavities and porosity, failing to meet part performance requirements.

[0005] Shrinkage cavities and porosity in castings are caused by the narrow mushy zone of nickel-based superalloys, with a temperature difference of 200°C between the solidus and liquidus, making mushy solidification very likely to occur during solidification. This mushy solidification phenomenon prevents the last solidified area of ​​the casting from receiving replenishment of molten metal, resulting in shrinkage cavities and porosity, which in turn compromises the performance of the casting.

[0006] In summary, the existing gating system cannot provide shrinkage feeding for the solidification part of nickel-based high-temperature alloy castings. Summary of the Invention

[0007] The purpose of the present invention is to solve the problem that the existing pouring system cannot provide shrinkage compensation for the solidification part of the nickel-based high-temperature alloy casting, and further provide a molding device suitable for nickel-based high-temperature alloy ring bodies of different chord lengths, so as to achieve defect-free production of guard ring castings in a simple and efficient manner.

[0008] The technical solution of the present invention is:

[0009] A molding device for a nickel-based high-temperature alloy ring body with different chord lengths includes a pouring system and two cavities, the two cavities being located on the left and right sides of the pouring system, and the pouring system being connected to the upper and lower parts of the two cavities for pouring.

[0010] Among them, the pouring system includes a pouring cup, a sprue, a gate nest, an upper sprue and a lower sprue. The upper sprue and the lower sprue are arranged in parallel up and down and are respectively connected to the upper and lower parts of the two cavities in a dispersed manner to feed the shrinkage into the cavity. The sprue is vertically arranged at the geometric center of the upper sprue and the lower sprue. The sprue is connected to the contact part of the upper sprue and the lower sprue. The pouring cup and the gate nest are respectively installed at the upper and lower ends of the sprue.

[0011] Furthermore, the sprue is truncated and arranged vertically, the upper end of the sprue is connected to the pouring cup, the lower end of the sprue is connected to the upper sprue and extends downward until it is connected to the pouring socket at the lower end of the lower sprue.

[0012] Furthermore, the cross-sectional area of ​​the sprue connected to the pouring cup is larger than the cross-sectional area of ​​the sprue connected to the upper runner and the lower runner.

[0013] Preferably, the gate cavity is hemispherical, and its radius is the same as the radius of the end cross-section circle of the sprue, and the top of the gate cavity is flush with the bottom surface of the lower runner.

[0014] Preferably, the upper runner and the lower runner are dispersedly connected to the mold cavity in a fishbone shape.

[0015] Furthermore, the upper runner includes an upper horizontal runner and multiple upper ingrowns, all of which have rectangular cross-sectional shapes and whose geometric centers are located at the center of the circle of the straight runner cross-sectional area. The multiple upper ingrowns are symmetrically installed on the left and right sides of the upper horizontal runner with the length direction of the upper horizontal runner as the center line.

[0016] Furthermore, the lower runner includes a lower transverse runner and multiple lower ingrains, the multiple lower ingrains are evenly distributed on the left and right sides of the lower transverse runner to form a fishbone shape, and the outer edge contours of the upper ingrain and the lower ingrain are arc-shaped.

[0017] Furthermore, the ratio of the cross-sectional area of ​​the upper runner to the cross-sectional area of ​​the upper ingrown runner is less than or equal to 1:3.

[0018] Preferably, the number of the upper ingrows and the number of the lower ingrows are both even.

[0019] Preferably, the cavity is an arc-shaped cavity.

[0020] Compared with the prior art, the present invention has the following effects:

[0021] 1. The present invention utilizes an investment casting system tailored to the shape and structure of the casting, adaptable to nickel-based superalloy rings of varying chord lengths. By employing runners and ingates to feed the mold cavity 2, shrinkage cavities and porosity are avoided, while also improving the casting yield and reducing casting costs.

[0022] 2. The cross runner of the present invention evenly distributes the molten metal from the sprue (through the lower cross runner 14 and the lower ingredient 16) to each ingredient, ensuring that the molten metal can flow smoothly into each part of the mold cavity 2, making the quality of each part of the casting more uniform.

[0023] 3. The intersection of the straight runner and the cross runner of the present invention constitutes the first buffer zone. When the molten metal flows from the straight runner into the cross runner, the cross runner can play a certain buffering role, reducing the flow rate and impact force of the molten metal, and avoiding excessive impact of the molten metal on the casting. The smaller the impact, the less defects such as sand inclusion, air holes, cold shut, and deformation can be reduced, thereby improving the strength of the casting, enabling the casting to meet the working performance requirements and extending the service life of the casting.

[0024] 4. Since the position and number of ingates can affect the solidification sequence of the casting, the present invention achieves sequential solidification of the casting during the solidification process by arranging the ingates in a certain manner and in a certain number of them, i.e., solidification starts from the position away from the ingates and gradually advances toward the ingates, which is beneficial to shrinkage compensation and reduction of defects such as shrinkage cavities and shrinkage porosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 It is a structural schematic diagram of the pouring system of the present invention;

[0027] Figure 3 Schematic diagram of the location of shrinkage holes in a ring body with a chord length of 190 mm when the present invention is applied;

[0028] Figure 4 Schematic diagram of the location of shrinkage holes in a ring body with a chord length of 240 mm when the present invention is applied;

[0029] Figure 5 Schematic diagram of the location of shrinkage holes in a ring body with a chord length of 290 mm when the present invention is applied;

[0030] Figure 6 This is a schematic diagram of the guard ring body parts cast by the present invention.

[0031] 1. Pouring system, 11. Gate cup, 12. Sprue, 13. Upper runner, 131. Extension end, 14. Lower runner, 15. Upper ingrown runner, 16. Lower ingrown runner, 17. Gate nest, 2. Cavity. DETAILED DESCRIPTION

[0032] Specific implementation method 1: Combination Figures 1 to 2 and Figure 6This embodiment includes a gating system 1 and two mold cavities 2. The two mold cavities 2 are located on the left and right sides of the gating system 1, and the gating system 1 is connected to the upper and lower parts of the two mold cavities 2 to achieve pouring.

[0033] Among them, the pouring system 1 includes a pouring cup 11, a straight runner 12, a pouring nest 17, an upper runner and a lower runner. The upper runner and the lower runner are arranged in parallel up and down and are respectively connected to the upper and lower parts of the two cavities 2 in a dispersed manner to feed the shrinkage into the cavity 2. The straight runner 12 is vertically arranged at the geometric center of the upper runner and the lower runner. The straight runner 12 is connected to the contact part of the upper runner and the lower runner. The pouring cup 11 and the pouring nest 17 are respectively installed at the upper end and the lower end of the straight runner 12.

[0034] The cross-sectional area ratio of the straight runner, the cross runner in the upper runner and the lower runner, and the ingrown runner in this embodiment is less than or equal to 1:2:6. As the cross-sectional ratio increases, the flow rate of the molten metal in the pouring system gradually decreases. The decrease in flow rate makes the molten metal more stable when entering the mold cavity, which can avoid casting defects such as air entrainment, sand blasting, cold shut, and deformation. The end of the ingrown runner in this embodiment is connected to the casting. The position corresponding to the ingrown runner is the position where the casting is prone to shrinkage cavities and shrinkage, including the middle and edge parts of the ring body. In order to achieve the shrinkage compensation effect for ring bodies with different chord lengths, one cavity corresponds to six ingrowns. The distance between two adjacent ingrowns is 30 mm. To facilitate cutting, a 3 mm chamfer is set on the ingrown runner.

[0035] Specific implementation method 2: Combination Figures 1 to 2 To illustrate this embodiment, the sprue 12 of this embodiment is truncated cone-shaped and arranged vertically, the upper end of the sprue 12 is connected to the pouring cup 11, and the lower end of the sprue 12 is connected to the upper sprue and extends downward until it is connected to the pouring nest 17 located at the lower end of the lower sprue.

[0036] With this arrangement, the pouring cup 11 is located directly above the sprue 12, and its bottom is connected to the top of the sprue 12, which can effectively prevent the molten metal from splashing out during the pouring process. The bottom of the sprue 12 is connected to the pouring nest 17, and the radius of the pouring nest 17 is consistent with the radius of the bottom of the sprue. Under the action of the static pressure head, the pouring system converts the gravitational potential energy of the molten metal into kinetic energy through the pouring cup 11 and the sprue 12, thereby better achieving mold filling. The pouring nest connected to the sprue provides a buffer for the molten metal, changes the flow direction of the molten metal, and prevents the occurrence of turbulence.

[0037] Other components and implementation methods are the same as those in the first specific implementation method.

[0038] The cross section of the sprue 12 of this embodiment is circular, and the cross sections of the runner and the ingrown are both rectangular; a 3 mm chamfer is provided at the connection between the ingrown and the casting to facilitate cleaning and polishing of the casting after cooling.

[0039] Specific implementation method three: Combination Figures 1 to 2 To illustrate this embodiment, the cross-sectional area of ​​the straight runner 12 connected to the pouring cup 11 of this embodiment is larger than the cross-sectional area of ​​the straight runner 12 connected to the upper runner and the lower runner, and the ratio of the cross-sectional area of ​​the straight runner to the cross-sectional area of ​​the runner in the upper runner and the lower runner is less than or equal to 1:2.

[0040] This arrangement can control the flow rate of the molten metal in the runner and reduce the possibility of sand erosion and sand inclusion in the casting. Other components and connection relationships are the same as those in the first or second embodiment.

[0041] The sprue of this embodiment is truncated cone-shaped, with its top connected to the pouring cup and its bottom connected to the pouring nest. The sprue provides a static head of 145 mm for the molten metal, allowing it to fill the mold cavity under the action of gravity potential energy.

[0042] Specific implementation method four: Combination Figures 1 to 2 To describe this embodiment, the gate cavity 17 of this embodiment is hemispherical, and its radius is the same as the radius of the end cross-sectional circle of the sprue 12 . The top of the gate cavity 17 is flush with the bottom surface of the lower runner.

[0043] Other components and connection relationships are the same as any one of the specific embodiments one to three.

[0044] Specific implementation method five: Combination Figures 1 to 2 The present embodiment is described. The upper runner and the lower runner of the present embodiment are dispersed in a fishbone shape and communicate with the cavity 2 .

[0045] With this arrangement, the runner and the sprue are distributed vertically, and the two form a bend, which can change the flow direction of the molten metal, thus facilitating filling of the mold. The geometric center of the runner is located on the axis of the sprue, which facilitates the simultaneous filling of the molten metal on both sides of the mold. The ingrown runner and the runner form a second bend, and are symmetrically distributed on both sides of the sprue. The bend here changes the flow direction of the molten metal again, which can reduce the flow rate of the molten metal and prepare for the molten metal to smoothly enter the mold cavity. The other components and connection relationships are the same as any one of the specific embodiments one to four.

[0046] In this embodiment, the sprue and runner are perpendicular to each other, and the runner and ingates are also perpendicular. The center of the sprue coincides with the geometric center of the runner, and the ingates are evenly and equidistantly spaced on either side of the runner. This facilitates shrinkage feeding of the casting through the ingates and facilitates simultaneous filling of the two cavities.

[0047] The ingates in this embodiment (referred to as lower runner 14 and lower ingrate 16) are located at the upper and lower ends of the mold, connected to the mold sidewalls. The sidewalls of the ingrate cup are angled 30 degrees to the mold axis and are 60 mm high. The ingrates connected to the mold sidewalls provide a feeding channel for thermal nodes; the ingrate cup design reduces the risk of metal splashing during pouring.

[0048] Specific implementation method six: combination Figures 1 to 2 To illustrate this embodiment, the upper runner of this embodiment includes an upper horizontal runner 13 and multiple upper ingrowns 14, all of which have rectangular cross-sectional shapes, and the geometric center is located at the center of the circle of the straight runner cross-section. The multiple upper ingrowns 14 are symmetrically installed on the left and right sides of the upper horizontal runner 13 with the length direction of the upper horizontal runner 13 as the center line.

[0049] With this arrangement, both the upper and lower parts of the casting can be fed, effectively preventing the occurrence of shrinkage cavities and shrinkage defects inside the casting and improving the density of the casting. The other components and connection relationships are the same as any one of the specific embodiments 1 to 5.

[0050] Specific implementation method seven: combination Figures 1 to 2 To illustrate this embodiment, the lower runner of this embodiment includes a lower transverse runner 15 and multiple lower ingredients 16. The multiple lower ingredients 16 are evenly distributed on the left and right sides of the lower transverse runner 15 to form a fishbone shape, and the outer edge contour shape of the upper ingredient 14 and the lower ingredient 16 is arc-shaped.

[0051] With such arrangement, the lower runner 14 provides shrinkage compensation for the casting while filling the mold. Other components and connection relationships are the same as any one of the specific embodiments one to six.

[0052] Specific implementation method eight: combination Figures 1 to 2 To describe this embodiment, the ratio of the cross-sectional area of ​​the upper runner 13 to the cross-sectional area of ​​the upper ingrate 14 is less than or equal to 1:3.

[0053] With this arrangement, the filling is smooth, the slag is easy to float up, and the temperature distribution is reasonable. The other components and connection relationships are the same as any one of the specific implementation methods one to seven.

[0054] Specific implementation method nine: Combination Figures 1 to 2 To explain this embodiment, the numbers of the upper ingates 14 and the lower ingates 16 in this embodiment are both even numbers.

[0055] Preferably, there are 6 or 8.

[0056] Specific implementation method ten: Combination Figures 1 to 2In this embodiment, cavity 2 is an arc-shaped cavity. Because the gas turbine shroud body is assembled from multiple components, each component has a curved shape. This cavity shape design serves two purposes: facilitating assembly and adjusting the distance between the two sides of the cavity and the sprue to facilitate pre-solidification. The remaining components and connections are identical to those in any of the first through ninth embodiments.

[0057] In this embodiment, the two cavities are annular cavities, and the bottom and top of the cavities correspond to the positions of the ingates.

[0058] The present invention provides shrinkage compensation for castings by arranging top cross runners and inner runners, thereby avoiding the generation of shrinkage cavities and shrinkage porosity inside ring castings with different chord lengths, improving process yield and reducing costs.

[0059] Combine Figures 1 to 6 Describe the embodiments of the present invention:

[0060] Example 1:

[0061] This example uses the above-mentioned gating system to design a molding process for a ring with a chord length of 240 mm. The gating system mainly includes a gating system 1 and a mold cavity 2. Specifically:

[0062] The pouring system 1 includes a pouring cup 11, a sprue 12, an upper runner 13, a lower runner 14, an upper ingrown runner 15, a lower ingrown runner 16, and a gate 17;

[0063] ① The height of the pouring cup 11 is 60 mm, and the angle between the side wall of the pouring cup and its axis is 30°; the end of the pouring cup 11 is connected to the head end of the sprue 12;

[0064] ② The end of the sprue 12 is connected to the gate cavity 17; the center of the sprue 12 is located at the geometric center of the upper runner 13 and the lower runner 14, and the sprue 12 is vertically distributed to the upper runner 13 and the lower runner 14;

[0065] ③ The upper surface of the upper runner 13 is flush with the top of the casting cavity 2. The runner length is 205mm, the runner width is 34mm, and the runner height is 24mm. The lower surface of the lower runner 14 is flush with the bottom of the casting cavity 2. The runner length is 160mm, the runner width is 34mm, and the runner height is 20mm.

[0066] ④ The runners and ingates are arranged in a fishbone pattern, located in the center of the two casting cavities. The ingates are symmetrically positioned on either side of the upper runner 13, with a 10mm extension 131 at the ends. Each runner is 30mm wide and maintains the same height as the runner itself, preventing problems such as air entrainment and mold shell damage caused by excessive filling speeds.

[0067] ⑤ The flow rate of the lower inner runners on both sides is less than 1m / s. The shrinkage cavities and shrinkage porosity are located at the upper ends of the pouring cup 11 and the sprue 12 of the pouring system 1. There are no shrinkage cavities or shrinkage porosity defects in the casting cavity.

[0068] Example 2

[0069] This example uses the same pouring system as Example 1 and is applied to the molding process design of a ring body with a chord length of 240 mm. No shrinkage cavities or shrinkage defects appear in the ring body.

[0070] Example 3

[0071] This example uses the same pouring system as Example 1 and is applied to the molding process design of a ring body with a chord length of 240 mm. No shrinkage cavities or shrinkage defects appear in the ring body.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A forming device for nickel-based high-temperature alloy ring bodies of different chord lengths, characterized by: It comprises a pouring system (1) and two cavities (2), the two cavities (2) being located on the left and right sides of the pouring system (1), and the pouring system (1) being connected to the upper and lower parts of the two cavities (2) respectively to achieve pouring; The pouring system (1) includes a pouring cup (11), a sprue (12), a sprue nest (17), an upper sprue and a lower sprue. The upper sprue and the lower sprue are arranged in parallel and are respectively connected to the upper and lower parts of the two cavities (2) in a dispersed manner to feed the cavities (2). The sprue (12) is vertically arranged at the geometric center of the upper sprue and the lower sprue. The sprue (12) is connected to the contact portion of the upper sprue and the lower sprue. The pouring cup (11) and the sprue nest (17) are respectively installed at the upper end and the lower end of the sprue (12). The upper runner and the lower runner are dispersed in a fishbone shape and communicate with the mold cavity (2); The upper runner includes an upper horizontal runner (13) and a plurality of upper ingrowns (14), each of which has a rectangular cross-section and a geometric center located at the center of the cross-section of the straight runner. The plurality of upper ingrowns (14) are symmetrically installed on the left and right sides of the upper horizontal runner (13) with the length direction of the upper horizontal runner (13) as the center line. The upper runner includes an upper horizontal runner (13) and a plurality of upper ingrowns (14), the cross-sectional shapes of which are all rectangular, and the geometric center is located at the center of the circle of the straight runner cross-sectional shape. The plurality of upper ingrowns (14) are symmetrically installed on the left and right sides of the upper horizontal runner (13) with the length direction of the upper horizontal runner (13) as the center line. The lower runner includes a lower horizontal runner (15) and a plurality of lower ingrowns (16). The plurality of lower ingrowns (16) are evenly distributed on the left and right sides of the lower horizontal runner (15) to form a fishbone shape, and the outer edge contour shape of the upper ingrown runner (14) and the lower ingrown runner (16) is an arc. The cavity (2) is an arc-shaped cavity; the cross-sectional area ratio of the sprue (12), the upper sprue, the cross sprue in the lower sprue, and the inner sprue is less than or equal to 1:2:

6.

2. The forming device for nickel-based high-temperature alloy ring bodies of different chord lengths according to claim 1, characterized in that: The sprue (12) is truncated and arranged vertically. The upper end of the sprue (12) is connected to the pouring cup (11), and the lower end of the sprue (12) is connected to the upper sprue and extends downward until it is connected to the sprue nest (17) located at the lower end of the lower sprue.

3. The forming device for nickel-based high-temperature alloy ring bodies of different chord lengths according to claim 2, characterized in that: The cross-sectional area where the sprue (12) is connected to the pouring cup (11) is larger than the cross-sectional area where the sprue (12) is connected to the upper pouring channel and the lower pouring channel.

4. The forming device for nickel-based high-temperature alloy ring bodies of different chord lengths according to claim 3, characterized in that: The gate cavity (17) is hemispherical, and its radius is the same as the radius of the end cross-section circle of the sprue (12). The top of the gate cavity (17) is flush with the bottom surface of the lower sprue.

5. The forming device for nickel-based high-temperature alloy ring bodies of different chord lengths according to claim 4, characterized in that: The number of the upper ingrows (14) and the lower ingrows (16) are both even.

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