Forming device suitable for nickel-based superalloy ring bodies with different chord lengths

Abstract

The invention discloses a forming device suitable for nickel-based superalloy ring bodies with different chord lengths, and relates to the technical field of gas turbine part casting. The casting system solves the problem that an existing casting system cannot provide feeding for the solidification part of the nickel-based high-temperature alloy casting. The two cavities are located on the left side and the right side of the pouring system correspondingly, the pouring system communicates with the upper portions and the lower portions of the two cavities correspondingly, and pouring is achieved; the pouring system comprises a pouring cup, a sprue, a sprue base, an upper pouring gate and a lower pouring gate, the upper pouring gate and the lower pouring gate are arranged in parallel up and down and are respectively and dispersedly communicated with the upper parts and the lower parts of the two cavities, feeding is carried out in the cavities, the sprue is vertically arranged at the geometric center of the upper pouring gate and the lower pouring gate, and the sprue base is vertically arranged at the geometric center of the sprue base. The sprue is communicated with the contact part of the upper pouring gate and the lower pouring gate, and the sprue cup and the sprue base are respectively arranged at the upper end and the lower end of the sprue. The method is used for casting the upper retaining ring of the gas turbine.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbine component casting, and 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 power machine that uses a continuously flowing gas as a working fluid to drive the impeller to rotate at high speed, converting the energy of the fuel into useful work. It is a rotating impeller heat engine. The huge gas turbine unit is composed of many structural components, which work together to complete the work of power generation.

[0003] The gas turbine retaining ring is a part used to protect and fasten the rotor winding end. It is a high-strength, non-magnetic, metal ring-shaped component mainly used to prevent the rotor components and the excitation winding end from deformation, displacement and eccentricity under the action of electromagnetic force and high-speed centrifugal force. It is one of the most important parts of the steam turbine generator.

[0004] The retaining ring has the characteristics of thin wall, variable cross section, high temperature resistance, etc. When the retaining ring body is produced by investment casting, a top-injection or bottom-injection gating system is often used. Whether it is a top-injection gating system or a bottom-injection gating system, the casting has casting defects such as shrinkage cavities and shrinkage, which cannot meet the performance requirements of the parts.

[0005] The reason why shrinkage cavities and shrinkage are present in castings is that the mushy zone of nickel-based high-temperature alloys is narrow, and the temperature difference between the solid and liquid phases is 200°C, so mushy solidification is very likely to occur during solidification. It is the appearance of mushy solidification that causes the last solidified part of the casting to not be supplemented with molten metal, resulting in shrinkage cavities and shrinkage defects, which in turn harms the performance of the casting.

[0006] In summary, the existing gating system cannot provide shrinkage compensation for the solidification part of the nickel-based high-temperature alloy casting. 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 then provide a molding device suitable for a nickel-based high-temperature alloy ring body with different chord lengths, so as to simply and efficiently realize the defect-free production of the guard ring casting.

[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 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;

[0010] Among them, 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. The pouring cup and the pouring 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 nest 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 pouring channel and the lower pouring channel.

[0013] Preferably, the gate cavity is hemispherical, and its radius is the same as the radius of the end cross-sectional 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 ingates, the multiple lower ingates 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 ingates and the lower ingates 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 ingates and the number of the lower ingates are both even numbers.

[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 adopts an investment casting pouring system according to the shape and structure of the casting, which can be applied to nickel-based high-temperature alloy rings of different chord lengths. By using a cross runner and an inner runner to compensate for the shrinkage of the cavity 2, thereby avoiding the generation of shrinkage cavities and shrinkage porosity, the process yield of the casting can be improved, and it is also beneficial to reduce the casting cost.

[0022] 2. The cross runner of the present invention evenly distributes the molten metal from the straight runner (through the lower cross runner 14 and the lower ingender 16) to each ingender, ensuring that the molten metal can smoothly flow 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, reduce the flow rate and impact force of the molten metal, and avoid 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 ingates, that is, solidification starts from a position far away from the ingates and gradually advances toward the ingates, thereby facilitating shrinkage compensation and reducing defects such as shrinkage cavities and shrinkage porosity. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0027] Figure 3 This is a 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 This is a 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 This is a 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 It is a schematic diagram of the guard ring body part cast by the present invention.

[0031] 1. Casting system, 11. Gate cup, 12. Straight runner, 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 Figure 1 to Figure 2 and Figure 6This embodiment is described. This embodiment includes a pouring system 1 and two cavities 2. The two cavities 2 are located on the left and right sides of the pouring system 1, and the pouring system 1 is connected to the upper and lower parts of the two cavities 2, respectively, to achieve pouring.

[0033] Among them, the pouring system 1 includes a pouring cup 11, a straight runner 12, a gate 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 compensate for shrinkage in 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 gate nest 17 are respectively installed at the upper and lower ends 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 ingates 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 allows the molten metal to enter the cavity more smoothly, avoiding casting defects such as air entrainment, sand blasting, cold shut, and deformation. The end of the ingates in this embodiment is connected to the casting. The position corresponding to the ingates is the position where shrinkage cavities and shrinkage are prone to occur in the casting, including the middle and edge parts of the ring body. In order to achieve the shrinkage compensation effect for rings of different chord lengths, one cavity corresponds to six ingates. The distance between two adjacent ingates is 30 mm. To facilitate cutting, a 3 mm chamfer is set on the ingates.

[0035] Specific implementation method 2: Combination Figure 1 to Figure 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 runner and extends downward until it is connected to the pouring nest 17 located at the lower end of the lower runner.

[0036] With such a configuration, 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] The other components and implementation methods are the same as those of 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 ingates are both rectangular; a 3 mm chamfer is provided at the connection between the ingates and the casting to facilitate cleaning and polishing of the casting after cooling.

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

[0040] Such arrangement can control the flow rate of the molten metal in the runner and reduce the possibility of sand flushing and sand inclusion in the casting. The other components and connection relationships are the same as those in the first or second specific implementation.

[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, so that it fills the mold cavity under the action of gravity potential energy.

[0042] Specific implementation method four: Combination Figure 1 to Figure 2 The present embodiment is described. The gate cavity 17 of the present 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] The other components and connection relationships are the same as any one of the specific implementation modes 1 to 3.

[0044] Specific implementation method five: Combination Figure 1 to Figure 2 The present embodiment is described. The upper runner and the lower runner of the present embodiment are distributed and communicated with the cavity 2 in a herringbone shape.

[0045] With such an arrangement, the runner and the sprue are vertically distributed, and the two form a bend, which can change the flow direction of the molten metal, thus facilitating the filling of the mold. The geometric center of the runner is located on the axis of the sprue, which is convenient for the molten metal to fill both sides of the mold at the same time. The ingrowth 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 implementation methods one to four.

[0046] The sprue and runner of this embodiment are perpendicular to each other, and the runner and ingates are also vertically distributed. The center of the sprue coincides with the geometric center of the runner, and the ingates are evenly and equidistantly distributed on both sides of the runner; this facilitates the ingates to compensate for the shrinkage of the casting, and is also conducive to achieving synchronous filling of the two cavities.

[0047] The ingates (lower cross runner 14 and lower ingates 16) of this embodiment are located at the upper and lower ends of the mold and connected to the side wall of the mold. The side wall of the pouring cup is 30 degrees to its axis and its height is 60 mm. The ingates connected to the side wall of the mold provide a shrinkage feeding channel for the hot spot; the design of the pouring cup reduces the risk of splashing of molten metal during the pouring process.

[0048] Specific implementation method six: Combination Figure 1 to Figure 2 To illustrate the present embodiment, the upper runner of the present embodiment includes an upper horizontal runner 13 and a plurality of upper ingates 14, all of which have rectangular cross-sectional shapes, and whose geometric centers are located at the center of a circle of the cross-sectional area of ​​the straight runner. The plurality of upper ingates 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 compensated for shrinkage, effectively preventing the occurrence of shrinkage cavities and shrinkage defects inside the casting, and improving the compactness of the casting. Other components and connection relationships are the same as any one of the specific implementation methods 1 to 5.

[0050] Specific implementation method seven: Combination Figure 1 to Figure 2 To illustrate this embodiment, the lower runner of this embodiment includes a lower transverse runner 15 and a plurality of lower ingates 16. The plurality of lower ingates 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 ingates 14 and the lower ingates 16 is an arc shape.

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

[0052] Specific implementation method eight: Combination Figure 1 to Figure 2 To explain the present embodiment, the ratio of the cross-sectional area of ​​the upper runner 13 to the cross-sectional area of ​​the upper ingrate 14 in the present embodiment is less than or equal to 1:3.

[0053] With such 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 modes one to seven.

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

[0055] Preferably, there are 6 or 8.

[0056] Specific implementation method ten: Combination Figure 1 to Figure 2This embodiment is described. The cavity 2 of this embodiment is an arc-shaped cavity. With such a configuration, since the gas turbine guard ring body is assembled from multiple bodies, each body has an arc. Through the design of the cavity shape, it can play two roles at the same time. One role is to facilitate assembly, and the other role is to adjust the distance between the two sides of the cavity and the sprue for early solidification. The other components and connection relationships are the same as any one of the specific embodiments one to nine.

[0057] In the present embodiment, the two cavities are annular cavities, and the bottom and top of the cavities correspond to the positions of the inner gates.

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

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

[0060] Embodiment 1:

[0061] This example uses the above-mentioned pouring system and is applied to the molding process design of a ring body with a chord length of 240 mm, which mainly includes a pouring system 1 and a 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 ingrate 15, a lower ingrate 16, and a pouring nest 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 nest 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 with 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 length of the runner is 205mm, the width of the runner is 34mm, and the height of the runner is 24mm; the lower surface of the lower runner 14 is flush with the bottom of the casting cavity 2. The length of the runner is 160mm, the width of the runner is 34mm, and the height of the runner is 20mm;

[0066] ④ The runner and ingates are fishbone-shaped and located in the center of the two casting cavities. The ingates are symmetrically arranged on both sides of the upper runner 13, and a 10mm extension end 131 is arranged at the end of the runner. The width of each runner is 30mm, and the height is consistent with the height of the runner, which can avoid problems such as air entrainment and damage to the mold shell caused by excessive filling speed.

[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 straight runner 12 of the pouring system 1, and there are no shrinkage cavities and 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 occur 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 occur 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 embodiments of the present invention.

Claims

1. A forming device for a nickel-based high-temperature alloy ring body with different chord lengths, characterized in that: It comprises a pouring system (1) and two cavities (2), wherein the two cavities (2) are respectively located on the left and right sides of the pouring system (1), and the pouring system (1) is respectively connected to the upper part and the lower part of the two cavities (2) to achieve pouring; The pouring system (1) comprises a pouring cup (11), a sprue (12), a pouring nest (17), an upper pouring channel and a lower pouring channel. The upper pouring channel and the lower pouring channel are arranged in parallel and are respectively connected to the upper and lower parts of the two cavities (2) in a dispersed manner to compensate for shrinkage in the cavities (2). The sprue (12) is vertically arranged at the geometric center of the upper pouring channel and the lower pouring channel. The sprue (12) is connected to the contact part of the upper pouring channel and the lower pouring channel. The pouring cup (11) and the pouring nest (17) are respectively installed at the upper end and the lower end of the sprue (12).

2. The forming device for a nickel-based high-temperature alloy ring body with 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 pouring channel and extends downward until it is connected to the pouring hole (17) located at the lower end of the lower pouring channel.

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

4. The forming device for a nickel-based high-temperature alloy ring body with 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-sectional 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 a nickel-based high-temperature alloy ring body with different chord lengths according to claim 4, characterized in that: The upper runner and the lower runner are dispersedly connected to the mold cavity (2) in a fishbone shape.

6. The forming device for a nickel-based high-temperature alloy ring body with different chord lengths according to claim 5, characterized in that: The upper runner includes an upper horizontal runner (13) and a plurality of upper ingates (14), all of which have rectangular cross-sectional shapes and whose geometric centers are located at the center of the cross-sectional area of ​​the straight runner. The plurality of upper ingates (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.

7. The forming device for a nickel-based high-temperature alloy ring body with different chord lengths according to claim 6, characterized in that: The lower runner comprises a lower horizontal runner (15) and a plurality of lower ingates (16), wherein the plurality of lower ingates (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 contours of the upper ingates (14) and the lower ingates (16) are arc-shaped.

8. The forming device for a nickel-based high-temperature alloy ring body with different chord lengths according to claim 1, characterized in that: The ratio of the cross-sectional area of ​​the upper runner (13) to the cross-sectional area of ​​the upper ingrown (14) is less than or equal to 1:

3.

9. The forming device for nickel-based high-temperature alloy ring bodies with different chord lengths according to claim 8, characterized in that: The number of the upper ingates (14) and the number of the lower ingates (16) are both even.

10. The forming device for nickel-based high-temperature alloy ring bodies with different chord lengths according to claim 1, characterized in that: The cavity (2) is an arc-shaped cavity.

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