A casting mold and manufacturing process for nuclear power plant sealing tiles

Abstract

This invention discloses a nuclear power plant sealing tile casting mold, belonging to the field of centrifugal casting technology. It includes a transmission plate, an outer mold, a mold pad, a bushing, a mold cover, a slide rail, a feeding assembly, a ventilation assembly, and a cooling assembly. The transmission plate is fixedly installed at the output end of the centrifuge, and the outer mold is fixedly installed at the outer end of the transmission plate. The mold pad, bushing, and mold cover are sequentially assembled inside the outer mold. The feeding assembly and ventilation assembly are both movable and mounted on the slide rail. The discharge end of the feeding assembly is located inside the bushing, and the ventilation end of the ventilation assembly is located at the middle of the outer side of the outer end face of the mold cover. Two cooling assemblies are symmetrically fixedly installed on the slide rail. The invention also discloses a nuclear power plant sealing tile production process. The design of the mold, as well as the arrangement of the feeding assembly, ventilation assembly, and cooling assembly, ensures uniform pouring of molten metal and achieves synchronous internal and external cooling and precise temperature control of the casting, effectively reducing defects such as segregation and shrinkage porosity in the casting and improving the casting yield.

Description

Technical Field

[0001] This invention belongs to the field of centrifugal casting technology, and specifically provides a casting mold and production process for nuclear power plant sealing tiles. Background Technology

[0002] Sealing tiles used in nuclear power plants are crucial sealing components in nuclear reactors, playing a vital role in ensuring their safe operation. The performance of these sealing tiles not only affects the safety of the nuclear power plant but also directly impacts its overall economic efficiency.

[0003] To ensure the quality of sealing tiles for nuclear power plants, castings must meet the PT (Potential Testing) Level 3 standard and pass UT (Universal Testing) inspection. In terms of composition, sealing tiles must contain 14% to 16% tin (Sn) and 84% to 86% copper (Cu). Furthermore, the lead (Pb) content must be less than 0.1%, and the total of all other impurities must not exceed 0.3%. During the production process, castings must strictly avoid defects that significantly affect quality, such as voids, slag inclusions, linear defects, segregation, inclusions, and large columnar crystals. Linear defects, in particular, require special attention due to their potential hazards, and their absence must be ensured.

[0004] However, in existing casting processes, defects are prone to appear in the inner diameter, indicating that the defects are located in the final solidification region of the casting. These regions are usually accompanied by traces similar to segregation. The reasons for the segregation are analyzed as follows:

[0005] 1. Due to the uneven temperature field distribution, the cooling rate of different parts of the casting is different (the outer layer cools rapidly and the center cools slowly), which causes the solute to accumulate in the last solidified area, thus forming macroscopic segregation;

[0006] 2. In terms of elemental properties, low-melting-point elements (such as tin, Sn) tend to be enriched at grain boundaries or in the last solidification region;

[0007] 3. Under the influence of centrifugal force, density difference becomes the dominant factor in solute distribution: high-density components (such as copper Cu, with a density of 8.96 g / cm³) tend to migrate outward, while low-density components (such as tin Sn, with a density of 7.3 g / cm³) tend to accumulate inward, thus forming macroscopic segregation.

[0008] Therefore, to solve the above problems, a casting mold and production process for nuclear power plant sealing tiles are proposed. Summary of the Invention

[0009] To address the above problems, this invention provides a casting mold and production process for nuclear power plant sealing tiles.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a nuclear power plant sealing tile casting mold, comprising a transmission plate, an outer mold, a mold pad, a bushing, a mold cover, a slide rail, a feeding assembly, a ventilation assembly, and a cooling assembly. The transmission plate is fixedly installed at the output end of a centrifuge, and the outer mold is fixedly installed at the outer end of the transmission plate. The mold pad, bushing, and mold cover are sequentially assembled inside the outer mold. The feeding assembly and the ventilation assembly are both movably mounted on the slide rail. The discharge end of the feeding assembly is located inside the bushing, and the ventilation end of the ventilation assembly is located at the middle of the outer side of the outer end face of the mold cover. Two cooling assemblies are symmetrically fixedly installed on the slide rail, and the cooling assemblies are used to cool the outer mold.

[0011] Furthermore, a connecting plate is fixedly installed on the inner end of the transmission plate, and the connecting plate is fixedly installed on the output end of the motor. A cylindrical groove and an air inlet hole communicating with the cylindrical groove are opened on the outer end face of the connecting plate. Through holes are opened in the middle of the transmission plate, the mold pad and the mold cover, and the ventilation end of the ventilation component corresponds to the through hole.

[0012] Furthermore, the upper surface of the slide rail is provided with a slide track, and support plates are fixedly installed on both sides of the slide rail. An auxiliary wheel is fixedly installed on the upper surface of the support plate, and the auxiliary wheel is used to support and position the transmission plate and the outer mold.

[0013] Furthermore, the cooling assembly includes a cooling support frame, a cooling connecting plate, a cooling plate, and water pipes. The cooling support frame is fixedly installed on the support plate, and the cooling connecting plate is fixedly installed on the upper end of the cooling support frame. A cooling plate is fixedly installed on the inner side of the upper end of the cooling connecting plate. Branch pipes are evenly fixedly installed on the outer wall of the water pipes. An atomizing nozzle is fixedly installed on the outer end of the branch pipe. The atomizing nozzle is fixedly installed on the outer wall of the cooling plate, and the liquid outlet end of the atomizing nozzle penetrates the cooling plate and faces the outer mold. A solenoid valve is assembled between the atomizing nozzle and the water pipe.

[0014] Furthermore, the feeding assembly includes a feeding support frame and a feeding pipe, and the feeding support frame is movably mounted on a slide rail, and the side wall of the discharge end of the feeding pipe is provided with a side-opening sprue.

[0015] Furthermore, both the inlet and outlet ends of the feed pipe are horizontally arranged, and the middle section of the feed pipe is a downward-curved pipe. The diameter of the inlet end of the feed pipe is larger than the diameter of the outlet end, and a spiral plate is fixedly installed inside the middle section of the feed pipe.

[0016] Furthermore, the side-opening sprue is inclined, and the side of the side-opening sprue facing the feed pipe inlet is higher than the other side.

[0017] Furthermore, the ventilation assembly includes a ventilation support frame, an air pump, a support pipe, and a flow guide ring. The ventilation support frame is movably mounted on a slide rail and is located between the outer mold and the feed support frame. The air pump is fixedly installed on the upper end of the ventilation support frame, and a support pipe is fixedly installed on the air pump. The flow guide ring is fixedly installed on the upper end of the support pipe and is sleeved on the feed pipe.

[0018] Furthermore, the drainage ring is composed of an outer metal ring, a middle metal ring, and an inner metal ring connected together. The two ends of the outer metal ring are respectively connected to the middle metal ring and the inner metal ring. An annular cavity is formed between the outer metal ring and the middle metal ring, and an air outlet cavity is formed between the middle metal ring and the inner metal ring. The annular cavity and the air outlet cavity are connected, and the outlet of the air outlet cavity is far away from the outer mold.

[0019] A manufacturing process for nuclear power plant sealing tiles, using the aforementioned nuclear power plant sealing tile casting mold, specifically includes the following steps:

[0020] Step 1: Mold installation. Install the mold at the output end of the centrifuge and complete the setup of the feeding assembly, ventilation assembly, and cooling assembly.

[0021] Step 2: Preheat the mold. Use a gas or electric heating device to preheat the bushing in the mold to 180-300℃. Then, evenly spray heat-resistant coating on the inner walls of the mold pad, bushing, and mold cover.

[0022] Step 3, centrifugal casting: Start the centrifuge and inject molten metal into the mold through the feeding assembly. Through the combined action of the side-opening gate and centrifugal force, the molten metal is uniformly formed, and the ventilation assembly is started at the same time to assist in heat dissipation of the inner surface of the casting.

[0023] Step 4, centrifugal solidification: After casting is completed, the centrifuge and ventilation components continue to work, while the cooling components are activated. Through ventilation and heat dissipation inside the casting and spray cooling outside the mold, internal and external synergistic cooling is achieved, reducing the solidification time of the molten metal, inhibiting the flow of liquid phase between dendrites, and reducing segregation.

[0024] Step 5: Casting removal and post-processing. After the casting has cooled to a certain temperature below the solidus line, stop the centrifuge rotation, remove the casting, and then perform casting cleaning and non-destructive testing.

[0025] The beneficial effects of using this invention are:

[0026] 1. The design of the mold, as well as the setting of the feeding component, ventilation component, and cooling component of this invention, can ensure the uniform pouring of molten metal and achieve synchronous internal and external cooling and precise temperature control of the casting, effectively reducing the occurrence of defects such as segregation and shrinkage porosity in the casting and improving the qualification rate of the casting.

[0027] 2. This invention designs a feeding assembly. By designing the shape of the feeding pipe, the flow rate of the molten metal can be increased, allowing the speed of the molten metal to be closer to the rotation speed of the mold, thereby improving the stability of the casting process. The spiral plate set inside the feeding pipe can guide the flow direction of the molten metal, making the molten metal flow out more smoothly. At the same time, the design of the side-slit gate allows the molten metal to flow out evenly along the side-slit gate, spreading smoothly in the bushing in a curtain shape, significantly reducing turbulence and splashing.

[0028] 3. The ventilation component designed in this invention can generate uniform axial airflow, promote air circulation inside the casting, improve the cooling efficiency inside the casting, eliminate the temperature gradient of the casting, reduce the segregation phenomenon of the casting, and at the same time, the generated airflow can also assist in cooling the molten metal in the feed pipe, making it easier to adjust the pouring temperature.

[0029] 4. The present invention designs a cooling device that sprays the outer mold through atomizing nozzles on the cooling plate. At the same time, based on the temperature feedback from the temperature measuring device and the control of the solenoid valve, the spraying degree can be adjusted according to different casting stages, and local overheating can be avoided, so as to achieve more effective and stable cooling. Attached Figure Description

[0030] Figure 1 This is one of the three-dimensional schematic diagrams of the present invention.

[0031] Figure 2 This is a second three-dimensional schematic diagram of the present invention.

[0032] Figure 3 This is a front sectional view of the present invention.

[0033] Figure 4 This is a three-dimensional schematic diagram of the connecting plate of the present invention.

[0034] Figure 5 This is a three-dimensional schematic diagram of the feeding component of the present invention.

[0035] Figure 6 This is a three-dimensional schematic diagram of the ventilation component of the present invention.

[0036] Figure 7 For the present invention Figure 3 A magnified view of part a in the middle.

[0037] Figure 8 This is a three-dimensional schematic diagram of the cooling component of the present invention.

[0038] Figure 9 For the present invention Figure 8 A magnified view of part b in the middle.

[0039] The reference numerals in the attached drawings include: 1. Transmission plate, 11. Connecting plate, 12. Cylindrical groove, 13. Air inlet, 2. Outer mold, 3. Mold pad, 4. Bushing, 5. Mold cover, 6. Slide rail, 61. Support plate, 62. Auxiliary wheel, 7. Feeding assembly, 71. Feeding support frame, 72. Feeding pipe, 73. Spiral plate, 74. Side-opening sprue, 8. Ventilation assembly, 81. Ventilation support frame, 82. Air pump, 83. Support pipe, 84. Drainage ring, 841. Annular cavity, 842. Air outlet cavity, 9. Cooling assembly, 91. Cooling support frame, 92. Cooling connecting plate, 93. Cooling plate, 94. Water pipe, 95. Solenoid valve, 96. Atomizing nozzle. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] Reference Figures 1 to 9 A nuclear power plant sealing tile casting mold includes a transmission plate 1, an outer mold 2, a mold pad 3, a bushing 4, a mold cover 5, a slide rail 6, a feeding assembly 7, a ventilation assembly 8, and a cooling assembly 9. The transmission plate 1 is fixedly installed at the output end of a centrifuge, and the outer mold 2 is fixedly installed at the outer end of the transmission plate 1. The mold pad 3, the bushing 4, and the mold cover 5 are sequentially assembled inside the outer mold 2. The feeding assembly 7 and the ventilation assembly 8 are both movably mounted on the slide rail 6. The discharge end of the feeding assembly 7 is located inside the bushing 4, and the ventilation end of the ventilation assembly 8 is located at the middle of the outer side of the outer end face of the mold cover 5. Two cooling assemblies 9 are symmetrically fixedly installed on the slide rail 6, and the cooling assemblies 9 are used to cool the outer mold 2.

[0043] The mold consists of an outer mold 2, a mold pad 3, a bushing 4, and a mold cover 5. The space between the mold pad 3, the bushing 4, and the mold cover 5 is a cavity. After centrifugal casting, a ring-shaped casting is obtained.

[0044] Transmission plate 1 is used to mount the mold and its rotation is controlled by the centrifuge, such as... Figure 1 As shown, a platform is provided on the outside of the transmission plate 1, and a cover is installed on the platform. The centrifuge, coupling, bearing and other components are all located inside the cover. The cover provides protection. The output shaft of the centrifuge is connected to the transmission plate 1 and is used to drive the transmission plate 1 to rotate, thereby driving the mold to rotate.

[0045] The outer mold 2 and the transmission plate 1 are generally connected by bolts and nuts.

[0046] The slide rail 6 is installed at one end of the platform to adjust the position of the feeding assembly 7 and the ventilation assembly 8, and to install the cooling assembly 9.

[0047] The feeding assembly 7 is used to pour molten metal into the mold cavity.

[0048] The ventilation component 8 is used to guide the airflow inside the casting, improve the cooling efficiency inside the casting, eliminate the temperature gradient of the casting, reduce the segregation phenomenon of the casting, and at the same time assist in cooling the molten metal in the feeding component 7 and regulate the pouring temperature of the molten metal.

[0049] The cooling component 9 is used to spray cool the outer mold 2, thereby improving the cooling efficiency of the outer side of the casting and reducing the segregation phenomenon of the casting.

[0050] Specifically, such as Figures 2 to 4 As shown, a connecting plate 11 is fixedly installed on the inner end of the transmission plate 1. The connecting plate 11 is fixedly installed on the output end of the motor. A cylindrical groove 12 and an air inlet 13 communicating with the cylindrical groove 12 are opened on the outer end face of the connecting plate 11. Through holes are opened in the middle of the transmission plate 1, the mold pad 3 and the mold cover 5, and the ventilation end of the ventilation component 8 corresponds to the through hole.

[0051] The design of the cylindrical groove 12 and air inlet 13 on the connecting plate 11, as well as the through hole design, creates an air channel near the axis of the mold. With the help of the ventilation component 8, air circulation is achieved, which assists in cooling the inside of the casting.

[0052] An air pipe can be installed at the outer end of the air inlet 13, and a filter or purification component can be installed at the outer end of the air pipe to ensure that the air flowing into the inside of the casting is free of impurities and clean, so as to avoid affecting the quality of the casting.

[0053] Specifically, such as Figure 1 As shown, the upper surface of the slide rail 6 is provided with a slide rail, and support plates 61 are fixedly installed on both sides of the slide rail 6. Auxiliary wheels 62 are fixedly installed on the upper surface of the support plates 61, and the auxiliary wheels 62 are used to support and position the transmission plate 1 and the outer mold 2.

[0054] The auxiliary wheel 62 is used to support the mold and can rotate without affecting the rotation of the mold.

[0055] In practical applications, annular grooves can be provided at the corresponding positions of the outer mold 2 and the auxiliary wheel 62, and annular protrusions corresponding to the annular grooves can be provided on the surface of the auxiliary wheel 62 to assist in positioning.

[0056] Specifically, such as Figure 8 and Figure 9As shown, the cooling assembly 9 includes a cooling support frame 91, a cooling connecting plate 92, a cooling plate 93, and a water pipe 94. The cooling support frame 91 is fixedly installed on the support plate 61. The cooling connecting plate 92 is fixedly installed on the upper end of the cooling support frame 91. The cooling plate 93 is fixedly installed on the inner side of the upper end of the cooling connecting plate 92. Branch pipes are evenly fixedly installed on the outer wall of the water pipe 94. Atomizing nozzles 96 are fixedly installed on the outer end of the branch pipes. The atomizing nozzles 96 are fixedly installed on the outer wall of the cooling plate 93, and the liquid outlet end of the atomizing nozzles 96 penetrates the cooling plate 93 and faces the outer mold 2. A solenoid valve 95 is assembled between the atomizing nozzles 96 and the water pipes 94.

[0057] Water pipe 94 is connected to an external water tank, which can contain either water or coolant.

[0058] The cooling support frame 91 and the cooling connecting plate 92 are used to define the position of the cooling plate 93; the cooling plate 93 is an arc-shaped plate corresponding to the surface of the outer mold 2, ensuring that the liquid outlet end of each atomizing nozzle 96 is at the same distance from the surface of the outer mold 2; the position of the cooling plate 93 corresponds to the position of the bushing 4, so that its cooling work is mainly applied to the bushing 4, thereby effectively cooling the outside of the casting.

[0059] Temperature measuring devices can be installed on the support plate 61 or other locations to monitor the temperature of the outer mold 2. The temperature data is fed back to the PLC, which then controls the solenoid valve 95 to work and dynamically adjust the flow rate of the atomizing nozzle 96, thereby achieving more precise cooling. This effectively avoids local overheating and ensures that the cooling process is uniform.

[0060] In this embodiment, two sets of cooling components 9 are provided, symmetrically arranged on both sides of the outer mold 2. In other cases, the number of cooling plates 93 can be increased.

[0061] Specifically, such as Figure 5 As shown, the feeding assembly 7 includes a feeding support frame 71 and a feeding pipe 72, and the feeding support frame 71 is movably mounted on the slide rail 6. The side wall of the discharge end of the feeding pipe 72 is provided with a side-opening sprue 74.

[0062] Specifically, such as Figure 3 As shown, the inlet and outlet ends of the feed pipe 72 are both horizontally set, and the middle section of the feed pipe 72 is a downwardly bent pipe. The diameter of the inlet end of the feed pipe 72 is larger than the diameter of the outlet end. A spiral plate 73 is fixedly installed inside the middle section of the feed pipe 72.

[0063] The molten metal is poured into the feed end of the feed pipe 72, and after passing through the feed pipe 72, it flows out from the discharge end and falls into the mold cavity. The design of the diameter and curvature of the feed pipe 72 can increase the flow rate of the molten metal, so that the speed of the molten metal can be closer to the rotation speed of the mold, reduce the energy loss of driving the rotation of the molten metal, and improve the stability of the mold rotation and the casting process.

[0064] A spiral plate 73 is installed inside the feed pipe 72 to guide the flow of molten metal, so that the molten metal flows out more smoothly from the side-opening nozzle 74, avoiding the molten metal from colliding with the inner wall of the discharge end of the feed pipe 72 and changing its flow direction, thereby avoiding turbulence in the flow of molten metal and significantly reducing turbulence.

[0065] In some production processes, the spiral plate 73 may not be required.

[0066] Specifically, such as Figure 5 As shown, the side-opening sprue 74 is opened at an angle, and the side of the side-opening sprue 74 facing the feed end of the feed pipe 72 is higher than the other side.

[0067] The inclined design of the side-opening gate 74 allows the molten metal to flow out evenly along the side-opening gate 74, preventing more molten metal from flowing out from one end of the side-opening gate 74. Instead, it flows out smoothly in a curtain shape and spreads within the bushing, significantly reducing turbulence and splashing, and allowing the casting to be formed faster.

[0068] The length, width, and inclination of the side-opening sprue 74 can be adjusted according to the actual production situation.

[0069] Specifically, such as Figure 6 As shown, the ventilation assembly 8 includes a ventilation support frame 81, an air pump 82, a support pipe 83, and a flow guide ring 84. The ventilation support frame 81 is movably mounted on the slide rail 6 and is located between the outer mold 2 and the feed support frame 71. The air pump 82 is fixedly installed on the upper end of the ventilation support frame 81. The support pipe 83 is fixedly installed on the air pump 82, and the flow guide ring 84 is fixedly installed on the upper end of the support pipe 83. The flow guide ring 84 is sleeved on the feed pipe 72.

[0070] The ventilation assembly 8 is powered by the air pump 82, which provides airflow. The airflow flows through the support pipe 83 to the guide ring 84 and finally flows out. This airflow is used to guide the airflow and form air circulation inside the casting to cool the inside of the casting.

[0071] The uniform cooling achieved by the ventilation component 8 can effectively suppress the forward movement of tin elements towards the inner diameter, thus avoiding segregation.

[0072] Both the feeding support frame 71 and the ventilation support frame 81 have sliders inserted into their lower ends. The sliders are set in the slide rails to limit the position and direction of movement of the feeding component 7 and the ventilation component 8. Both the feeding support frame 71 and the ventilation support frame 81 are equipped with self-locking wheels at their lower ends to facilitate the movement of the feeding component 7 and the ventilation component 8, and to self-lock when fixation is required.

[0073] Specifically, such as Figure 7As shown, the drainage ring 84 is composed of an outer metal ring, a middle metal ring, and an inner metal ring. The two ends of the outer metal ring are connected to the middle metal ring and the inner metal ring, respectively. An annular cavity 841 is formed between the outer metal ring and the middle metal ring, and an air outlet cavity 842 is formed between the middle metal ring and the inner metal ring. The annular cavity 841 and the air outlet cavity 842 are connected. The outlet of the air outlet cavity 842 is far away from the outer mold 2.

[0074] The structure of the guide ring 84 allows the airflow in the support tube 83 to first be distributed in the annular cavity 841, then flow to the air outlet cavity 842 and out, forming a uniform axial airflow and promoting air flow.

[0075] The outlet end of the inner metal ring bends inward to allow airflow to escape smoothly.

[0076] For the casting of nuclear power plant sealing tiles, considering the uneven temperature field distribution, the tendency of tin to accumulate at grain boundaries or in the final solidification region, and the segregation phenomenon caused by centrifugal force, in addition to the above structural design, the production process also needs to be adjusted. The following mainly explains the aspects of pouring temperature and centrifugal force.

[0077] Regarding pouring temperature, segregation can be reduced by lowering the pouring temperature:

[0078] Shorten liquid residence time: Use low temperature casting technology to enable the alloy to enter the solidification stage quickly, reduce the flow time of the liquid alloy at high temperature, thereby reducing the risk of low melting point tin elements being pushed to the surface;

[0079] Inhibits interdendritic liquid flow: The dendritic network formed by rapid solidification can close the liquid channels earlier, preventing the tin-rich liquid phase from migrating to the surface.

[0080] Regarding centrifugal force, the main focus is on reducing it:

[0081] By reducing centrifugal force, radial segregation can be mitigated, and density stratification of copper and tin can be reduced, thereby making the internal and external composition distribution of the casting more uniform.

[0082] Low-speed rotation may reduce forced convection, which helps in the formation of equiaxed crystals and refines the microstructure.

[0083] While appropriately reducing the centrifuge speed, slow down the later pouring speed to increase the inner diameter compensation time.

[0084] The processing and testing are carried out according to the table below for different pouring temperatures and centrifuge speeds.

[0085]

[0086] The data in the table above are partial data from multiple experiments. According to the Cu-Sn binary phase diagram, the liquidus temperature of CuSn15 is about 950℃. Therefore, the casting temperature was started from 980℃ for the experiment.

[0087] The table provides the rotational speed of the mold, which has a transmission ratio of approximately 1:1.6 with the centrifuge. Experiments were conducted by gradually increasing the rotational speed, with the centrifuge corresponding to number 8 having a rotational speed of approximately 1100 rpm.

[0088] In addition, the mold wall thickness can be appropriately increased to improve the cooling rate, ultimately ensuring that the percentage of tin in the sealing tile is between 14% and 16%, with a uniformly distributed 15% content, thus guaranteeing the qualification rate and quality of the casting.

[0089] Example 2

[0090] A nuclear power plant sealing tile manufacturing process, employing the nuclear power plant sealing tile casting mold as shown in Example 1, specifically includes the following steps:

[0091] Step 1: Mold installation. Install the mold at the output end of the centrifuge and complete the setup of the feeding assembly 7, ventilation assembly 8, and cooling assembly 9.

[0092] Install the outer mold 2 on the transmission plate 1, and install the mold pad 3, bushing 4, and mold cover 5 in sequence inside the outer mold. Correct the concentricity and dynamic balance of the mold and the centrifuge. Then move the flow ring 84 of the ventilation component 8 to the outside of the through hole of the mold cover 5. Move the feeding component 7 so that the discharge end of the feeding pipe 72 passes through the flow ring 84 until it reaches the inside of the bushing 4. Install the cooling component 9 on the support plate 61 and set the cooling plate 93 on the outside of the outer mold 2 to complete the mold installation.

[0093] Special attention needs to be paid to checking whether the pipe connections inside the cooling component 9 are intact and leak-free.

[0094] Step 2: Preheat the mold. Use a gas or electric heating device to preheat the bushing 4 in the mold to 180-300℃. Then, spray the coating evenly on the inner walls of the mold pad 3, bushing 4, and mold cover 5.

[0095] Preheating can prevent the formation of a chilled layer or cold shut when the molten metal comes into contact with the cold mold, and can also remove moisture that may be adsorbed in the mold cavity, and allow the subsequent sprayed coating to dry and form quickly.

[0096] The coating can be a water-based silica powder coating, with the coating thickness controlled between 0.5-1.5mm. It mainly serves to lubricate and protect the material, facilitating subsequent demolding.

[0097] Step 3, centrifugal casting: Start the centrifuge and inject molten metal into the mold through the feeding component 7. Through the combined action of the side-opening gate 74 and centrifugal force, the molten metal is uniformly formed, and the ventilation component 8 is started at the same time to assist in heat dissipation of the inner surface of the casting.

[0098] Start the centrifuge and rotate it at the set speed of 1100 rpm. At the same time, pour in molten metal at a pouring temperature of about 1050℃ to make the molten metal form evenly. The side-opening gate 74 allows the molten metal to spread evenly on the inner wall of the mold in a curtain-like manner with a suitable direction and initial velocity, avoiding impact and splashing.

[0099] During the pouring process, the pouring speed is slowed down in the later stages to increase the time for inner diameter shrinkage compensation;

[0100] During the pouring process, the ventilation component 8 is activated to generate a uniform axial airflow, which promotes air flow and provides auxiliary cooling to the inside of the casting.

[0101] Step 4, centrifugal solidification: After casting is completed, the centrifuge and ventilation components 8 continue to work, while the cooling components 9 are started. Through ventilation and heat dissipation inside the casting and spray cooling outside the mold, internal and external synergistic cooling is achieved, reducing the solidification time of the molten metal, inhibiting the flow of liquid phase between dendrites, and reducing segregation.

[0102] During the operation of the cooling component 9, the temperature of the outer mold 2 is monitored by the temperature measuring device. The temperature data is fed back to the PLC, which then controls the operation of the solenoid valve 95 to dynamically adjust the flow rate of the atomizing nozzle 96 and ensure that the cooling intensity is moderate, so as to achieve more precise cooling, effectively avoid local overheating, and make the cooling work uniform.

[0103] By using coordinated internal and external cooling, the casting solidifies sequentially from the outside in, shortening the solidification time and effectively suppressing the segregation of tin.

[0104] Step 5: Casting removal and post-processing. After the casting has cooled to a certain temperature below the solidus, stop the centrifuge rotation, remove the casting, and then perform casting cleaning and non-destructive testing.

[0105] The main cleaning work for castings includes preliminary cleaning tasks such as removing sand and grinding burrs and flash.

[0106] Non-destructive testing mainly involves penetrant testing (PT) and ultrasonic testing (UT) on castings to check for internal defects such as shrinkage porosity, air holes, and slag inclusions.

[0107] The above content is only a preferred embodiment of the present invention. For those skilled in the art, many changes can be made in the specific implementation and application scope based on the concept of the present invention. As long as these changes do not depart from the concept of the present invention, they all fall within the protection scope of the present invention.

Claims

1. A casting mold for nuclear power plant sealing tiles, characterized in that: The centrifuge includes a transmission plate, an outer mold, a mold pad, a bushing, a mold cover, a slide rail, a feeding assembly, a ventilation assembly, and a cooling assembly. The transmission plate is fixedly installed at the output end of the centrifuge, and the outer mold is fixedly installed at the outer end of the transmission plate. The mold pad, bushing, and mold cover are sequentially assembled inside the outer mold. The feeding assembly and the ventilation assembly are both movably mounted on the slide rail. The discharge end of the feeding assembly is located inside the bushing, and the ventilation end of the ventilation assembly is located at the middle of the outer side of the outer end face of the mold cover. Two cooling assemblies are symmetrically fixedly installed on the slide rail, and the cooling assemblies are used to cool the outer mold. A connecting plate is fixedly installed on the inner end of the transmission plate. The connecting plate is fixedly installed on the output end of the motor. A cylindrical groove and an air inlet hole communicating with the cylindrical groove are opened on the outer end face of the connecting plate. Through holes are opened in the middle of the transmission plate, the mold pad and the mold cover, and the ventilation end of the ventilation component corresponds to the through hole. The feeding assembly includes a feeding support frame and a feeding pipe, and the feeding support frame is movably mounted on a slide rail. The side wall of the discharge end of the feeding pipe is provided with a side-opening water outlet. The ventilation assembly includes a ventilation support frame, an air pump, a support pipe, and a flow guide ring. The ventilation support frame is movably mounted on a slide rail and is located between the outer mold and the infeed support frame. The air pump is fixedly installed on the upper end of the ventilation support frame. A support pipe is fixedly installed on the air pump, and a flow guide ring is fixedly installed on the upper end of the support pipe. The flow guide ring is sleeved on the infeed pipe. The drainage ring is composed of an outer metal ring, a middle metal ring, and an inner metal ring. The two ends of the outer metal ring are connected to the middle metal ring and the inner metal ring, respectively. An annular cavity is formed between the outer metal ring and the middle metal ring, and an air outlet cavity is formed between the middle metal ring and the inner metal ring. The annular cavity and the air outlet cavity are connected, and the outlet of the air outlet cavity is far away from the outer mold.

2. The nuclear power plant sealing tile casting mold according to claim 1, characterized in that: The upper surface of the slide rail is provided with a slide rail, and support plates are fixedly installed on both sides of the slide rail. Auxiliary wheels are fixedly installed on the upper surface of the support plates, and the auxiliary wheels are used to support and position the transmission plate and the outer mold.

3. The nuclear power plant sealing tile casting mold according to claim 2, characterized in that: The cooling assembly includes a cooling support frame, a cooling connecting plate, a cooling plate, and water pipes. The cooling support frame is fixedly installed on the support plate, and the cooling connecting plate is fixedly installed on the upper end of the cooling support frame. A cooling plate is fixedly installed on the inner side of the upper end of the cooling connecting plate. Branch pipes are evenly fixedly installed on the outer wall of the water pipes. An atomizing nozzle is fixedly installed on the outer end of the branch pipe. The atomizing nozzle is fixedly installed on the outer wall of the cooling plate, and the liquid outlet end of the atomizing nozzle penetrates the cooling plate and faces the outer mold. A solenoid valve is assembled between the atomizing nozzle and the water pipe.

4. The nuclear power plant sealing tile casting mold according to claim 1, characterized in that: The feed pipe has both its feed end and discharge end set horizontally, and the middle section of the feed pipe is a downward-curved pipe. The diameter of the feed end of the feed pipe is larger than the diameter of the discharge end, and a spiral plate is fixedly installed inside the middle section of the feed pipe.

5. A nuclear power plant sealing tile casting mold according to claim 4, characterized in that: The side-opening sprue is inclined, and the side of the side-opening sprue facing the feed pipe inlet is higher than the other side.

6. A nuclear power plant sealing tile manufacturing process, employing a nuclear power plant sealing tile casting mold as described in any one of claims 1 to 5, specifically comprising the following steps: Step 1: Mold installation. Install the mold at the output end of the centrifuge and complete the setup of the feeding assembly, ventilation assembly, and cooling assembly. Step 2: Preheat the mold. Use a gas or electric heating device to preheat the bushing in the mold to 180-300℃. Then, evenly spray heat-resistant coating on the inner walls of the mold pad, bushing, and mold cover. Step 3, centrifugal casting: Start the centrifuge and inject molten metal into the mold through the feeding assembly. Through the combined action of the side-opening gate and centrifugal force, the molten metal is uniformly formed, and the ventilation assembly is started at the same time to assist in heat dissipation of the inner surface of the casting. Step 4, centrifugal solidification: After casting is completed, the centrifuge and ventilation components continue to work, while the cooling components are activated. Through ventilation and heat dissipation inside the casting and spray cooling outside the mold, internal and external synergistic cooling is achieved, reducing the solidification time of the molten metal, inhibiting the flow of liquid phase between dendrites, and reducing segregation. Step 5: Casting removal and post-processing. After the casting has cooled to a certain temperature below the solidus line, stop the centrifuge rotation, remove the casting, and then perform casting cleaning and non-destructive testing.

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