Iron mold sand-coated process production method of nuclear electromagnetic yoke casting and demolding device

Abstract

The invention relates to the technical field of magnet yoke casting machining, in particular to an iron mold sand coating process production method of a nuclear magnet yoke casting and a demolding device. The method comprises the steps of 1, mold pretreatment; 2, sand-coated molding is carried out; 3, quality regulation and control; step 4, closing the mold and pouring; and 5, demolding and detecting. The sand scraping plate with the pressure feedback function is arranged, the compactness of sand is monitored in real time, the sand is vibrated through the multi-direction vibration auxiliary structure, the density distribution uniformity of all the positions of the sand is improved, and therefore the fitting degree of all the positions of the sand and a nuclear electromagnetic yoke casting is guaranteed, and the compactness of the nuclear electromagnetic yoke casting is improved. And the surface smoothness of the formed nuclear electromagnetic yoke casting is improved, so that the forming quality of the nuclear electromagnetic yoke casting is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic yoke casting processing, and particularly relates to an iron mold sand-coating process production method and demolding device for a nuclear magnetic yoke casting. BACKGROUND

[0002] The iron mold sand-coating casting technology is widely applied to complex structure castings (such as nuclear magnetic yokes) due to its high casting size precision and good surface quality. The traditional iron mold sand-coating process usually comprises the steps of mold preheating, sand-coating molding (wrapping a pre-prepared fusible model with sand material, and after the fusible model is melted, a cavity is formed in the sand material), mold closing and pouring and post-processing. However, in actual production, the surface of the nuclear magnetic yoke is not flat (there are recesses), and therefore the surface of the pre-prepared fusible model is also not flat. After the sand material wraps the fusible model, the density of the sand material at different positions is not uniform. Once this happens, the adhesion between the sand material and the fusible model is affected, especially for the nuclear magnetic yoke castings with holes and curved surfaces. After the fusible model is melted, the loose sand material causes the cavity to be deformed, which leads to a large number of recesses and protrusions on the surface of the formed casting, thereby affecting the surface smoothness of the formed casting and affecting the quality of the formed casting. SUMMARY

[0003] In order to overcome the shortcomings pointed out in the background, the present application provides an iron mold sand-coating process production method and demolding device for a nuclear magnetic yoke casting.

[0004] The technical scheme of the present application is as follows: an iron mold sand-coating process production method for a nuclear magnetic yoke casting, which comprises the following steps: Step 1: mold pretreatment, heating the upper mold and the lower mold made of metal to 220-260 DEG C, using sandblasting material with a particle size of 120 mesh or more to clean the surface of the mold cavity, so that the surface roughness Ra is less than 3.2 microns, and immediately performing anti-oxidation protection treatment after sandblasting; Step 2: sand-coating molding, uniformly spraying a demolding agent on the preheated mold plate, sealing the mold plate and the upper and lower molds, adjusting the sand injection working pressure to 0.35-0.45 MPa, using a sand scraping plate with pressure feedback to flatten the sand material, and using a multi-directional vibration auxiliary structure to vibrate the sand material during the flattening process to adjust the sand layer density, and then heating and solidifying after the sand layer density adjustment is completed; Step 3: quality control, real-time detection of pressure and sand type compactness, feedback adjustment, optimization of coating effect, and improvement of complex contour adhesion effect; Step 4: Mold closing and pouring. Lock the upper and lower molds together, preheat to 130℃~150℃, and pour molten iron at a temperature of 1485℃~1515℃. After the molten metal cools to 480℃~500℃, open the mold and remove the nuclear electromagnetic yoke casting. Step 5: Demolding and inspection. Remove the nuclear electromagnetic yoke casting and perform sand removal, shot blasting, and dimensional accuracy inspection.

[0005] Furthermore, the mold sandblasting process uses sandblasting material with a particle size of 120 mesh or higher, and the mold cavity surface is immediately subjected to anti-oxidation protection treatment after sandblasting, so that the surface roughness Ra of the cavity is less than 3.2 μm.

[0006] Furthermore, the sand material is high-purity quartz sand with narrow particle size distribution and high sphericity, and is doped with 3% to 5% high-performance resin reinforcing agent. The sand layer thickness is controlled at 2mm to 5mm. When filling and compacting the sand mold, the working air pressure of sand shooting is adjusted to 0.35MPa to 0.45MPa. A multi-directional vibration auxiliary structure is adopted, with a vibration frequency of 50Hz to 200Hz and a duration of 10 seconds to 30 seconds. The sand layer compaction is controlled by pressure feedback closed loop to significantly improve the density of the casting.

[0007] Furthermore, 0.5% to 1.0% of an anti-porosity agent is added to the sand material, and a low-temperature slow-speed casting process is adopted to ensure that the volume fraction of porosity and shrinkage defects in the finished casting is <0.2%, thereby controlling the quality of internal flaw detection.

[0008] The present invention also provides a sand-coated demolding device for nuclear electromagnetic yoke castings, which applies the above-mentioned sand-coated molding process. The demolding device includes a support frame, on which an electrically controlled vibration plate is mounted. The support frame is characterized by having several spaced-apart rotating shafts, each rotating shaft being fixedly connected to several spaced-apart flexible rings. Each flexible ring of the rotating shaft is provided with a base frame, all base frames being fixedly connected to the electrically controlled vibration plate. Each base frame is provided with a rotating frame fixedly connected to adjacent flexible rings on adjacent rotating shafts. Each rotating frame is fixedly connected to several circumferentially distributed support columns, and a support block is fixedly connected to the center of the rotating frame. A flexible sleeve is fixedly connected to the support block.

[0009] Preferably, the width of the upper part of the support block gradually increases from top to bottom, and the width of the upper part of the flexible sleeve gradually increases from top to bottom.

[0010] Preferably, the rotating frame is provided with a curved surface for guiding the sand material, and the support column and the support block are both located on adjacent curved surfaces.

[0011] Preferably, the bracket is fixedly connected to several sets of support plates, each set of support plates having two symmetrically distributed support plates, each support plate being provided with a symmetrically distributed first electromagnetic slide rail, the first electromagnetic slide rail of the support plate being slidably connected to a first electromagnetic slider, the first electromagnetic slider being fixedly connected to an elastic telescopic rod, the two support plates in the same set being slidably connected to two symmetrically distributed connecting rods, the telescopic part of the elastic telescopic rod being fixedly connected to the adjacent connecting rod.

[0012] Preferably, the support plate is provided with symmetrically distributed guide grooves, the connecting rod is slidably connected with symmetrically distributed sliding pins, the sliding pins are fixedly connected with an elastic element between them and the adjacent connecting rods, the guide grooves are used to guide the sliding pins, and a first guide block, a second guide block and a third guide block are fixedly connected in the guide grooves, the first guide block, the second guide block and the third guide block are all used to guide the adjacent sliding pins.

[0013] Preferably, the guide groove is a right-angled trapezoidal groove, the first guide block is located at the bottom edge of the adjacent guide groove, the second guide block is located at the vertical edge of the guide groove, and the third guide block is located at the inclined edge of the guide groove.

[0014] Preferably, the support block is fixedly connected to a straight rod passing through the flexible sleeve, and the straight rod of the support block is detachably connected to a stop block.

[0015] Preferably, the bracket is provided with a number of second electromagnetic slide rails equal to the number of support plates. The second electromagnetic slide rails of the bracket are slidably connected to second electromagnetic sliders. The rotating shaft is rotatably connected to the bracket. The second electromagnetic slider is driven by a gear and rack between the second and adjacent rotating shafts. The base frame is rotatably connected to a flexible ring of the adjacent rotating shaft. The base frame is rotatably connected to the adjacent rotating frame.

[0016] Preferably, the connecting rod is rotatably connected to a plurality of rotating plates spaced apart, the sum of the number of all the rotating plates being twice the number of the rotating frame, the rotating frame being located between two adjacent rotating plates, and a torsion spring being fixed between the rotating plate and the adjacent connecting rod.

[0017] Compared with existing technologies, the present invention has at least the following beneficial effects: The present invention uses a scraper with pressure feedback to monitor the compactness of the sand in real time, and utilizes a multi-directional vibration auxiliary structure to vibrate the sand, thereby increasing the uniformity of the density distribution throughout the sand, ensuring the adhesion between the sand and the casting, improving the surface smoothness of the casting after molding, and thus improving the quality of the casting. Furthermore, the use of support columns and flexible sleeves to vibrate the casting prevents it from contacting hard materials during vibration, reducing the impact of hard materials on the casting after cooling. This reduces the probability of thermal stress being triggered within the casting, thereby decreasing the probability of cracks caused by hard impacts. While cleaning the casting, it ensures the quality of casting production. At the same time, by impacting the sides, top, and bottom of the casting, and then causing the casting to swing back and forth after impact, the sand in the depressions on the casting falls off naturally due to gravity, reducing the amount of sand residue on the casting. This also reduces the probability of micro-cracks on the surface of the casting caused by random vibration on the electrically controlled vibrating plate, thus ensuring the quality of the casting after molding. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional structural cross-sectional view of the bracket of the present invention; Figure 3 This is a three-dimensional structural diagram of the electrically controlled vibration plate of the present invention; Figure 4 This is a three-dimensional structural diagram of the support plate of the present invention; Figure 5 This is a three-dimensional structural diagram of the connecting rod of the present invention; Figure 6 This is a three-dimensional structural diagram of the curved surface of the present invention; Figure 7 This is a three-dimensional structural cross-sectional view of the support plate of the present invention; Figure 8 This is a three-dimensional structural cross-sectional view of the rotating plate of the present invention.

[0019] The markings in the attached diagram are as follows: 1-bracket, 2-electrically controlled vibration plate, 3-rotating shaft, 4-base frame, 5-rotating frame, 6-support column, 7-support block, 8-flexible sleeve, 9-curved surface, 10-support plate, 11-first electromagnetic slider, 12-elastic telescopic rod, 13-connecting rod, 14-guide groove, 15-sliding pin, 16-first guide block, 17-second guide block, 18-third guide block, 19-stop block, 20-second electromagnetic slider, 21-rotating plate. Detailed Implementation

[0020] The following description is only a preferred embodiment of the present invention and does not limit the scope of protection of the present invention. Example 1

[0021] A method for producing nuclear electromagnetic yoke castings using an iron mold with sand coating, the method comprising the following steps: Step 1: Mold pretreatment. Heat the upper and lower metal molds to 220℃~260℃. Use sandblasting material with a particle size of 120 mesh or higher to sandblast and clean the surface of the mold cavity, so that the surface roughness Ra<3.2μm. Immediately after sandblasting, perform anti-oxidation protection treatment. Step 2: Sand molding. Spray release agent evenly on the preheated mold plate, seal the mold plate and the upper and lower molds, adjust the sand shooting working air pressure to 0.35MPa~0.45MPa, use a sand scraper with pressure feedback to flatten the sand, and use a multi-directional vibration auxiliary structure to vibrate the sand during the flattening process to adjust the sand layer density. Step 3: Quality control, real-time monitoring of pressure and sand mold compaction, and optimization of coating effect through feedback adjustment to improve adhesion to complex contours; Step 4: Mold closing and pouring. Lock the upper and lower molds together, preheat to 130℃~150℃, and pour molten iron at a temperature of 1485℃~1515℃. After the molten metal cools to 480℃~500℃, open the mold and remove the nuclear electromagnetic yoke casting. Step 5: Demolding and inspection. Remove the casting and perform sand removal, shot blasting, and dimensional accuracy inspection.

[0022] This embodiment specifically employs the following process conditions for the trial production of nuclear electromagnetic yoke castings: The mold sandblasting process uses sandblasting material with a particle size of 120 mesh or larger, and immediately after sandblasting, the mold cavity surface is treated with anti-oxidation protection to ensure that the surface roughness Ra < 3.2 μm. The sand is high-purity quartz sand with a narrow particle size distribution and high sphericity, and is doped with 3% to 5% high-performance resin reinforcing agent. The sand layer thickness is controlled at 2 mm to 5 mm. During sand mold filling and compaction, a multi-directional vibration-assisted structure is used with a vibration frequency of 50 Hz to 200 Hz and a duration of 10 to 30 seconds. The sand layer compaction is controlled through a pressure feedback closed loop to significantly improve the density of the casting. 0.5% to 1.0% of an anti-porosity agent is further added to the sand, and a low-temperature slow-speed pouring process is used to ensure that the volume fraction of porosity and shrinkage defects in the finished casting is < 0.2%, thus controlling the quality of internal flaw detection.

[0023] In existing technologies, coarse sandblasting particles or inadequate post-blasting oxidation prevention in molds easily leave residues, resulting in roughness and oxidation on the cavity surface, causing surface defects or unstable surface quality in castings. This invention utilizes sandblasting with a particle size of 120 mesh or higher, coupled with timely post-blasting oxidation prevention, achieving a mold surface roughness Ra < 3.2 μm and an extremely clean and delicate cavity surface. This significantly improves the smoothness of the formed castings and reduces surface defects such as sand inclusions and oxide scale. Furthermore, the high-purity quartz sand with a narrow particle size distribution and high sphericity, doped with 3%–5% high-performance resin reinforcing agent, significantly improves filling fluidity and density, replicating fine mold contours. Simultaneously, controlling the sand thickness to 2mm–5mm, combined with multi-directional vibration (50Hz–200Hz, 10 seconds–30 seconds) and pressure feedback closed-loop control, achieves high microstructure density. Real experimental data show that the molding sand has a fluidity of 88% and the surface roughness of the finished product Ra=3.0μm, which is better than the Ra=8μm~12μm of the existing process; the molten iron temperature is controlled at 1485℃~1515℃, and the mold temperature is 130℃~150℃ before mold closing; under X-ray or metallographic inspection, the grain size is ≥8 grade, the tensile strength is >420MPa, and the impact toughness is >8J / cm². The experimental results show that the as-cast structure is fine and uniform, and the mechanical properties are significantly improved, which meets the requirements of high-end nuclear power applications.

[0024] Furthermore, in this invention, 0.5% to 1.0% anti-porosity agent is added to the sand material, and low-temperature slow casting is used. The volume fraction of porosity and shrinkage defects is <0.2%, and the flaw detection quality reaches Level II. Experimental comparison shows that defects are reduced by more than 80%, and the batch yield is significantly improved.

[0025] The product measurement data generated by this process are as follows:

[0026] The preferred embodiment of this invention is as follows: A customized high-alloy cast iron mold is heated to 200°C in an electric heating furnace and maintained at this temperature for 30 minutes. 120-mesh quartz sand is then sprayed onto the entire surface of the mold cavity at a pressure of 0.5 MPa for 8 minutes. Immediately after sandblasting, an inorganic anti-oxidation coating with a thickness of approximately 10 μm is applied to prevent re-oxidation of the cavity surface.

[0027] The covering material is high-purity quartz sand ( It contains ≥98% phenolic resin powder, with a particle size distribution of 50-60 mesh and a sphericity of ≥90%.

[0028] A scraper with digital pressure control was used for sand compaction, with real-time display and pressure maintained at 2.5±0.2 kPa. A multi-directional vibration system was activated at a frequency of 170 Hz for 16 seconds to ensure a sand layer thickness of 3 mm±0.3 mm. Local sand samples were tested after compaction, and the average density after compaction was 1.72 g / cm³.

[0029] Before closing the mold, the upper and lower molds are preheated to 145℃. HT250 grade molten iron is smelted in a medium-frequency induction furnace with the following composition (%): C 3.1±0.1, Si 1.8±0.1, Mn 0.72, S<0.08, P<0.09, and the tapping temperature is 1500℃~1515℃.

[0030] The continuous pouring is completed within 30 seconds, and the mold is opened after the molten metal cools to 480°C.

[0031] After cooling, the castings were removed and subjected to pneumatic sand removal and 30-minute tracked shot blasting. Surface roughness Ra was measured to be 2.8μm–3.1μm, significantly better than conventional sand castings (Ra 6μm–12μm). Dimensional accuracy measured by coordinate measuring machine was better than 0.4mm. Three randomly selected locations on the castings underwent Φ20mm non-destructive X-ray inspection. The microstructure was dense, with porosity and shrinkage volume fractions all <0.1%, meeting all JB / T7902–1999 Class II standards. Tensile testing of 10mm×10mm×55mm test bars showed a tensile strength of 446 MPa and an elongation after fracture of 4.1%; the impact energy of the impact specimen was 10.5 J / cm². Example 2

[0032] Existing demolding devices often employ vibration structures to assist in demolding and sand removal of castings. However, the current method of directly subjecting the castings to rigid vibration can easily excite residual thermal stress inside the castings, leading to the gradual formation of microcracks on the surface or even fracture.

[0033] Based on Example 1, a sand-coated mold release device for nuclear electromagnetic yoke castings is provided, employing a sand-coated mold production method, such as... Figures 1-6As shown, the demolding device includes a bracket 1, a control terminal (not shown in the figure) mounted on the bracket 1, an electrically controlled vibrating plate 2 electrically connected to the control terminal, and several rotating shafts 3 spaced apart on the left and right sides. In this embodiment, the rotating shafts 3 are fixedly connected to the bracket 1, and several flexible rings spaced apart front and back are fixedly connected to the rotating shafts 3. A base frame 4 is mounted on each flexible ring of the rotating shaft 3. In this embodiment, the base frame 4 is fixedly connected to the flexible rings of adjacent rotating shafts 3. All base frames 4 are fixedly connected to the electrically controlled vibrating plate 2, which drives all base frames 4 to vibrate. Each base frame 4 is equipped with a rotating frame 5 fixedly connected to adjacent flexible rings on adjacent rotating shafts 3. In this embodiment, the base frame 4 and... Adjacent rotating frames 5 are fixedly connected. Several circumferentially distributed support columns 6 are fixedly connected to the rotating frames 5. The support columns 6 are made of flexible material. A model of the casting is shown in the figure. The support columns 6 are used to support the casting. A support block 7 is fixedly connected to the middle of the rotating frame 5. The support block 7 is used to insert into the hole of the casting to support the casting. The width of the upper part of the support block 7 gradually increases from top to bottom. A flexible sleeve 8 is fixedly connected to the support block 7. The width of the upper part of the flexible sleeve 8 gradually increases from top to bottom so that the flexible sleeve 8 can be inserted into the hole of the casting. The flexible sleeve 8 supports the casting to reduce the force of the hard impact on the casting during vibration, thereby reducing the probability of the casting being damaged during vibration after cooling.

[0034] like Figure 6 As shown, the rotating frame 5 is provided with a curved surface 9, and the support column 6 and support block 7 are both located on the adjacent curved surface 9. The curved surface 9 is used to guide the sand material to reduce the probability of the shaken sand material accumulating on the rotating frame 5.

[0035] The specific working principle is as follows: When the operator needs to use this device to demold the casting, the operator places the mold (the upper mold and the lower mold together contain several castings) above all the support columns 6, then opens the two molds to expose the castings inside the molds, and inserts the support block 7 and the flexible sleeve 8 into the hole in the middle of the casting, so that the casting is supported by the support columns 6 and the flexible sleeve 8.

[0036] After the casting is placed on the support column 6 and the flexible sleeve 8, the operator turns on the electrically controlled vibrating plate 2 through the control terminal. The electrically controlled vibrating plate 2 vibrates, and the vibration of the electrically controlled vibrating plate 2 is transmitted to the support column 6 and the support block 7 through the base frame 4 and the rotating frame 5. The support block 7 transmits the vibration to the flexible sleeve 8, and the support column 6 and the flexible sleeve 8 transmit the vibration to the casting, causing the casting to vibrate, assisting in the separation of the casting from the mold, and shaking off the sand on the casting.

[0037] After the casting is separated from the mold, the operator separates and collects the upper and lower molds. The casting continues to vibrate, and while vibrating the sand on the casting, the casting does not come into contact with hard materials during the vibration process. This reduces the probability of the casting being subjected to hard impacts after molding and cooling, which could trigger internal thermal stress in the casting. This reduces the probability of the casting cracking due to hard impacts, and thus ensures the quality of casting production while cleaning the casting.

[0038] After the casting is demolded and the sand is removed, the operator turns off the electrically controlled vibrating plate 2 through the control terminal, then collects the casting and the sand on the electrically controlled vibrating plate 2. Example 3

[0039] Based on Example 2, such as Figures 3-5 As shown, the bracket 1 is fixedly connected to several sets of support plates 10 spaced apart on the left and right. Each set of support plates 10 has two support plates 10 symmetrically distributed front and back. The support plates 10 are provided with first electromagnetic slide rails symmetrically distributed on the left and right. The first electromagnetic slider is electrically connected to the control terminal. The first electromagnetic slide rail of the support plate 10 is slidably connected to the first electromagnetic slider 11. The first electromagnetic slider 11 is fixedly connected to an elastic telescopic rod 12. The first electromagnetic slider 11 is used to drive the elastic telescopic rod 12 to move left and right. Initially, the telescopic parts of the two elastic telescopic rods 12 on the same support plate 10 are both in a stretched state. When the two elastic telescopic rods 12 move to their limit in opposite directions, the telescopic parts of the elastic telescopic rods 12 contract. The two support plates 10 in the same set are slidably connected to two connecting rods 13 symmetrically distributed on the left and right. The telescopic parts of the elastic telescopic rods 12 are fixedly connected to the adjacent connecting rods 13. The telescopic parts of the elastic telescopic rods 12 are used to drive the adjacent connecting rods 13 to move left and right, so that the two adjacent connecting rods 13 move in opposite directions and back to back synchronously. In this embodiment, the casting is impacted by the connecting rods 13.

[0040] like Figure 7 and Figure 8As shown, the support plate 10 is provided with two guide grooves 14 symmetrically distributed from left to right. The connecting rod 13 is slidably connected to two sliding pins 15 symmetrically distributed from front to back. An elastic element, specifically a compression spring, is fixed between the sliding pin 15 and the adjacent connecting rod 13. The guide groove 14 is a right-angled trapezoidal groove. The first guide block 16 is located at the lower bottom edge of the adjacent guide groove 14, the second guide block 17 is located at the vertical edge of the guide groove 14, and the third guide block 18 is located at the inclined edge of the guide groove 14. The guide groove 14 is used to guide the sliding pins 15. The first guide block 16, the second guide block 17, and the third guide block 18 are fixedly connected within the guide groove 14. The thickness of the first guide block 16 gradually decreases from near the adjacent second guide block 17 to far away, and the thickness of the third guide block 18 gradually increases from near the adjacent second guide block 17 to far away. All three guide blocks (16, 17, and 18) are used to guide the adjacent sliding pins 15. Initially, the sliding pins 15 are located at the lower bottom edge of the adjacent guide groove 14. At the lower part of the adjacent guide groove 14, when the two connecting rods 13 move synchronously in opposite directions, the sliding pin 15 moves horizontally. The first guide block 16 guides the adjacent sliding pin 15, and the sliding pin 15 moves under pressure, compressing the elastic element. When the sliding pin 15 moves horizontally to its limit, the telescopic part of the elastic telescopic rod 12 retracts and resets. The telescopic part of the elastic telescopic rod 12 drives the sliding pin 15 to move upward through the adjacent connecting rod 13. The second guide block 17 presses the sliding pin 15. When the sliding pin 15 moves upward to its limit position, the elastic element rebounds, causing the sliding pin 15 to move. The second guide block 17 blocks the adjacent sliding pin 15. When the two connecting rods 13 move in opposite directions, the third guide block 18 guides the adjacent sliding pin 15. The third guide block 18 squeezes the adjacent sliding pin 15, compressing the elastic element until the connecting rod 13 drives the adjacent sliding pin 15 to move and reset. The third guide block 18 no longer squeezes the adjacent sliding pin 15, the elastic element resets, and the sliding pin 15 moves and resets.

[0041] like Figure 5 and Figure 6 As shown, a straight rod passing through the flexible sleeve 8 is fixedly connected to the support block 7, and a stop block 19 is detachably connected to the straight rod of the support block 7.

[0042] The specific working principle is as follows: During the sand removal process of the casting, the operator activates the first electromagnetic slide rail through the control terminal, so that the two first electromagnetic sliders 11 on the same support plate 10 move towards each other. The first electromagnetic sliders 11 drive the elastic telescopic rod 12 to move, and the telescopic part of the elastic telescopic rod 12 drives the connecting rod 13 to move, so that the two adjacent connecting rods 13 move towards each other. During the vibration of the casting, the two adjacent connecting rods 13 move towards each other and jointly impact the casting to assist in the sand removal of the casting.

[0043] During the movement of the two adjacent connecting rods 13 in opposite directions, the connecting rods 13 drive the sliding pin 15 to move horizontally. The first guide block 16 guides the sliding pin 15 and squeezes the sliding pin 15, compressing the elastic element. When the sliding pin 15 moves horizontally to its limit, the telescopic part of the elastic telescopic rod 12 contracts. The telescopic part of the elastic telescopic rod 12 drives the sliding pin 15 to move upward through the connecting rod 13. The operator temporarily closes the first electromagnetic slide rail through the control terminal. The second guide block 17 presses the sliding pin 15. When the sliding pin 15 moves upward to its limit position, the elastic element rebounds, causing the sliding pin 15 to move. During the upward movement of the connecting rod 13, the two adjacent connecting rods 13 jointly drive the casting to move upward. When the connecting rod 13 moves upward to its limit, the casting impacts the stop block 19. The casting is subjected to a counter-impact force, causing the sand material at the bottom and on top of the casting to be shaken off.

[0044] After the connecting rod 13 moves upward to its limit position, the operator restarts the first electromagnetic slide rail through the control terminal. The first electromagnetic slider 11 moves back to its original position and drives the elastic telescopic rod 12 to move in the opposite direction. The telescopic part of the elastic telescopic rod 12 drives the connecting rod 13 to move in the opposite direction. The two adjacent connecting rods 13 move in opposite directions. When the two adjacent connecting rods 13 move in opposite directions, the connecting rod 13 drives the sliding pin 15 to move. The third guide block 18 guides the sliding pin 15. The third guide block 18 squeezes the sliding pin 15, and the elastic element is compressed. When the connecting rod 13 moves in the opposite direction until it loses contact with the casting, the casting falls downward under its own weight and hits the support column 6 and the flexible sleeve 8, so that the casting is subjected to a counter-impact force. The vibration and inertial force generated by the casting hitting the casting shake off the sand on the casting.

[0045] When the connecting rod 13 drives the sliding pin 15 to move and reset, the third guide block 18 no longer presses the sliding pin 15, the elastic element resets, and the sliding pin 15 moves and resets. The above steps are repeated continuously to impact the side, top and bottom of the casting, causing the sand on the casting to fall off. This reduces the amount of sand residue on the casting and lowers the probability of micro-cracks on the surface of the casting caused by direct vibration and sand removal on the electrically controlled vibration plate 2, thereby ensuring the quality of the casting after molding.

[0046] After the casting is demolded and the sand is removed, the operator turns off the electrically controlled vibrating plate 2 and the first electromagnetic slide rail through the control terminal, and then collects the casting and the sand on the electrically controlled vibrating plate 2. Example 4

[0047] Based on Example 3, such as Figure 2 and Figure 5As shown, the bracket 1 is provided with the same number of second electromagnetic slide rails as the support plate 10. The second electromagnetic slide rails are electrically connected to the control terminal. The second electromagnetic slide rails of the bracket 1 are slidably connected to the second electromagnetic sliders 20. In the above embodiment, the rotating shaft 3 is fixedly connected to the bracket 1. In this embodiment, the rotating shaft 3 is rotatably connected to the bracket 1. The second electromagnetic sliders 20 are connected to the adjacent rotating shaft 3 through a gear and rack transmission, wherein the gear is fixedly connected to the rotating shaft 3 and the rack is fixedly connected to the second electromagnetic sliders 20. In the above embodiment, the base frame 4 is fixedly connected to the flexible ring of the adjacent rotating shaft 3 and the base frame 4 is fixedly connected to the adjacent rotating frame 5. In this embodiment, the base frame 4 is rotatably connected to the flexible ring of the adjacent rotating shaft 3 and the base frame 4 is rotatably connected to the adjacent rotating frame 5. The second electromagnetic sliders 20 slide back and forth. The second electromagnetic sliders 20 drive the rotating shaft 3 through the gear and rack transmission, so that the rotating shaft 3 drives all the flexible rings on it to rotate back and forth, and the flexible rings drive the adjacent rotating frame 5 to rotate back and forth.

[0048] like Figure 4 and Figure 8As shown, the connecting rod 13 is rotatably connected to several spaced rotating plates 21. The total number of rotating plates 21 is twice the number of rotating frames 5. The rotating frames 5 are located between two adjacent rotating plates 21. In the above embodiment, the casting is impacted by the connecting rod 13. In this embodiment, it is not necessary to impact the casting by the connecting rod 13, but by the rotating plates 21. A torsion spring is fixed between the rotating plate 21 and the adjacent connecting rod 13. When the sliding pin 15 travels one revolution along the adjacent guide groove 14, the casting is impacted and the sand on it is loosened. At this time, the second electromagnetic slide rail of the bracket 1 is opened by the control terminal. The second electromagnetic slider 20 drives the rotating shaft 3 through the gear and rack, so that the rotating shaft 3 drives all the flexible rings on it to rotate. The flexible rings drive the adjacent rotating frames 5 to rotate. When the rotating frame 5 rotates, the rotating frame 5 drives the casting to rotate through the support block 7 and the flexible sleeve 8. The sand in the depression on the casting falls off naturally due to gravity, reducing the amount of sand adhering to the casting. When the casting After rotation, the distance between the casting and the corresponding rotating plate 21 decreases. Taking the upper part of the casting flipping to the left as an example, the distance between the casting and the adjacent rotating plate 21 on the left decreases. The left rotating plate 21 squeezes the casting, the rotating plate 21 rotates, the torsion spring twists and stores force, and then the above steps are repeated, so that the two adjacent connecting rods 13 move in opposite directions and the two adjacent rotating plates 21 move in opposite directions. At the same time, the operator controls the second electromagnetic slider 20 to reset through the control terminal. The second electromagnetic slider 20 drives the rotating shaft 3 through the gear and rack, so that the rotating shaft 3 drives all the flexible rings on it to reverse and reset. The flexible rings drive the adjacent rotating frame 5 to reverse and reset. The two adjacent rotating plates 21 move in opposite directions to clamp the casting. The torsion springs of the two adjacent rotating plates 21 twist. After the rotating frame 5 reverses and resets, the casting is no longer tilted. As the sliding pin 15 moves along the adjacent guide groove 14, the above steps are repeated to impact the casting. When the two adjacent connecting rods 13 move in opposite directions, the two adjacent rotating plates 21 move in opposite directions. The torsion spring resets and makes the rotating plate 21 reverse and reset.

[0049] The technical principles of the embodiments of the present invention have been described above with reference to specific examples. These descriptions are merely for explaining the principles of the embodiments of the present invention and should not be construed as limiting the scope of protection of the embodiments of the present invention in any way. Based on the explanation herein, those skilled in the art can conceive of other specific embodiments of the present invention without creative effort, and these embodiments will all fall within the scope of protection of the embodiments of the present invention.

Claims

1. A method for producing nuclear electromagnetic yoke castings using an iron mold sand coating process, characterized in that, The production process includes the following steps: Step 1: Mold pretreatment. Heat the upper and lower metal molds to 220-260℃. Use sandblasting material with a particle size of 120 mesh or higher to sandblast and clean the surface of the mold cavity, so that the surface roughness Ra < 3.2μm. Immediately after sandblasting, perform anti-oxidation protection treatment. Step 2: Sand molding. Spray release agent evenly on the preheated mold plate, seal the mold plate and the upper and lower molds, adjust the sand shooting working air pressure to 0.35MPa~0.45MPa, use a sand scraper with pressure feedback to flatten the sand, and use a multi-directional vibration auxiliary structure to vibrate the sand during the flattening process to adjust the sand layer density. After the sand layer density is adjusted, heat to cure. Step 3: Quality control, real-time monitoring of pressure and sand mold compaction, and optimization of coating effect through feedback adjustment to improve adhesion to complex contours; Step 4: Mold closing and pouring. Lock the upper and lower molds together, preheat to 130℃~150℃, and pour molten iron at a temperature of 1485℃~1515℃. After the molten metal cools to 480℃~500℃, open the mold and remove the nuclear electromagnetic yoke casting. Step 5: Demolding and inspection. Remove the nuclear electromagnetic yoke casting and perform sand removal, shot blasting, and dimensional accuracy inspection.

2. The method for producing nuclear electromagnetic yoke castings using iron mold sand coating process according to claim 1, characterized in that: In step 2, when sand is applied for molding, the entire process adopts a pressure feedback + multi-directional vibration closed-loop automatic control process. The vibration frequency is 50Hz to 200Hz and the duration is 10 seconds to 30 seconds. The pressure feedback closed-loop control compacts the sand layer to ensure that the sand density is consistent in complex curved surfaces, deep holes and other local areas.

3. The method for producing nuclear electromagnetic yoke castings using a sand-coating process with iron molds according to any one of claims 1 to 2, characterized in that: The sand covering and molding step 2 uses high-purity quartz sand with narrow particle size distribution and high sphericity. ≥98%), and doped with 3% to 5% high-performance resin reinforcing agent and 0.5% to 1.0% anti-porosity agent.

4. The method for producing nuclear electromagnetic yoke castings using a sand-coating process with iron molds according to any one of claims 1 to 3, characterized in that: Step 5 uses support columns and flexible sleeves to suspend the casting, and uses electrically controlled vibration and mechanical impact to make the sand material in the nuclear electromagnetic yoke casting and its recessed parts fall off naturally, which greatly improves the sand removal efficiency and the surface quality of the finished product. After pneumatic sand removal and shot blasting (30 min), the three-coordinate measuring machine and X-ray flaw detection are performed to ensure that the surface roughness Ra of the nuclear electromagnetic yoke casting is <3.2 μm and the defect volume fraction is <0.2%.

5. A sand-coated demolding device for nuclear electromagnetic yoke castings, employing the sand-coated molding process described in any one of claims 1 to 4, wherein the demolding device comprises a support (1), and the support (1) is equipped with an electrically controlled vibration plate (2), characterized in that, The support (1) is provided with a plurality of rotating shafts (3) spaced apart. The rotating shafts (3) are fixedly connected to a plurality of flexible rings spaced apart. The flexible rings of the rotating shafts (3) are provided with a base frame (4). All the base frames (4) are fixedly connected to the electrically controlled vibration plate (2). The base frame (4) is provided with a rotating frame (5) fixedly connected to the adjacent flexible rings on the adjacent rotating shafts (3). The rotating frame (5) is fixedly connected to a plurality of circumferentially distributed support columns (6). The middle part of the rotating frame (5) is fixedly connected to a support block (7). The support block (7) is fixedly connected to a flexible sleeve (8).

6. The iron mold sand-coating demolding device for nuclear electromagnetic yoke casting according to claim 5, characterized in that, The width of the upper part of the support block (7) gradually increases from top to bottom, and the width of the upper part of the flexible sleeve (8) gradually increases from top to bottom.

7. The iron mold sand-coating demolding device for nuclear electromagnetic yoke casting according to claim 6, characterized in that, The rotating frame (5) is provided with a curved surface (9) for guiding the sand material. The support column (6) and the support block (7) are both located on the adjacent curved surface (9).

8. The iron mold sand-coating demolding device for nuclear electromagnetic yoke casting according to claim 5, characterized in that, The bracket (1) is fixedly connected to several sets of support plates (10). Each set of support plates (10) has two support plates (10) symmetrically distributed. The support plates (10) are provided with symmetrically distributed first electromagnetic slide rails. The first electromagnetic slide rails of the support plates (10) are slidably connected to a first electromagnetic slider (11). The first electromagnetic slider (11) is fixedly connected to an elastic telescopic rod (12). The two support plates (10) in the same set are slidably connected to two symmetrically distributed connecting rods (13). The telescopic part of the elastic telescopic rod (12) is fixedly connected to the adjacent connecting rod (13).

9. A sand-coated demolding device for an iron mold of a nuclear electromagnetic yoke casting according to claim 8, characterized in that, The support plate (10) is provided with symmetrically distributed guide grooves (14), and the connecting rod (13) is slidably connected with symmetrically distributed sliding pins (15). The sliding pins (15) are fixedly connected to the adjacent connecting rods (13) with elastic elements. The guide grooves (14) are used to guide the sliding pins (15). The guide grooves (14) are fixedly connected with a first guide block (16), a second guide block (17) and a third guide block (18). The first guide block (16), the second guide block (17) and the third guide block (18) are all used to guide the adjacent sliding pins (15).

10. A sand-coated demolding device for an iron mold of a nuclear electromagnetic yoke casting according to claim 9, characterized in that, The guide groove (14) is a right-angled trapezoidal groove. The first guide block (16) is located at the bottom edge of the adjacent guide groove (14), the second guide block (17) is located at the vertical edge of the guide groove (14), and the third guide block (18) is located at the inclined edge of the guide groove (14).

11. The iron mold sand-coating demolding device for nuclear electromagnetic yoke casting according to claim 5, characterized in that, The support block (7) is fixedly connected to a straight rod that passes through the flexible sleeve (8), and the straight rod of the support block (7) is detachably connected to a stop block (19).

12. A sand-coated demolding device for an iron mold of a nuclear electromagnetic yoke casting according to claim 8, characterized in that, The bracket (1) is provided with a number of second electromagnetic slide rails that are the same as the number of support plates (10). The second electromagnetic slide rails of the bracket (1) are slidably connected to a second electromagnetic slider (20). The rotating shaft (3) is rotatably connected to the bracket (1). The second electromagnetic slider (20) is connected to the adjacent rotating shaft (3) by a gear and rack transmission. The base frame (4) is rotatably connected to the flexible ring of the adjacent rotating shaft (3). The base frame (4) is rotatably connected to the adjacent rotating frame (5).

13. The iron mold sand-coating demolding device for nuclear electromagnetic yoke casting according to claim 8, characterized in that, The connecting rod (13) is rotatably connected to a plurality of rotating plates (21) spaced apart. The sum of the number of all the rotating plates (21) is twice the number of the rotating frame (5). The rotating frame (5) is located between two adjacent rotating plates (21). A torsion spring is fixed between the rotating plate (21) and the adjacent connecting rod (13).

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