Gear ring casting process

Abstract

The invention relates to the technical field of gear ring casting, in particular to a gear ring casting process which comprises the following steps: S1, preparing a sand mold; s2, die casting; s3, overturning is carried out; s4, auxiliary agent spraying is conducted, specifically, a composite ceramic precursor auxiliary agent is sprayed to the surface of the turned casting, the spraying thickness is controlled to be 0.1 mm-0. 3 mm, the spraying pressure is 0.2 MPa-0. 5 MPa, so that the surface quality of the casting is improved, and oxidation is reduced; s5, combustion of the surface auxiliary agent: the surface of the casting sprayed with the composite ceramic precursor auxiliary agent is subjected to combustion treatment, the combustion temperature is controlled at 500-800 DEG C, the combustion time is 10-50 s, so that the composite ceramic precursor auxiliary agent forms a layer of uniform oxidation film on the surface of the casting, and the wear resistance and corrosion resistance of the casting are improved; s6, cooling and cleaning; and S7, defect inspection and post-treatment. The technical problem that an existing gear ring is prone to abrasion and corrosion to cause performance reduction is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of gear ring casting, and in particular to a gear ring casting process. Background Art

[0002] Currently, ring gears, as key components in mechanical transmissions, are widely used in automotive, engineering machinery, aerospace, and other fields. Their casting quality significantly impacts the performance and reliability of mechanical transmission systems. The casting process can be referenced in a casting process disclosed in Chinese Patent Publication No. CN116237492A. This process includes the following steps: Step 1: Melt the raw materials into a molten state; Step 2: pouring the melted raw materials into a mold consisting of a base plate, an outer frame and an inner frame for casting; Step 3: driving the pressing block I and the pressing block II to move up and down to punch the raw material formed in the mold; Step 4: Demolding the molded parts and collecting them for storage.

[0003] However, existing ring gear casting processes have numerous shortcomings. For example, poor surface treatment often results in castings with insufficient wear and corrosion resistance to meet the requirements of high-end machinery. Without effective surface treatment, castings are susceptible to wear and corrosion during use, leading to performance degradation and shortened service life. Furthermore, achieving effective spray coating to address the problem of coating peeling is crucial. Summary of the Invention

[0004] Therefore, in response to the above problems, the present invention proposes a gear ring casting process, which solves the technical problem that the existing gear ring is easy to wear and corrode, resulting in performance degradation.

[0005] To achieve the above object, the present invention adopts the following technical solution: a gear ring casting process, comprising the following steps: S1. Sand mold preparation: According to the gear ring design drawings, the sand mold is quickly manufactured using 3D printing technology. The sand mold shrinkage rate is controlled within 1% to 3%, and the processing allowance is controlled within 5mm to 10mm; S2. Die casting: The molten metal raw material is injected into the sand mold, and pressure is applied by the die casting equipment to fully fill the sand mold cavity with the metal raw material. The die casting pressure is controlled at 50MPa-150MPa, and the die casting speed is controlled at 20mm / s-100mm / s; S3. Flipping: After die casting is completed, the sand mold is flipped at an angle of 180° so that the casting can further evenly fill the cavity under the action of gravity and reduce internal defects. The flipping time is controlled within 5s-15s after the die casting is completed. S4. Spraying auxiliary agent: spray the composite ceramic precursor auxiliary agent on the surface of the turned casting with a spraying thickness of 0.1mm to 0.3mm and a spraying pressure of 0.2MPa to 0.5MPa to improve the surface quality of the casting and reduce oxidation; S5. Burning surface auxiliary agent: The surface of the casting sprayed with the composite ceramic precursor auxiliary agent is burned. The combustion temperature is controlled at 500℃-800℃ and the combustion time is 10s-50s, so that the composite ceramic precursor auxiliary agent forms a uniform oxide film on the surface of the casting, thereby improving the wear resistance and corrosion resistance of the casting; S6. Cooling and cleaning: After the molten metal solidifies, remove the casting from the sand mold. Control the flow and temperature of the cooling air to ensure that the casting is evenly heated throughout the cooling process. The cooling air flow is controlled at 100m³ / h to 500m³ / h and the temperature is controlled at 20℃ to 50℃ to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Clean the sand, paint, oxide, and oil impurities on the casting surface through mechanical or chemical cleaning. S7. Defect inspection and post-processing: Carefully inspect the surface and interior of the casting for cracks, pores, and shrinkage defects. Perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties. The annealing heat treatment temperature is controlled at 850℃~900℃, and the holding time is 6h~12h. After mechanical processing to achieve the required size and accuracy, paint it to obtain the gear ring casting.

[0006] Furthermore, in step S4, the composite ceramic precursor auxiliary agent comprises, by mass percentage, 30% to 40% of silica sol, 20% to 30% of alumina powder, 15% to 25% of silicone resin, and 10% to 15% of a diluent.

[0007] Furthermore, the preparation process of the composite ceramic precursor auxiliary agent is as follows: Add silica sol, alumina powder and silicone resin into a stirring container in proportion, and mix them thoroughly with a high-speed stirrer at a stirring speed of 500 r / min to 1500 r / min for 10 min to 30 min. During the mixing process, gradually add diluent to adjust the viscosity of the auxiliary agent to a range suitable for spraying, and control the viscosity within 50mPa·s to 200mPa·s; After mixing is completed, the auxiliary agent is filtered using a 100-300 mesh screen to remove impurities and particles to ensure spraying quality.

[0008] Furthermore, in step S1, the sand mold material is selected from high-strength resin sand, whose compressive strength is not less than 5 MPa, to ensure that the sand mold is not deformed or damaged during the die-casting process.

[0009] Furthermore, in step S2, the molten metal raw material is alloy structural steel 42CrMo or carburizing steel 20CrMnTi. The metal raw material needs to be preheated before being injected into the sand mold. The preheating temperature is controlled at 200°C to 300°C to reduce the temperature difference between the molten metal and the sand mold and reduce the impact of thermal stress on the casting.

[0010] Furthermore, in step S3, the flipping device has automatic positioning and locking functions, and the flipping speed is controlled at 5° / s to 20° / s to ensure the stability of the sand mold and casting during the flipping process and avoid deformation or damage of the casting due to improper flipping.

[0011] Furthermore, in step S5, the combustion treatment uses natural gas or liquefied gas as fuel, and the surface of the casting is heated by a burner. The burner is equipped with a temperature control system that can accurately control the combustion temperature to ensure that the auxiliary agent is fully burned to form a uniform oxide film.

[0012] Furthermore, in step S6, a high-pressure water gun is used during the cleaning process, with the pressure controlled at 10 MPa to 30 MPa to remove impurities on the surface of the casting.

[0013] Furthermore, in step S7, the defect inspection adopts a non-destructive testing method, including ultrasonic testing, magnetic particle testing, or radiographic testing, to accurately detect defects inside and on the surface of the casting.

[0014] Furthermore, the method further includes step S8, a static stop process, comprising: S81, static stage: move the cast gear ring to the gear ring casting in the curing room and let it stand for 2h-4h; S82, heating stage: after the static period, the temperature in the curing room is raised, and the heating rate is strictly controlled to not exceed 60℃ / h, and the heating is stopped when the temperature reaches 60℃ to 120℃; S83, constant temperature stage: maintain at a temperature of 60°C to 120°C for 4h-8h; S84, cooling stage: After the constant temperature stage, start cooling slowly, with the cooling rate not exceeding 30℃ / h until it reaches room temperature.

[0015] By adopting the above technical solution, the beneficial effects of the present invention are: 1. This ring gear casting process integrates multiple key steps to form a systematic and efficient solution. The sand mold preparation and die-casting steps ensure precise shaping of the casting; the flipping step reduces internal defects; and the spraying and combustion steps significantly improve the casting's surface quality, enhancing wear and corrosion resistance. Furthermore, a composite ceramic precursor additive can be sprayed after the sand mold preparation step to effectively isolate the molten metal from direct contact with the mold cavity surface, reducing casting defects such as sand sticking and slag inclusions, and significantly enhancing the casting's surface finish and aesthetics. Furthermore, the composite ceramic precursor additive forms a uniform, dense oxide film after combustion. This oxide film not only possesses extremely high hardness and wear resistance, effectively resisting scratches and abrasion from external objects, but also exhibits excellent corrosion resistance, resisting attack from acids, alkalis, and other chemicals, significantly extending the service life of the ring gear casting. Furthermore, the combustion process eliminates surface defects such as microcracks and pores, further improving the overall quality of the casting.

[0016] 2. The components of this composite ceramic precursor auxiliary agent work together to achieve outstanding performance. Silica sol, as the main film-forming substance, provides good adhesion and film-forming properties, making the coating more uniform and dense. The addition of alumina micropowder significantly enhances the hardness and wear resistance of the coating, improving the wear resistance of the casting surface. The silicone resin further improves the flexibility and corrosion resistance of the coating, allowing the casting to adapt to various complex working environments. The addition of a diluent adjusts the viscosity of the auxiliary agent, making it easier to spray and evenly cover the casting surface. Overall, this composite ceramic precursor auxiliary agent not only improves the surface quality of the ring gear casting, but also significantly enhances its wear resistance and corrosion resistance, providing a strong guarantee for the long-term and stable operation of the ring gear.

[0017] 3. High-speed stirring ensures thorough mixing of all components, improving the uniformity and stability of the additive. Gradually adding diluent allows precise control of the additive's viscosity, ensuring it reaches the appropriate spraying range. Filtration removes impurities and particles from the additive, ensuring spray quality. These steps collectively guarantee the performance of the additive and the spraying effect, thereby improving the surface quality and wear resistance of the casting.

[0018] 4. High-strength resin sand has excellent compressive strength and heat resistance, effectively preventing deformation and damage to sand molds during the die-casting process. This ensures precise molding of castings, improving production efficiency and yield rate. Furthermore, the use of high-strength resin sand reduces the frequency of sand mold replacement and lowers production costs.

[0019] 5. Alloy structural steel 42CrMo or carburizing steel 20CrMnTi is selected as the raw metal. These two materials have excellent mechanical properties and wear resistance, and can meet the requirements of the ring gear. Preheat treatment reduces the temperature difference between the molten metal and the sand mold, reducing the impact of thermal stress on the casting, thereby reducing defects such as cracks and deformation during the cooling process, and improving the quality and reliability of the casting.

[0020] 6. Automatic positioning and locking functions improve the accuracy and safety of flipping, making the flipping operation more reliable and efficient.

[0021] 7. The temperature control system equipped with the burner can accurately control the combustion temperature to ensure that the auxiliary agent is fully burned to form a uniform oxide film.

[0022] 8. Non-destructive testing methods can accurately detect internal and surface defects such as cracks, pores and shrinkage holes without destroying the casting. This helps to promptly detect and deal with quality problems of castings, thereby improving the quality and reliability of castings.

[0023] 9. By controlling the casting's resting, heating, constant temperature, and cooling processes under specific temperature conditions, residual stress and deformation within the casting can be significantly reduced, further stabilizing its performance. The resting stage allows the casting to gradually cool under natural conditions, eliminating internal thermal stresses. The heating stage precisely controls the heating rate and temperature to gradually homogenize the casting's internal structure. The constant temperature stage maintains the casting at a specific temperature for a period of time, promoting further stabilization of the internal structure and improving performance. The cooling stage involves slow cooling to avoid defects such as cracks caused by rapid temperature changes. Overall, the resting treatment steps significantly improve the overall quality and reliability of the ring gear casting, providing a strong guarantee for its long-term stable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a process flow diagram of the present invention.

[0025] Figure 2 It is a process flow diagram of the static stop stage.

[0026] Figure 3 It is a schematic diagram of the overall structure of the vibrating sand shaker.

[0027] Figure 4 It is the side view of the overall structure of the vibrating sand shaker.

[0028] Figure 5 This is a cross-sectional view of the sand bucket of the vibrating sand shaker.

[0029] Figure 6 for Figure 5 Enlarged view of part A in .

[0030] Figure 7 This is the rear view of the overall structure of the vibrating sand shaker.

[0031] The accompanying drawings are: 1. Base; 2. Top plate; 3. Air spring shock absorber; 4. Vibration motor; 5. Mounting port; 6. Sand dropout hopper; 7. Grille plate; 8. Screening plate; 9. Groove; 10. Air pipe; 11. Nozzle; 12. Slide; 13. Air pump; 14. Telescopic hose; 15. First filter; 16. Second filter; 17. Limiting groove; 18. Limiting block; 19. Fixing hole. DETAILED DESCRIPTION

[0032] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0033] refer to Figure 1 and Figure 2 , this embodiment provides a gear ring casting process, comprising the following steps: S1. Sand mold preparation: According to the gear ring design drawings, the sand mold is quickly manufactured using 3D printing technology. The sand mold shrinkage rate is controlled within 1% to 3%, and the processing allowance is controlled within 5mm to 10mm; S2. Die casting: The molten metal raw material is injected into the sand mold, and pressure is applied by the die casting equipment to fully fill the sand mold cavity with the metal raw material. The die casting pressure is controlled at 50MPa-150MPa, and the die casting speed is controlled at 20mm / s-100mm / s; S3. Flipping: After die casting is completed, the sand mold is flipped at an angle of 180° so that the casting can further evenly fill the cavity under the action of gravity and reduce internal defects. The flipping time is controlled within 5s-15s after the die casting is completed. S4. Spraying auxiliary agent: spray the composite ceramic precursor auxiliary agent on the surface of the turned casting with a spraying thickness of 0.1mm to 0.3mm and a spraying pressure of 0.2MPa to 0.5MPa to improve the surface quality of the casting and reduce oxidation; S5. Burning surface auxiliary agent: The surface of the casting sprayed with the composite ceramic precursor auxiliary agent is burned. The combustion temperature is controlled at 500℃-800℃ and the combustion time is 10s-50s, so that the composite ceramic precursor auxiliary agent forms a uniform oxide film on the surface of the casting, thereby improving the wear resistance and corrosion resistance of the casting; S6. Cooling and cleaning: After the molten metal solidifies, remove the casting from the sand mold. Control the flow and temperature of the cooling air to ensure that the casting is evenly heated throughout the cooling process. The cooling air flow is controlled at 100m³ / h to 500m³ / h and the temperature is controlled at 20℃ to 50℃ to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Clean the sand, paint, oxide, and oil impurities on the casting surface through mechanical or chemical cleaning. S7. Defect inspection and post-processing: Carefully inspect the surface and interior of the casting for cracks, pores, and shrinkage defects. Perform annealing heat treatment on the casting to eliminate internal stress and improve microstructure and performance. The annealing heat treatment temperature is controlled at 850°C to 900°C and the holding time is 6h to 12h. The casting is machined to the required size and accuracy and then painted to obtain the ring gear casting. S8, static stop processing, including: S81, static stage: move the cast gear ring to the gear ring casting in the curing room and let it stand for 2h-4h; S82, heating stage: after the static period, the temperature in the curing room is raised, and the heating rate is strictly controlled to not exceed 60℃ / h, and the heating is stopped when the temperature reaches 60℃ to 120℃; S83, constant temperature stage: maintain at a temperature of 60°C to 120°C for 4h-8h; S84, cooling stage: After the constant temperature stage, start cooling slowly, with the cooling rate not exceeding 30℃ / h until it reaches room temperature.

[0034] In step S2, the molten metal raw material is alloy structural steel 42CrMo or carburizing steel 20CrMnTi. The metal raw material needs to be preheated before being injected into the sand mold. The preheating temperature is controlled at 200°C to 300°C to reduce the temperature difference between the molten metal and the sand mold and reduce the impact of thermal stress on the casting.

[0035] In step S3, the flipping device is a conventional device. It only needs to have automatic positioning and locking functions, and the flipping speed is controlled within 5° / s to 20° / s to ensure the stability of the sand mold and casting during the flipping process and avoid deformation or damage to the casting due to improper flipping.

[0036] In step S5, the combustion process uses natural gas or liquefied gas as fuel, and the surface of the casting is heated by a burner. The burner is equipped with a temperature control system, which can accurately control the combustion temperature to ensure that the auxiliary agent is fully burned to form a uniform oxide film.

[0037] In step S6, a high-pressure water gun is used during the cleaning process, with the pressure controlled at 10 MPa to 30 MPa to remove impurities on the surface of the casting.

[0038] In step S7, defect inspection uses non-destructive testing methods, including ultrasonic testing, magnetic particle testing, or radiographic testing, to accurately detect defects inside and on the surface of the casting.

[0039] The sand mold shrinkage is controlled at 1.5%, and the machining allowance is controlled at 7mm. This shrinkage range effectively compensates for metal shrinkage during cooling, while the machining allowance ensures ease of subsequent machining. The above numerical range can be selected based on actual conditions and needs. For example, the die-casting pressure is controlled at 100MPa and the die-casting speed is controlled at 60mm / s. The metal raw material is preheated at a temperature of 250°C. The turning time is controlled within 10 seconds after die-casting. The spraying thickness is controlled at 0.2mm and the spraying pressure is 0.3MPa. The surface of the casting sprayed with the auxiliary agent is burned at a temperature of 650°C for 30 seconds. The cooling air flow rate is controlled at 300m³ / h and the temperature is controlled at 30°C. The annealing heat treatment temperature is controlled at 880°C and the holding time is 9 hours to eliminate internal stress and improve microstructure and properties.

[0040] In step S4, the composite ceramic precursor auxiliary agent comprises, by mass percentage, 30% to 40% silica sol, 20% to 30% alumina powder, 15% to 25% silicone resin, and 10% to 15% diluent. Preferably, the composite ceramic precursor auxiliary agent comprises, by mass percentage, 35% silica sol, 25% alumina powder, 20% silicone resin, and 20% diluent.

[0041] The preparation process of the composite ceramic precursor auxiliary agent is as follows: Add silica sol, alumina powder and silicone resin into a stirring container in proportion, and mix them thoroughly with a high-speed stirrer at a stirring speed of 500 r / min to 1500 r / min for 10 min to 30 min. During the mixing process, gradually add diluent to adjust the viscosity of the auxiliary agent to a range suitable for spraying, and control the viscosity within 50mPa·s to 200mPa·s; After mixing is completed, the auxiliary agent is filtered using a 100-300 mesh screen to remove impurities and particles to ensure spraying quality.

[0042] In step S1, the sand mold material is high-strength resin sand with a compressive strength of not less than 5 MPa to ensure that the sand mold is not deformed or damaged during the die-casting process.

[0043] Preferably, the stirring speed is 1000 r / min and the stirring time is 20 min. During the mixing process, the diluent is gradually added to adjust the viscosity of the auxiliary agent to 100 mPa·s, and then the mixture is filtered through a 200 mesh screen to remove impurities.

[0044] During the static stage, multiple ultrasonic generators were installed in the curing room to further improve the uniformity of the ring gear casting's interior. These ultrasonic generators utilize existing, proven equipment; their specific operating principles and internal structure will not be detailed here. However, they ensure the ability to stably emit ultrasonic waves with a frequency of 30kHz-60kHz. During the treatment process, an intermittent operating mode is adopted, with the ultrasonic generator activated every 30 minutes for 5-10 minutes. This precisely controlled ultrasonic vibration effectively promotes the uniform distribution of the material within the ring gear casting, reduces internal stress concentration, and lays a good foundation for subsequent treatment. The specific location and layout of the ultrasonic generators can be flexibly adjusted based on the actual space in the curing room and the placement requirements of the ring gear casting to achieve the optimal treatment effect.

[0045] After entering the constant temperature stage, in order to further optimize the performance of the ring gear casting, a multi-dimensional composite vibration treatment technology was introduced. Specifically, while maintaining the temperature of the curing room stable at 60°C, the ring gear casting was subjected to vibration with a frequency of 15Hz-20Hz and an amplitude controlled at 1.0mm-1.5mm. This vibration not only occurs in the horizontal direction, but also adds a vibration component in the vertical direction, forming a multi-dimensional vibration mode that combines the horizontal and vertical directions. By precisely controlling the ratio of horizontal and vertical vibration accelerations to 2:1-3:1, a more comprehensive and uniform vibration treatment of the ring gear casting is achieved. This multi-dimensional composite vibration method effectively promotes the densification and homogenization of the internal structure of the casting, further improving the overall quality and performance stability of the ring gear casting.

[0046] In the above step S6, a vibrating sand shaker is used for preliminary cleaning.

[0047] refer to Figures 3 to 7 A vibrating sand-falling machine comprises a base 1, a top plate 2 is provided above the base 1, a plurality of evenly distributed air spring shock absorbers 3 are fixedly provided between the bottom of the top plate 2 and the top of the base 1, the air spring shock absorber 3 seals the gas in a closed container and utilizes the dynamic characteristics of the gas to achieve a shock-absorbing effect, a vibration motor 4 is fixedly provided on both sides of the bottom of the top plate 2, and the vibration motor 4 is installed with a group of adjustable eccentric blocks at both ends of the rotor shaft, and the exciting force is obtained by the centrifugal force generated by the high-speed rotation of the shaft and the eccentric blocks, and the vibration motor 4 is arranged between the two air spring shock absorbers 3.

[0048] The top plate 2 has a mounting opening 5 at the front end, a sand dropout hopper 6 is fixed inside the mounting opening 5, and a grid plate 7 and a screening plate 8 are provided inside the sand dropout hopper 6. A plurality of evenly distributed fixing holes 19 are provided on the top of the base 1, and the plurality of fixing holes 19 are spaced apart from the air spring shock absorber 3. Fastening bolts (not shown in the figure) are placed in the plurality of fixing holes 19 to improve the stability of the base 1.

[0049] In actual use, the casting falls onto the grid plate 7 in the sand falling hopper 6, and the two vibration motors 4 run synchronously to generate an exciting force, causing the top plate 2 and the sand falling hopper 6 to vibrate at high frequency, and multiple air spring shock absorbers 3 are used to reduce the impact of vibration on the base 1, so that the entire device remains stable. The casting falling on the grid plate 7 vibrates with the grid plate 7, and the molding sand on the casting is separated from the casting due to inertia and falls from the gap of the grid plate 7, while the casting slides or rolls along the surface of the grid plate 7 to the discharge end, thereby realizing sand and parts separation. After the molding sand falls onto the screening plate 8 through the grid plate 7, the sieve hole size on the screening plate 8 is smaller than the grid screen plate, so that the molding sand can be further screened, so that finer molding sand falls through the sieve hole, and the remaining sand clumps and debris are left on the screening plate 8, and then flow out from the discharge end of the screening plate 8, and finally the fine molding sand flows out from the discharge end of the sand falling hopper 6, thereby realizing automatic screening.

[0050] Two upper and lower chutes 12 are provided on the inner walls of both sides of the sand dropout hopper 6, and the grille plate 7 and the screening plate 8 are inserted into the chutes 12 near the side of the chutes 12; the chutes 12 are used to support the grille plate 7 and the screening plate 8, which is convenient for subsequent disassembly and replacement, thereby improving replacement efficiency.

[0051] The inner wall at the rear end of the sand dropout hopper 6 is provided with a plurality of grooves 9 distributed in sequence from top to bottom, and an air pipe 10 is fixedly provided inside each groove 9, and the air pipe 10 is connected to a plurality of evenly distributed nozzles 11. An air pump 13 is fixedly provided at the rear end of the base 1. The air pump 13 is a device that generates air pressure or transports gas by compressing gas. The air outlet of the air pump 13 is connected to the plurality of air pipes 10 through a telescopic hose 14, and a first filter 15 is fixedly provided inside the air inlet of the air pump 13. The first filter 15 can filter dust and impurities in the external environment to prevent dust and impurities from clogging the air pump 13.

[0052] In addition, a second filter screen 16 is fixedly provided inside each groove 9 . The second filter screen 16 is provided outside the nozzle 11 . The second filter screen 16 is used to block the molding sand to prevent the molding sand from clogging the nozzle 11 .

[0053] The air is delivered to the multiple air pipes 10 through the air pump 13. When the gas is ejected from the multiple nozzles 11, the residual molding sand in the sand dropping hopper 6 can be blown out from the discharge end, which can assist the staff to quickly clean the inside of the sand dropping hopper 6.

[0054] Limiting grooves 17 are provided on the inner walls on both sides of the installation opening 5, and limiting blocks 18 adapted to the limiting grooves 17 are fixed on both sides of the sand falling hopper 6, and the limiting blocks 18 are inside the limiting grooves 17; by utilizing the limiting blocks 18 to cooperate with the limiting grooves 17, the top plate 2 can support the sand falling hopper 6, thereby improving the connection firmness between the sand falling hopper 6 and the top plate 2.

[0055] The vibrating sand-falling machine drives the top plate 2 and the sand-falling hopper 6 to vibrate at high frequency through the vibrating motor 4, so that the castings and the molding sand on the grid plate 7 and the screening plate 8 can be quickly separated, thereby improving the screening efficiency. At the same time, the grid plate 7 and the screening plate 8 are detachable from the sand-falling hopper 6, so that the staff can quickly disassemble the two and facilitate cleaning and replacement.

[0056] In addition, the air is delivered to the multiple air pipes 10 through the air pump 13, and the gas is ejected from the multiple nozzles 11, which can blow the residual molding sand in the sand hopper 6 out from the discharge end, helping the staff to quickly clean the inside of the sand hopper.

[0057] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A gear ring casting process, characterized in that: The following steps are involved: S1. Sand mold preparation: According to the gear ring design drawings, the sand mold is quickly manufactured using 3D printing technology. The sand mold shrinkage rate is controlled within 1% to 3%, and the processing allowance is controlled within 5mm to 10mm; S2. Die casting: The molten metal raw material is injected into the sand mold, and pressure is applied by the die casting equipment to fully fill the sand mold cavity with the metal raw material. The die casting pressure is controlled at 50MPa-150MPa, and the die casting speed is controlled at 20mm / s-100mm / s; S3. Flipping: After die casting is completed, the sand mold is flipped at an angle of 180° so that the casting can further evenly fill the cavity under the action of gravity and reduce internal defects. The flipping time is controlled within 5s-15s after the die casting is completed. S4. Spraying auxiliary agent: spray the composite ceramic precursor auxiliary agent on the surface of the turned casting with a spraying thickness of 0.1mm to 0.3mm and a spraying pressure of 0.2MPa to 0.5MPa to improve the surface quality of the casting and reduce oxidation; S5. Burning surface auxiliary agent: The surface of the casting sprayed with the composite ceramic precursor auxiliary agent is burned. The combustion temperature is controlled at 500℃-800℃ and the combustion time is 10s-50s, so that the composite ceramic precursor auxiliary agent forms a uniform oxide film on the surface of the casting, thereby improving the wear resistance and corrosion resistance of the casting; S6. Cooling and cleaning: After the molten metal solidifies, remove the casting from the sand mold. Control the flow and temperature of the cooling air to ensure that the casting is evenly heated throughout the cooling process. The cooling air flow is controlled at 100m³ / h to 500m³ / h and the temperature is controlled at 20℃ to 50℃ to avoid excessive local temperature differences. After natural cooling, use a grinder to remove the casting gate and riser. Clean the sand, paint, oxide, and oil impurities on the casting surface through mechanical or chemical cleaning. S7. Defect inspection and post-processing: Carefully inspect the surface and interior of the casting for cracks, pores, and shrinkage defects. Perform annealing heat treatment on the casting to eliminate internal stress and improve organizational properties. The annealing heat treatment temperature is controlled at 850℃~900℃, and the holding time is 6h~12h. After mechanical processing to achieve the required size and accuracy, paint it to obtain the gear ring casting.

2. A gear ring casting process according to claim 1, characterized in that: In step S4, the composite ceramic precursor auxiliary agent comprises, by mass percentage, 30% to 40% of silica sol, 20% to 30% of alumina powder, 15% to 25% of organic silicon resin, and 10% to 15% of a diluent.

3. A gear ring casting process according to claim 2, characterized in that: The preparation process of the composite ceramic precursor auxiliary agent is as follows: Add silica sol, alumina powder and silicone resin into a stirring container in proportion, and mix them thoroughly with a high-speed stirrer at a stirring speed of 500 r / min to 1500 r / min for 10 min to 30 min. During the mixing process, gradually add diluent to adjust the viscosity of the auxiliary agent to a range suitable for spraying, and control the viscosity within 50mPa·s to 200mPa·s; After mixing is completed, the auxiliary agent is filtered using a 100-300 mesh screen to remove impurities and particles to ensure spraying quality.

4. A gear ring casting process according to claim 1, characterized in that: In step S1, the sand mold material is high-strength resin sand with a compressive strength of not less than 5 MPa to ensure that the sand mold is not deformed or damaged during the die-casting process.

5. The gear ring casting process according to claim 1, characterized in that: In step S2, the molten metal raw material is alloy structural steel 42CrMo or carburizing steel 20CrMnTi. The metal raw material needs to be preheated before being injected into the sand mold. The preheating temperature is controlled at 200°C to 300°C to reduce the temperature difference between the molten metal and the sand mold and reduce the impact of thermal stress on the casting.

6. A gear ring casting process according to claim 1, characterized in that: In step S3, the flipping device has automatic positioning and locking functions, and the flipping speed is controlled at 5° / s to 20° / s to ensure the stability of the sand mold and the casting during the flipping process and avoid deformation or damage of the casting due to improper flipping.

7. A gear ring casting process according to claim 1, characterized in that: In step S5, the combustion process uses natural gas or liquefied gas as fuel, and the surface of the casting is heated by a burner. The burner is equipped with a temperature control system, which can accurately control the combustion temperature to ensure that the auxiliary agent is fully burned to form a uniform oxide film.

8. The gear ring casting process according to claim 1, characterized in that: In step S6, a high-pressure water gun is used during the cleaning process, with the pressure controlled at 10 MPa to 30 MPa to remove impurities on the surface of the casting.

9. A gear ring casting process according to claim 1, characterized in that: In step S7, defect inspection uses non-destructive testing methods, including ultrasonic testing, magnetic particle testing, or radiographic testing, to accurately detect defects inside and on the surface of the casting.

10. The gear ring casting process according to claim 1, characterized in that: The method further includes step S8, a static stop process, including: S81, static stage: move the cast gear ring to the gear ring casting in the curing room and let it stand for 2h-4h; S82, heating stage: after the static period, the temperature in the curing room is raised, and the heating rate is strictly controlled to not exceed 60℃ / h, and the heating is stopped when the temperature reaches 60℃ to 120℃; S83, constant temperature stage: maintain at a temperature of 60°C to 120°C for 4h-8h; S84, cooling stage: After the constant temperature stage, start cooling slowly, with the cooling rate not exceeding 30℃ / h until it reaches room temperature.

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