Casting process design method for reducing sand-iron ratio of sand mold casting

Abstract

The invention discloses a casting process design method for reducing the sand-iron ratio of sand mold casting. The casting process design method comprises the following steps that S1, the shrinkage rate, the machining allowance and the correction amount of a casting are designed; s2, a pouring position is planned; s3, designing a riser feeding system; s4, designing a pouring system; s5, the sand thickness is designed; s6, designing a 3D sand mold; s7, format conversion; s8, a sand mold is printed; s9, sand mold post-treatment and casting operation; s10, mold closing and casting; and S11, sand cleaning and cutting are conducted. The process design method has the advantages that the whole casting production process has high repeatability and controllability on the basis of accurate parameter design and a digital 3D modeling and printing technology, compared with a traditional process, various parameters and operation steps in the production process are more standard and standardized, quality monitoring is facilitated, and the production efficiency is improved. And the product quality stability is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of sand casting technology, and in particular to a casting process design method for reducing the sand-to-iron ratio of sand casting. Background Art

[0002] As a traditional and widely used metal forming process, sand casting occupies an important position in modern industrial production. However, in the sand casting process, the sand-iron ratio has always been a key process parameter that needs to be optimized. The sand-iron ratio of sand casting is an important casting process parameter. Sand-iron ratio = weight of sand mold ÷ weight of molten steel. It is an important indicator to ensure the quality of castings, especially to control production costs. It is generally hoped that the sand-iron ratio is as low as possible. Too high a sand-iron ratio will lead to a large amount of molding sand and increase production costs; the corresponding sand consumption will also increase, which is not conducive to the exhaust of the sand mold, increases the tendency to produce porosity defects and affects the mechanical properties of the material. At present, the most commonly used is such Figure 1 As shown, the sand mold is made into a whole block. In order to reduce the weight of the molding sand, a homemade hollow iron bucket 19 is usually placed in the sand mold. Specifically, when the sand is placed in the mold, the iron bucket 19 with four sides closed is placed inside the sand box 1. The iron bucket 19 will occupy a certain space, and the space it occupies is the saved molding sand volume. However, this method requires a self-made closed iron bucket 19 in advance, which undoubtedly increases the production cost. Moreover, when the iron bucket 19 vibrates and drops the sand after the sand mold is poured, it will be deformed and damaged due to the inevitable collision and friction. The subsequent repeated repair work is not only time-consuming and labor-intensive, but also further increases the cost. At the same time, the iron bucket 19 itself has a certain weight. Whether it is manually carried or placed in the sand box 1, it is extremely inconvenient, which significantly increases the labor intensity of the workers. In addition, since the iron bucket 19 is manually placed, it is difficult to ensure the accuracy of the placement position. Once the iron bucket is placed too close to the casting cavity surface, it is very easy to cause fire defects, which seriously affects the quality of the casting. Moreover, in actual large-scale production, this manual operation is difficult to manage, the operation is quite random, and it is difficult to stably achieve the expected effect of reducing the molding sand, resulting in the difficulty in effectively reducing the sand-to-iron ratio.

[0003] Another traditional method is to reduce the sand-iron ratio by manually removing the molding sand. The process of manually removing the molding sand is extremely arbitrary. It is difficult for workers to accurately control the amount of molding sand removed, and it is impossible to achieve quantitative operation, which also cannot guarantee that the ideal effect of reducing the sand-iron ratio can be achieved every time. This lack of precision makes it difficult to effectively manage and control the quality of the production process, and manual sand removal undoubtedly increases the labor intensity of workers, reduces production efficiency, and is not conducive to the efficient development of large-scale industrial production. To this end, we propose a casting process design method for reducing the sand-iron ratio of sand casting to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to solve the problems in the prior art and to propose a casting process design method for reducing the sand-iron ratio of sand casting.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A casting process design method for reducing the sand-iron ratio of sand casting comprises the following steps:

[0007] S1. Design the shrinkage rate, machining allowance and correction amount of the casting; accurately design the shrinkage rate of the casting according to the material characteristics, shape structure and expected dimensional accuracy requirements of the casting, reasonably determine the machining allowance according to the processing requirements of different parts, and determine the correction amount according to the complexity of the shape of the casting and the particularity of the process;

[0008] S2. Pouring position planning: In-depth analysis of the structural characteristics of the casting, including wall thickness distribution, shape symmetry, and internal quality requirements, to determine the optimal pouring position;

[0009] S3. Design of riser feeding system: Design the riser feeding system according to the shape, size and solidification characteristics of the casting, and determine the number, size, shape and position of the risers by calculating the solidification time, volume shrinkage and hot spot position of the casting;

[0010] S4. Design of pouring system: comprehensively consider factors such as the fluidity of molten steel, pouring speed requirements, and exhaust performance of sand molds to determine the type of pouring system, the size and shape of the gate, the layout of the runner, etc.;

[0011] S5. Sand intake design: For thick and large parts of castings, a relatively large but accurately calculated sand intake is designed, taking into account factors such as large heat capacity, long solidification time and high sand mold strength requirements during the casting process;

[0012] S6. 3D sand mold design: With the help of professional 3D drawing software, according to the previously determined parameters and sand intake design, a 3D model of the sand mold is constructed. In the software, accurate modeling is performed for the sand intake at different thickness positions;

[0013] S7, format conversion: To ensure its structural integrity and stability in the actual casting process, convert the optimized sand mold cavity 3D image into the stl file format, import the stl file into the high-precision sand mold 3D printing equipment, and set appropriate printing parameters such as printing layer thickness, printing speed, printing temperature, etc. according to the characteristics of the sand mold material and the casting process requirements;

[0014] S8, printing sand mold; start the 3D printing device, and start printing the sand mold layer by layer according to the preset program. During the printing process, the device will accurately stack the sand mold material layer by layer according to the model data in the stl file;

[0015] S9, sand mold post-processing and casting operation; After the sand mold is printed, keep it still on the printing platform to allow the sand mold to fully solidify for more than 1 hour, then use a soft brush to gently clean the surface of the sand mold cavity to remove excess sand or impurities that may be attached during the printing process to ensure the smoothness of the cavity surface, and evenly apply anti-sand coating on the cleaned sand mold cavity surface;

[0016] S10, casting by assembling the mold; accurately buckle the upper mold sand mold coated with paint on the lower mold sand mold, and perform the assembling operation. During the assembling process, ensure that the upper and lower mold sand molds are accurately positioned, smelt the molten steel, and steadily pour the molten steel into the mold cavity of the sand mold after assembling the mold through the pouring system. During the pouring process, strictly control the pouring speed and pouring temperature to ensure that the molten steel can fill the mold cavity and achieve the expected solidification sequence to form a solid casting;

[0017] S11. Sand cleaning and cutting: After the casting is heat-insulated and solidified in the sand mold, the sand cleaning operation is carried out to completely remove the molding sand on the surface and inside of the casting. The casting after sand cleaning is cut to remove the shrinkage feeding system and the pouring system.

[0018] In the above-mentioned casting process design method for reducing the sand-to-iron ratio of sand casting, during the 3D modeling process of step S6, the difference command in the Boolean operation is used to generate 3D drawings of the upper and lower cavities of the sand mold, respectively, and then a connecting rib plate is created at the parting surface, and the thickness is strictly controlled to be greater than 50 mm. Through the solid modeling function in the software, the connecting rib plate is organically combined with the sand mold cavity body.

[0019] In the above-mentioned casting process design method for reducing the sand-to-iron ratio of sand casting, during the 3D modeling process, a virtual strength analysis is performed on the overall contour structure of the designed sand mold to check whether it can withstand various stresses during the casting process. If weak positions are found, such as stress concentration points or structural transition areas, reinforcing ribs are added in the software in a timely manner with a thickness set greater than 30 mm. By continuously optimizing the 3D model of the sand mold, its structural integrity and stability during the actual casting process are ensured.

[0020] In the casting process design method for reducing the sand-to-iron ratio of sand casting, the casting obtained after sand cleaning and cutting in step S11 is post-processed, and the cut casting is subjected to post-processing steps such as heat treatment, finishing and non-destructive testing in sequence. Castings that have passed all post-processing steps and passed the inspection are put into storage and are ready to enter subsequent processing or assembly links.

[0021] In the above-mentioned casting process design method for reducing the sand-iron ratio of sand casting, embedded parts are provided in both the upper sand mold and the lower sand mold, and the two embedded parts are connected by a locking assembly.

[0022] In the above-mentioned casting process design method for reducing the sand-to-iron ratio of sand casting, an upper ring tube is pre-embedded in the connecting rib plate connected to the upper sand mold, and a lower ring tube is pre-embedded in the connecting rib plate connected to the lower sand mold. A plurality of installation slots are provided on the two connecting rib plates, and the upper ring tube and the lower ring tube are connected by a plurality of locking components, and each locking component is located in two installation slots corresponding to the position.

[0023] In the above-mentioned casting process design method for reducing the sand-iron ratio of sand casting, a plurality of support frames are symmetrically arranged on the lower ring tube, and adjacent support frames are perpendicular to and connected to each other, and each support frame is vertically connected to the lower ring tube.

[0024] In the above-mentioned casting process design method for reducing the sand-iron ratio of sand casting, a holder is commonly provided at the lower ends of two adjacent support frames, and a base is commonly installed at the lower ends of four holders.

[0025] In the above-mentioned casting process design method for reducing the sand-to-iron ratio of sand casting, each of the clamping seats is installed on the upper surface of the base by a locking screw, and each of the clamping seats is provided with a first clamping slot and a second clamping slot, and the first clamping slot and the second clamping slot are perpendicular to and connected to each other, and the lower ends of the two adjacent support frames are clamped in the first clamping slot and the second clamping slot.

[0026] In the above-mentioned casting process design method for reducing the sand-to-iron ratio of sand casting, the locking assembly includes a lower fixed seat and an upper fixed seat, and the upper fixed seat is located on the upper ring tube, and a hook is fixedly connected to the upper fixed seat, and the lower fixed seat is located on the lower ring tube, and a rotating handle is rotatably connected to the lower fixed seat, a spring is installed between the lower fixed seat and the rotating handle, and a locking ring is rotatably connected to the rotating handle, and the locking ring is clamped on the hook at the corresponding position.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The casting process design method of the present invention can accurately design the sand consumption at different positions according to the actual needs of various parts of the casting and the process system. Compared with the traditional integral block sand mold design, this refined design can minimize the use of molding sand while ensuring the quality of the casting, thereby significantly reducing the sand-iron ratio and effectively reducing the production cost.

[0029] 2. Due to the reasonable design of sand intake and the optimization of sand mold structure, the exhaust performance of sand mold in the casting process is significantly improved, reducing the occurrence of defects such as pores, shrinkage holes, and shrinkage. At the same time, the precise pouring position and riser shrinkage system design can better control the solidification sequence of molten steel and improve the organizational uniformity and mechanical properties of castings.

[0030] 3. Abandoning the traditional manual iron bucket placement and manual sand shoveling operations, operators no longer need to perform tedious and difficult-to-control manual operations to reduce the use of molding sand. The entire casting process is automated through precise design and 3D printing technology in the early stage, which greatly reduces the workload of workers and reduces labor intensity. At the same time, due to the improved precision of sand mold production and the enhanced stability of the casting process, the scrap rate caused by sand mold problems is reduced and production efficiency is improved.

[0031] 4. The process design method of the present invention is based on precise parameter design and digital 3D modeling and printing technology, which makes the entire casting production process highly repeatable and controllable. Compared with traditional processes, the various parameters and operating steps in the production process are more standardized, which is convenient for production management and quality monitoring, and effectively improves the company's production management level and product quality stability.

[0032] In summary, the process design method of the present invention is based on precise parameter design and digital 3D modeling and printing technology, which makes the entire casting production process highly repeatable and controllable. Compared with traditional processes, the various parameters and operating steps in the production process are more standardized and convenient for quality monitoring, and effectively improves the stability of product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of sand mold of conventional design;

[0034] Figure 2 Schematic diagram of the locations of different thicknesses of castings and process systems;

[0035] Figure 3 for Figure 2 A cross-sectional view of

[0036] Figure 4 Schematic diagram for designing the amount of sand intake at different thickness positions;

[0037] Figure 5 A schematic diagram of the outer contour of a sand mold designed according to the casting process method;

[0038] Figure 6 A schematic diagram of the structure of the upper molding sand in a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0039] Figure 7 A structural schematic diagram of the connection state of the upper molding sand and the connecting rib plate in a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0040] Figure 8 A schematic diagram of the structure of lower molding sand in a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0041] Fig. 9 A structural schematic diagram of the connection state between the lower molding sand and the connecting rib plate of a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0042] Fig.10 A schematic diagram of the structure of a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention, in which the mold sand is connected to a supporting mechanism after the mold sand box is assembled;

[0043] Fig.11 for Fig.10 Schematic diagram of the structure for removing the molding sand and the upper ring pipe;

[0044] Fig.12 for Fig.10 A magnified view of the middle deck;

[0045] Fig.13 A structural schematic diagram of the connection state of an upper ring tube and a lower ring tube in a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0046] Fig.14 It is a structural schematic diagram of the connection state between the lower molding sand and the embedded parts in a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0047] Fig.15 It is a structural schematic diagram of the connection state of upper molding sand and embedded parts in a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0048] Fig.16 It is a structural schematic diagram of the connection state of the upper ring tube and the upper fixing seat in a casting process design method for reducing the sand-iron ratio of sand casting proposed by the present invention;

[0049] Fig.17 This is an enlarged structural diagram of a locking assembly in a casting process design method for reducing the sand-to-iron ratio of sand casting proposed by the present invention.

[0050] In the figure: 1 sand box, 2 upper sand mold, 3 connecting rib plate, 4 upper ring tube, 5 lower sand mold, 6 lower ring tube, 7 mounting notch, 8 support frame, 9 holder, 10 base, 11 first holder slot, 12 second holder slot, 13 lower fixing seat, 14 upper fixing seat, 15 hook, 16 rotating handle, 17 locking ring, 18 shrinkage feeding system, 19 hollow iron bucket, 20 pouring system, 21 casting. DETAILED DESCRIPTION

[0051] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0052] Example

[0053] Reference Figure 1-9 A casting process design method for reducing the sand-iron ratio of sand casting comprises the following steps:

[0054] S1. Design the shrinkage rate, machining allowance and correction amount of the casting 21; accurately design the shrinkage rate of the casting 21 according to the material characteristics, shape structure and expected dimensional accuracy requirements of the casting 21. The determination of this parameter can ensure that the sand mold cavity can provide just the right space during the solidification shrinkage process of the casting 21, avoiding casting defects caused by insufficient or excessive shrinkage;

[0055] Design of machining amount of casting 21; according to the machining requirements of different parts, reasonably determine the machining allowance, and reduce unnecessary machining allowance while ensuring that casting 21 can meet the requirements of final product dimensional accuracy and surface quality, thereby indirectly reducing the overall volume and weight of the sand mold, which helps to reduce the sand-iron ratio;

[0056] Correction amount design of casting 21; the correction amount is determined according to the complexity of the shape of casting 21 and the particularity of the process. The setting of the correction amount can compensate for various dimensional deviations that may occur during the casting process, ensuring that the size of the final casting 21 meets the design requirements.

[0057] S2. Pouring position planning: In-depth analysis of the structural characteristics of the casting, including factors such as wall thickness distribution, shape symmetry, and internal quality requirements, to determine the optimal pouring position. The choice of pouring position directly affects the flow path of the molten steel in the sand mold cavity, the filling speed, and the solidification sequence. For example, for castings with uneven wall thickness, placing the thick-walled part at the end of the pouring system 20 is conducive to sequential solidification and reducing the occurrence of defects such as shrinkage cavities and shrinkage. It also helps to optimize the thermal distribution of the sand mold, thereby affecting the reasonable design of the sand intake.

[0058] S3, riser feeding system 18; the riser feeding system 18 is designed according to the shape, size and solidification characteristics of the casting, and the number, size, shape and position of the risers are determined by calculating the solidification time, volume shrinkage and hot spot position of the casting. The main function of the riser is to replenish liquid metal during the solidification process of the casting to prevent the occurrence of shrinkage cavities, shrinkage and other defects. A reasonably designed riser feeding system 18 can not only ensure the quality of the casting 21, but also minimize the volume and weight of the riser while meeting the feeding requirements, thereby reducing the overall load of the sand mold, which is conducive to reducing the sand-iron ratio.

[0059] S4. Design of pouring system 20: comprehensively considering factors such as the fluidity of the molten steel, the pouring speed requirements, and the exhaust performance of the sand mold, determine the type of pouring system 20, the size and shape of the gate, the layout of the runner, etc. The optimized pouring system 20 can ensure that the molten steel fills the sand mold cavity smoothly and quickly, reduce the generation of turbulence and oxide inclusions, and avoid damage to the sand mold or an increase in the sand-to-iron ratio due to excessive scouring of the sand mold during the pouring process.

[0060] S5. Sand intake design (such as Figure 4 As shown); for the thick position of the casting 21, considering its large heat capacity, long solidification time and high sand mold strength requirements during the casting process, a relatively large but accurately calculated sand intake is designed, which can not only ensure the stability of the sand mold under long-term high temperature, but also avoid the waste of molding sand due to excessive sand intake. For the thin-walled position, due to its fast cooling speed, it is easy to produce defects such as cold shut and insufficient pouring. When designing the sand intake, on the premise of ensuring that the sand mold has sufficient strength to support the molding of the thin-walled part, the sand intake is appropriately reduced to speed up the heat dissipation of the sand mold, promote the rapid solidification of the thin-walled part, and improve the casting. 21 quality and reduce the sand-iron ratio. The design of the sand intake at the position 18 of the riser feeding system needs to take into account the feeding effect of the riser and the overall stability of the sand mold. While ensuring that the riser can effectively play the role of feeding, the sand intake should be reasonably controlled to prevent the excessive thickness of the sand mold around the riser from affecting the feeding channel of the molten steel and the exhaust performance of the sand mold. The design of the sand intake at the position 20 of the pouring system needs to consider the flow characteristics and impact force of the molten steel during the pouring process. At the entrance of the molten steel and around the flow channel, an appropriate amount of sand intake should be designed to withstand the scouring of the molten steel and guide the molten steel to enter the sand mold cavity smoothly, while avoiding turbulence of the molten steel or damage to the sand mold due to unreasonable sand intake.

[0061] S6. 3D sand mold design and molding: With the help of professional 3D drawing software, such as CAD or professional casting simulation software, according to the previously determined parameters and sand intake design, build a 3D model of the sand mold. In the software, accurately model the sand intake at different thickness positions, and generate 3D images of the upper and lower mold cavities of the sand mold through the difference command in Boolean operation. This process can accurately simulate the cavity structure inside the sand mold and the thickness relationship of each part, providing an accurate digital model for subsequent sand mold manufacturing. In order to enhance the overall rigidity of the sand mold, create connecting ribs at the parting surface. The thickness of plate 3 is strictly controlled to be greater than 50mm. Through the solid modeling function in the software, the connecting rib plate 3 is organically combined with the sand mold cavity body to ensure that it can effectively enhance the stability of the sand mold in structure. The virtual strength analysis of the designed overall contour structure of the sand mold is carried out to check whether it can withstand various stresses in the casting process. If weak positions are found, such as stress concentration points or structural transition areas, reinforcing ribs are added in the software in time, and the thickness is set to be greater than 30mm. By continuously optimizing the 3D model of the sand mold, its structural integrity and stability in the actual casting process are ensured.

[0062] S7, format conversion: convert the optimized sand mold cavity 3D image into the stl file format, which can be recognized by widely used 3D printing equipment, import the stl file into the high-precision sand mold 3D printing equipment, and set appropriate printing parameters such as printing layer thickness, printing speed, printing temperature, etc. according to the characteristics of the sand mold material and the casting process requirements.

[0063] S8, printing sand mold; start the 3D printing equipment and start printing the sand mold layer by layer according to the preset program. During the printing process, the equipment will accurately stack the sand mold material layer by layer according to the model data in the stl file.

[0064] S9. Post-processing and casting operation of sand mold. After the sand mold is printed, keep it still on the printing platform to allow the sand mold to fully solidify. The solidification time is generally set to be greater than 1 hour. This process can make the binder in the sand mold material fully play its role and improve the strength and stability of the sand mold. Use a soft brush to gently clean the surface of the sand mold cavity to remove excess sand or impurities that may be attached during the printing process, ensure the smoothness of the cavity surface, and avoid affecting the surface quality of the casting due to residual impurities. Evenly apply anti-sand sticking coating on the surface of the cleaned sand mold cavity. The choice of coating should be determined according to factors such as the material of the casting, the casting process and the sand mold material. Its main function is to prevent the adhesion of molten steel to the sand mold, facilitate the demolding of the casting, and reduce the sand sticking defects on the surface of the casting.

[0065] S10, combined casting; the upper sand mold 2 coated with paint is accurately buckled on the lower sand mold 5 to carry out the combined operation. During the combined process, the upper sand mold 2 and the lower sand mold 5 must be accurately positioned to avoid dislocation or offset, which will affect the dimensional accuracy and molding quality of the casting 21. The molten steel is melted according to the pre-established operating instructions. According to the material requirements of the casting 21, the chemical composition, melting temperature and melting time of the molten steel are accurately controlled to ensure that the quality of the molten steel meets the casting requirements. The molten steel is steadily poured into the sand mold cavity after the combined operation through the pouring system 20. During the pouring process, the pouring speed and pouring temperature must be strictly controlled to ensure that the molten steel can fill the cavity and achieve the expected solidification sequence to form a solid casting 21.

[0066] S11, sand cleaning and cutting; after the casting 21 is heat-insulated and solidified in the sand mold, the sand cleaning operation is carried out. Appropriate sand cleaning equipment and methods, such as vibration sand removal, hydraulic sand cleaning or mechanical sand cleaning, are used to thoroughly remove the molding sand on the surface and inside of the casting 21. The casting 21 after sand cleaning is cut to remove the shrinkage feeding system 18 and the pouring system 20. During the cutting process, it is necessary to control the cutting parameters, such as cutting speed, cutting depth and cutting temperature, to avoid damage to the casting 21 body.

[0067] S12 Casting post-processing; the cut casting 21 is subjected to post-processing processes such as heat treatment, finishing and non-destructive testing in sequence. Heat treatment can improve the organizational structure and mechanical properties of the casting. The finishing process can remove defects such as flash, burrs and oxide scale on the surface of the casting. Non-destructive testing can ensure that the internal quality of the casting meets the acceptance standards. Castings that have passed all post-processing processes and inspections will go through warehousing procedures and are ready to enter subsequent processing or assembly links.

[0068] refer to Figure 10-17, embedded parts are provided in the upper sand mold 2 and the lower sand mold 5, and the two embedded parts are connected by a locking assembly. An upper ring tube 4 is embedded in the connecting rib plate 3 connected to the upper sand mold 2, and a lower ring tube 6 is embedded in the connecting rib plate 3 connected to the lower sand mold 5. A plurality of mounting slots 7 are provided on the two connecting rib plates 3. The upper ring tube 4 and the lower ring tube 6 are connected by a plurality of locking assemblies, and each locking assembly is located in two mounting slots 7 corresponding to the position. A plurality of support frames 8 are symmetrically provided on the lower ring tube 6, and adjacent support frames 8 are perpendicular to each other and connected, and each support frame 8 is vertically connected to the lower ring tube 6. A holder 9 is commonly provided at the lower ends of two adjacent support frames 8, and a base 10 is commonly installed at the lower ends of the four holders 9. Each The holders 9 are all installed on the upper surface of the base 10 by locking screws. Each holder 9 is provided with a first slot 11 and a second slot 12, and the first slot 11 and the second slot 12 are perpendicular to each other and connected. The lower ends of the two adjacent support frames 8 are clamped in the first slot 11 and the second slot 12. The locking assembly includes a lower fixed seat 13 and an upper fixed seat 14, and the upper fixed seat 14 is located on the upper ring tube 4. The upper fixed seat 14 is fixedly connected with a hook 15. The lower fixed seat 13 is located on the lower ring tube 6. The lower fixed seat 13 is rotatably connected with a rotating handle 16. A spring is installed between the lower fixed seat 13 and the rotating handle 16. The rotating handle 16 is rotatably connected with a locking ring 17, and the locking ring 17 is clamped on the corresponding hook 15.

[0069] An upper ring tube 4 and a lower ring tube 6 are pre-embedded in the upper sand mold 2 and the lower sand mold 5. These embedded parts are tightly combined with the connecting rib plate 3. The connecting rib plate 3 not only enhances the structural strength of the sand mold, but the upper ring tube 4 and the lower ring tube 6 pre-embedded therein also provide a basis for subsequent connection and support structure; a plurality of locking components are distributed in the corresponding installation slots 7 to connect the upper ring tube 4 and the lower ring tube 6. The upper fixing seat 14 is fixed on the upper ring tube 4 and has a hook 15. The lower fixing seat 13 is located on the lower ring tube 6 and is rotatably connected with the rotating handle 16. When the rotating handle 16 is rotated, the locking ring 17 is driven to move. During installation, the rotating handle 16 is rotated to make the locking ring 17 snap into the hook 15, so as to achieve the connection and fixation of the upper ring tube 4 and the lower ring tube 6, thereby further fixing the upper sand mold 2 and the lower sand mold 5 relatively; the spring between the lower fixing seat 13 and the rotating handle 16 plays an auxiliary role. For example, when unlocking, the spring can help the rotating handle 16 return to the initial position or provide a certain operating feel to assist, so that the locking ring 17 is easier to disengage from the hook 15; the multiple support frames 8 on the lower ring tube 6 are vertically connected to each other to form a stable support structure.

[0070] The lower ends of adjacent support frames 8 are fixed to the base 10 through the holder 9. The first slot 11 and the second slot 12 on the holder 9 are vertically connected to each other and can just accommodate the lower ends of the adjacent support frames 8. Through this slot structure, accurate positioning and stable fixation of the support frames 8 are achieved. The locking screws further ensure the firm connection between the holder 9 and the base 10, so that the entire sand mold structure can be stably supported in the vertical and horizontal directions, preventing the sand mold from being displaced or deformed due to the impact of molten steel, gravity and other factors during the casting process, thereby ensuring the molding accuracy and quality of the casting.

[0071] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A casting process design method for reducing the sand-iron ratio of sand casting, characterized in that: The following steps are involved: S1. Designing the shrinkage rate, machining allowance and correction amount of the casting (21); accurately designing the shrinkage rate of the casting 21 according to the material characteristics, shape structure and expected dimensional accuracy requirements of the casting (21); reasonably determining the machining allowance according to the machining requirements of different parts; and determining the correction amount according to the shape complexity of the casting 21 and the particularity of the process; S2, pouring position planning; in-depth analysis of the structural characteristics of the casting (21), including factors such as wall thickness distribution, shape symmetry, and internal quality requirements, to determine the optimal pouring position; S3, design of a riser feeding system (18); designing a riser feeding system according to the shape, size and solidification characteristics of the casting (21), and determining the number, size, shape and position of the risers by calculating the solidification time, volume shrinkage and hot spot position of the casting (21); S4, pouring system (20) design; comprehensively considering factors such as the fluidity of the molten steel, the pouring speed requirements, and the exhaust performance of the sand mold, determine the type of pouring system, the size and shape of the gate, the layout of the runner, etc.; S5. Sand intake design: For thick and large parts of castings, a relatively large but accurately calculated sand intake is designed, taking into account factors such as large heat capacity, long solidification time and high sand mold strength requirements during the casting process; S6. 3D sand mold design: With the help of professional 3D drawing software, according to the previously determined parameters and sand intake design, a 3D model of the sand mold is constructed. In the software, accurate modeling is performed for the sand intake at different thickness positions; S7, format conversion; To ensure its structural integrity and stability in the actual casting process, convert the optimized sand mold cavity 3D image into the stl file format, import the stl file into the high-precision sand mold 3D printing equipment, and set appropriate printing parameters such as printing layer thickness, printing speed, printing temperature, etc. according to the characteristics of the sand mold material and the casting process requirements; S8, printing sand mold; Start the 3D printing device and start printing the sand mold layer by layer according to the preset program. During the printing process, the device will accurately stack the sand mold material layer by layer according to the model data in the stl file; S9, sand mold post-processing and casting operation; After the sand mold is printed, keep it still on the printing platform to allow the sand mold to fully solidify for more than 1 hour, then use a soft brush to gently clean the surface of the sand mold cavity to remove excess sand or impurities that may be attached during the printing process to ensure the smoothness of the cavity surface, and evenly apply anti-sand coating on the cleaned sand mold cavity surface; S10, assembling and casting; the upper sand mold (2) coated with paint is accurately buckled on the lower sand mold (5) to carry out the assembling operation. During the assembling process, the upper sand mold (2) and the lower sand mold (5) must be accurately positioned, and the molten steel is melted. The molten steel is steadily poured into the sand mold cavity after the assembling through the pouring system (20). During the pouring process, the pouring speed and pouring temperature must be strictly controlled to ensure that the molten steel can fill the mold cavity and achieve the expected solidification sequence to form a solid casting; S11, sand cleaning and cutting; after the casting is heat-insulated and solidified in the sand mold, the sand cleaning operation is performed to completely remove the molding sand on the surface and inside of the casting (21), and the casting (21) after sand cleaning is cut to remove the shrinkage feeding system (18) and the pouring system (20).

2. A casting process design method for reducing the sand-iron ratio in sand casting according to claim 1, characterized in that: In the 3D modeling process of step S6, the difference command in the Boolean operation is used to generate 3D images of the upper and lower mold cavities of the sand mold, respectively. Then, a connecting rib plate (3) is created at the parting surface, and the thickness is strictly controlled to be greater than 50 mm. Through the solid modeling function in the software, the connecting rib plate (3) is organically combined with the sand mold cavity body.

3. A casting process design method for reducing the sand-iron ratio of sand casting according to claim 2, characterized in that: During the 3D modeling process, a virtual strength analysis is performed on the designed overall contour structure of the sand mold to check whether it can withstand the various stresses in the casting process. If weak positions are found, such as stress concentration points or structural transition areas, reinforcing ribs are added in the software in a timely manner with a thickness set greater than 30 mm. By continuously optimizing the 3D model of the sand mold, its structural integrity and stability in the actual casting process are ensured.

4. A casting process design method for reducing the sand-iron ratio of sand casting according to claim 1, characterized in that: The casting (21) obtained after sand cleaning and cutting in step S11 is subjected to post-casting treatment, and the cut casting (21) is subjected to post-processing steps such as heat treatment, finishing and non-destructive testing in sequence. The casting that has passed all the post-processing steps and passed the inspection is put into storage and is ready to enter the subsequent processing or assembly link.

5. The casting process design method for reducing the sand-iron ratio in sand casting according to claim 1, characterized in that: The upper sand mold (2) and the lower sand mold (5) are both provided with embedded parts, and the two embedded parts are connected by a locking assembly.

6. A casting process design method for reducing the sand-iron ratio of sand casting according to claim 5, characterized in that: An upper ring tube (4) is pre-buried in the connecting rib plate (3) connected to the upper sand mold (2), and a lower ring tube (6) is pre-buried in the connecting rib plate (3) connected to the lower sand mold (5). A plurality of mounting slots (7) are provided on the two connecting rib plates (3). The upper ring tube (4) and the lower ring tube (6) are connected via a plurality of locking components, and each locking component is located in two mounting slots (7) at corresponding positions.

7. A casting process design method for reducing the sand-iron ratio of sand casting according to claim 6, characterized in that: A plurality of support frames (8) are symmetrically arranged on the lower ring tube (6), and adjacent support frames (8) are perpendicular to and connected to each other, and each support frame (8) is perpendicularly connected to the lower ring tube (6).

8. A casting process design method for reducing the sand-iron ratio of sand casting according to claim 7, characterized in that: A holder (9) is commonly provided at the lower ends of two adjacent support frames (8), and a base (10) is commonly installed at the lower ends of the four holders (9).

9. A casting process design method for reducing the sand-iron ratio in sand casting according to claim 8, characterized in that: Each of the card seats (9) is mounted on the upper surface of the base (10) by means of locking screws, and each of the card seats (9) is provided with a first card slot (11) and a second card slot (12), and the first card slot (11) and the second card slot (12) are perpendicular to and connected to each other, and the lower ends of two adjacent support frames (8) are clamped in the first card slot (11) and the second card slot (12).

10. A casting process design method for reducing the sand-iron ratio in sand casting according to claim 6, characterized in that: The lock assembly comprises a lower fixing seat (13) and an upper fixing seat (14), wherein the upper fixing seat (14) is located on the upper ring tube (4), a hook (15) is fixedly connected to the upper fixing seat (14), the lower fixing seat (13) is located on the lower ring tube (6), a rotating handle (16) is rotatably connected to the lower fixing seat (13), a spring is installed between the lower fixing seat (13) and the rotating handle (16), a locking ring (17) is rotatably connected to the rotating handle (16), and the locking ring (17) is clamped on the hook (15) at a corresponding position.

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