Manufacturing process of fan-shaped supporting piece

Abstract

The invention relates to the technical field of metal processing, in particular to a fan-shaped supporting piece manufacturing process which comprises the following steps that firstly, casting raw materials are smelted and injected to be filled into a forming mold; 2, after solidification forming, a casting is cleaned; step 3, annealing and heating; fourthly, residual stress in the fan-shaped blank is released through vibration aging equipment; 5, the fan-shaped blank piece is put into a shaping mold, pressure is applied to the shaping mold, and then the pressure borne by the shaping mold is unloaded stage by stage; and sixthly, the fan-shaped blank is machined to the size of a finished product. According to the manufacturing process of the fan-shaped supporting piece, a vibration time-effect method is adopted in advance to eliminate residual stress of the fan-shaped supporting piece, then pressure is applied to the fan-shaped supporting piece through the mold cavity, residual micro stress in the fan-shaped supporting piece is promoted to be evenly differentiated and relaxed, it is ensured that the size of the fan-shaped supporting piece is stable, and the precision of the fan-shaped supporting piece is improved; the problems of surface deformation and out-of-tolerance parallelism of the fan-shaped supporting piece are solved.

Description

Technical Field

[0001] This invention relates to the field of metal processing technology, and specifically to a manufacturing process for a fan-shaped support component. Background Technology

[0002] The sector component is a key component used in rail transit braking systems. Its surface is fitted with friction pairs to achieve train braking. Therefore, the quality of the sector component directly affects the safe operation of the railcar. In their published paper, "Analysis and Prevention of Cracks in Precision Cast K242 Alloy Positioning Fan-Shaped Parts," Wang Hua, Sun Zhijun, Zhang Lingfeng, and Chang Taoqi explained that cracks perpendicular to the machining direction appear on the surface of the fan-shaped parts during casting. The cracks extend along the dendritic carbide network, which is related to slow casting cooling and carbide aggregation. Traditional casting processes use integral module heat preservation and slow cooling, which easily leads to coarse grains and stress concentration in the fan-shaped castings. During machining, thermal stress and cutting stress are superimposed, causing cracks.

[0003] In their published paper, "Optimization of Processing Technology and Efficiency Improvement for Sector-Shaped Parts," Ru Leilei, Su Bin, Liu Hao, Wang Rui, Guo Liang, Li Tao, Yan Wangxing, Xiao Junyu, and Li Pengfei explain that during the casting process of sector-shaped parts, the milling amount on surface B is small and uniform, while the milling amount on surface A is large and uneven. Furthermore, residual stress remains after milling, and the difference in milling amounts between surfaces A and B leads to deformation after stress release. This results in excessive parallelism of surfaces A and B, as well as the machining holes on them, preventing assembly with higher-level components. The published paper proposes a reverse deformation method to suppress deformation during sector-shaped part processing. After semi-finish milling, a hydraulic jack is used to apply a reaction force in the deformation direction, causing plastic deformation of surface B and forcibly counteracting the deformation trend caused by processing stress. Then, low-temperature tempering is used until the stress is completely released, reducing the risk of deformation during subsequent finishing and ensuring that flatness and parallelism meet standards.

[0004] However, using a hydraulic jack to apply a reaction force in the deformation direction to cause macroscopic plastic deformation of surface B of the sector component makes it impossible to determine the amount of deformation of surface B. The amount of deformation of surface B is prone to error, and there may be a situation where the deformation of surface B exceeds the deformation trend caused by the processing stress, resulting in deformation of surface A of the sector component. The parallelism of surfaces A and B of the sector component still has the problem of exceeding the tolerance. Moreover, when performing precision milling and hole machining on the sector component, the clamping force applied by the fixture on the machine tool will cause elastic deformation. If the machine tool processes the surface of the sector component flat in a deformed state, it will cause the sector component to spring back after the fixture is removed, resulting in deformation of the machined surface and affecting the machining accuracy of the sector component.

[0005] Therefore, there is an urgent need for a manufacturing process for fan-shaped support components that can eliminate the effects of stress deformation and improve manufacturing accuracy, in order to solve the problems mentioned in the background art. Summary of the Invention

[0006] The purpose of this invention is to provide a manufacturing process for a fan-shaped support component. This process involves first using a vibration aging method to eliminate most of the residual stress generated during the casting and processing of the fan-shaped support component. Then, pressure is applied to the fan-shaped support component through a mold cavity to promote the uniform differentiation and relaxation of the extremely low residual stress inside the fan-shaped support component, ensuring dimensional stability and improving its accuracy, thereby solving the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A manufacturing process for a fan-shaped support component, comprising the following steps: Step 1: Place the casting raw material into an induction furnace and heat it to 720-750℃ to melt it into molten metal. Then, pour the molten metal into the pressure chamber of the die casting machine. The molten metal in the pressure chamber of the die casting machine fills the cavity of the forming mold and holds the pressure for 8-12 seconds. Step 2: The molten metal cools and solidifies in the mold cavity. After the mold is opened and the casting is removed, the gate and burrs on the surface of the casting are cut off, and the oxide scale, rust and oil stains on the surface of the casting are removed by shot blasting to obtain a fan-shaped blank. Step 3: Anneal the fan-shaped blank to 300-350℃, hold for 2-3 hours, then furnace cool to ≤250℃ and remove from the furnace for cooling. Step 4: Support the fan-shaped blank on the processing platform with elastic rubber pads, and apply vibration to the fan-shaped blank near its natural frequency using a vibration aging device to release the residual stress inside the fan-shaped blank. Step 5: Place the fan-shaped blank into the forming mold, ensuring that the positioning reference of the fan-shaped blank is precisely matched with the positioning mechanism of the mold. Apply 200-300t of pressure to the forming mold using a press. Then, unload the pressure on the forming mold in stages. After the pressure is unloaded, open the forming mold and take out the fan-shaped blank. Step 6: Using the fan-shaped surface and end face of the fan-shaped blank as the positioning reference, turn the outer diameter, end face, and positioning step of the end face of the fan-shaped blank. Turn the fan-shaped blank to the required finishing dimensions. Then, drill and bore the fan-shaped blank to remove the pre-made process holes on the surface of the fan-shaped blank. Finally, grind the fan-shaped blank to the finished dimensions to obtain the fan-shaped support.

[0008] As a further embodiment of the present invention: the shaping mold proposed in step five includes an upper mold base and a lower mold base, wherein the internal cavity of the upper mold base is made according to the concave and convex shape of surface A of the fan-shaped blank, and the concave and convex surface of surface A of the fan-shaped blank is completely fitted with the internal cavity of the upper mold base; the internal cavity of the lower mold base is made according to the concave and convex shape of surface B of the fan-shaped blank, and the concave and convex surface of surface B of the fan-shaped blank is completely fitted with the internal cavity of the lower mold base.

[0009] As a further aspect of the present invention, the depth of the internal cavity of the upper mold base and the internal cavity of the lower mold base are both less than half the thickness of the fan-shaped blank.

[0010] As a further aspect of the present invention: the pressure borne by the stage unloading shaping mold proposed in step five is 20% of the total unloading pressure over 5 minutes.

[0011] As a further aspect of the present invention: the shot blasting equipment for the casting surface proposed in step two is a tracked shot blasting machine, which uses cast steel shot with a diameter of 0.8-1.2mm and a hardness of HRC40-45 as abrasive, and the abrasive shot velocity is 60-80m / s.

[0012] As a further aspect of the present invention: the perpendicularity of the end face of the fan-shaped blank after turning in step six to the outer circle is ≤0.02mm / m, the flatness of the end face is ≤0.03mm, and the tolerance of the positioning step is ±0.05mm.

[0013] As a further aspect of the present invention: the surface roughness of the fan-shaped plane of the fan-shaped blank after turning in step six is ​​Ra1.6μm, and the flatness is ≤0.02mm / m.

[0014] Compared with the prior art, the advantages of the present invention are as follows: The manufacturing process of the fan-shaped support proposed in this invention involves heating the casting to an appropriate temperature and holding it thereafter through annealing, allowing the internal atoms to rearrange and migrate, releasing the internal stress of the casting, and improving the dimensional stability of the casting. Then, the vibration aging method is used to eliminate most of the residual stress generated during the casting process, putting the casting in a low-stress and relatively stable state. Then, pressure is applied to the casting through a forming mold that fully fits the cavity with surfaces A and B, causing the residual micro-stress inside the casting to evenly differentiate and relax, increasing the casting's resistance to deformation and fatigue crack initiation, and achieving the purpose of correcting and locking the shape of the casting. This state is used as the clamping reference for subsequent finishing, reducing machining errors caused by clamping deformation and improving the accuracy of the fan-shaped support. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the manufacturing process of a fan-shaped support member according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a fan-shaped support member according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the assembly of a fan-shaped support member and a forming mold according to an embodiment of the present invention. Detailed Implementation

[0016] Combination Figures 1-3As shown, in this embodiment, the manufacturing process of the fan-shaped support includes the following steps: Step 1: Select casting raw materials, put the casting raw materials into an induction furnace and heat them to 720-750℃ to obtain molten metal. Then, pour the molten metal into the pressure chamber of the die casting machine. The die casting machine injects at low speed to make the molten metal pass smoothly through the runner, while expelling the gas in the pressure chamber to avoid splashing of the molten metal. After the molten metal reaches the gate, the molten metal is injected at high speed to fill the mold cavity and hold the pressure for 8-12 seconds to compensate for the volume shrinkage of the molten metal during the solidification process, prevent shrinkage cavities or porosity inside the casting, and ensure that the casting structure is dense.

[0017] In this embodiment, after the molten metal cools and solidifies in the mold cavity in step two, the casting is removed after the mold is opened. The casting is then placed in the trimming mold, and a 315t punch press is used to apply a pressure of 30-50t to remove the gate and burrs on the surface of the fan-shaped blank. The size of the fan-shaped casting is controlled, and a allowance of ≤0.3mm is reserved to balance the cutting force distribution and reduce the risk of stress release deformation after precision milling.

[0018] In this embodiment, after cleaning the gate and burrs on the surface of the fan-shaped blank, the fan-shaped blank is placed in a crawler-type shot blasting machine. Cast steel shot with a diameter of 0.8-1.2mm and a hardness of HRC40-45 is selected as the abrasive. The abrasive shot velocity is 60-80m / s, and the shot blasting treatment lasts for 15-20 minutes to remove the oxide scale, rust and oil stains on the surface of the fan-shaped blank, so that the surface roughness of the fan-shaped blank reaches Ra12.5μm or less.

[0019] In this embodiment, step three involves annealing the fan-shaped blank to 300-350°C, holding it for 2-3 hours, then furnace cooling to ≤250°C before removing it from the furnace for further cooling. This completes the annealing process of the fan-shaped blank, allowing the atoms inside the blank to rearrange and migrate, releasing the internal stress of the blank, and improving the dimensional stability of the blank.

[0020] In this embodiment, step four involves supporting the fan-shaped blank on the processing platform using elastic pads, and clamping the vibrator of the vibration aging equipment onto the fan-shaped blank. The vibration aging equipment identifies the multiple natural frequencies and resonance peaks of the fan-shaped blank using spectrum harmonic technology. The vibrator applies an alternating load to the fan-shaped blank for 10-30 minutes according to the main resonant frequency of 30-100Hz to release the residual stress inside the fan-shaped blank.

[0021] In this embodiment, step five involves assembling the B side of the fan-shaped blank into the inner cavity of the lower mold base of the forming mold, and closing the forming mold. The upper mold base of the forming mold is then pressed against the A side of the fan-shaped blank through its inner cavity. A 630t press is then used to apply a pressure of 200-300t to the forming mold, which promotes the uniform differentiation and relaxation of the residual micro-stress inside the fan-shaped blank, increases the fan-shaped blank's resistance to deformation and fatigue crack initiation, and ensures the dimensional stability of the fan-shaped blank. Then, the pressure on the forming mold is unloaded in stages. After the pressure is unloaded, the forming mold is opened and the fan-shaped blank is removed.

[0022] In this embodiment, step six involves clamping and fixing the fan-shaped blank onto the chuck of a CNC lathe. Using the fan-shaped surface and end face of the blank as positioning references, the outer diameter, end face, and positioning step of the fan-shaped blank are machined to ensure that the perpendicularity between the end face and the outer circle of the fan-shaped blank is ≤0.02mm / m, the flatness of the end face is ≤0.03mm, and the tolerance of the positioning step is ±0.05mm.

[0023] In this embodiment, the fan-shaped blank is clamped on a vertical CNC milling machine. The outer circle and end face of the fan-shaped blank are used as positioning references. A face milling cutter is used to cut the fan-shaped plane and complex groove of the fan-shaped blank, so that the surface roughness of the fan-shaped plane of the fan-shaped blank is Ra1.6μm and the flatness is ≤0.02mm / m.

[0024] In this embodiment, the fan-shaped blank is clamped on the worktable of the drilling and tapping machine. The plane of the fan-shaped blank after turning is used as the positioning reference. A drill bit is used to drill holes at the designed hole positions on the plane of the fan-shaped blank. After drilling is completed, the drill bit is replaced with a tap, and the tap is used to tap the drilled holes to obtain the fan-shaped support.

[0025] In this embodiment, a high-pressure water gun with a pressure of 0.8-1.2 MPa is used to rinse the surface of the fan-shaped support to remove chips, coolant, and dust. Then, a compressed air gun with a pressure of 0.5-0.6 MPa is used in conjunction with a wire brush to clean the residue inside the drilled and threaded holes, ensuring that there is no residue inside the drilled holes. After that, the surface of the fan-shaped support with oil stains is soaked in an alkaline cleaning agent with a concentration of 5-8% for 10-15 minutes, then wiped, rinsed, and dried, completing the surface cleaning of the fan-shaped support.

[0026] In this embodiment, at least two layers of bubble wrap with a thickness of ≥0.08mm are used to tightly wrap the cleaned fan-shaped support, and the bubble wrap joints are sealed with tape. Then, the individually packaged fan-shaped support is neatly placed into a wooden packaging box. The fan-shaped support is separated from each other by corrugated cardboard and filled with foam plastic. Finally, the packaged and boxed fan-shaped support is stored in the warehouse for easy transportation later.

[0027] In this embodiment, the forming mold includes an upper mold base and a lower mold base. The internal cavity of the upper mold base is made according to the concave and convex shape of surface A of the fan-shaped blank, and the concave and convex surface of surface A of the fan-shaped blank is completely fitted with the internal cavity of the upper mold base. The internal cavity of the lower mold base is made according to the concave and convex shape of surface B of the fan-shaped blank, and the concave and convex surface of surface B of the fan-shaped blank is completely fitted with the internal cavity of the lower mold base. The upper mold base and the lower mold base are completely fitted with the concave and convex surfaces A and B of the fan-shaped blank through their internal mold cavities, clamping the fan-shaped blank between the upper mold base and the lower mold base and applying pressure to prevent the fan-shaped blank from deforming when subjected to pressure. This promotes the uniform differentiation and relaxation of the extremely small residual stress inside the fan-shaped blank, increases the fan-shaped blank's resistance to deformation and fatigue crack initiation, and ensures the dimensional stability of the fan-shaped support.

[0028] In this embodiment, the depth of the inner cavity of the upper mold base and the inner cavity of the lower mold base is less than half the thickness of the fan-shaped blank. This can prevent the upper mold base and the lower mold base from interfering with each other after the mold is closed, ensure that the pressure application of the fan-shaped blank is carried out, avoid new damage or stress concentration to the fan-shaped blank caused by excessively high rigidity of the mold cavity, and ensure uniform pressure distribution.

[0029] In this embodiment, the pressure borne by the stage unloading shaping mold is 20% of the total unloading pressure in 5 minutes; every 5 minutes, 20% of the total pressure is unloaded to control the elastic recovery rate and degree of the fan-shaped blank. After the pressure is unloaded, the shaping mold is opened and the fan-shaped blank in the lower mold base is taken out to prevent the fan-shaped blank from suddenly losing its constraint and causing violent rebound or deformation, thus ensuring the stability of the shape of the fan-shaped blank.

[0030] The working principle of this invention is as follows: The manufacturing process of the fan-shaped support component proposed in this invention involves heating the die-cast fan-shaped blank to an appropriate temperature and holding it at that temperature through annealing. This allows the internal atoms to rearrange and migrate, releasing the internal stress of the fan-shaped blank and improving its dimensional stability. Then, the fan-shaped blank is supported on a processing platform using elastic pads, and the vibrator of a vibration aging device is clamped onto the blank. The vibration aging device identifies the multiple natural frequencies and resonance peaks of the fan-shaped blank using spectral harmonic technology. The vibrator applies an alternating load to the fan-shaped blank according to the main resonant frequency, releasing the residual stress inside the blank and placing it in a low-stress and relatively stable state. Then, pressure is applied to the fan-shaped blank through the upper and lower mold bases to promote the uniform differentiation and relaxation of the residual micro-stress inside the fan-shaped blank, increase the fan-shaped blank's resistance to deformation and fatigue crack initiation, and ensure the dimensional stability of the fan-shaped blank. Finally, 20% of the total pressure is unloaded every 5 minutes to control the elastic recovery rate and degree of the fan-shaped blank until the pressure is unloaded. Then, the forming mold is opened and the fan-shaped blank in the lower mold base is taken out to prevent the fan-shaped blank from suddenly losing its constraint and causing violent rebound or deformation. This achieves the purpose of correcting and locking the shape of the fan-shaped blank. This state is used as the clamping reference for subsequent finishing, reducing the machining error caused by clamping deformation and improving the accuracy of the fan-shaped support.

[0031] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A manufacturing process for a fan-shaped support component, characterized in that, The manufacturing process includes the following steps: Step 1: Place the casting raw material into an induction furnace and heat it to 720-750℃ to melt it into molten metal. Then, pour the molten metal into the pressure chamber of the die casting machine. The molten metal in the pressure chamber of the die casting machine fills the cavity of the forming mold and holds the pressure for 8-12 seconds. Step 2: The molten metal cools and solidifies in the mold cavity. After the mold is opened and the casting is removed, the gate and burrs on the surface of the casting are cut off, and the oxide scale, rust and oil stains on the surface of the casting are removed by shot blasting to obtain a fan-shaped blank. Step 3: Anneal the fan-shaped blank to 300-350℃, hold for 2-3 hours, then furnace cool to ≤250℃ and remove from the furnace for cooling. Step 4: Support the fan-shaped blank on the processing platform with elastic rubber pads, and apply vibration to the fan-shaped blank near its natural frequency using a vibration aging device to release the residual stress inside the fan-shaped blank. Step 5: Place the fan-shaped blank into the forming mold, ensuring that the positioning reference of the fan-shaped blank is precisely matched with the positioning mechanism of the mold. Apply 200-300t of pressure to the forming mold using a press. Then, unload the pressure on the forming mold in stages. After the pressure is unloaded, open the forming mold and take out the fan-shaped blank. Step 6: Using the fan-shaped surface and end face of the fan-shaped blank as the positioning reference, turn the outer diameter, end face and positioning step of the fan-shaped blank to the finishing dimensions. Then, drill and bore the fan-shaped blank to remove the pre-made process holes on the surface of the fan-shaped blank. Finally, grind the fan-shaped blank to the finished dimensions to obtain the fan-shaped support.

2. The manufacturing process of a fan-shaped support member according to claim 1, characterized in that, The forming mold proposed in step five includes an upper mold base and a lower mold base. The internal cavity of the upper mold base is made according to the concave and convex shape of surface A of the fan-shaped blank, and the concave and convex surface of surface A of the fan-shaped blank is completely fitted with the internal cavity of the upper mold base. The internal cavity of the lower mold base is made according to the concave and convex shape of surface B of the fan-shaped blank, and the concave and convex surface of surface B of the fan-shaped blank is completely fitted with the internal cavity of the lower mold base.

3. The manufacturing process of a fan-shaped support member according to claim 2, characterized in that, The depth of the inner cavity of the upper mold base and the inner cavity of the lower mold base is less than half the thickness of the fan-shaped blank.

4. The manufacturing process of a fan-shaped support member according to claim 1, characterized in that, The pressure that the shaping mold withstands during the staged unloading in step five is 20% of the total unloading pressure over 5 minutes.

5. The manufacturing process of a fan-shaped support member according to claim 1, characterized in that, The shot blasting equipment for the casting surface proposed in step two is a tracked shot blasting machine, which uses cast steel shot with a diameter of 0.8-1.2mm and a hardness of HRC40-45 as abrasive, and the abrasive shot velocity is 60-80m / s.

6. The manufacturing process of a fan-shaped support member according to claim 1, characterized in that, In step six, the perpendicularity of the end face of the fan-shaped blank to the outer circle after turning is ≤0.02mm / m, the flatness of the end face is ≤0.03mm, and the tolerance of the positioning step is ±0.05mm.

7. The manufacturing process of a fan-shaped support member according to claim 1, characterized in that, The surface roughness of the fan-shaped plane of the fan-shaped blank after turning in step six is ​​Ra1.6μm, and the flatness is ≤0.02mm / m.

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