A casting process method for improving the quality of flywheel blank castings

Abstract

The application discloses a casting process method for improving the quality of flywheel blank castings, which is characterized by the synergic optimization of a gating system and a flywheel wooden mold, and comprises a preparation stage, a modeling stage, a pouring stage and a checking stage. The flywheel wooden mold is integrated with the flywheel body to avoid the position deviation of the tooth-shaped splicing during the box matching. The open pouring system comprising the cross-riser surrounding the flywheel body and the multiple inner risers with the cross-sectional area set according to the opening ratio is used for pouring, so that the effective slag resistance, slow liquid injection and uniform and stable mold filling are realized, and the casting sand inclusion defects are prevented. The five-tooth sleeve plate is used for checking the tooth shape of the flywheel blank casting, and the unqualified products are removed, so as to ensure the tooth shape precision of the flywheel blank casting. The application effectively improves the metal liquid flow state and the slag resistance, reduces the casting sand inclusion defects, improves the quality of the flywheel blank casting, ensures the tooth shape size precision, improves the production efficiency, reduces the repair rate and the production cost, and is suitable for the casting operation of the flywheel blank castings of large marine diesel engines.

Description

Technical Field

[0001] This invention relates to the manufacturing process of large diesel engine components, specifically to a casting process method for improving the quality of flywheel blank castings, belonging to the field of casting technology. Background Technology

[0002] As a large and critical component in marine diesel engine power systems, the flywheel plays a vital role in energy storage, smooth operation, maintaining inertia, and assisting in starting. Its product quality is extremely important, especially the quality of the tooth surface, which directly affects the smoothness of transmission and the overall reliability of the engine. Due to the enormous size and mass of marine diesel engine flywheels, the industry currently typically uses a casting process to manufacture flywheel blanks.

[0003] Flywheel blanks manufactured using existing technology commonly suffer from defects such as sand inclusions, slag inclusions, shrinkage pits, and poor tooth dimensional accuracy. The reasons for this are twofold: First, traditional gating systems fail to effectively block molten slag, and the flow is uneven. Molten iron directly enters the ingate through the sprue and runner, causing slag and oxide scale impurities to be swept into the mold cavity, resulting in casting defects such as sand inclusions. Second, traditional casting processes involve separately fabricating tooth-shaped cores, which are then manually placed into the wheel body mold cavity to form the integral casting cavity for the flywheel blank. This method not only requires a mold-fitting process, placing high demands on operators and resulting in a complex process and low production efficiency, but also makes it difficult to precisely control the relative position of the tooth-shaped core and the wheel body mold cavity during mold-fitting, easily leading to misalignment of the casting teeth, exceeding dimensional tolerances, and increasing the risk of quality defects.

[0004] Chinese invention patent application CN118875216A discloses a mold structure for casting large flywheel teeth. This technology uses an integrated wooden mold to form the flywheel body and teeth as a single unit during the molding process, avoiding the tooth misalignment defects that occur in the traditional manual tooth core assembly process. However, in this mold structure, the cavity of the integral flywheel is assembled from four 1 / 4 circle assembly plates. This split wooden mold has seams, which can easily lead to joint protrusions on the flywheel blank casting, affecting the dynamic balance of the finished flywheel during operation. It is also difficult to avoid positional deviations in the tooth connection of each segment of the entire circle caused by the error in the wooden mold manufacturing, reducing the accuracy of the tooth dimensions, and in severe cases, even directly leading to scrap. In addition, this mold structure does not consider shrinkage compensation, which can easily lead to out-of-tolerance diameter of the tooth root circle and insufficient machining allowance in the casting. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a casting process method to improve the quality of flywheel blank castings. This method involves synergistic optimization of the gating system and the flywheel wooden mold to effectively eliminate casting defects, improve the dimensional accuracy of the tooth profile, and fundamentally enhance the internal and external quality of the flywheel blank castings. This results in increased production efficiency, reduced production costs, guaranteed product quality, and reduced rework rate.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A casting process method for improving the quality of flywheel blank castings, wherein the dimensions of the flywheel blank casting are the dimensions of the finished flywheel plus machining allowance, is characterized by the coordinated optimization of the gating system and the flywheel wooden mold. An integrated flywheel wooden mold with tooth profiles and wheel body is used for molding to avoid misalignment of the tooth profiles during mold assembly. An open gating system is used, comprising a horizontal sprue surrounding the flywheel body and multiple ingates with cross-sectional areas set according to the open ratio, to effectively prevent slag, slow down the pouring, and ensure uniform and stable mold filling, thus preventing sand inclusion defects in the casting. A five-tooth blank sleeve is used to verify the tooth profile of the flywheel blank casting, rejecting defective products and ensuring the accuracy of the flywheel blank casting's tooth profile.

[0007] Furthermore, the flywheel wooden mold is an integral wooden mold with the tooth profile and the wheel body, and its size is expanded outward by 1.25% of the casting shrinkage rate according to the size of the flywheel blank casting, including the wheel body part and the tooth profile part; the wheel body part is a disc-shaped base, and the tooth profile part is all the flywheel teeth integrally machined on the outer edge of the wheel body part.

[0008] Furthermore, the surface of the toothed portion is coated with a paint coating layer to compensate for tooth shrinkage after the flywheel blank casting is poured.

[0009] Furthermore, the paint coating layer is made of epoxy resin paint with a total thickness of 1~1.5mm.

[0010] Furthermore, the tooth shape of the flywheel wooden mold is verified using a wooden mold tooth shape template. This wooden mold tooth shape template is an arc-shaped template containing tooth-shaped grooves, with the arc covering 5 complete tooth shapes. The size of the tooth-shaped grooves is the size of the tooth-shaped part of the flywheel wooden mold plus the thickness of the paint patch layer.

[0011] Furthermore, the blank five-tooth sleeve plate is an arc-shaped template containing toothed grooves, with the arc covering five complete tooth shapes. The size of the toothed grooves is based on the size of the flywheel blank casting, and a 1mm gap is left on each side of the two teeth of the tooth shape.

[0012] Furthermore, the open gating system also includes a sprue, the sprue surrounds the flywheel body and has a trapezoidal cross-section, multiple U-shaped ingates are respectively connected between the sprue and the flywheel body and have circular cross-sections, and the sprue is connected to the inlet of the sprue.

[0013] Furthermore, by calculating the liquid level height and pouring speed in the pouring cup, the cross-sectional area ratio of the horizontal runner to the ingate is determined, thereby controlling the molten iron flow velocity at the ingate to below 2 m / s.

[0014] Furthermore, a foam ceramic filter screen for filtering residue and stabilizing flow is provided at the inlet of the inlet of the inlet.

[0015] Furthermore, the bottom of the cast-in-place channel is lined with refractory bricks to prevent molten iron from washing away sand.

[0016] Furthermore, within the molded cavity of the flywheel body, several chills are arranged at the positions corresponding to the flywheel crankshaft connection holes to generate a localized cooling effect and refine the grains.

[0017] Furthermore, the casting process includes the following specific steps: I. Preparation Stage — 1) Construct an integral wooden mold for the flywheel and gating system, integrating the gear shape and wheel body. High-quality wood is selected to create a flywheel mold with an integrated tooth profile and wheel body, based on the dimensions of the flywheel blank casting and a casting shrinkage rate of 1.25%. This flywheel mold includes a wheel body and a tooth profile, with the surface of the tooth profile coated with a paint layer. High-quality wood is also used to create a gating system mold, which includes a sprue, a runner, and several ingates connected in sequence, and is connected to the outer periphery of the tooth profile of the flywheel mold. The cross-sectional area ratio of the runner to the ingate of the gating system mold is determined by calculating the liquid level height in the pouring cup and the pouring speed. The pouring speed of the molten iron at the ingate is set to be below 2 m / s. 1) Make a blank five-tooth sleeve plate and a wooden mold tooth pattern for verification; II. Styling Stage — The bottom box and the top box are shaped using the integral wooden mold made in step 1). Refractory bricks are placed at the bottom of the sprue. After demolding, the mold cavity is coated with paint. Foam ceramic filter screens are set at the inlet of each inlet. Chips are arranged at the positions of the flywheel crankshaft connection holes in the mold cavity. After the mold is closed, the mold cavity is baked with hot air and the temperature is measured to reach the predetermined temperature. III. Pouring Stage — When the temperature of the molten iron drops to 1330±10℃ after smelting, pouring begins. The pouring speed is controlled so that the flow rate of the molten iron at the inlet of the ingate is <2m / s. During the pouring process, the molten iron is kept continuous and stable. The pouring cup is filled with molten iron. After the molten iron enters the horizontal runner, the flow rate slows down and the slag floats to the surface. The slag is filtered and the flow is stabilized by the foam ceramic filter screen. Finally, the molten iron fills the cavity simultaneously and stably from multiple directions through the evenly distributed ingate. After standing and keeping warm, the casting is removed and the sand is cleaned, the risers and gating gates are removed, and the flash and burrs are cleaned to obtain the flywheel blank casting. IV. Verification Phase — Using the five-tooth sleeve plate made in step 1), the tooth shape of the flywheel blank casting is verified. At five different positions of the tooth shape of the flywheel blank casting, the tooth groove of the five-tooth sleeve plate is gently fitted into the tooth shape. If the toothed grooves can be easily fitted without significant wobbling, it indicates that the tooth profile of the flywheel blank casting is qualified. Stamp "Tooth Inspection Qualified" and fill in the inspection record. If the toothed groove wobbles excessively after being fitted, it indicates that the machining allowance for the toothed part is insufficient. The flywheel blank casting should be isolated and then determined to be reworked or scrapped. If the toothed groove cannot be fitted or gets stuck, it indicates that the tooth is too thick or misaligned. Mark the area, measure and record the maximum deviation value, and then arrange for rework. Compared with the prior art, the beneficial effects of the present invention are: 1. This invention adopts an integral flywheel wooden mold with the toothed shape and wheel body as one piece, which brings the following technical effects: 1) The flywheel teeth are made directly on the whole wooden mold. After molding, the sand mold already has a complete tooth cavity. Therefore, compared with the existing technology, there is no need to make an extra tooth core, completely eliminating the box matching process and eliminating the need for box matching and adjustment. At the same time, it avoids the complicated operations such as seam sealing and filling of the center seat during the box matching process, reducing multiple processes, greatly simplifying the molding process and improving production efficiency.

[0018] 2) The flywheel teeth and the wheel body are integrated on the wooden mold. The teeth are directly formed by the whole wooden mold, which avoids the splicing position deviation of the tooth core during the box assembly and the positioning error of the box assembly operation. The position of the teeth is completely guaranteed by the precision of the wooden mold making, thereby improving the shape and position accuracy of the flywheel blank casting teeth.

[0019] 3) The integrated structure of the flywheel wooden mold reduces the segmentation and splicing of the mud core, thereby reducing the joint protrusions of the entire casting, ensuring the continuity and integrity of the wheel body and tooth profile, and fundamentally solving the problem of dimensional deviation.

[0020] 2. The integral wooden mold of the present invention is coated with epoxy resin paint of 1~1.5mm thickness on the tooth-shaped parts, especially the root circle, tip circle and tooth side. When the molten iron solidifies, the paint coating layer offsets the cooling shrinkage of the blank casting, reduces the defect of insufficient machining allowance of the blank casting, and improves the tooth shape dimensional accuracy of the flywheel blank casting after cooling. After multiple tests, this compensation amount can ensure that the deviation of the as-cast tooth shape dimensional is controlled within ±0.5mm, and the diameter of the root circle can accurately meet the drawing requirements.

[0021] 3. This invention uses a toothed template with 5 continuous toothed grooves to verify the tooth shape of the flywheel wooden mold and the flywheel blank casting, and removes unqualified products, thereby further ensuring the tooth shape accuracy of the flywheel blank casting. 4. This invention optimizes the gating system by adopting an open gating system, which effectively improves the flow state of the molten metal and the slag removal capacity, significantly reduces casting defects, and improves the quality of casting products. 1) This invention determines the cross-sectional area ratio of the horizontal runner and the ingate by calculating the liquid level height and pouring speed in the pouring cup. With the goal of controlling the molten iron flow velocity at the ingate to below 2 m / s, the structure of the gating system ensures the realization of slow-flow and low-speed filling. This allows the molten iron to float the slag in the horizontal runner and enter the mold cavity simultaneously and smoothly from multiple directions through the evenly distributed ingate. The filling process is free of dead corners, thereby avoiding the formation of slag inclusion defects in flywheel castings.

[0022] 2) The casting system of the present invention is equipped with a foam ceramic filter screen at the inlet of the inlet of the inlet. It not only filters impurities such as slag, sand particles, and oxides from the molten iron, but its porous structure also plays a role in throttling and stabilizing the flow of the molten iron, making the molten iron entering the cavity more uniform and stable. 3) The bottom of the sprue of the casting system of the present invention is padded with refractory bricks, which reduces the impact of molten iron on the sand mold, prevents sand scouring and sand particles from entering the mold cavity, and reduces the sand inclusion defects in the casting.

[0023] In summary, the casting process described in this invention effectively improves the flow state of molten metal and its slag-blocking ability, significantly reduces sand inclusion defects in castings, improves the quality of flywheel blank castings and ensures the accuracy of tooth dimensions, greatly improves production efficiency, reduces rework rate and production costs, and is suitable for casting large marine diesel engine flywheel blank castings. Attached Figure Description

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

[0025] Figure 2 This is a top view of the wooden mold.

[0026] Figure 3 This is a bottom view of the wooden model.

[0027] Figure 4 This is a partial schematic diagram of the wooden mold.

[0028] Figure 5 This is a cross-sectional view of the molding process of the present invention.

[0029] Figure 6 for Figure 5 A bottom view.

[0030] Figure 7 for Figure 6 CC partial sectional view.

[0031] Figure 8 for Figure 6 A partial sectional view of DD.

[0032] In the picture: 10-Integral wooden mold, 20-Foam ceramic filter screen, 30-Chilled iron, 40-Refractory brick, 11-Wheel body, 12-Toothed part, 13-Paint patch layer, 21-Straight sprue, 22-Horizontal sprue, 23-Inner sprue, A-Parting surface. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0034] Please see Figure 2 This invention relates to the casting process of large marine engine flywheel blanks, and optimizes the gating system and flywheel wooden mold in a coordinated manner to improve the casting quality and dimensional accuracy of the tooth profile of the flywheel blank casting.

[0035] Example Please see Figure 1 The casting process method for improving the quality of flywheel blank castings according to the present invention includes the following specific steps: I. Preparation stage – Making an integral wooden mold of the flywheel and gating system, which integrates the tooth profile and wheel body, as well as a template for tooth profile inspection.

[0036] 1) Construct an integral wooden mold for the flywheel and gating system, integrating the gear shape and wheel body. Please refer to the following: Figure 2 , Figure 3 and Figure 4 The overall wooden mold 10 is made of high-quality wood and includes a central flywheel mold and a gating system mold connected to the outer periphery of the flywheel mold.

[0037] Please refer to the following: Figure 2 and Figure 3The flywheel wooden mold is made by expanding outward by 1.25% of the casting shrinkage rate according to the shape and size of the flywheel blank casting, forming a wooden mold with the tooth shape and wheel body integrated. It includes a wheel body part 11 and a tooth shape part 12. The wheel body part 11 is a disc-shaped base, and all the teeth of the flywheel are integrally machined on the outer edge of the wheel body part 11 to form the tooth shape part 12. The surface of the tooth shape part 12 (especially the root circle, tip circle and flank) is coated with a paint subsidy layer 13 with a total thickness of 1~1.5mm to compensate for the shrinkage of the tooth shape after the flywheel blank casting is poured, and to ensure that the root circle diameter of the flywheel blank casting meets the technical requirements of the blank drawing. This paint subsidy layer 13 is usually epoxy resin paint.

[0038] The process of making the flywheel wooden mold: Step 1: Construct the main body of the one-piece flywheel wooden mold High-quality wood is selected to make an integral wooden mold body for the flywheel, based on the shape of the flywheel blank casting and the casting shrinkage rate of 1.25%. The main body of the flywheel mold body includes the wheel body 11 and the tooth profile 12 of all the wheels.

[0039] Step 2, apply a coat of paint as a base coat. Two to three layers of quick-drying epoxy resin paint are evenly applied to the toothed portion 12 (especially the root circle, tip circle, and side of the tooth), with each layer being approximately 0.3 to 0.5 mm thick. The total coating thickness is controlled to be 1 to 1.5 mm. The resulting paint coating layer 13 is used to compensate for the shrinkage during the solidification process of the molten iron, ensuring that the root circle diameter of the flywheel blank casting finally reaches the design dimensions of the blank drawing.

[0040] Step 3, Drying and Trimming The flywheel wooden mold with the applied paint layer 13 is placed in a drying room at 40~50℃ for 24 hours to dry. After the paint film has completely hardened, the tooth surface is sanded with fine sandpaper to remove drips and burrs. The tooth profile shape is checked tooth by tooth with a wooden mold tooth template to ensure that there is no deformation. The wooden mold tooth template is an arc-shaped template with tooth grooves made of metal plate. The arc covers 5 complete tooth shapes. The size of the tooth groove is the size of the tooth part 12 of the flywheel wooden mold plus the thickness of the paint layer 13.

[0041] Step 4, Marking and Storage The drawing number, model, shrinkage rate, and "integral teeth" mark are engraved on the end face of the made flywheel wooden mold. It is then stored in a constant temperature (20±5℃) and dry mold library to prevent it from getting damp and deformed.

[0042] Please refer to the following: Figure 2 , Figure 3 and Figure 4 The casting system of the integral wooden mold 10 is also made of high-quality wood, including a straight sprue 21, a horizontal sprue 22 and an inner sprue 23 connected in sequence.

[0043] Please refer to the following: Figure 3 and Figure 4 Two arc-shaped horizontal sprues 22 surround the two sides of the flywheel mold, with a trapezoidal cross-section. Fourteen U-shaped ingates 23 connect the horizontal sprues 22 and the flywheel mold, with a cross-section of [missing information]. Φ The 40mm circle has an outlet connected to the toothed part 12 and an inlet (ingate) connected to the runner 22. The inlet of the sprue 23 is also used to install a foam ceramic filter screen 20 with a size of 130*150*40mm. The sprue 21 is connected to the inlet of the runner 22.

[0044] This invention employs an integral flywheel wooden mold that integrates the tooth profile and the wheel body. This not only forms a unified structure between the flywheel tooth profile and the wheel body on the wooden mold, avoiding the splicing position deviation that occurs when the tooth profile core is assembled, thus ensuring the dimensional accuracy of the flywheel casting tooth profile, but also reduces splicing by creating an integral structure between the tooth profile part 12 and the wheel body part 11. This minimizes the number of joint protrusions in the entire casting and ensures the continuity and integrity of the wheel body and tooth profile. Furthermore, the paint coating layer 13 offsets the shrinkage caused by pouring, ensuring that the tooth profile dimensions of the flywheel casting accurately meet the drawing requirements after cooling, fundamentally solving the problem of dimensional deviation.

[0045] This invention also optimizes the gating system by adopting an open gating system. The structure of the wooden mold of the gating system includes a horizontal sprue 22 with a trapezoidal cross-section on the outer ring and an inner sprue 23 set according to the open ratio. The 14 inner sprues 23 are evenly distributed along the outer ring of the flywheel. By calculating the liquid level height of the pouring cup and the pouring speed, the cross-sectional area of ​​the horizontal sprue 22 is large, and the diameter of the circular inner sprue 23 is set to 40mm. This slows down the flow rate of the molten iron after entering the horizontal sprue 22, and the slag floats and stays on the top of the horizontal sprue 22. Furthermore, the molten iron enters the mold cavity simultaneously and smoothly from multiple directions through the evenly distributed inner sprues 23, achieving low-speed filling of the molten iron with a flow rate of less than 2m / s. This reduces the impact on the sand mold, thereby avoiding the turbulent flow of molten iron carrying slag into the mold cavity and preventing sand particles from peeling off and forming sand inclusion defects in the flywheel casting.

[0046] 1) Make a blank five-toothed template and a wooden mold toothed template for verification. The five-tooth blank template is used for tooth profile verification of flywheel blank castings. Its shape is a fan-shaped or bow-shaped arc template with tooth profile grooves, the curvature covering five complete tooth profiles (including tooth tip, tooth root, and tooth flank). The tooth profile groove dimensions of the five-tooth blank template are designed according to the flywheel blank casting drawing, that is, the theoretical tooth profile dimensions of the finished flywheel plus machining allowance. A 1mm gap is left on each side of the tooth profile groove (tooth flank), which is slightly larger than the finished tooth profile on each side by 1mm to allow for a certain range of positional offset in the blank casting tooth profile.

[0047] The manufacturing process of the blank five-tooth sleeve plate: Step 1, Drawing Design: Based on the tooth shape dimensions (without shrinkage) of the blank casting in the flywheel blank drawing, add a 1mm single-sided gap to the side (tooth side) and design the tooth shape groove of the five-tooth sleeve plate of the blank. Step 2, Material selection and rough machining: Select wear-resistant cast iron or tool steel, and after forging and annealing, rough machine the shape; Step 3, Tooth profile finishing and hardening: Wire EDM is used to machine the tooth profile groove, leaving a 0.2mm grinding allowance. Heat treatment is performed to HRC50~55, and then the tooth profile is ground to the final size using a profile grinding machine. The tooth profile error is checked to be ≤0.08mm. Step 4, Marking: Mark the blank five-tooth sleeve plate with words such as "for blank only", "no shrinkage", and "1mm gap".

[0048] The wooden tooth template is used for tooth profile verification of the flywheel wooden mold. It is made of metal plate and has a fan-shaped or bow-shaped arc template with toothed grooves. The arc covers five complete tooth profiles (including tooth tip, tooth root, and tooth side). The size of the toothed groove is the size of the toothed part 12 of the flywheel wooden mold plus the thickness of the paint patch layer 13. The size of the toothed part 12 of the flywheel wooden mold is expanded outward by 1.25% of the casting shrinkage rate according to the size of the flywheel blank casting. That is, the size of the toothed groove of the wooden mold tooth template is the toothed part of the flywheel blank casting expanded outward by 1.25% of the casting shrinkage rate + the thickness of the paint patch layer 13.

[0049] II. Styling Stage — Step 1, shaping the bottom and top boxes Base box design: Please refer to the following: Figure 5 and Figure 6 According to the process documents, the integral wooden mold 10, which integrates the tooth profile and wheel body, and the casting system, is stably placed in the base box. The bottom of the sprue 21 of the integral wooden mold 10 is supported by refractory bricks 40 (see...). Figure 7 To prevent molten iron from impacting the sand mold and causing sand erosion, sand is then filled into the bottom box. Sand is tamped down in sequence, first the surface sand and then the back sand, with a focus on compacting the area around the wooden mold of the casting system. Box molding: Place the wooden mold and riser of the box according to the process drawing. The riser height is >600mm. If it is less than 600mm, add a riser ring. Fill the box with face sand and back sand, then stabilize the riser and compact the molding sand. Step 2: After the molding sand hardens, the mold is removed. The integral wooden mold 10, the cover box wooden mold and the riser are removed respectively, and the mold cavity is coated with paint. Step 3, fix a foam ceramic filter screen 20 with a specification of 150×150×40mm at the inlet of each inlet gate 23 (see Figure 8The interface is sealed with refractory clay. The foam ceramic filter screen 20 has a three-dimensional mesh structure. According to the process drawing, several hard lines are engraved at the position of the flywheel crankshaft connection hole in the cavity and chills 30 are arranged to control local solidification and refine the grains. The spacing between each chill 30 is uniform to ensure local quenching effect. Step 4, Box Closing Operation Level the mold, clean the parting surface, sprinkle parting powder, add positioning pins, and hang sand hooks; after closing the mold, tighten it with bolts, with at least three bolts on each side, and place the pouring cup on the top of the sprue 21; use at least two Φ16mm sealing strips to reinforce the parting surface, maintain the system's airtightness, prevent molten iron from escaping from the parting surface, and avoid secondary oxidation.

[0050] Step 5, Baking and Temperature Measurement Hot air is introduced into the riser and sprue 21 of the mold cavity to bake the sand mold for ≥14 hours until the mold cavity temperature is ≥80℃. The outlet temperature of the riser and sprue 21 is confirmed by measuring with an infrared thermometer.

[0051] III. Pouring Stage — Step 1, Iron molten metal smelting and treatment C3Cu was smelted in a medium-frequency furnace at an inoculation temperature of 1460~1490℃. No inoculation occurred during the first tapping and cooling process, and inoculation was carried out during the second tapping (YFY-280 0.15%). The slag was then removed. Step 2, pouring When the molten iron temperature drops to 1330±10℃, pouring begins. The pouring speed is controlled to achieve low-speed filling, ensuring the flow velocity at the inlet of the ingate 23 is <2m / s (this can be achieved by calculating the liquid level in the pouring cup). Low-speed filling avoids turbulent flow and splashing of the molten iron, reducing erosion of the sand mold and preventing sand particles from peeling off and entering the mold cavity, thus preventing sand inclusion defects. The pouring process is continuous and stable, with the pouring cup always filled with molten iron to prevent gas entrapment. After the molten iron enters the runner 22, the flow velocity slows down, and the slag, due to its lower density, floats to the runner 22. The top of 2 is not easy to enter the inner sprue 23. The molten iron enters the cavity simultaneously and smoothly from multiple directions through the evenly distributed inner sprue 23, realizing filling without dead corners and avoiding local high temperature or eddy current carrying slag. When the molten iron passes through the foam ceramic filter screen 20, in addition to using mechanical interception and adsorption to filter impurities such as slag, sand particles, and oxides with a diameter larger than the mesh, only clean molten iron enters the cavity. Its porous structure also plays a role in throttling and stabilizing the flow, making the molten iron entering the cavity more uniform and stable. Step 3, Cooling and Unpacking After pouring, let it stand for ≥48 hours to keep it warm. Once the casting has cooled to below 300℃, open the mold, remove the flywheel blank, clean the sand, remove the gating gate and riser, and clean the flash and burrs to obtain the flywheel blank casting.

[0052] The invention utilizes an optimized gating system to achieve slow-flowing slag in the horizontal gating channel, uniform low-speed filling in multiple ingates, and slag blocking by a foam ceramic filter screen, thus effectively improving slag blocking capability, significantly reducing sand inclusion defects in the casting, improving the quality of the flywheel blank casting, and ensuring the accuracy of the tooth dimensions.

[0053] IV. Verification Phase — The tooth profile of the flywheel blank casting is verified using a blank five-tooth sleeve plate.

[0054] Step 1: Place the flywheel blank casting stably on the inspection platform with the toothed surface facing upwards; Step 2: Blow away any residual sand, dust, or other debris from the tooth grooves. Step 3: Select five positions evenly distributed around the circumference of the gear ring of the flywheel blank casting, and take the five-tooth sleeve plate of the blank one by one and gently fit the tooth-shaped groove of the five-tooth sleeve plate into the tooth-shaped part of the flywheel blank casting at each position. If the toothed groove can be easily fitted into the toothed part without obvious wobbling, it indicates that the tooth profile is qualified and the machining allowance is sufficient. If the toothed groove cannot be fitted into the toothed part or gets stuck, it indicates that the tooth is too thick or misaligned. Mark the area with a red pen. If the blank five-tooth sleeve plate wobbles too much from side to side after the toothed groove is fitted into the toothed part, it indicates that the tooth is too thin and the machining allowance is insufficient. Mark the flywheel blank casting as rework or scrap. Step 4: In the marked defect area, use a depth gauge to measure the actual gap between the blank five-tooth sleeve plate and the tooth side of the flywheel blank casting, record the maximum positive and negative deviation values, and determine whether rework is possible by comparing with the allowance standard of the flywheel casting blank drawing. Step 5: Move the blank five-tooth sleeve plate around the tooth ring of the flywheel blank casting for half a turn and check each tooth one by one to feel the uniformity of the overall tooth shape. If there are multiple jams or looseness, the tooth shape of the flywheel blank casting is determined to be unqualified and isolated. Step 6: After the flywheel blank casting has been verified and qualified, stamp "Gear Inspection Qualified" on the end face and fill in the inspection record.

[0055] This invention uses a tooth profile template with five continuous tooth-shaped grooves to verify the tooth profile of the flywheel blank casting, eliminating defective products and further ensuring the tooth profile accuracy of the flywheel blank casting.

[0056] Undoubtedly, the present invention is not limited to the parameter values ​​mentioned in the above embodiments, but should also include other process parameter selections; in short, the scope of protection claimed by the present invention should also include those variations and substitutions that are obvious to those skilled in the art.

Claims

1. A casting process method for improving the quality of flywheel blank castings, wherein the dimensions of the flywheel blank casting are the dimensions of the finished flywheel plus machining allowance, characterized in that, The gating system and flywheel mold were optimized in a coordinated manner. A flywheel mold with an integrated tooth profile and wheel body was used for molding to avoid misalignment of the tooth profile during mold assembly. An open gating system was used for casting, which included a horizontal sprue surrounding the flywheel body and multiple ingates with cross-sectional areas set according to the open ratio. This effectively prevented slag, slowed liquid injection, and uniform and stable mold filling, preventing sand inclusion defects in the casting. A five-tooth blank was used to verify the tooth profile of the flywheel blank casting, and unqualified products were removed to ensure the tooth profile accuracy of the flywheel blank casting.

2. The casting process method for improving the quality of flywheel blank castings according to claim 1, characterized in that, The aforementioned flywheel wooden mold is an integral wooden mold with the tooth profile and the wheel body. Its dimensions are based on the dimensions of the flywheel blank casting, expanded outward by 1.25% of the casting shrinkage rate. It includes a wheel body portion and a tooth profile portion. The wheel body portion is a disc-shaped base, and the tooth profile portion consists of all the flywheel teeth integrally machined on the outer edge of the wheel body portion.

3. The casting process method for improving the quality of flywheel blank castings according to claim 2, characterized in that, The surface of the toothed portion is coated with a paint coating layer to compensate for the shrinkage of the toothed portion after the flywheel blank casting is poured.

4. The casting process method for improving the quality of flywheel blank castings according to claim 3, characterized in that, The paint coating layer is made of epoxy resin paint, with a total thickness of 1~1.5mm.

5. The casting process method for improving the quality of flywheel blank castings according to claim 3, characterized in that, The tooth shape of the flywheel wooden mold is verified using a wooden mold tooth shape template. This wooden mold tooth shape template is an arc-shaped template containing tooth-shaped grooves, with the arc covering 5 complete tooth shapes. The size of the tooth-shaped grooves is the size of the tooth-shaped part of the flywheel wooden mold plus the thickness of the paint patch layer.

6. The casting process method for improving the quality of flywheel blank castings according to claim 5, characterized in that, The aforementioned blank five-tooth sleeve plate is an arc-shaped template containing toothed grooves, with the arc covering five complete tooth shapes. The size of the toothed grooves is based on the size of the flywheel blank casting, and a 1mm gap is left on each side of the two teeth of the tooth shape.

7. The casting process method for improving the quality of flywheel blank castings according to claim 1, characterized in that, The open gating system also includes a sprue, which surrounds the flywheel body and has a trapezoidal cross-section. Multiple U-shaped ingates are connected between the sprue and the flywheel body and have circular cross-sections. The sprue is connected to the inlet of the sprue.

8. The casting process method for improving the quality of flywheel blank castings according to claim 7, characterized in that, By calculating the liquid level height and pouring speed in the pouring cup, the cross-sectional area ratio of the horizontal runner to the ingate is determined, thereby controlling the molten iron flow velocity at the ingate to below 2 m / s.

9. The casting process method for improving the quality of flywheel blank castings according to claim 7, characterized in that, The inlet of the inlet is equipped with a foam ceramic filter screen for filtering residue and stabilizing flow.

10. The casting process method for improving the quality of flywheel blank castings according to claim 7, characterized in that, The bottom of the cast-in-place channel is lined with refractory bricks to prevent molten iron from washing away sand.

11. The casting process method for improving the quality of flywheel blank castings according to claim 1, characterized in that, In the molded cavity of the flywheel body, several chills are arranged at the positions corresponding to the flywheel crankshaft connection holes to produce a localized cooling effect and refine the grains.

12. The casting process method for improving the quality of flywheel blank castings according to claim 6, characterized in that, The casting process includes the following specific steps: I. Preparation Stage — 1) Construct an integral wooden mold for the flywheel and gating system, integrating the gear shape and wheel body. High-quality wood is selected to create a flywheel wooden mold with an integrated tooth profile and wheel body, based on the dimensions of the flywheel blank casting and a casting shrinkage rate of 1.25%. This flywheel wooden mold includes a wheel body and a tooth profile, with the surface of the tooth profile coated with a paint coating. High-quality wood is also used to create a gating system wooden mold, which includes a sprue, a runner, and several ingates connected in sequence, and is connected to the outer periphery of the tooth profile of the flywheel wooden mold. The cross-sectional area ratio of the runner to the ingate of the gating system wooden mold is determined by calculating the liquid level height in the pouring cup and the pouring speed. The pouring speed of the molten iron at the ingate is set to be below 2 m / s. 1) Make a blank five-tooth sleeve plate and a wooden mold tooth pattern for verification; II. Styling Stage — The bottom box and the top box are shaped using the integral wooden mold made in step 1). Refractory bricks are placed at the bottom of the sprue. After demolding, the mold cavity is coated with paint. Foam ceramic filter screens are set at the inlet of each inlet. Chips are arranged at the positions of the flywheel crankshaft connection holes in the mold cavity. After the mold is closed, the mold cavity is baked with hot air and the temperature is measured to reach the predetermined temperature. III. Pouring Stage — When the temperature of the molten iron drops to 1330±10℃ after smelting, pouring begins. The pouring speed is controlled so that the flow rate of the molten iron at the inlet of the ingate is <2m / s. During the pouring process, the molten iron is kept continuous and stable. The pouring cup is filled with molten iron. After the molten iron enters the horizontal runner, the flow rate slows down and the slag floats to the surface. The slag is filtered and the flow is stabilized by the foam ceramic filter screen. Finally, the molten iron fills the cavity simultaneously and stably from multiple directions through the evenly distributed ingate. After standing and keeping warm, the casting is removed and the sand is cleaned, the risers and gating gates are removed, and the flash and burrs are cleaned to obtain the flywheel blank casting. IV. Verification Phase — Using the five-tooth sleeve plate made in step 1), the tooth shape of the flywheel blank casting is verified. At five different positions of the tooth shape of the flywheel blank casting, the tooth groove of the five-tooth sleeve plate is gently fitted into the tooth shape. If the toothed grooves can be easily fitted without significant wobbling, it indicates that the tooth profile of the flywheel blank casting is qualified. Stamp "Tooth Inspection Qualified" and fill in the inspection record. If the toothed groove wobbles excessively after being fitted, it indicates that the machining allowance for the toothed part is insufficient. The flywheel blank casting should be isolated and then determined to be reworked or scrapped. If the toothed groove cannot be fitted or gets stuck, it indicates that the tooth is too thick or misaligned. Mark the area, measure and record the maximum deviation value, and then arrange for rework.

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