An apparatus and method for casting high-silicon carbon ratio cast iron pieces using a metal mold

Abstract

The application discloses a device and method for casting high-silicon carbon ratio cast iron parts by adopting metal casting, and belongs to the casting technical field, and solves the problems of uneven temperature field distribution, low sand covering efficiency and the inability of a gating system to be actively closed in the prior art. The device comprises a mold base support assembly, a casting mold assembly and a sand covering heating mechanism. The casting mold assembly comprises an upper mold base, a lower mold base, a metal cavity, a sand covering layer and a gating system. The sand covering heating mechanism, the gating active closing assembly and the mold closing linkage part are cooperatively matched. The sand covering heating mechanism provides sufficient liquid feeding time window for the gating active closing assembly. The gating active closing assembly creates conditions for stable forming after the mold closing linkage part switches the posture. The mold closing linkage part lays a foundation for the temperature field uniformity of the heating mechanism by improving the sand covering efficiency and quality. The three parts jointly act, and finally, the high-performance castings with compact internal organization and no shrinkage are obtained.

Description

Technical Field

[0001] This invention belongs to the field of casting technology, specifically relating to an apparatus and method for casting high silicon-to-carbon ratio cast iron parts using a metal mold. Background Technology

[0002] In the foundry industry, gray cast iron is widely used in the manufacture of various mechanical parts such as machine tool beds, engine cylinder blocks, and lathe chucks due to its excellent casting performance, good vibration damping, and low cost. Among them, HT300, as a typical pearlitic gray cast iron, has high strength requirements, and its traditional production methods mostly adopt sand casting processes such as wet sand casting or resin sand casting.

[0003] As the manufacturing industry continues to demand higher quality castings, traditional sand casting is gradually revealing some limitations: The precision and surface quality of castings are limited. Ordinary sand casting is greatly affected by the compactness of molding sand, moisture content and environmental humidity. The surface roughness of castings is high, the dimensional accuracy is difficult to control, and defects such as sand inclusions and porosity are easy to occur.

[0004] Insufficient internal density and relatively low mold stiffness make the mold wall prone to migration (sand expansion) during the solidification process of molten iron, resulting in internal defects such as shrinkage cavities and porosity in the casting, which affects the mechanical properties and service life of the casting.

[0005] Production efficiency and environmental protection issues: Traditional sand casting involves complex processes, with high labor intensity in molding, sand removal, and other stages, and the dust and waste sand generated put significant pressure on the environment.

[0006] Iron mold sand casting is a composite casting process. Its principle involves covering the inner cavity of a metal mold (iron mold) with a thin layer of sand to form a high-strength cavity before pouring the casting. This process typically uses thermosetting pre-coated sand. Initially, the mold needs to be electrically heated to 200-250℃, and subsequent production mainly utilizes the residual heat of the iron mold after pouring to maintain the temperature. Iron mold sand casting combines the advantages of metal mold casting and shell mold casting, significantly improving the surface and internal quality of castings while simplifying production processes and saving production costs.

[0007] Chinese patent CN112427618B discloses a die-casting mold with a heating mechanism, including a bottom support, a fixed mold, and a steam generator. A movable mold is movably mounted on the bottom support away from the fixed mold. The movable mold contains a heating mechanism, which includes side heat exchange pipes and a vortex heat exchange plate. By using the side heat exchange pipes and vortex heat exchange plate, the movable mold is rapidly heated during the first few die-casting operations. This allows the movable mold to be heated in the early stages of casting production through reflow heating, effectively suppressing the rapid solidification of molten metal due to the cold mold in the early stages of production, which could block the casting passage and prevent castings from failing to meet requirements due to passage blockage. However, the heating mechanism of this die-casting mold lacks localized enhanced heating methods for the gating area, resulting in uneven temperature distribution between thick parts and the gating area. This can easily cause shrinkage porosity in the casting or premature blockage of the gating, making it difficult to meet the high density requirements of HT300 grade castings and making it difficult to effectively eliminate the tendency for internal shrinkage porosity in the casting.

[0008] Meanwhile, Chinese patent CN120115645A discloses a die-casting mold with a heating mechanism, including a base, a frame at the upper end of the base, a mold closing assembly installed on one side of the frame, a horizontal plate at the top of the frame, a docking assembly on one side of the horizontal plate, a mold assembly installed on one side of the mold closing assembly, and an auxiliary fastening assembly installed inside the mold assembly. This die-casting mold assembly for coated sand casting, through a mold closing assembly and a docking assembly, controls the first and second molds to approach each other while precisely activating the auxiliary fastening assembly at the right moment, significantly improving the automation level of the device. The auxiliary fastening assembly ensures a stable fit between the first and second molds, enhancing structural stability and mold stability during the casting process. This prevents gaps or displacement during high-pressure casting, improving the precision and quality of the castings. However, this die-casting mold closing assembly uses a rigid horizontal opening and closing method, with the upper mold base always maintaining a horizontal posture. In the coated sand molding process, cleaning residual coated sand and sand injection operations require manual intervention or complex external tooling. Incomplete cleaning of residual coated sand can easily lead to uneven coated sand thickness, and the fluidity of the coated sand is limited in a horizontal posture, making it difficult to avoid dead angles in sand injection, resulting in low coated sand efficiency. Furthermore, the lack of shock absorption protection for the coated sand layer during mold closing makes it susceptible to damage from rigid impacts, affecting the quality of the casting.

[0009] In summary, existing iron mold sand casting devices lack localized intensified heating methods for the gating area, resulting in uneven temperature distribution between thick sections and the gating area. This fails to provide a reliable temperature environment for the graphitization expansion and self-compensating of high silicon-carbon ratio HT300 cast iron. Furthermore, the mold clamping mechanism lacks shock-absorbing and guiding designs to protect the sand coating layer, and the upper mold base cannot be switched to a vertical position, leading to low efficiency and unstable sand coating quality during cleaning and blowing operations. Additionally, existing technologies do not address active sealing and backflow prevention mechanisms for the gating system, failing to effectively cut off the ingate before graphitization expansion begins, thus hindering the full utilization of self-compensating behavior and resulting in insufficient internal density of the casting. Therefore, we propose a device and method for casting high silicon-carbon ratio cast iron parts using a metal mold. Summary of the Invention

[0010] The purpose of this invention is to address the shortcomings of existing technologies by providing an apparatus and method for casting high silicon-to-carbon ratio cast iron parts using a metal mold. This method enables uniform preheating of the metal cavity and ingate during the sand casting process, localized enhanced heating and heat preservation of the gating area, precise sealing and backflow prevention of the main gate during the graphitization expansion stage, and smooth switching of the upper mold base from horizontal downward to vertical longitudinal posture with sand layer protection. Ultimately, this results in a high-performance HT300 grade gray cast iron part with a dense internal structure and no shrinkage porosity.

[0011] This invention is achieved by providing an apparatus for casting high-silicon-to-carbon ratio cast iron parts using a metal mold, the apparatus comprising: A mold base support assembly, comprising two sets of symmetrically arranged mold supports; A casting mold assembly, mounted on the mold support, includes an upper mold base, a lower mold base, a metal cavity, a sand coating layer, and a gating system. The upper mold base and the lower mold base are respectively installed in the mold support, and the metal cavity is opened between the upper mold base and the lower mold base. The inner wall surface of the metal cavity is pre-attached with a sand coating layer, and the gating system is used to pour molten metal into the metal cavity. The sand-coated heating mechanism is located inside the lower mold base and is used to assist in the casting of the coated sand mold and extend the feeding time of the molten metal. The sand-coating heating mechanism includes an independent heating tank, a gating heating tank, an adjustable heating part, a gating local reinforcement part, a first air pump, and a heating linkage part. The independent heating tank is set corresponding to the metal cavity, and the gating heating tank is set corresponding to the inner gating. The independent heating tank and the gating heating tank are connected. The adjustable heating part is set in the independent heating tank, and the gating local reinforcement part is set in the gating heating tank. The heating linkage part is connected to the adjustable heating part and is connected to the first air pump.

[0012] Preferably, the gating system includes: The ingate is located in the middle of the upper mold base and the lower mold base, and the ingate is connected to the metal cavity respectively; The main gate is located inside the upper mold base and is connected to the ingate. A gating riser is circumferentially formed inside the metal cavity, and one end of the gating riser penetrates the upper mold base; An active gate sealing component is installed inside the main gate to seal the main gate and prevent molten metal from flowing back during the graphitization expansion stage.

[0013] Preferably, the active sealing component of the gating system includes: The second air pump is fixedly embedded in the upper mold base; The first piston seat is fixedly installed inside the upper mold base, and one end of the first piston seat is connected to the second air pump. The first piston plate is slidably installed inside the first piston seat, and a first return spring is fixedly connected to one side of the first piston plate. The second piston seat is located on one side of the first piston seat, and a second piston plate is slidably installed inside the second piston seat. A first push rod is provided between the first piston seat and the second piston seat. The two ends of the first push rod are fixedly connected to the first piston plate and the second piston plate, respectively. The end of the second piston seat away from the first piston seat is connected to the main gate through an anti-backflow air pipe. The linkage sealing part is connected to the first push rod, driven by the first push rod, and actively closes the main gate.

[0014] Preferably, the linkage closure part includes: A closed linkage seat is fixedly sleeved on the outer wall of the first push rod, and a linkage drive groove is fixedly installed inside the closed linkage seat; The first hinge seat is located on one side of the closed linkage seat, and one end of the first hinge seat is slidably connected to the linkage drive groove. The first hinge seat is fixedly installed at the end of the inner drive rod. The second hinge seat is located on the other side of the closed linkage seat, and one end of the second hinge seat is also slidably connected to the linkage drive groove. The second hinge seat is fixedly sleeved on the end of the outer drive sleeve. The inner drive rod passes through the outer drive sleeve and is rotatably connected to the outer drive sleeve. The first sealing plate is fixedly installed on the side wall of the inner drive rod; The second sealing plate is fixedly installed on the outer wall of the outer drive sleeve, and the first and second sealing plates are used to simultaneously seal the main gate.

[0015] Preferably, the locally reinforced part of the gating system includes: The inner heat collector rod is fixedly embedded in the heating groove of the gating system; A thermal expansion spiral ring is fixedly sleeved on the outer wall of the inner heat collector rod, and Each electric heating jacket is provided with three sets, which are respectively fixedly sleeved on the outer wall of the inner heat collecting rod; The adjustable heating element includes: The first gear is rotatably mounted on the top of the independent heating tank, and one side of the first gear is inserted into the heating ring support. The heating ring support is rotatably installed inside the independent heating tank; A spiral heating ring is detachably installed within the heating ring support bracket, and the spiral heating ring is used to heat an independent heating tank. An arc-shaped expansion plate is fixedly installed on the side wall of the independent heating tank.

[0016] Preferably, the heating linkage unit includes: The linkage rack is slidably installed in the lower mold base, and the linkage rack meshes with the first gear for transmission; A rack drive frame is fixedly connected to a linkage rack, and the rack drive frame is slidably connected to the lower mold base. A second push rod is fixedly connected to one side of the rack drive frame. The third piston seat is fixedly embedded in the lower mold base, and the third piston plate is slidably installed in the third piston seat. A second return spring is fixedly connected to one side of the third piston plate, and the other side of the third piston plate is connected to the second push rod. The third piston seat is connected to the first air pump through the pump inlet guide pipe. The drive slide rod is fixedly installed inside the rack drive frame, and both ends of the drive slide rod pass through the slide rod support seat. The slide rod support seat is fixedly installed inside the lower mold base. An acceleration swing arm is rotatably installed inside the slide rod support seat. An acceleration swing spring is fixedly connected to one end of the acceleration swing arm, and one end of the acceleration swing spring is fixedly connected to the drive slide rod.

[0017] Preferably, the mold base support assembly further includes: A mold closing drive unit is disposed inside a mold support. The mold closing drive unit includes a mold closing motor, a second gear, a third gear, and a mold closing drive rod. The mold closing drive rod is rotatably mounted inside the mold support. The third gear is fixedly sleeved on the outer wall of the mold closing drive rod. The second gear is disposed on one side of the third gear and meshes with the third gear for transmission. One side of the second gear is fixedly connected to the mold closing motor, and the mold closing motor is fixedly mounted on the mold support. The mold closing linkage is symmetrically arranged in the mold support, and the mold closing linkage is connected to the mold closing drive and the upper mold base respectively. The mold closing linkage is used to drive the upper mold base and the lower mold base to close the mold, and to assist the upper mold base and the lower mold base to open the mold.

[0018] Preferably, the mold closing linkage unit includes: The mold support is fixedly installed on both sides of the upper mold base, and the side walls of the mold support are respectively fixedly installed with an upper hinge shaft and a lower hinge shaft; A Y-shaped guide groove is formed inside the mold support, and the upper hinge shaft and the lower hinge shaft are slidably embedded in the Y-shaped guide groove respectively; The upper hinge rod is hinged at one end to the mold closing drive rod and at the other end to the lower hinge rod. The end of the lower hinge rod away from the upper hinge rod is rotatably connected to the lower hinge shaft. An inclined limiting slide is slidably embedded in the inner wall of the mold support, and one side of the inclined limiting slide is slidably connected to the mold support. A spring telescopic rod is fixedly connected to the bottom of the inclined limiting slide, and the spring telescopic rod is fixedly installed on the surface of the mold support.

[0019] On the other hand, the present invention also provides a method for casting high silicon-to-carbon ratio cast iron parts using a metal mold, the method comprising: S10, turn on the spiral heating ring. The spiral heating ring starts to heat the independent heating tank, so that the independent heating tank transfers heat to the corresponding metal cavity. After the metal cavity is heated to 200-250℃, it is kept at the temperature. Then, the core shooter blows the fluid coated sand into the metal cavity. After the fluid coated sand comes into contact with the surface of the metal cavity, it solidifies for 1-2 minutes to form a sand coating layer with a thickness of 7-9mm. S20, the mold closing motor is turned on. The forward rotation of the mold closing motor drives the second gear to rotate, which in turn drives the third gear and the mold closing drive rod to rotate. The mold closing drive rod drives the upper hinge rod and the lower hinge rod to swing, which in turn drives the lower hinge shaft to slide in the Y-shaped guide groove. Simultaneously, it drives the upper hinge seat to slide along the Y-shaped guide groove, which in turn drives the upper hinge shaft and the lower hinge shaft to move the mold support. This causes the mold support to drive the upper mold seat to change from a longitudinal state to a horizontal downward state and close with the lower mold seat. At the same time, the mold support presses against the inclined limit slide, which in turn presses against the spring telescopic rod, which provides shock absorption and protection for the upper mold seat. S30, after the upper mold base and lower mold base are closed, molten metal is injected into the main gate. The molten metal enters the inlet runner and the metal cavity through the molten metal. At the same time, the first air pump, electric heating jacket and spiral heating ring are turned on. The spiral heating ring starts to heat the independent heating tank, so that the independent heating tank transfers heat to the corresponding metal cavity. At the same time, the electric heating jacket heats the runner heating tank, and the thermal expansion spiral ring and arc expansion plate expand due to heat, which increases the pressure of the independent heating tank and the runner heating tank, realizing rapid heat conduction to the metal cavity and the inlet runner. S40, the first air pump starts and pumps gas into the third piston seat, thereby pushing the third piston plate and the second push rod to slide horizontally. This causes the second push rod to drive the rack drive frame and the linkage rack to reciprocate horizontally. The linkage rack drives the first gear to rotate, which in turn drives the spiral heating ring to rotate, thereby accelerating the flow of hot air in the independent heating tank and the gating heating tank. At the same time, the movement of the rack drive frame can drive the drive slide rod to move, so that the acceleration swing arm accelerates the horizontal reciprocating motion of the drive slide rod under the action of the acceleration swing spring, thereby accelerating the flow of hot air in the independent heating tank and the gating heating tank. S50, after the molten metal fills the metal cavity, the second air pump is turned on. The second air pump drives the first piston plate, the second piston plate and the first push rod to slide, so that the second piston plate pumps the gas in the second piston seat into the anti-backflow air pipe, and then enters the main gate from the anti-backflow air pipe to prevent the molten metal in the main gate from flowing back. At the same time, the first push rod drives the closed linkage seat to move, so that the closed linkage seat drives the first hinge seat and the second hinge seat to rotate synchronously. The first hinge seat drives the inner drive rod and the first closing plate to rotate, and the second hinge seat drives the outer drive sleeve and the second closing plate to rotate, so that the first closing plate and the second closing plate close the main gate. S60: After the main gate is closed, liquid feeding is performed through the gating riser. After the molten metal cools and solidifies, the mold closing motor is turned in reverse. The mold closing motor drives the second gear to rotate, which in turn drives the third gear and the mold closing drive rod to rotate. The mold closing drive rod drives the upper hinge rod and the lower hinge rod to swing, which in turn drives the lower hinge shaft to slide in the Y-shaped guide groove. Simultaneously, it drives the upper hinge seat to slide along the Y-shaped guide groove, which in turn drives the upper hinge shaft and the lower hinge shaft to move the mold support. This causes the mold support to drive the upper mold base from a horizontal downward state to a vertical state, completing the demolding of the upper mold base and the lower mold base.

[0020] Preferably, the molten metal comprises the following raw materials by weight percentage: C 3.0-3.1%, Si 2.30-2.40%, Mn 0.9-1.0%, S 0.06%-0.08%, P 0.08%, with the balance being Fe.

[0021] The embodiments of this application have the following main advantages: In this embodiment of the invention, the independent heating tank and the gating heating tank in the sand-coating heating mechanism are connected, and the adjustable heating part and the gating local strengthening part work together to achieve the organic unity of metal cavity preheating and inlet gating local strengthening heating and heat preservation. This effectively extends the liquid feeding time of molten metal in thick parts and gating areas, providing a stable and reliable temperature field environment for the graphitization expansion self-feeding of high silicon-carbon ratio HT300 cast iron. At the same time, the gating active sealing component, driven by the second air pump, accurately seals the main gate before the graphitization expansion begins through the linkage of the first piston seat, the second piston seat and the linkage sealing part, and forms a pressure barrier with the help of the anti-backflow air pipe to prevent the molten metal from flowing back, ensuring the full utilization of the self-feeding behavior and the density of the internal structure of the casting. In addition, the mold closing linkage part, through the cooperation of the Y-shaped guide slide, the hinge rod mechanism and the spring telescopic rod, realizes the upper mold seat from horizontal to vertical. The smooth transition from the lower state to the vertical longitudinal state facilitates the complete removal of residual coating sand under gravity during sand cleaning, and also ensures uniform flow of coating sand from top to bottom without dead corners during sand injection. Furthermore, the shock absorption protection provided by the inclined limiting slide and spring telescopic rod effectively prevents damage to the integrity of the coating sand layer caused by mold closing impact. The sand coating heating mechanism, the active sprue closing component, and the mold closing linkage do not operate in isolation, but rather coordinate and support each other. Through the coordinated cooperation of the sand coating heating mechanism, the active sprue closing component, and the mold closing linkage, the sand coating heating mechanism provides sufficient liquid shrinkage time window for the active sprue closing component, the active sprue closing component creates conditions for stable molding after the mold closing linkage switches postures, and the mold closing linkage lays the foundation for the uniformity of the temperature field of the heating mechanism by improving the efficiency and quality of sand coating. The combined effect of these three components ultimately yields a high-performance casting with a dense internal structure and no shrinkage porosity.

[0022] In this embodiment of the invention, both the sand-covering heating mechanism and the active sealing component of the gating system are pneumatically driven. This not only simplifies the equipment structure and improves operational reliability under high-temperature environments, but also allows the air pressure output from the first air pump to enter the third piston seat through the pump-in conduit, pushing the third piston plate to compress the second return spring and causing the second push rod to slide horizontally. This, in turn, drives the rack drive frame and the linkage rack to reciprocate. The linkage rack drives the first gear to rotate, causing the spiral heating ring to rotate, accelerating the flow of hot air between the independent heating tank and the gating heating tank. Simultaneously, the rack drive frame drives the drive slide rod to further accelerate its reciprocating motion under the synergistic effect of the acceleration swing arm and the acceleration swing spring, thereby enhancing the efficiency of hot air circulation and achieving rapid and uniform preheating of the metal cavity and the inner gating area. On the other hand, this pneumatic power and the second air pump of the active sealing component of the gating system form a co-current mechanism. Through synchronous control of the air pressure signal, the two can be controlled by the pneumatic power source after the molten metal fills the metal cavity. The second air pump immediately initiates the main gate sealing action, while the first air pump continuously maintains the heating cycle during the preheating stage and the initial pouring stage. The timing of the two air pumps is precisely coupled through the control system, ensuring that the sand heating mechanism continuously provides heat during the feeding stage and the active gate sealing component precisely cuts off the channel before graphitization expansion begins. The rapid response and pressure controllability of the pneumatic power ensure seamless connection between the two key actions of temperature field maintenance and pouring sealing, avoiding insufficient feeding time or delayed sealing timing due to power switching delays. In addition, the working medium of the pneumatic system is compressed air, which is clean, environmentally friendly, and readily available. It has good compatibility with the high-temperature environment of iron mold sand casting and will not contaminate the coated sand or casting surface due to hydraulic oil leakage. At the same time, the pneumatic drive can maintain pressure briefly through the accumulator in the event of a power failure, providing a safety redundancy for gate sealing in emergency situations. This improves the overall operational reliability, maintenance convenience, and process stability of the device.

[0023] In this embodiment of the invention, the active sealing component of the gating system is pneumatically driven. Compressed gas from a second air pump pushes a first piston plate to compress a first return spring, causing a first push rod to slide horizontally. Simultaneously, the first push rod drives a second piston plate to compress gas within the second piston seat. This gas is then directed into the main gating system via an anti-backflow air pipe, forming a positive pressure barrier before the main gating system is fully closed. This pressure barrier exerts a downward thrust on the molten metal within the main gating system, ensuring continuous injection of molten metal into the metal cavity during the sealing operation, preventing backflow or interruption of filling due to momentary disturbances during the rotation of the sealing plate. Simultaneously, the first and second sealing plates are completely... The main gate channel is cut off by splicing. At this time, the air pressure barrier automatically switches to a sealed and pressure-holding state to prevent the high-pressure molten metal in the cavity from rushing back and breaking through the sealing surface during the graphitization expansion stage. In addition, the pneumatic drive and the first air pump of the sand-coating heating mechanism form a co-source collaborative mechanism. The two achieve time-series linkage through a unified air pressure control system. During the pouring stage, the sand-coating heating mechanism maintains a high-temperature environment in the metal cavity and the ingate to delay solidification. The active sealing component of the ingate is activated immediately after the molten metal fills the cavity. The rapid pneumatic response ensures the precise matching of the sealing timing with the graphitization expansion start point, thereby achieving reliable sealing of the ingate and full utilization of the self-compensating behavior while ensuring sufficient injection of molten metal.

[0024] This invention, through the deep coupling of the sand-coating heating mechanism, the active sprue sealing component, and the mold-closing linkage, exhibits synergistic gains that a single mechanism cannot achieve under extreme working conditions. On a continuous production line, the mold-closing linkage uses a Y-shaped guide groove to flip the upper mold base to a vertical orientation, not only using gravity to achieve online, non-stop sand-coating residue self-cleaning, but also completing maintenance operations in ultra-narrow spaces that traditional equipment requires a large opening and closing stroke. At the same time, the sand-coating heating mechanism breaks the thermal field boundary layer with pneumatic pulses, ensuring temperature uniformity in the narrow space, while the active sprue sealing component completes air-driven cutoff and backflow prevention within a millisecond time window. The three components achieve seamless connection of cleaning-heating-sealing through pneumatic linkage. This synergistic mechanism enables the equipment to break through the dependence of traditional casting equipment on working space and downtime for maintenance, successfully adapting to extreme scenarios such as online mold changing on precision machine tools and side-line casting in narrow machining workshops. While ensuring that the density of high silicon-carbon ratio HT300 castings meets the standard, it compresses non-production time to near zero, achieving high-quality continuous casting under extreme working conditions.

[0025] In this embodiment of the invention, the heating linkage unit operates continuously during the preheating stage and the initial pouring stage to maintain a high-temperature environment in the metal cavity and the ingate, providing a sufficient liquid feeding time window for the molten metal. The active gate sealing component is activated immediately after the molten metal fills the cavity. The rapid pneumatic response ensures seamless connection between the two key actions of temperature field maintenance and pouring sealing. At the same time, the reciprocating motion characteristics of the heating linkage unit match the periodic opening and closing action of the mold closing linkage unit. When the upper mold base switches to the vertical longitudinal state for sand cleaning and sand injection, the heating linkage unit can simultaneously switch to a low-speed heat preservation mode to reduce energy consumption. When the upper mold base switches to the horizontal downward state to prepare for mold closing and pouring, the heating linkage unit automatically switches to a high-speed circulation mode to quickly increase the cavity temperature. The three work together to ultimately achieve overall optimization of sand coating efficiency, temperature field uniformity, and pouring sealing accuracy.

[0026] In this embodiment of the invention, the mold closing linkage unit, through the precise cooperation of a crank-slider type double-link mechanism and a Y-shaped guide groove, achieves the organic unity of upper mold base posture transformation, improved sand coating operation efficiency, and mold closing impact protection. It also forms a coordinated operation throughout the entire process cycle with the sand coating heating mechanism and the active sealing component of the gating system. Furthermore, the upper and lower hinge shafts drive the mold support and upper mold base to smoothly transition from a vertical longitudinal state to a horizontal downward state. When the mold support presses against the inclined limit slide, the spring telescopic rod contracts under pressure to provide elastic buffering, effectively absorbing the impact energy at the moment of mold closing and protecting the integrity of the sand coating layer on the inner wall of the metal cavity. The conversion function works in conjunction with the sand coating heating mechanism. When the upper mold base is in a vertical longitudinal state, the cleaning residue of the coating sand can fall off naturally under the action of gravity. When the sand is injected, the coating sand flows evenly from top to bottom without any horizontal dead corners, which significantly improves the sand coating efficiency and the uniformity of the coating layer thickness. This lays a good foundation for the uniform temperature field control of the subsequent heating linkage. At the same time, the shock absorption and protection of the inclined limit slide and the spring telescopic rod ensure that the coating layer and the metal cavity are tightly fitted after the mold is closed, avoiding local temperature loss caused by damage to the coating layer. This ensures the stability of the temperature field constructed by the local reinforcement part of the sprue and the adjustable heating part. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the device structure provided by the present invention for casting high silicon-to-carbon ratio cast iron parts using a metal mold.

[0028] Figure 2 This is an isometric view of the device provided by the present invention for casting high silicon-to-carbon ratio cast iron parts using a metal mold.

[0029] Figure 3 This is a top view of the apparatus provided by the present invention for casting high silicon-to-carbon ratio cast iron parts using a metal mold.

[0030] Figure 4 yes Figure 3A cross-sectional view along line AA shows an internal schematic diagram of the apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold.

[0031] Figure 5 This is a schematic diagram of the upper mold base provided by the present invention.

[0032] Figure 6 This is an isometric view of the upper mold base provided by the present invention.

[0033] Figure 7 This is a schematic diagram of the active sealing component for the gating system provided by the present invention.

[0034] Figure 8 This is a front view of the active sealing component for the gating system provided by the present invention.

[0035] Figure 9 yes Figure 8 A cross-sectional view along line BB shows an internal schematic diagram of the active sealing component of the gating system.

[0036] Figure 10 yes Figure 7 A magnified view of part A in the diagram.

[0037] Figure 11 This is a schematic diagram of the structure of the lower mold base provided by the present invention.

[0038] Figure 12 This is a three-dimensional structural diagram of the lower mold base provided by the present invention.

[0039] Figure 13 This is a bottom view of the lower mold base provided by the present invention.

[0040] Figure 14 This is a schematic diagram of the heating linkage unit provided by the present invention.

[0041] Figure 15 This is an isometric view of the heating linkage unit provided by the present invention.

[0042] Figure 16 This is a schematic diagram of the internal structure of the third piston seat provided by the present invention.

[0043] Figure 17 This is a schematic diagram of the mold closing drive unit provided by the present invention.

[0044] Figure 18 This is a schematic diagram of the mold closing linkage part provided by the present invention.

[0045] Figure 19 The metallographic structure test results of the high silicon-to-carbon ratio cast iron parts prepared according to the embodiments of the present invention are shown.

[0046] In the diagram: 1-Mold base support assembly, 11-Mold bracket, 12-Mold closing drive unit, 121-Mold closing motor, 122-Second gear, 123-Third gear, 124-Mold closing drive rod, 13-Mold closing linkage unit, 131-Mold support, 132-Y-shaped guide slide, 133-Lower hinge shaft, 134-Upper hinge shaft, 135-Upper hinge rod, 136-Lower hinge rod, 137-Angled limit slide, 138-Spring telescopic rod, 2-Casting mold assembly, 2 1-Upper mold base, 22-Lower mold base, 23-Metal cavity, 24-Sand coating layer, 25-Gating system, 251-Inner sprue, 252-Main gate, 253-Gating riser, 3-Sand coating heating mechanism, 31-Independent heating groove, 32-Gating groove, 33-Adjustable heating part, 331-First gear, 332-Heating ring support, 333-Spiral heating ring, 334-Arc-shaped expansion plate, 34-Gating local reinforcement part, 341-Inner heat collector rod, 3 42-Electric heating jacket, 343-Thermal expansion spiral ring, 35-Heating linkage part, 351-Linkage rack, 352-Rack drive frame, 353-Second push rod, 354-Third piston seat, 3541-Third piston plate, 3542-Second return spring, 355-Pump inlet guide pipe, 356-Drive slide rod, 357-Slide rod support, 358-Acceleration swing spring, 359-Acceleration swing arm, 36-First air pump, 4-Active sealing assembly for gating, 41 - Second air pump, 42- First piston seat, 421- First piston plate, 422- First return spring, 43- Second piston seat, 431- Second piston plate, 432- Anti-backflow air pipe, 44- First push rod, 45- Linkage sealing part, 451- Sealed linkage seat, 452- Linkage drive groove, 453- First hinge seat, 454- Second hinge seat, 455- Inner drive rod, 456- Outer drive sleeve, 457- First sealing plate, 458- Second sealing plate. Detailed Implementation

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0048] This invention addresses the industry pain points of high silicon-to-carbon ratio HT300 gray cast iron in iron mold sand casting, such as shrinkage porosity, uneven hardness, and deteriorated machinability due to insufficient temperature field control, low sand coating efficiency, and lack of timing for gating system closure at 25°C. Targeted research and development was conducted, and it was found that existing technologies (CN112427618B, a die-casting mold with a heating mechanism; CN120115645A, a die-casting mold with a heating mechanism) can only solve single problems (CN112427618B can only achieve overall mold preheating, but cannot provide localized enhanced heating and insulation of the gating area to extend the shrinkage compensation time; CN120115645A can only achieve rigid mold closing and tightening, but cannot simultaneously address sand coating layer protection, mold closing vibration reduction, and upper mold seat posture switching to improve sand coating efficiency). These technologies cannot simultaneously meet the systemic process requirements of metal cavity preheating, coordinated heating and insulation of the gating area, improved sand coating cleaning and blowing efficiency, and active closure and backflow prevention of the gating system in iron mold sand casting.

[0049] Based on existing conventional designs, this invention innovatively proposes an overall technical solution for a device for casting high silicon-to-carbon ratio cast iron parts using a metal mold. Through the organic combination of the sand heating mechanism 3, the active sealing component of the gating system 4, and the mold closing linkage part 13, multiple core actions are achieved, including the coordinated preheating of the metal cavity 23 and the local enhanced heating of the gating system, the vertical and longitudinal attitude switching of the upper mold base 21 for sand coating, and the active sealing and anti-backflow of the main gate 252.

[0050] This invention not only solves the problems of uneven temperature field distribution, low sand coating efficiency, and the inability of the gating system 25 to actively close in the prior art, but also achieves unexpected overall technical effects: Under the constraint of high rigidity of the iron mold, the synergistic effect of the sand coating heating mechanism 3 preheating the metal cavity 23 and the local strengthening heating of the gating system allows the high silicon-carbon ratio HT300 molten iron to obtain sufficient liquid feeding time before the graphitization expansion begins. At the same time, the active gating system closing component 4 cuts off the main gate 252 at a precise time and prevents the molten metal from flowing back. Then, the mold closing linkage part 13 is used to realize the vertical and longitudinal posture switching of the upper mold base 21 to improve the efficiency of sand coating cleaning and blowing. Finally, a high-performance casting with a tensile strength of over 300MPa, a hardness of 190-210HBW, an internal and external hardness difference of ≤10HBW, and a dense internal structure without shrinkage porosity is obtained. This effect is the result of the synergistic effect of multiple mechanisms, rather than a simple superposition of the effects of a single component, nor a conventional combination of common knowledge in the field. It is something that those skilled in the art could not have predicted based on the prior art.

[0051] In summary, in this embodiment of the invention, the interconnected design of the independent heating tank 31 and the gating heating tank 32 in the sand-coating heating mechanism 3, combined with the coordinated work of the adjustable heating part 33 and the gating local reinforcement part 34, achieves the organic unity of preheating of the metal cavity 23 and local reinforcement heating and heat preservation of the inner gating 251. This effectively extends the liquid feeding time of the molten metal in the thick parts and gating area, providing a stable and reliable temperature field environment for the graphitization expansion self-feeding of high silicon-carbon ratio HT300 cast iron. At the same time, the gating active sealing component 4, driven by the second air pump 41, precisely seals the main gate 252 before the graphitization expansion begins through the linkage of the first piston seat 42, the second piston seat 43 and the linkage sealing part 45, and forms a pressure barrier with the help of the anti-backflow air pipe 432 to prevent the molten metal from flowing back, ensuring the full utilization of the self-feeding behavior and the density of the internal structure of the casting. In addition, the mold closing linkage part 13, through the cooperation of the Y-shaped guide slide 132, the hinge rod mechanism and the spring telescopic rod 138, achieves The smooth switching of the upper mold base 21 from a horizontal downward state to a vertical longitudinal state facilitates the complete removal of residual coating sand under gravity during sand cleaning, and also ensures that the coating sand flows evenly from top to bottom without dead corners during sand injection. Furthermore, the shock absorption protection provided by the inclined limiting slide 137 and the spring telescopic rod 138 effectively avoids damage to the integrity of the coating sand layer 24 caused by mold closing impact. The coating sand heating mechanism 3, the active sprue sealing component 4, and the mold closing linkage part 13 do not operate in isolation, but rather cooperate and support each other. Through the coordinated cooperation of the coating sand heating mechanism 3, the active sprue sealing component 4, and the mold closing linkage part 13, the coating sand heating mechanism 3 provides the active sprue sealing component 4 with sufficient liquid shrinkage time window, the active sprue sealing component 4 creates conditions for stable molding after the mold closing linkage part 13 switches postures, and the mold closing linkage part 13 lays the foundation for the uniformity of the temperature field of the heating mechanism by improving the coating sand efficiency and quality. The three work together to ultimately obtain a high-performance casting with a dense internal structure and no shrinkage porosity.

[0052] Furthermore, this invention, through the deep coupling of the sand-coating heating mechanism 3, the active sealing component 4 of the gating system, and the mold-closing linkage 13, exhibits synergistic gains that a single mechanism cannot achieve under extreme working conditions. On a continuous production line, the mold-closing linkage 13 uses the Y-shaped guide groove 132 to flip the upper mold base 21 to a vertical position, not only achieving self-cleaning of sand-coating residue online without stopping the machine using gravity, but also completing maintenance operations in ultra-narrow spaces that traditional equipment requires a large opening and closing stroke to achieve; at the same time, the sand-coating heating mechanism 3 breaks the thermal field boundary layer with the help of pneumatic pulses, ensuring... Maintaining temperature uniformity within the confined space, while the active sealing component 4 of the gating system completes air-driven cutoff and backflow prevention within a millisecond time window, the three achieve seamless connection between cleaning, heating, and sealing through air circuit linkage. This collaborative mechanism enables the equipment to break through the dependence of traditional casting equipment on working space and downtime maintenance, successfully adapting to extreme scenarios such as online mold changing on precision machine tools and side-line casting in confined machining workshops. While ensuring that the density of high silicon-carbon ratio HT300 castings meets the standards, it compresses non-production time to near zero, achieving high-quality continuous casting under extreme working conditions.

[0053] This invention provides an apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold, such as... Figures 1-4 The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold, as shown, specifically includes: The mold base support assembly 1 includes two sets of symmetrically arranged mold supports 11, wherein the two sets of mold supports 11 are arranged in parallel along the longitudinal direction and are fixedly connected at the bottom by a crossbeam; The casting mold assembly 2, mounted on the mold support 11, includes an upper mold base 21, a lower mold base 22, a metal cavity 23, a sand coating layer 24, and a gating system 25. The upper mold base 21 and lower mold base 22 are respectively installed within the mold support 11, and the metal cavity 23 is formed between the upper mold base 21 and the lower mold base 22. The inner wall surface of the metal cavity 23 is pre-attached with a sand coating layer 24. The gating system 25 is used to pour molten metal into the metal cavity 23. For example... Figures 5-6 As shown, the upper mold base 21 has a rectangular plate structure, and the lower mold base 22 has a corresponding groove structure. When the upper mold base 21 and the lower mold base 22 are closed, a complete cavity space is formed, and the metal cavity 23 is opened between the upper mold base 21 and the lower mold base 22. The inner wall surface of the metal cavity 23 is pre-attached with a sand coating layer 24. The sand coating layer 24 is formed by thermosetting coated sand through hot pressing and curing, and the thickness is 7-9mm. The gating system 25 is used to pour molten metal into the metal cavity 23. The ingate 251 is opened at the middle joint surface of the upper mold base 21 and the lower mold base 22. It can be a tapered channel with a gradually narrowing horizontal cross section. The main gate 252 is opened at the top center of the upper mold base 21 and is vertically downward connected to the ingate 251. The gating riser 253 is opened circumferentially at the top of the metal cavity 23 and penetrates the upper mold base 21. The sand-coated heating mechanism 3 is located inside the lower mold base 22 and is used to assist in the sand-coated casting mold and extend the feeding time of the molten metal. The sand-coating heating mechanism 3 includes an independent heating tank 31, a gating heating tank 32, an adjustable heating part 33, a gating local reinforcement part 34, a first air pump 36, and a heating linkage part 35. The independent heating tank 31 is provided corresponding to the metal cavity 23, and the gating heating tank 32 is provided corresponding to the inner gating 251. The independent heating tank 31 and the gating heating tank 32 are connected. The adjustable heating part 33 is provided in the independent heating tank 31, and the gating local reinforcement part 34 is provided in the gating heating tank 32. The heating linkage part 35 is connected to the adjustable heating part 33 and is connected to the first air pump 36.

[0054] In this embodiment, the independent heating groove 31 is provided corresponding to the metal cavity 23 and has an annular groove structure. The gating heating groove 32 is provided corresponding to the inner gating 251. The independent heating groove 31 and the gating heating groove 32 are interconnected through the flow guide channel to form a connected heat medium circulation space. An adjustable heating part 33 is provided in the independent heating groove 31. The adjustable heating part 33 includes a spiral heating ring 333, a heating ring support frame 332 and an arc-shaped expansion plate 334. The spiral heating ring 333 is spirally wound in the heating ring support frame 332. The heating ring support frame 332 is rotatably installed on the top of the independent heating groove 31. The arc-shaped expansion plate 334 is fixedly installed on the side wall of the independent heating groove 31 and is evenly distributed along the circumference. A gating local reinforcement part 34 is provided in the gating heating groove 32. The heating linkage part 35 is connected to the adjustable heating part 33 and is connected to the first air pump 36.

[0055] In this embodiment of the invention, both the sand-covering heating mechanism 3 and the gating active sealing component 4 are pneumatically driven. This not only simplifies the equipment structure and improves operational reliability under high-temperature environments, but also allows the air pressure output by the first air pump 36 to enter the third piston seat 354 through the pump-in conduit 355, pushing the third piston plate 3541 to compress the second return spring 3542 and drive the second push rod 353 to slide horizontally. This, in turn, drives the rack drive frame 352 and the linkage rack 351 to reciprocate. The linkage rack 351 drives the first gear 331 to rotate, causing the spiral heating ring 333 to rotate, accelerating the flow of hot air between the independent heating tank 31 and the gating heating tank 32. At the same time, the rack drive frame 352 drives the drive slide rod 356 to further accelerate the reciprocating motion under the synergistic effect of the acceleration swing arm 359 and the acceleration swing spring 358, thereby enhancing the efficiency of hot air circulation and achieving rapid and uniform preheating of the metal cavity 23 and the inner gating 251 area. On the other hand, this pneumatic power and the second air pump 41 of the gating active sealing component 4 form a co-source synergistic mechanism, and the two are connected through... Synchronous control of the air pressure signal allows the second air pump 41 to immediately activate the main gate 252 for sealing after the molten metal fills the metal cavity 23. Meanwhile, the first air pump 36 continuously maintains the heating cycle during the preheating stage and the initial pouring stage. The timing of the two air pumps is precisely coupled through the control system, ensuring that the sand-coated heating mechanism 3 continuously provides heat during the feeding stage and the active gate sealing component 4 precisely cuts off the channel before graphitization expansion begins. The rapid response and pressure controllability of the pneumatic power ensure seamless connection between the two key actions of temperature field maintenance and pouring sealing, avoiding insufficient feeding time or delayed sealing due to power switching delays. In addition, the working medium of the pneumatic system is compressed air, which is clean, environmentally friendly, and readily available. It is compatible with the high-temperature environment of iron mold sand casting and will not contaminate the coated sand or casting surface due to hydraulic oil leakage. At the same time, the pneumatic drive can maintain pressure briefly through the accumulator in the event of a power failure, providing a safety redundancy for gate sealing in emergency situations. This improves the overall operational reliability, maintenance convenience, and process stability of the device.

[0056] In a further preferred embodiment of the present invention, such as Figures 5-6 As shown, the gating system 25 includes: The ingate 251 is located in the middle of the upper mold base 21 and the lower mold base 22, and the ingate 251 is connected to the metal cavity 23. The ingate 251 is located at the mating surface in the middle of the upper mold base 21 and the lower mold base 22, and is arranged horizontally symmetrically. The inlet end of the ingate 251 is vertically connected to the bottom of the main gate 252, and the ingate 251 is connected to the metal cavity 23. The main gate 252 is located inside the upper mold base 21 and is connected to the ingate 251. The main gate 252 has an inverted conical funnel-shaped structure that is larger at the top and smaller at the bottom. The top opening of the main gate 252 is a circular sprue cup, and the bottom narrows into a cylindrical straight channel that intersects the ingate 251 perpendicularly. The inner wall of the main gate 252 is smoothly transitioned to reduce the flow resistance of molten metal. A gating riser 253 is circumferentially opened in the metal cavity 23, and one end of the gating riser 253 penetrates the upper mold base 21. The gating riser 253 is circumferentially opened at the top hot spot position in the metal cavity 23, and has multiple cylindrical riser mouths distributed in a ring. One end of the gating riser 253 penetrates the upper mold base 21 and is open to the external atmosphere, while the other end extends downward to the inner wall of the metal cavity 23. The connection between the riser mouth and the cavity has a smooth transition necking structure to facilitate the smooth flow of molten metal during liquid feeding. The active sealing component 4 of the gating system is installed inside the main gating 252 to seal the main gating 252 and prevent the molten metal from flowing back during the graphitization expansion stage.

[0057] In a further preferred embodiment of the present invention, such as Figures 7-9 As shown, the active sealing component 4 of the gating system includes: The second air pump 41 is fixedly embedded in the upper mold base 21. The air inlet of the second air pump 41 extends to the outside of the surface of the upper mold base 21, and the second air pump 41 is fixedly installed by buckles or bolts. The air outlet of the second air pump 41 is sealed and connected to the end of the first piston seat 42 through the air guide pipe. The second air pump 41 is a miniature high-pressure air pump with stable and controllable output air pressure. A first piston seat 42 is fixedly installed inside the upper mold seat 21, and one end of the first piston seat 42 is connected to the second air pump 41. A first piston plate 421 is slidably installed inside the first piston seat 42. A first return spring 422 is fixedly connected to one side of the first piston plate 421. The first piston seat 42 has a horizontally arranged cylindrical structure, and the first piston plate 421 has a disc-shaped structure that is precisely fitted with the inner wall of the first piston seat 42. A first return spring 422 is fixedly connected to one side of the first piston plate 421. The first return spring 422 is spirally compressed and arranged axially along the first piston seat 42. One end of the first return spring 422 abuts against the first piston plate 421 and the other end abuts against the end cap of the first piston seat 42, and is used to drive the first piston plate 421 back to its original position after the closing action is completed. The second piston seat 43 is disposed on one side of the first piston seat 42, and a second piston plate 431 is slidably installed inside the second piston seat 43. A first push rod 44 is disposed between the first piston seat 42 and the second piston seat 43, and the two ends of the first push rod 44 are fixedly connected to the first piston plate 421 and the second piston plate 431 respectively. The end of the second piston seat 43 away from the first piston seat 42 is connected to the main gate 252 through the anti-backflow air pipe 432. The second piston seat 43 is also a horizontally arranged cylindrical structure and is coaxially arranged with the first piston seat 42. The second piston plate 431 is slidably installed inside the second piston seat 43, and the second piston plate 431 has a disc-shaped structure and is flush with the inner wall of the second piston seat 43. With precise fit, a first push rod 44 is provided between the first piston seat 42 and the second piston seat 43. The first push rod 44 has a horizontal long rod structure. The two ends of the first push rod 44 are fixedly connected to the first piston plate 421 and the second piston plate 431 respectively. The first push rod 44 passes through the end cap of the first piston seat 42 and slides and seals with the end cap. The end of the second piston seat 43 away from the first piston seat 42 is connected to the upper side wall of the main gate 252 through the anti-backflow air pipe 432. The anti-backflow air pipe 432 has a flexible corrugated pipe structure. One end is sealed to the end of the second piston seat 43, and the other end is obliquely inserted into the inner wall of the main gate 252 for directional blowing of the compressed gas in the second piston seat 43 into the main gate 252. The linkage sealing part 45 is connected to the first push rod 44, driven by the first push rod 44, and actively closes the main gate 252.

[0058] In a further preferred embodiment of the present invention, such as Figure 10 As shown, the linkage closure part 45 includes: A closed linkage seat 451 is fixedly sleeved on the outer wall of the first push rod 44, and a linkage drive groove 452 is fixedly installed inside the closed linkage seat 451. The first hinge seat 453 is disposed on one side of the closed linkage seat 451, and one end of the first hinge seat 453 is slidably connected to the linkage drive groove 452. The first hinge seat 453 is fixedly installed at the end of the inner drive rod 455. The second hinge seat 454 is disposed on the other side of the closed linkage seat 451, and one end of the second hinge seat 454 is also slidably connected to the linkage drive groove 452. The second hinge seat 454 is fixedly sleeved on the end of the outer drive sleeve 456. The inner drive rod 455 passes through the outer drive sleeve 456 and is rotatably connected to the outer drive sleeve 456. The first sealing plate 457 is fixedly installed on the side wall of the inner drive rod 455; The second sealing plate 458 is fixedly installed on the outer wall of the outer drive sleeve 456, and the first and second sealing plates 458 are used to simultaneously seal the main gate 252. The sealing linkage seat 451 has a square block structure, and a linkage drive groove 452 is fixedly installed inside the sealing linkage seat 451. The linkage drive groove 452 has a rectangular groove structure. The first hinge seat 453 is located on one side of the sealing linkage seat 451 and is slidably connected to one end of the linkage drive groove 452. The first hinge seat 453 is fixedly installed at the end of the inner drive rod 455, which has a slender cylindrical structure. The second hinge seat 454 is located on the other side of the sealing linkage seat 451 and is slidably connected to the other end of the linkage drive groove 452. The second hinge seat 454 is fixedly sleeved on the outer drive sleeve 456. At the 6 end, the outer drive sleeve 456 has a hollow cylindrical structure, the inner drive rod 455 passes through the outer drive sleeve 456 and is rotatably connected to the outer drive sleeve 456, the first sealing plate 457 is fixedly installed on the side wall of the inner drive rod 455, and the second sealing plate 458 is fixedly installed on the outer wall of the outer drive sleeve 456. Both the first sealing plate 457 and the second sealing plate 458 have a semi-circular plate structure. Under the drive of the first push rod 44, they rotate synchronously in opposite directions and join together to form a complete circular sealing surface, so as to actively close the main gate 252. The first sealing plate 457 and the second sealing plate 458 are made of heat-resistant ductile iron or chromium-based heat-resistant cast iron. A layer of hard alloy is deposited on the surface of the sealing plate or nitriding treatment is performed, which can effectively prevent molten metal from sticking together, greatly reduce the equipment manufacturing cost and extend the maintenance cycle.

[0059] In this embodiment of the invention, the active sealing component 4 of the gating system is pneumatically driven. Compressed gas output from the second air pump 41 pushes the first piston plate 421 to compress the first return spring 422, causing the first push rod 44 to slide horizontally. Simultaneously, the first push rod 44 drives the second piston plate 431 to compress the gas within the second piston seat 43. This gas is then directed into the main gating 252 via the anti-backflow air pipe 432, forming a positive pressure barrier before the linkage sealing part 45 completely closes the main gating 252. This pressure barrier applies a downward thrust to the molten metal within the main gating 252, ensuring that the molten metal continues to be injected into the metal cavity 23 during the sealing action, preventing backflow or interruption of filling due to momentary disturbances during the rotation of the sealing plate. Simultaneously, the first sealing plate 45... 7. When the second sealing plate 458 is fully assembled, the main gate 252 channel is cut off. At this time, the air pressure barrier automatically transforms into a sealed and pressure-holding state to prevent the high-pressure molten metal in the cavity from rushing back and breaking through the sealing surface during the graphitization expansion stage. In addition, the pneumatic drive and the first air pump 36 of the sand-coated heating mechanism 3 form a co-source mechanism. The two achieve time-series linkage through a unified air pressure control system. During the pouring stage, the sand-coated heating mechanism 3 maintains a high-temperature environment in the metal cavity 23 and the ingate 251 to delay solidification. The active sealing component 4 of the gating system is activated immediately after the molten metal fills the cavity. The rapid pneumatic response ensures the precise matching of the sealing timing with the graphitization expansion start point. Thus, under the premise of ensuring sufficient injection of molten metal, reliable sealing of the ingate 251 and full utilization of its self-compensating behavior are achieved.

[0060] In a further preferred embodiment of the present invention, such as Figures 11-13 As shown, the local reinforcement part 34 of the gating system includes: The inner heat collection rod 341 is fixedly embedded in the gating heating groove 32; The thermal expansion spiral ring 343 is fixedly sleeved on the outer wall of the inner heat collector rod 341, and Each electric heating jacket 342 is provided with three sets, which are respectively fixedly sleeved on the outer wall of the inner heat collection rod 341; The inner heat collector rod 341 is cylindrical and made of a metal with high thermal conductivity. It is fixedly embedded in the gating heating groove 32, with its axis coinciding with the center line of the gating heating groove 32. The end of the inner heat collector rod 341 is fixedly connected to the end of the gating heating groove 32, forming a longitudinally continuous support structure. The thermal expansion spiral ring 343 is made of a high expansion coefficient alloy and has a continuous spiral tightly wound structure. It is fixedly sleeved on the middle section of the outer wall of the inner heat collector rod 341. The inner diameter of the thermal expansion spiral ring 343 is interference-fitted with the outer wall of the inner heat collector rod 341. The outer diameter of the ring 343 maintains a gap with the inner wall of the gating heating groove 32 to absorb the heat of the inner heat collecting rod 341 and radiate heat to the surrounding air. There are three sets of electric heating sleeves 342, which are fixedly sleeved on both ends and the middle section of the outer wall of the inner heat collecting rod 341. The three sets of electric heating sleeves 342 are arranged at equal intervals. Each set of electric heating sleeves 342 has a cylindrical structure and wraps around the outer wall of the inner heat collecting rod 341. The inner wall of the electric heating sleeve 342 is tightly fitted with the outer wall of the inner heat collecting rod 341, and the outer wall maintains an annular gap with the inner wall of the gating heating groove 32. The three sets of electric heating sleeves 342 can be independently powered and controlled to achieve segmented and precise heating of the gating area.

[0061] The adjustable heating element 33 includes: The first gear 331 is rotatably mounted on the top of the independent heating tank 31, and one side of the first gear 331 is inserted into the heating ring support bracket 332. The heating ring support bracket 332 is rotatably installed inside the independent heating groove 31; A spiral heating ring 333 is detachably installed within the heating ring support 332, and the spiral heating ring 333 is used to heat the independent heating groove 31. An arc-shaped expansion plate 334 is fixedly installed on the side wall of the independent heating tank 31.

[0062] In this embodiment, the first gear 331 is rotatably mounted at the top center of the independent heating tank 31, and one side of the first gear 331 is inserted into the heating ring support 332 via a spline structure, forming a detachable transmission connection; the heating ring support 332 has a circular frame structure, and its outer edge is rotatably engaged with the inner wall of the independent heating tank 31 via ball bearings. The heating ring support 332 is rotatably mounted in the independent heating tank 31, and the rotation axis of the heating ring support 332 coincides with the center line of the independent heating tank 31; the spiral heating ring 333 is made of resistance wire wound into a planar spiral structure. The spiral heating ring 333 is detachably mounted in the heating ring support 332. The outer end of the spiral heating ring 333 is snapped and fixed to the inner edge of the heating ring support 332, and the inner end is connected to the center terminal. The spiral heating ring 333 uses... The air inside the independent heating tank 31 is radiantly heated. The spiral plane of the spiral heating ring 333 is arranged parallel to the bottom wall of the independent heating tank 31. The arc-shaped expansion plate 334 is made of bimetallic sheet material and has an arc-shaped sheet structure. Multiple arc-shaped expansion plates 334 are provided and evenly distributed along the circumference. The arc-shaped expansion plates 334 are fixedly installed on the side wall of the independent heating tank 31 to sense the temperature inside the independent heating tank 31 and deform to adjust the cross-sectional area of ​​the hot air flow channel. When the temperature inside the independent heating tank 31 rises, the arc-shaped expansion plate 334 bends and deforms into the tank due to heat, reducing the cross-sectional area of ​​the hot air flow channel and accelerating the flow of hot air towards the gating heating tank 32. When the temperature drops, the arc-shaped expansion plate 334 springs back to its original position, increasing the cross-sectional area of ​​the channel and slowing down the flow speed of hot air, thereby realizing the self-regulation of the hot air flow in the independent heating tank 31.

[0063] In a further preferred embodiment of the present invention, such as Figures 14-15 As shown, the heating linkage unit 35 includes: The linkage rack 351 is slidably installed in the lower mold base 22, and the linkage rack 351 meshes with the first gear 331 for transmission. The linkage rack 351 has a long strip structure, and its top surface is machined with standard rack tooth profile. The linkage rack 351 is slidably installed in the horizontal guide groove in the lower mold base 22, and the sliding direction of the linkage rack 351 is parallel to the length direction of the lower mold base 22. The rack drive frame 352 is fixedly connected to the linkage rack 351, and the rack drive frame 352 is slidably connected to the lower mold base 22. A second push rod 353 is fixedly connected to one side of the rack drive frame 352. The second push rod 353 has a horizontal cylindrical rod structure. Third piston seat 354, such as Figure 16As shown, a third piston plate 3541 is fixedly embedded in the lower mold base 22 and slidably installed in the third piston seat 354. A second return spring 3542 is fixedly connected to one side of the third piston plate 3541, and the other side of the third piston plate 3541 is connected to the second push rod 353. The third piston seat 354 is connected to the first air pump 36 through the pump inlet guide pipe 355. The third piston seat 354 has a horizontally arranged cylindrical structure. The third piston seat 354 is fixedly embedded in the lower mold base 22 and slidably installed in the third piston seat 354. The third piston plate 3541 has a disc-shaped structure and is precisely fitted with the inner wall of the third piston seat 354. A second return spring 3542 is fixedly connected to one side of the third piston plate 3541. The second return spring 3542 is spirally compressed and arranged along the axial direction of the third piston seat 354. A drive slide rod 356 is fixedly installed inside the rack drive frame 352, and both ends of the drive slide rod 356 pass through a slide rod support 357. The slide rod support 357 is fixedly installed inside the lower mold base 22. An acceleration swing arm 359 is rotatably installed inside the slide rod support 357. An acceleration swing spring 358 is fixedly connected to one end of the acceleration swing arm 359. One end of the acceleration swing spring 358 is fixedly connected to the drive slide rod 356. The acceleration swing arm 359 has a rectangular rod structure. One end of the acceleration swing arm 359 is rotatably connected to the slide rod support 357 through a pin. An acceleration swing spring 358 is fixedly connected to one end of the acceleration swing arm 359. The acceleration swing spring 358 has a tension spiral structure. One end of the acceleration swing spring 358 is fixedly connected to the side wall of the drive slide rod 356, and the other end is fixedly connected to the end of the acceleration swing arm 359. The other end of the acceleration swing arm 359 is a free swing end, which is used to generate an inertial acceleration effect when the drive slide rod 356 reciprocates.

[0064] In this embodiment of the invention, the heating linkage unit 35 operates continuously during the preheating stage and the initial pouring stage to maintain a high-temperature environment between the metal cavity 23 and the inner runner 251, providing sufficient liquid feeding time window for the molten metal. The active sealing component 4 of the runner is activated immediately after the molten metal fills the cavity. The rapid pneumatic response ensures seamless connection between the two key actions of temperature field maintenance and pouring sealing. At the same time, the reciprocating motion characteristics of the heating linkage unit 35 match the periodic opening and closing action of the mold closing linkage unit 13. When the upper mold base 21 switches to the vertical longitudinal state for sand cleaning and sand injection, the heating linkage unit 35 can simultaneously switch to the low-speed heat preservation mode to reduce energy consumption. When the upper mold base 21 switches to the horizontal downward state to prepare for mold closing and pouring, the heating linkage unit 35 automatically switches to the high-speed circulation mode to quickly increase the cavity temperature. The three work together to achieve overall optimization of sand coating efficiency, temperature field uniformity and pouring sealing accuracy.

[0065] In a further preferred embodiment of the present invention, such as Figure 1 As shown, the mold base support assembly 1 further includes: The mold closing drive unit 12 is disposed inside the mold support 11, such as... Figure 17 As shown, the mold closing drive unit 12 includes a mold closing motor 121, a second gear 122, a third gear 123, and a mold closing drive rod 124. The mold closing drive rod 124 is rotatably installed inside the mold support 11. The third gear 123 is fixedly sleeved on the outer wall of the mold closing drive rod 124. The second gear 122 is disposed on one side of the third gear 123, and the second gear 122 meshes with the third gear 123 for transmission. One side of the second gear 122 is fixedly connected to the mold closing motor 121, and the mold closing motor 121 is fixedly installed on the mold support 11. The mold closing linkage part 13 is symmetrically arranged in the mold support 11, and the mold closing linkage part 13 is connected to the mold closing drive part 12 and the upper mold base 21 respectively. The mold closing linkage part 13 is used to drive the upper mold base 21 and the lower mold base 22 to close the mold, and assist the upper mold base 21 and the lower mold base 22 to open the mold.

[0066] In this embodiment, the mold closing motor 121 is a horizontal geared motor, whose output shaft is horizontally arranged and fixedly installed on the mounting platform on the outer wall of the mold support 11. The mold closing drive rod 124 has a horizontal long shaft structure. The two ends of the mold closing drive rod 124 are rotatably installed in the bearing seats inside the mold support 11 through deep groove ball bearings. The third gear 123 is fixedly sleeved in the middle of the outer wall of the mold closing drive rod 124. The mold closing drive rod 124 serves as the power input shaft for the entire mold closing action, transmitting the rotational motion of the mold closing motor 121 to the mold closing linkage part 13. The mold closing linkage part 13 is symmetrically arranged inside the mold support 11 and located on both sides of the mold closing drive rod 124. The mold closing linkage part 13 is connected to the mold closing drive part 12 and the upper mold base 21 respectively. The mold closing linkage part 13 is used to drive the upper mold base 21 and the lower mold base 22 to close the mold and assist the upper mold base 21 and the lower mold base 22 to open the mold. The mold closing linkage part 13 adopts a double linkage slider mechanism to realize the posture conversion and motion guidance of the upper mold base 21.

[0067] In a further preferred embodiment of the present invention, such as Figure 18 As shown, the mold closing linkage unit 13 includes: Mold support 131 is fixedly installed on both sides of upper mold base 21, and upper hinge shaft 134 and lower hinge shaft 133 are fixedly installed on the side wall of mold support 131 respectively. Mold support 131 has a block structure and is provided in two sets. The two sets of mold support 131 are symmetrically fixedly installed on the two side walls of upper mold base 21, and upper hinge shaft 134 and lower hinge shaft 133 are fixedly installed on the side wall of mold support 131 respectively. Mold support 131 is fixedly connected to upper mold base 21 by buckle or bolt. Y-shaped guide groove 132 is formed inside the mold support 11, and the upper hinge shaft 134 and the lower hinge shaft 133 are slidably embedded in the Y-shaped guide groove 132. The Y-shaped guide groove is composed of a vertical section and a middle inclined section, and the whole has a Y-shaped bifurcated structure. The vertical section is used to position the upper hinge shaft 134 in the vertical longitudinal state, and the middle inclined section is a posture conversion transition slide. The upper hinge rod 135 is hinged at one end to the mold closing drive rod 124, and at the other end to the lower hinge rod 136. The end of the lower hinge rod 136 away from the upper hinge rod 135 is rotatably connected to the lower hinge shaft 133. The upper hinge rod 135 has a long rod structure. One end of the upper hinge rod 135 is hinged to the end of the mold closing drive rod 124 through a pin, and the other end is hinged to the lower hinge rod 136 through a pin. The lower hinge rod 136 also has a long rod structure. The end of the lower hinge rod 136 away from the upper hinge rod 135 is rotatably connected to the lower hinge shaft 133 through a bearing. The upper hinge rod 135 and the lower hinge rod 136 form two connecting rods in a planar four-bar linkage mechanism. The mold support 131 serves as a connecting rod, and the mold bracket 11 serves as a frame, together forming a crank-slider type attitude conversion mechanism. An inclined limiting slide 137 is slidably embedded in the inner wall of the mold support 11, and one side of the inclined limiting slide 137 is slidably connected to the mold support 131. A spring telescopic rod 138 is fixedly connected to the bottom of the inclined limiting slide 137, and the spring telescopic rod 138 is fixedly installed on the surface of the mold support 11.

[0068] In this embodiment, the inclined limiting slide 137 has a wedge-shaped block structure, and its inclined surface slides and fits against the corresponding inclined surface of the side wall of the mold support 131. The inclined limiting slide 137 is slidably embedded in the guide groove of the inner wall of the mold support 11, and one side of the inclined limiting slide 137 is slidably connected to the mold support 131. A spring telescopic rod 138 is fixedly connected to the bottom of the inclined limiting slide 137. The spring telescopic rod 138 consists of an outer sleeve, an inner slide rod, and a compression spring. The outer sleeve is fixedly installed on the mold support 11. On the surface of the mold support 11, the upper end of the inner slide rod is fixedly connected to the bottom surface of the inclined limiting slide 137, and the lower end slides through the top wall of the outer sleeve. The compression spring is sleeved on the outer periphery of the inner slide rod and abuts between the bottom surface of the inclined limiting slide 137 and the top surface of the outer sleeve. It is used to provide elastic buffering force at the end of mold closing, absorb the impact energy at the moment when the upper mold base 21 and the lower mold base 22 close, protect the integrity of the sand coating layer 24, and at the same time provide auxiliary ejection force in the early stage of mold opening to assist the upper mold base 21 to disengage from the lower mold base 22.

[0069] In this embodiment of the invention, the mold closing linkage 13, through the precise cooperation of a crank-slider type double-link mechanism and a Y-shaped guide groove 132, achieves the organic unity of upper mold base 21 posture conversion, sand coating operation efficiency improvement, and mold closing impact protection, and forms a coordinated operation with the sand coating heating mechanism 3 and the gating active sealing component 4 throughout the entire process cycle; and enables the upper hinge shaft 134 and lower hinge shaft 133 to drive the mold support 131 and upper mold base 21 to complete a smooth transition from a vertical longitudinal state to a horizontal downward state. When the mold support 131 presses against the inclined limit slide 137, the spring telescopic rod 138 is compressed and contracts to provide elastic buffer, effectively absorbing the impact energy at the moment of mold closing and protecting the integrity of the sand coating layer 24 on the inner wall of the metal cavity 23. The posture conversion function works in conjunction with the sand coating heating mechanism 3. When the upper mold base 21 is in a vertical longitudinal state, the cleaning residue of the coating sand can fall off naturally under the action of gravity. When the sand is injected, the coating sand flows evenly from top to bottom without horizontal dead corners, which significantly improves the sand coating efficiency and the uniformity of the coating layer 24 thickness. This lays a good foundation for the uniform temperature field control of the subsequent heating linkage part 35. At the same time, the shock absorption protection of the inclined limit slide 137 and the spring telescopic rod 138 ensures the tight fit between the coating layer 24 and the metal cavity 23 after the mold is closed, avoiding local temperature loss caused by damage to the coating layer 24. This ensures the stability of the temperature field constructed by the local reinforcement part 34 of the sprue and the adjustable heating part 33.

[0070] On the other hand, embodiments of the present invention also provide a method for casting high silicon-to-carbon ratio cast iron parts using a metal mold, the method comprising: S10, turn on the spiral heating ring 333. The spiral heating ring 333 starts to heat the independent heating tank 31, so that the independent heating tank 31 transfers heat to the corresponding metal cavity 23. After the metal cavity 23 is heated to 200-250℃, it is kept at the temperature. Then, the core shooter blows the fluid coated sand into the metal cavity 23. After the fluid coated sand comes into contact with the surface of the metal cavity 23, it solidifies for 1-2 minutes to form a sand coating layer 24 with a thickness of 7-9mm. S20, the mold closing motor 121 is turned on. The mold closing motor 121 rotates in the forward direction, driving the second gear 122 to rotate. The second gear 122 drives the third gear 123 and the mold closing drive rod 124 to rotate. The mold closing drive rod 124 drives the upper hinge rod 135 and the lower hinge rod 136 to swing. This causes the lower hinge rod 136 to drive the lower hinge shaft 133 to slide along the Y-shaped guide groove 132, and simultaneously drive the upper hinge seat to slide along the Y-shaped guide groove 132. This causes the upper hinge shaft 134 and the lower hinge shaft 133 to drive the mold support 131 to move. This causes the mold support 131 to drive the upper mold seat 21 to change from a longitudinal state to a horizontal downward state and close with the lower mold seat 22. At the same time, the mold support 131 presses the inclined limit slide 137, and the inclined limit slide 137 presses the spring telescopic rod 138, so that the spring telescopic rod 138 provides shock absorption and protection for the upper mold seat 21. S30, after the upper mold base 21 and the lower mold base 22 are closed, molten metal is injected into the main gate 252. The molten metal enters the inner runner 251 and the metal cavity 23. At the same time, the first air pump 36, the electric heating jacket 342 and the spiral heating ring 333 are turned on. The spiral heating ring 333 starts to heat the independent heating groove 31, so that the independent heating groove 31 transfers heat to the corresponding metal cavity 23. At the same time, the electric heating jacket 342 heats the runner heating groove 32, and the thermal expansion spiral ring 343 and the arc expansion plate 334 expand due to heat, which increases the pressure of the independent heating groove 31 and the runner heating groove 32, realizing rapid heat conduction to the metal cavity 23 and the inner runner 251. S40, the first air pump 36 starts to pump gas into the third piston seat 354, thereby pushing the third piston plate 3541 and the second push rod 353 to slide horizontally. This causes the second push rod 353 to drive the rack drive frame 352 and the linkage rack 351 to reciprocate horizontally. The linkage rack 351 drives the first gear 331 to rotate, which in turn drives the spiral heating ring 333 to rotate, thereby accelerating the flow of hot air in the independent heating tank 31 and the gating heating tank 32. At the same time, the movement of the rack drive frame 352 can drive the drive slide rod 356 to move, so that the acceleration swing arm 359 accelerates the horizontal reciprocating motion of the drive slide rod 356 under the action of the acceleration swing spring 358, thereby accelerating the flow of hot air in the independent heating tank 31 and the gating heating tank 32. S50, after the molten metal fills the metal cavity 23, the second air pump 41 is turned on. The second air pump 41 drives the first piston plate 421, the second piston plate 431 and the first push rod 44 to slide, so that the second piston plate 431 pumps the gas in the second piston seat 43 into the anti-backflow air pipe 432, and then enters the main gate 252 from the anti-backflow air pipe 432 to prevent the molten metal in the main gate 252 from flowing back. At the same time, the first push rod 44 drives the closed linkage seat 451 to move, so that the closed linkage seat 451 drives the first hinge seat 453 and the second hinge seat 454 to rotate synchronously. The first hinge seat 453 drives the inner drive rod 455 and the first sealing plate 457 to rotate, and the second hinge seat 454 drives the outer drive sleeve 456 and the second sealing plate 458 to rotate, so that the first sealing plate 457 and the second sealing plate 458 close the main gate 252. After the main gate 252 is closed, liquid feeding is performed through the pouring riser 253. After the molten metal cools and solidifies, the mold closing motor 121 is turned in reverse. The mold closing motor 121 drives the second gear 122 to rotate, which in turn drives the third gear 123 and the mold closing drive rod 124 to rotate. The mold closing drive rod 124 drives the upper hinge rod 135 and the lower hinge rod 136 to swing, which causes the lower hinge rod 136 to drive the lower hinge shaft 133 in the Y-shaped guide groove 132, and simultaneously drives the upper hinge seat to slide along the Y-shaped guide groove 132. This causes the upper hinge shaft 134 and the lower hinge shaft 133 to drive the mold support 131 to move, which causes the mold support 131 to drive the upper mold base 21 to change from a horizontal downward state to a vertical state, completing the demolding of the upper mold base 21 and the lower mold base 22, and producing a high silicon-carbon ratio cast iron part.

[0071] In this embodiment, the molten metal comprises the following raw materials by weight percentage: C 3.0-3.1%, Si 2.30-2.40%, Mn 0.9-1.0%, S 0.06%-0.08%, P 0.08%, with the balance being Fe.

[0072] This invention employs a method for casting high-silicon-carbon ratio cast iron parts using a metal mold. By increasing the silicon-carbon ratio to 0.74-0.80 and the carbon equivalent to 3.76-3.90, combined with a secondary inoculation process, the high-silicon-carbon ratio molten metal, under the high-rigidity constraint of the metal cavity 23, achieves self-compensation through graphitization expansion. Simultaneously, an 8mm sand coating layer 24 precisely controls the cooling rate, ensuring that the cooling rate is greater than that of sand casting to refine the microstructure and improve mechanical properties, while avoiding the formation of white iron microstructure due to excessively rapid cooling. This ensures that the hardness of the high-silicon-carbon ratio cast iron parts is controlled within the machinable range of 190-210 HBW. This method uses a coating layer... The film sand molding process allows for recyclable production, eliminating the impact of climatic conditions on production, effectively solving porosity and sand inclusion defects, and significantly improving the dimensional accuracy and surface finish of castings. The mold's good rigidity, combined with the precise sealing of the 251 inlet before graphitization expansion, solves defects such as sand expansion, shrinkage cavities, and porosity, enabling riserless or low-riser casting and saving production costs. Ultimately, high-performance castings with a tensile strength exceeding 300 MPa, an internal and external hardness difference ≤10 HBW, and a dense internal structure without shrinkage cavities are obtained. This comprehensively achieves a harmonious unity of mechanical properties, machinability, and casting processability. Figure 19 The metallographic structure test results of the high silicon-to-carbon ratio cast iron parts prepared according to embodiments of the present invention are shown, wherein, Figure 19Image (a) in 19 is a 100x magnified image before etching. It shows that the graphite is uniformly distributed in small flakes with moderate length and diffuse distribution. There is no obvious graphite aggregation or coarsening. Image (b) in 19 is a 100x magnified image after etching. After etching with 4% nitric acid alcohol solution, it is clear that the matrix structure is fine lamellar pearlite with small interlamellar spacing and extremely low ferrite content. There are no free cementite or phosphorus eutectic and other harmful phases precipitated in the matrix, and the grain boundaries are clear and complete. The metallographic characteristics indicate that, under the high rigidity constraint of the metal cavity 23, combined with the moderate cooling rate control of the 8mm sand coating layer 24 and the combined effect of the high silicon-to-carbon ratio HT300 chemical composition and the secondary inoculation process, graphitization is fully carried out during the solidification of the casting, and the degree of pearlitization of the matrix is ​​high. This ensures that the casting body has excellent mechanical properties with a tensile strength of over 300MPa, a hardness of 190-210HBW, and an internal and external hardness difference of ≤10HBW. At the same time, the internal structure is dense and free of shrinkage porosity, verifying the significant technical effect of the device and method described in this invention in eliminating shrinkage porosity defects and improving the density of castings.

[0073] In summary, this invention provides an apparatus and method for casting high silicon-to-carbon ratio cast iron parts using a metal mold. In this embodiment, the conductive design of the independent heating tank 31 and the gating heating tank 32 in the sand-coating heating mechanism 3, combined with the coordinated work of the adjustable heating section 33 and the gating local strengthening section 34, achieves the organic unity of preheating the metal cavity 23 and local strengthening heating and heat preservation of the inner gating 251. This effectively extends the liquid feeding time of the molten metal in thick sections and the gating area, thus improving the casting efficiency of high silicon-to-carbon ratio HT300 cast iron. The graphitization expansion self-compensation provides a stable and reliable temperature field environment. Simultaneously, driven by the second air pump 41, the gating active sealing component 4 precisely seals the main gating 252 before graphitization expansion begins through the linkage of the first piston seat 42, the second piston seat 43, and the linkage sealing part 45. It also forms a pressure barrier with the help of the anti-backflow air pipe 432 to prevent molten metal backflow, ensuring full utilization of the self-compensation behavior and the density of the casting's internal structure. Furthermore, the mold closing linkage part 13, through the Y-shaped guide groove 132 and the hinge rod mechanism… In conjunction with the spring telescopic rod 138, the upper mold base 21 smoothly switches from a horizontal downward state to a vertical longitudinal state. This facilitates the complete removal of residual coating sand under gravity during sand cleaning and ensures uniform flow of the coating sand from top to bottom without dead zones during sand injection. Furthermore, the shock absorption protection provided by the inclined limiting slide 137 and the spring telescopic rod 138 effectively prevents damage to the integrity of the coating layer 24 from mold closing impacts. The sand heating mechanism 3, the active sprue sealing component 4, and the mold closing linkage 13 do not operate in isolation but are interconnected. Through mutual cooperation and support, the sand covering heating mechanism 3, the active sprue sealing component 4, and the mold closing linkage part 13 work together. The sand covering heating mechanism 3 provides the active sprue sealing component 4 with a sufficient liquid shrinkage time window. The active sprue sealing component 4 creates conditions for stable molding after the mold closing linkage part 13 switches postures. The mold closing linkage part 13 lays the foundation for the uniformity of the temperature field of the heating mechanism by improving the sand covering efficiency and quality. The three work together to finally obtain a high-performance casting with a dense internal structure and no shrinkage porosity.

[0074] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. An apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold, characterized in that, The device includes: A mold base support assembly, comprising two sets of symmetrically arranged mold supports; A casting mold assembly, mounted on the mold support, includes an upper mold base, a lower mold base, a metal cavity, a sand coating layer, and a gating system. The upper mold base and the lower mold base are respectively installed in the mold support, and the metal cavity is opened between the upper mold base and the lower mold base. The inner wall surface of the metal cavity is pre-attached with a sand coating layer, and the gating system is used to pour molten metal into the metal cavity. The sand-coated heating mechanism is located inside the lower mold base and is used to assist in the casting of the coated sand mold and extend the feeding time of the molten metal. The sand-coating heating mechanism includes an independent heating tank, a gating heating tank, an adjustable heating part, a gating local reinforcement part, a first air pump, and a heating linkage part. The independent heating tank is set corresponding to the metal cavity, and the gating heating tank is set corresponding to the inner gating. The independent heating tank and the gating heating tank are connected. The adjustable heating part is set in the independent heating tank, and the gating local reinforcement part is set in the gating heating tank. The heating linkage part is connected to the adjustable heating part and is connected to the first air pump.

2. The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 1, characterized in that: The gating system includes: The ingate is located in the middle of the upper mold base and the lower mold base, and the ingate is connected to the metal cavity respectively; The main gate is located inside the upper mold base and is connected to the ingate. A gating riser is circumferentially formed inside the metal cavity, and one end of the gating riser penetrates the upper mold base; An active gate sealing component is installed inside the main gate to seal the main gate and prevent molten metal from flowing back during the graphitization expansion stage.

3. The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 2, characterized in that: The active sealing component for the gating system includes: The second air pump is fixedly embedded in the upper mold base; The first piston seat is fixedly installed inside the upper mold base, and one end of the first piston seat is connected to the second air pump. The first piston plate is slidably installed inside the first piston seat, and a first return spring is fixedly connected to one side of the first piston plate. The second piston seat is located on one side of the first piston seat, and a second piston plate is slidably installed inside the second piston seat. A first push rod is provided between the first piston seat and the second piston seat. The two ends of the first push rod are fixedly connected to the first piston plate and the second piston plate, respectively. The end of the second piston seat away from the first piston seat is connected to the main gate through an anti-backflow air pipe. The linkage sealing part is connected to the first push rod, driven by the first push rod, and actively closes the main gate.

4. The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 3, characterized in that: The linkage sealing part includes: A closed linkage seat is fixedly sleeved on the outer wall of the first push rod, and a linkage drive groove is fixedly installed inside the closed linkage seat; The first hinge seat is located on one side of the closed linkage seat, and one end of the first hinge seat is slidably connected to the linkage drive groove. The first hinge seat is fixedly installed at the end of the inner drive rod. The second hinge seat is located on the other side of the closed linkage seat, and one end of the second hinge seat is also slidably connected to the linkage drive groove. The second hinge seat is fixedly sleeved on the end of the outer drive sleeve. The inner drive rod passes through the outer drive sleeve and is rotatably connected to the outer drive sleeve. The first sealing plate is fixedly installed on the side wall of the inner drive rod; The second sealing plate is fixedly installed on the outer wall of the outer drive sleeve, and the first and second sealing plates are used to simultaneously seal the main gate.

5. The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 1, characterized in that: The locally reinforced part of the gating system includes: The inner heat collector rod is fixedly embedded in the heating groove of the gating system; A thermal expansion spiral ring is fixedly sleeved on the outer wall of the inner heat collector rod, and Each electric heating jacket is provided with three sets, which are respectively fixedly sleeved on the outer wall of the inner heat collecting rod; The adjustable heating element includes: The first gear is rotatably mounted on the top of the independent heating tank, and one side of the first gear is inserted into the heating ring support. The heating ring support is rotatably installed inside the independent heating tank; A spiral heating ring is detachably installed within the heating ring support bracket, and the spiral heating ring is used to heat an independent heating tank. An arc-shaped expansion plate is fixedly installed on the side wall of the independent heating tank.

6. The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 5, characterized in that: The heating linkage unit includes: The linkage rack is slidably installed in the lower mold base, and the linkage rack meshes with the first gear for transmission; A rack drive frame is fixedly connected to a linkage rack, and the rack drive frame is slidably connected to the lower mold base. A second push rod is fixedly connected to one side of the rack drive frame. The third piston seat is fixedly embedded in the lower mold base, and the third piston plate is slidably installed in the third piston seat. A second return spring is fixedly connected to one side of the third piston plate, and the other side of the third piston plate is connected to the second push rod. The third piston seat is connected to the first air pump through the pump inlet guide pipe. The drive slide rod is fixedly installed inside the rack drive frame, and both ends of the drive slide rod pass through the slide rod support seat. The slide rod support seat is fixedly installed inside the lower mold base. An acceleration swing arm is rotatably installed inside the slide rod support seat. An acceleration swing spring is fixedly connected to one end of the acceleration swing arm, and one end of the acceleration swing spring is fixedly connected to the drive slide rod.

7. The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 1, characterized in that: The mold base support assembly also includes: A mold closing drive unit is disposed inside a mold support. The mold closing drive unit includes a mold closing motor, a second gear, a third gear, and a mold closing drive rod. The mold closing drive rod is rotatably mounted inside the mold support. The third gear is fixedly sleeved on the outer wall of the mold closing drive rod. The second gear is disposed on one side of the third gear and meshes with the third gear for transmission. One side of the second gear is fixedly connected to the mold closing motor, and the mold closing motor is fixedly mounted on the mold support. The mold closing linkage is symmetrically arranged in the mold support, and the mold closing linkage is connected to the mold closing drive and the upper mold base respectively. The mold closing linkage is used to drive the upper mold base and the lower mold base to close the mold, and to assist the upper mold base and the lower mold base to open the mold.

8. The apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 7, characterized in that: The mold closing linkage unit includes: The mold support is fixedly installed on both sides of the upper mold base, and the side walls of the mold support are respectively fixedly installed with an upper hinge shaft and a lower hinge shaft; A Y-shaped guide groove is formed inside the mold support, and the upper hinge shaft and the lower hinge shaft are slidably embedded in the Y-shaped guide groove respectively; The upper hinge rod is hinged at one end to the mold closing drive rod and at the other end to the lower hinge rod. The end of the lower hinge rod away from the upper hinge rod is rotatably connected to the lower hinge shaft. An inclined limiting slide is slidably embedded in the inner wall of the mold support, and one side of the inclined limiting slide is slidably connected to the mold support. A spring telescopic rod is fixedly connected to the bottom of the inclined limiting slide, and the spring telescopic rod is fixedly installed on the surface of the mold support.

9. A method for casting high silicon-to-carbon ratio cast iron parts using a metal mold, implemented based on the apparatus for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in any one of claims 1-8, characterized in that: The method for casting high silicon-to-carbon ratio cast iron parts using a metal mold includes: S10, turn on the spiral heating ring. The spiral heating ring starts to heat the independent heating tank, so that the independent heating tank transfers heat to the corresponding metal cavity. After the metal cavity is heated to 200-250℃, it is kept at the temperature. Then, the core shooter blows the fluid coated sand into the metal cavity. After the fluid coated sand comes into contact with the surface of the metal cavity, it solidifies for 1-2 minutes to form a sand coating layer with a thickness of 7-9mm. S20, the mold closing motor is turned on. The forward rotation of the mold closing motor drives the second gear to rotate, which in turn drives the third gear and the mold closing drive rod to rotate. The mold closing drive rod drives the upper hinge rod and the lower hinge rod to swing, which in turn drives the lower hinge shaft to slide in the Y-shaped guide groove. Simultaneously, it drives the upper hinge seat to slide along the Y-shaped guide groove, which in turn drives the upper hinge shaft and the lower hinge shaft to move the mold support. This causes the mold support to drive the upper mold seat to change from a longitudinal state to a horizontal downward state and close with the lower mold seat. At the same time, the mold support presses against the inclined limit slide, which in turn presses against the spring telescopic rod, which provides shock absorption and protection for the upper mold seat. S30, after the upper mold base and lower mold base are closed, molten metal is injected into the main gate. The molten metal enters the inlet runner and the metal cavity through the molten metal. At the same time, the first air pump, electric heating jacket and spiral heating ring are turned on. The spiral heating ring starts to heat the independent heating tank, so that the independent heating tank transfers heat to the corresponding metal cavity. At the same time, the electric heating jacket heats the runner heating tank, and the thermal expansion spiral ring and arc expansion plate expand due to heat, which increases the pressure of the independent heating tank and the runner heating tank, realizing rapid heat conduction to the metal cavity and the inlet runner. S40, the first air pump starts and pumps gas into the third piston seat, thereby pushing the third piston plate and the second push rod to slide horizontally. This causes the second push rod to drive the rack drive frame and the linkage rack to reciprocate horizontally. The linkage rack drives the first gear to rotate, which in turn drives the spiral heating ring to rotate, thereby accelerating the flow of hot air in the independent heating tank and the gating heating tank. At the same time, the movement of the rack drive frame can drive the drive slide rod to move, so that the acceleration swing arm accelerates the horizontal reciprocating motion of the drive slide rod under the action of the acceleration swing spring, thereby accelerating the flow of hot air in the independent heating tank and the gating heating tank. S50, after the molten metal fills the metal cavity, the second air pump is turned on. The second air pump drives the first piston plate, the second piston plate and the first push rod to slide, so that the second piston plate pumps the gas in the second piston seat into the anti-backflow air pipe, and then enters the main gate from the anti-backflow air pipe to prevent the molten metal in the main gate from flowing back. At the same time, the first push rod drives the closed linkage seat to move, so that the closed linkage seat drives the first hinge seat and the second hinge seat to rotate synchronously. The first hinge seat drives the inner drive rod and the first closing plate to rotate, and the second hinge seat drives the outer drive sleeve and the second closing plate to rotate, so that the first closing plate and the second closing plate close the main gate. S60: After the main gate is closed, liquid feeding is performed through the gating riser. After the molten metal cools and solidifies, the mold closing motor is turned in reverse. The mold closing motor drives the second gear to rotate, which in turn drives the third gear and the mold closing drive rod to rotate. The mold closing drive rod drives the upper hinge rod and the lower hinge rod to swing, which in turn drives the lower hinge shaft to slide in the Y-shaped guide groove. Simultaneously, it drives the upper hinge seat to slide along the Y-shaped guide groove, which in turn drives the upper hinge shaft and the lower hinge shaft to move the mold support. This causes the mold support to drive the upper mold base from a horizontal downward state to a vertical state, completing the demolding of the upper mold base and the lower mold base.

10. The method for casting high silicon-to-carbon ratio cast iron parts using a metal mold as described in claim 9, characterized in that: The molten metal comprises the following raw materials by weight percentage: C 3.0-3.1%, Si 2.30-2.40%, Mn 0.9-1.0%, S 0.06%-0.08%, P 0.08%, with the balance being Fe.

Images