Pouring box

Abstract

The utility model discloses a pouring box, which relates to the technical field of aluminum alloy casting and comprises a main box body, an aluminum alloy melt is accommodated in the main box body, and a pouring gate is arranged at the bottom of the main box body and is used for being communicated with a cavity; the device further comprises an electromagnetic system, and the electromagnetic system is used for generating a pulsed magnetic field in the main box body and applying electromagnetic energy to the aluminum alloy melt in the main box body so as to carry out pretreatment. According to the utility model, the nucleation rate can be improved, so that the refining and homogenization of an aluminum alloy as-cast structure are promoted, and the mechanical property of a casting is finally improved.

Description

Technical Field

[0001] The utility model relates to the technical field of aluminum alloy casting, in particular to a pouring box. Background Art

[0002] The sand casting process is a casting method with sand as the main molding material and is one of the most common casting methods; aluminum alloy sand casting has the characteristics of short production cycle, low cost, and can form complex-shaped and cavity parts, etc., and is often used in the production of castings with complex contours and large specifications such as automobile wheels and boxes, as well as single-piece or small-batch castings. The aluminum alloys used for sand casting include Al-Si alloys, Al-Cu alloys, Al-Mg alloys, Al-Zn alloys, etc.

[0003] The aluminum alloy sand casting process flow is: sand mixing, mold making, core making, molding, pouring, shakeout, grinding and processing; among them, the pouring process is the key step for the casting to take shape. The aluminum alloy melt after melting, refining, and purification is poured into the pouring box for buffering and then flows into the cavity through the sprue bar at the bottom of the pouring box. The pouring box is usually a box with a rectangular or square cross-section, with a funnel shape at the bottom, and is made of ordinary carbon steel, and its function is to buffer and stabilize the flow of the aluminum alloy melt.

[0004] However, the casting structure of aluminum alloy is coarse, and there are often defects such as shrinkage cavities, porosity, and segregation. These defects reduce the tissue uniformity and greatly affect the mechanical properties of the casting; in the current sand casting process, the pouring box is only an intermediate buffering device and has no pretreatment function for the aluminum alloy melt, and cannot have a beneficial effect on the coarse casting structure and casting defects such as shrinkage cavities, porosity, and segregation. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a pouring box to solve the problems existing in the prior art, which can increase the nucleation rate, thereby promoting the refinement and uniformity of the as-cast structure of aluminum alloy and ultimately improving the mechanical properties of the casting.

[0006] To achieve the above purpose, the utility model provides the following scheme:

[0007] The utility model provides a pouring box, which includes a main box body for accommodating the aluminum alloy melt, and a sprue is arranged at the bottom of the main box body for communicating with the cavity; it also includes an electromagnetic system for generating a pulsed magnetic field in the main box body and applying electromagnetic energy to the aluminum alloy melt in the main box body for pretreatment.

[0008] Preferably, the electromagnetic system is arranged outside the pouring box and includes an electromagnetic coil and a special control power supply, and the electromagnetic coil is electrically connected to the special control power supply.

[0009] Preferably, the electromagnetic coil includes a wire and an iron core, and the wire is wound around the iron core.

[0010] Preferably, a heat insulation plate is further arranged on the outer side of the main box body.

[0011] Preferably, a protection box body is further included, and the electromagnetic coil is arranged in the protection box body.

[0012] Preferably, a heat dissipation fan is further arranged in the protection box body, and the heat dissipation fan is electrically connected to a power supply.

[0013] Preferably, a junction box is further included, the electromagnetic coil is electrically connected to the dedicated control power supply through the junction box, and the heat dissipation fan is electrically connected to the power supply through the junction box.

[0014] Preferably, the bottom of the main box body is fixed on a fixing plate, the main box body can be fixed on the cavity through the fixing plate, a fixing frame is further arranged on the fixing plate, and the main box body is fixedly connected to the fixing frame.

[0015] Preferably, the fixing frame is arranged around the main box body, and a lifting ring is arranged at the top of the fixing frame.

[0016] Preferably, the main box body is an I-shaped or convex box body, and the material of the main box body is stainless steel.

[0017] The present utility model has achieved the following technical effects compared with the prior art:

[0018] An electromagnetic system is provided in the present utility model, which can apply electromagnetic energy to the aluminum alloy melt in the main box body. When the pulsed magnetic field acts on the aluminum alloy melt, the probability of collision between atoms or atomic groups in the melt is increased, that is, the energy fluctuation in the melt is increased, providing energy for the formation of critical nuclei. The action of the pulsed magnetic field increases the number of effective crystallization nuclei in the melt at the initial stage of nucleation, creating conditions for the improvement of the nucleation rate, thereby promoting the refinement and homogenization of the as-cast structure of the aluminum alloy and ultimately improving the mechanical properties of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic diagram of an I-shaped pouring box in an embodiment of the present utility model;

[0021] Figure 2Schematic diagram of the convex pouring box in the embodiment of the present utility model;

[0022] Figure 3 Overall structural schematic diagram of the I-shaped pouring box in the embodiment of the present utility model;

[0023] Figure 4 Schematic diagram of the core and electromagnetic coil positions of the I-shaped pouring box in the embodiment of the present utility model;

[0024] Figure 5 Pulse magnetic field waveform diagram in the embodiment of the present utility model;

[0025] Figure 6 Schematic diagram of the magnetic field direction of the I-shaped pouring box in the embodiment of the present utility model;

[0026] Figure 7 Schematic diagram of the magnetic field direction of the convex pouring box in the embodiment of the present utility model;

[0027] Figure 8 Magnetic field simulation results inside the I-shaped pouring box in the embodiment of the present utility model;

[0028] Figure 9 Magnetic field simulation results inside the convex-shaped pouring box in the embodiment of the present utility model.

[0029] In the figure: 100 - pouring box, 1 - main box body, 2 - cavity, 3 - fixing plate, 4 - fixing frame, 5 - junction box, 6 - lifting ring, 7 - cooling fan, 8 - wire, 9 - core, 10 - coil fixing frame, 11 - gate. Specific implementation manners

[0030] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0031] The purpose of the present utility model is to provide a pouring box to solve the problems existing in the prior art, which can improve the nucleation rate, thereby promoting the refinement and homogenization of the as-cast structure of aluminum alloy and ultimately improving the mechanical properties of the casting.

[0032] To make the above objects, features, and advantages of the present utility model more obvious and understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0033] Embodiment 1

[0034] As Figures 1 - 4As shown in the figure, in this embodiment, a pouring box 100 is provided, which includes a main box body 1 for accommodating aluminum alloy melt. A gate 11 is provided at the bottom of the main box body 1 for communicating with the cavity 2. It further includes an electromagnetic system for generating a pulsed magnetic field in the main box body 1 and applying electromagnetic energy to the aluminum alloy melt in the main box body 1 for pretreatment.

[0035] According to the classical nucleation theory, when homogeneous nucleation occurs and the liquid phase transforms into the solid phase, the total free energy change of the system is:

[0036]

[0037] Among them, ΔG is the total free energy change of the melt, ΔG v is the free energy change per unit volume of the liquid and solid phases, σ is the specific surface energy, and r is the radius of the assumed crystal embryo.

[0038] The critical crystal nucleus radius for nucleation is:

[0039] The nucleation work when forming the critical radius is:

[0040] Among them, T m is the melting point, L m is the heat of fusion, and ΔT is the degree of supercooling.

[0041] The surface area of the critical crystal nucleus is:

[0042] Then, when forming the critical crystal nucleus, the total free energy change is:

[0043] The actual nucleation process is heterogeneous nucleation, and the total free energy change is:

[0044]

[0045] Among them, σ αL is the specific surface energy of the crystal nucleus-liquid phase interface, and θ is the contact angle between the crystal nucleus and the heterogeneous nucleation particle.

[0046] When heterogeneous nucleation occurs, the critical crystal nucleus radius is:

[0047] It can be seen from this that when forming the critical crystal nucleus, the free energy change G * > 0, and its increment is equal to 1 / 3 of its surface energy, that is, the volume free energy difference between the liquid and solid phases compensates for 2 / 3 of the energy required to form the critical crystal nucleus surface, and the remaining 1 / 3 is supplemented by the energy fluctuations existing in the liquid phase.

[0048] Therefore, in this embodiment, when the electromagnetic system applies electromagnetic energy to the aluminum alloy melt in the main box body 1 and the pulsed magnetic field acts on the aluminum alloy melt, it can increase the undercooling degree of the melt solidification and also increase the probability of collision between atoms or atomic clusters in the melt, that is, increase the energy fluctuation in the melt, providing energy for the formation of critical nuclei. The pulsed magnetic field action increases the number of effective crystallization nuclei in the melt at the initial stage of nucleation, creating conditions for the improvement of the nucleation rate, thereby promoting the refinement and homogenization of the as-cast structure of the aluminum alloy and ultimately improving the mechanical properties of the casting.

[0049] In this embodiment, the main box body 1 is welded and processed from 304 stainless steel and is used to accommodate the aluminum alloy melt. The existing pouring boxes made of ordinary carbon steel cannot achieve the magnetic field effect. In this embodiment, the main box body 1 made of stainless steel is selected to facilitate the realization of the magnetic field effect. Further, the outer shape structure of the main box body 1 is of two types: I-shaped or convex. The I-shaped main box body 1 has a structure with wide ends and a narrow middle, and the convex main box body 1 has a structure with one wide end and one narrow end. Among them, the I-shaped structure is preferably selected.

[0050] In this embodiment, the bottom of the main box body 1 is fixed on the fixing plate 3, and the main box body 1 can be fixed on the cavity 2 through the fixing plate 3. A fixing frame 4 is also provided on the fixing plate 3, and the main box body 1 is fixedly connected to the fixing frame 4, specifically, it can be a welded connection.

[0051] Further, in this embodiment, the fixing frame 4 is of a cuboid structure and is arranged around the main box body 1. Hoisting rings 6 are welded at the tops of the four corners of the fixing frame 4 for realizing the transfer, position adjustment and hoisting of the pouring box 100 after pouring.

[0052] In this embodiment, the electromagnetic system is arranged outside the pouring box 100 and mainly includes an electromagnetic coil and a special control power supply. The electromagnetic coil is electrically connected to the special control power supply. Through the special control power supply, power can be supplied and parameters such as the frequency, peak current, and duty cycle of the magnetic field of the electromagnetic coil can be adjusted to generate a pulsed magnetic field with the required magnetic induction intensity in the main box body 1.

[0053] In this embodiment, the electromagnetic coil mainly includes a wire 8 and an iron core 9. The wire 8 is wound around the iron core 9, and the iron core 9 is clamped on the coil fixing frame 10, and the coil fixing frame 10 can be fixed on the fixing frame 4 by threaded connection.

[0054] In this embodiment, a heat insulation board is further arranged on the outer side of the main box body 1, which is used to block the outward heat dissipation of the aluminum alloy melt, play a heat preservation role for the aluminum alloy melt, and cooperate with the heat dissipation fan 7 described below to protect the electromagnetic coil and prevent the magnetic induction intensity from decreasing due to overheating of the electromagnetic coil. Among them, the heat insulation board is arranged around the periphery of the main box body 1 and is bonded to the outer side of the main box body 1 through heat insulation glue.

[0055] In this embodiment, a protection box body is further included. The electromagnetic coil is arranged in the protection box body, which can protect the electromagnetic coil. Moreover, a heat dissipation fan 7 is further arranged in the protection box body. The heat dissipation fan 7 is electrically connected to the power supply. The heat dissipation fan 7 is fixed on the fan fixing plate through threaded connection, and the fan fixing plate is welded on the fixing frame 4. The function of the heat dissipation fan 7 is to reduce the temperature of the electromagnetic coil and prevent the electromagnetic coil from losing its function due to excessive temperature during operation.

[0056] In this embodiment, the fan fixing plate and multiple sealing plates together form the protection box body. The fan fixing plate is located on the side of the protection box body facing away from the main box body 1, and a ventilation opening is arranged on the fan fixing plate for air to flow through. A filter screen is arranged on the ventilation opening for filtering dust particles in the air. The sealing plates are welded on the fixing frame 4 to prevent dust particles in the air from entering the electromagnetic coil and the heat dissipation fan 7.

[0057] In this embodiment, a wiring box 5 is further welded on the fixing frame 4. The electromagnetic coil is electrically connected to the special control power supply through the wiring box 5. The heat dissipation fan 7 can be electrically connected to the power supply through the wiring box 5 or directly to the power supply.

[0058] The usage process of the pouring box 100 in this embodiment is as follows:

[0059] In this embodiment, the pouring box 100 is hoisted above the sand mold by a crane, and the bottom gate 11 of the pouring box 100 is aligned with the gate rod of the sand mold. The electromagnetic coil is connected to the special control power supply, the heat dissipation fan 7 is connected to the power supply, and the power supply is started. The magnetic field parameters such as frequency, peak current, and duty cycle are set through the special control power supply. When the aluminum alloy melt flows into the main box body 1, the special control power supply is started. The aluminum alloy stays in the main box body 1 for 60 - 90 s, the bottom gate plug is removed, and pouring begins. After pouring is completed, the special control power supply is turned off.

[0060] The functions of the main structures in this embodiment during use are as follows:

[0061] The main box body 1 is used to accommodate the aluminum alloy melt;

[0062] The electromagnetic coil is connected to the special control power supply, powered by the special control power supply, and adjusts parameters such as frequency, peak current, and duty cycle to generate a pulsed magnetic field with the required magnetic induction intensity in the main box body 1.

[0063] The junction box 5 can connect the electromagnetic coil and the dedicated control power supply;

[0064] The heat insulation plate is used to block the outward heat dissipation of the aluminum alloy melt, play a heat preservation role for the melt, and also, together with the cooling fan 7, play a protective role for the electromagnetic coil to prevent the electromagnetic coil from overheating and causing a decrease in magnetic induction intensity;

[0065] The cooling fan 7 is used to reduce the temperature of the electromagnetic coil and prevent the electromagnetic coil from losing its function due to excessive temperature during operation.

[0066] In this embodiment, the size of the iron core 9 of the electromagnetic coil is 120 - 140 * 80 - 100 * 180 - 200 mm, the specification of the wire 8 is 5 * 10 mm, the wire 8 is selected to be set in 10 - 12 layers, with 15 - 17 turns per layer, the iron core 9 is 15 - 30 mm away from the end face of the coil wound by the wire 8, and the iron core 9 is 15 - 30 mm away from the side surface of the aluminum alloy melt; the dedicated control power supply adjusts the peak current to 100 - 200 A, the frequency is 20 - 50 Hz, and the duty cycle is 20% - 50%; according to the size of the main box body 1, an appropriate configuration of the number of coil layers, turns and winding method is carried out.

[0067] Embodiment Two

[0068] In this embodiment, the magnetic field distributions in two types of gating boxes, namely I-shaped and convex-shaped, are simulated by comsol multiphysics software; the iron core size is selected as 80 * 140 * 180 mm, the wire specification is 5 * 10 mm, the coil has 204 turns (12 layers and 17 turns), the dedicated control power supply selects a triangular waveform, the frequency is 40 Hz, the current is 100 A, and the duty cycle is 20%. The magnetic field waveform diagram is as Figure 5 shown, and the magnetic field direction in the gating box is as Figure 6 、 Figure 7 shown. The simulation results show (as Figure 8 、 Figure 9 shown) that the volume percentage of the magnetic induction intensity > 10 mT in the I-shaped gating box is 56.4%, and the volume percentage of the magnetic induction intensity > 10 mT in the convex-shaped gating box is 28.2%.

[0069] In the present utility model, specific examples are used to elaborate on the principle and implementation manner of the present utility model. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present utility model; at the same time, for those of ordinary skill in the art, based on the idea of the present utility model, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present utility model.

Claims

1. A pouring box, comprising a main box body, the main box body is used to contain aluminum alloy melt, and the bottom of the main box body is provided with a gate for communicating with a mold cavity; characterized in that: It also includes an electromagnetic system, which is used to generate a pulsed magnetic field in the main box and apply electromagnetic energy to the aluminum alloy melt in the main box for pretreatment.

2. The pouring box according to claim 1, characterized in that: The electromagnetic system is arranged outside the pouring box, and comprises an electromagnetic coil and a dedicated control power supply, and the electromagnetic coil is electrically connected to the dedicated control power supply.

3. The pouring box according to claim 2, characterized in that: The electromagnetic coil includes a conducting wire and an iron core, and the conducting wire is wound around the iron core.

4. The pouring box according to claim 2, characterized in that: A heat insulation board is also arranged on the outer side of the main box.

5. The pouring box according to any one of claims 2 to 4, characterized in that: It also includes a protective box, in which the electromagnetic coil is arranged.

6. The pouring box according to claim 5, characterized in that: A cooling fan is also provided in the protection box, and the cooling fan is electrically connected to a power supply.

7. The pouring box according to claim 6, characterized in that: It also includes a junction box, through which the electromagnetic coil is electrically connected to the dedicated control power supply, and through which the cooling fan is electrically connected to the power supply.

8. The pouring box according to claim 1, characterized in that: The bottom of the main box body is fixed on a fixing plate, and the main box body can be fixed on the cavity through the fixing plate. A fixing frame is also provided on the fixing plate, and the main box body is fixedly connected to the fixing frame.

9. The pouring box according to claim 8, characterized in that: The fixing frame is arranged around the main box body, and a hanging ring is arranged on the top of the fixing frame.

10. The pouring box according to claim 1, characterized in that: The main box body is an I-shaped or convex box body, and the material of the main box body is stainless steel.

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