CN109338146B - Solenoid electromagnetic stirrer with control ring - Google Patents

Abstract

The invention provides a solenoid electromagnetic stirrer with a control ring, which comprises: the control ring, the shell, the solenoid coil, the crucible, the resistance wire heating unit and the heat insulation layer; a coil supporting wall is arranged in the shell, a solenoid coil is wound on the coil supporting wall, and radial and axial electromagnetic force can be provided for the metal melt after the solenoid coil is electrified; the resistance wire heating unit is used for heating the crucible and keeping the molten state of the metal melt; the heat insulation layer is used for isolating the high-temperature protection solenoid coil; the control ring is positioned between the heat insulating layer and the inner wall of the shell and can be divided into enhancement type and weakening type and used for controlling different stirring modes. In the invention, the control ring can control the solenoid coil to generate different radial and axial electromagnetic force distribution, so that the metal melt flows in a turbulent flow mode, the turbulence degree is greatly improved compared with the traditional electromagnetic stirring, and the disorder of the melt movement is increased, therefore, the stirring efficiency of the solenoid electromagnetic stirrer is greatly improved compared with the traditional electromagnetic stirrer.

Description

A solenoid electromagnetic stirrer with a control loop

Technical field

The invention belongs to the field of electromagnetic casting, and more specifically, relates to a solenoid electromagnetic stirrer with a control ring.

Background technique

With the rapid development of technology and manufacturing, it is difficult for a single metal material to meet industrial design requirements. Therefore, the development of composite materials with excellent properties of multiple materials has become one of today's research hotspots. Among them, particle-reinforced metal matrix composites have been widely used in various fields such as aviation, aerospace, and automobiles due to their simple preparation, superior performance, and low cost. The mechanical stirring method uses a rotating paddle to stir the metal melt added with reinforced particles so that the reinforced particles and the metal melt are fully mixed. It is currently the most mature method for preparing particle-reinforced metal matrix composite materials. However, mechanical stirring also has the tendency to bring in There are defects such as impurities, uneven stirring force, and strict high temperature resistance requirements for stirring paddle materials. However, electromagnetic stirring technology has the advantages of non-contact, no stirring blind area, difficulty in bringing in impurities, and improved metal microstructure. It is particularly suitable for particle reinforced metal matrix composite casting. The field has great application prospects. At present, traditional electromagnetic stirring technology mainly has three different stirring forms: (1) rotating magnetic field type, in which the metal melt is rotated by the circumferential electromagnetic force under the action of the rotating magnetic field; (2) traveling wave magnetic field type, in which the metal melt is rotated in Under the action of the traveling wave magnetic field, it is subject to the electromagnetic force with constant direction and makes linear motion; (3) Spiral magnetic field type, that is, the rotating magnetic field and the traveling wave magnetic field are superimposed. The metal melt is subject to both circumferential force and axial force under the action of the spiral magnetic field. Instead do an upward or downward spiral movement. The invention patents with publication numbers CN107116191A and CN103182495A respectively point out that the compound spiral electromagnetic stirrer can produce the above three different stirring modes in different working modes. However, traditional electromagnetic stirring still has the following shortcomings: (1) The mixing efficiency is not high. The electromagnetic force of stirring has no radial component, which makes the flow disorder of the metal melt less, which is not conducive to the internal heat transfer of the metal melt and the interaction between the metal melt and the reinforced particles. Mixing; (2) The stirring speed is constrained by the skin effect of electromagnetic force. Accelerating the flow rate of the metal melt requires increasing the operating current frequency. The increase in frequency causes the electromagnetic force on the melt to be mainly distributed in the area near the winding and the central area of the melt. It is almost not affected by electromagnetic force; (3) The circumferential rotation of the metal melt forms a large central vortex on the liquid surface, which easily causes the particles to agglomerate during the casting of particle-reinforced metal matrix composite materials and reduces the performance of the composite material; (4) Electromagnetic The agitator has many windings, a complex structure, and is difficult to maintain.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a solenoid electromagnetic stirrer with a control ring, aiming to solve the problem of the existing technology in the casting of particle-reinforced metal matrix composite materials due to the single stirring form and the lack of metal melt. The low degree of flow disorder leads to technical problems such as poor mixing effect and low efficiency of metal melt and reinforced particles.

The invention provides a solenoid electromagnetic stirrer with a control ring, which includes: a control ring, a shell, a solenoid coil, a crucible, a resistance wire heating unit and an insulation layer; a coil support wall is provided in the shell , the solenoid coil is wound on the coil support wall, and the solenoid coil can provide radial and axial electromagnetic force after being energized; the resistance wire heating unit is used to heat the crucible and keep the metal The molten state of the melt; the thermal insulation layer is used to isolate high temperature and protect the solenoid coil; the control ring is located between the thermal insulation layer and the inner wall of the housing and is used to control different stirring methods.

The control loop can be divided into two types: enhanced type and weakened type. The enhanced control ring is a ring made of materials with high electrical conductivity and low magnetic permeability, such as pure copper. It has good electrical conductivity, but poor magnetic permeability. It can excite a secondary magnetic field under the energized solenoid coil, so It can enhance the electromagnetic stirring force of the metal melt near the control ring, causing the metal melt in this area to flow inward in the radial direction; the weakened control ring is a ring made of high magnetic permeability and low electrical conductivity materials, such as stacked silicon steel sheets, etc. , has good magnetic permeability and weakens the magnetic field near the control ring, but its ability to generate induced current and excite the secondary magnetic field is weak, so it can weaken the electromagnetic stirring force of the metal melt near the control ring, causing the metal melt in this area to move along the Radially outward flow.

When working, the enhanced control ring can increase the magnetic field in the area near the same height as the control ring, causing the spatial magnetic field in the crucible to be unevenly distributed in the axial direction. The metal in the area near the same height as the control ring The average electromagnetic force experienced by the melt is greater than other areas, so the metal melt in the area near the same height as the control ring will flow radially inward, while the melt in other areas will move outward, and the entire melt forms a " "Double-loop" flow trajectory, this "double-loop" turbulent motion similar to mechanical stirring can efficiently stir the entire melt.

As an embodiment of the present invention, when the control ring is an enhanced type and is located outside half the height of the metal melt, the magnetic field jointly generated by the solenoid coil and the control ring reaches the maximum two ends in the middle of the metal melt. Slightly smaller, the electromagnetic force received by the metal melt at the same time is also distributed in a distribution characteristic of being larger in the middle and smaller at the two ends.

As an embodiment of the present invention, when the control loop is weakened and is located outside half the height of the metal melt, the magnetic field generated by the solenoid coil is slightly larger at the smaller two ends in the middle of the metal melt. The electromagnetic force received by the metal melt at the same time also shows a distribution characteristic of being smaller in the middle and larger at the two ends.

As an embodiment of the present invention, when the control ring is an enhanced type, it is arranged at the upper end outside the metal melt. During operation, the upper end of the metal melt receives a larger electromagnetic force, and the lower end receives a smaller electromagnetic force. The upper end of the metal melt The melt flows inward along the radial direction while the metal melt at the lower end flows outward. The metal melt forms an integral circulation loop and the flow pattern is turbulent.

As an embodiment of the present invention, when the control ring is of a weakened type, it is arranged at the upper end outside the metal melt. During operation, the electromagnetic force received by the upper end of the metal melt is smaller, and the electromagnetic force received by the lower end is larger. The melt flows outward along the radial direction while the metal melt at the lower end flows inward. The metal melt forms an integral circulation loop and the flow pattern is turbulent.

As an embodiment of the present invention, when two control rings are used, one is an enhanced type and the other is a weakened type, the enhanced control ring is arranged at the lower end outside the metal melt, and the weakened control ring is arranged outside the metal melt. When working, the electromagnetic force received by the upper end of the metal melt is smaller than that without the control ring, and the electromagnetic force received by the lower end of the metal melt is increased compared with that without the control ring. Therefore, the metal melt at the upper end flows outward in the radial direction. The metal melt at the lower end flows inward, and the metal melt forms an overall circulation loop, and the flow form is turbulent flow.

As an embodiment of the present invention, when the control ring is an enhanced type, it is arranged between the lower end and the middle of the outside of the metal melt. During operation, the metal melt receives a greater electromagnetic force near the height of the control ring, and in other areas The electromagnetic force received is small, the "double loop" flow trajectory formed by the metal melt appears axially asymmetrical, and the flow form is turbulent.

As an embodiment of the present invention, when the control ring is of weakened type, it is arranged between the lower end and the middle of the outside of the metal melt. During operation, the electromagnetic force received by the metal melt near the height of the control ring is small, and other areas The electromagnetic force received is relatively large, and the "double loop" flow trajectory formed by the metal melt appears axially asymmetrically distributed, and the flow form is turbulent.

Wherein, the solenoid coil is a solid copper wire or a hollow copper tube. When a hollow copper tube is used, water can be passed through the tube to further improve the heat dissipation performance of the coil.

In the embodiment of the present invention, the solenoid electromagnetic stirrer with a control loop also includes: a frequency converter and a power supply, one end of the frequency converter is connected to the solenoid coil, and the other end of the frequency converter is connected to the Power supply, the frequency converter can arbitrarily change the frequency of the current flowing through the solenoid coil between 0 and 100 Hz, and the power supply can arbitrarily change the effective value of the current flowing through the solenoid coil between 0 and 400A. .

In the embodiment of the present invention, the resistance wire heating unit includes: a resistance wire, a thermocouple and a temperature adjustment circuit; the resistance wire is used to heat the crucible, and the thermocouple is used to detect the temperature of the crucible and feed the temperature back to the temperature adjustment circuit, The temperature regulation circuit maintains the crucible temperature at a user-set temperature based on thermocouple feedback.

The invention has the following technical effects:

(1) Simple control and diversified stirring forms. Simply changing the type, position and combination of the control rings can produce electromagnetic forces with different distribution characteristics. Therefore, different stirring forms can be customized according to the metal melt to be stirred or the metal melt containing reinforced particles with different physical properties, which is suitable for metal Continuous casting, particle reinforced metal matrix composite casting, semi-solid casting and other scenarios.

(2) Reduce the limitation of the stirring effect caused by increasing the current frequency. When the current frequency increases, the electromagnetic force increases. However, due to the skin effect, the electromagnetic force is mainly distributed outside the metal melt, and the electromagnetic stirring force received inside is smaller. The solenoid electromagnetic stirrer applies to the metal melt. The electromagnetic force is mainly radial force, and the metal melt generates radial velocity and circulates between the outside and the inside, reducing the influence of small internal stirring force.

(3) High stirring efficiency; because the solenoid coil generates radial and axial electromagnetic forces, and the radial electromagnetic force is unevenly distributed along the axial direction, the metal melt forms a flow loop similar to mechanical stirring, and the form of motion is turbulent flow. The degree of disorder is greatly improved compared with traditional electromagnetic stirring, which increases the disorder of metal melt movement. Therefore, the stirring efficiency of solenoid electromagnetic stirrer is greatly improved compared with traditional electromagnetic stirrer. It is also non-contact and has no stirring blind area. It has the advantages of traditional electromagnetic stirring such as being less likely to bring in impurities and improving the microstructure of metals.

(4) During the stirring process, there is no central vortex formed on the metal melt liquid surface, so during the casting of particle-reinforced metal matrix composite materials, the agglomeration of reinforced particles in the area near the liquid surface will not occur.

(5) The structure of the magnetic field generation and control device is a solenoid coil and a control ring, and only requires one power supply device. It has a simple structure, small size, stable performance and long life.

Description of the drawings

Figure 1 is a schematic structural diagram of a solenoid electromagnetic stirrer provided by an embodiment of the present invention;

Figure 2(a) is a schematic diagram of the magnetic field lines generated by the solenoid coil without the influence of the control loop;

Figure 2(b) is a schematic diagram of the magnetic field lines generated by the solenoid coil under the influence of the enhanced control loop;

Figure 2(c) is a schematic diagram of the magnetic field lines generated by the solenoid coil under the influence of the weakened control loop;

Figure 3(a) is a schematic diagram of the phase relationship between the magnetic field, induced electric field, induced current and electromagnetic force in the metal melt;

Figure 3(b) is a schematic diagram of a typical force field and flow field of a solenoid electromagnetic stirrer;

Figure 4(a) is a cross-sectional view of the flow field under single-coil mode stirring of a solenoid electromagnetic stirrer;

Figure 4(b) is a cross-sectional view of the flow field stirred by a traditional mechanical stirrer;

Figure 5 is a structural diagram and flow field cross-sectional view of the first embodiment of the present invention;

Figure 6 is a structural diagram and flow field cross-sectional view of the second embodiment of the present invention;

Figure 7 is a structural diagram and flow field cross-sectional view of the third embodiment of the present invention;

Figure 8 is a structural diagram and flow field cross-sectional view of the fourth embodiment of the present invention;

Figure 9 is a structural diagram and flow field cross-sectional view of the fifth embodiment of the present invention;

Figure 10 is a structural diagram and flow field cross-sectional view of the sixth embodiment of the present invention;

Figure 11 is a structural diagram and flow field cross-sectional view of the seventh embodiment of the present invention;

In the figure, 1 is the control ring, 2 is the shell, 3 is the upper cover of the shell, 4 is the solenoid coil, 5 is the crucible, 6 is the heating resistance wire, 7 is the insulation layer, and 8 is the metal melt (liquid metal). ).

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention.

The invention is applied in the fields of electromagnetic casting and electromagnetic processing of materials, and is particularly aimed at electromagnetic stirrers used in metal continuous casting, semi-solid casting and particle-reinforced metal matrix composite material casting. The invention provides a solenoid-type stirrer with a control ring that has a simple structure, long working life, diverse stirring forms, high stirring efficiency, and convenient control. It can drive the metal melt to perform turbulent motion and realize the stirring of the metal melt. Or mix metal melt and solid particles quickly and evenly.

The solenoid stirrer provided by the invention includes: a shell, a shell upper cover, a solenoid coil, a crucible, a resistance wire heating unit and an insulation layer; the shell plays the role of support, isolation and protection; the shell upper cover It plays the role of isolation and protection; the solenoid coil is wound around the coil support wall inside the housing; the crucible is surrounded by resistance wire and used as a container; the resistance wire heating unit heats the crucible and maintains the molten state of the metal melt ; The thermal insulation layer is located outside the resistance wire, and its function is to protect the solenoid coil and isolate the resistance wire from high temperatures.

In the embodiment of the present invention, the control loops are divided into enhanced type and weakened type, and the number can be single or multiple combinations. The enhanced control ring generates a larger electromagnetic force in the metal melt in the area near its height, while the weakened control ring generates a smaller electromagnetic force in the metal melt in the area near its height. This can be achieved by different control ring types, quantities, The combination of positions can produce electromagnetic stirring forces with different distributions. The combination form can be changed according to different usage scenarios, metal matrix and reinforced particles with different physical properties.

In the embodiment of the present invention, the solenoid coil is connected to the frequency converter and the power supply. The power supply provides electric energy to the frequency converter and the coil, and can arbitrarily change the effective value of the current flowing through the solenoid coil between 0 and 400A. The frequency converter can Randomly change the frequency of the current flowing through the coil between 0 and 100Hz. According to the principle of electromagnetic induction, the current amplitude remains unchanged. The higher the frequency, the greater the electromagnetic stirring force generated. However, due to the skin effect, the area where the electromagnetic force acts is also The smaller, although the solenoid electromagnetic stirrer provided by the present invention can provide radial electromagnetic force to reduce the limitation of the current frequency increase on the stirring effect, it is not enough to completely offset it, while the metal melt and reinforced particles with different physical properties are in Stirring corresponds to different optimal current frequencies and sizes. The frequency converter and power supply enable the present invention to achieve optimal current frequencies and sizes in different usage scenarios.

The shape of the solenoid coil is not limited to solid copper wires. Hollow copper tubes can be used to pass water to further improve its heat dissipation capacity.

In the embodiment of the present invention, the resistance wire heating unit is composed of a resistance wire, a thermocouple and a temperature adjustment circuit. The resistance wire is used to heat the crucible, and the thermocouple is used to detect the temperature of the crucible and feedback the temperature to the temperature adjustment circuit. The temperature adjustment circuit can keep the crucible temperature at the user-set temperature based on the thermocouple feedback.

In the present invention, when the solenoid stirrer does not contain a control ring, the energized solenoid coil generates an alternating magnetic field B, as shown in Figure 2(a). The magnetic field is composed of a radial component and an axial component. The magnetic field excites the induced electric field E in the metal melt. According to the law of electromagnetic induction, the phase of the induced electric field E lags behind the alternating magnetic field. Since the metal melt is an inductive load, the phase of the induced current density J in the melt will lag behind the induced electric field/> According to Ampere's force formula, the electromagnetic force experienced by unit volume of metal melt/> Since the magnetic field has radial and axial components, the metal melt is subject to axial and radial electromagnetic forces. The axial electromagnetic force can accelerate the movement of the metal melt in the axial direction and increase the disorder of the melt movement. For the radial electromagnetic force, due to the influence of the lagging phase α of the current density, the time and value of the radially inward electromagnetic force acting on the metal melt during an electrification cycle are greater than the radially outward electromagnetic force ( That is, in Figure 3(a)/> ), so the metal melt has an inward flow tendency. As the working time increases, the flow rate of the metal melt continues to increase until the movement resistance and electromagnetic force reach a dynamic balance.

When the solenoid stirrer contains an enhanced control loop, the control loop can produce two benefits based on the electromagnetic induction effect: 1) The control loop excites the secondary magnetic field and increases the axial magnetic field near it, causing the area near the control loop to The radial electromagnetic force experienced by the metal melt is greater than the area away from the control ring. Combined with the above analysis when the solenoid stirrer does not contain a control ring, it is known that the metal melt will have an inward flow trend. Since the metal melt The body mass is conserved, and eventually the melt will form a "double-loop" flow trajectory in which the area near the enhanced control ring flows inward and other areas flow outward. This "double-loop" turbulent motion similar to mechanical stirring can effectively affect the entire The melt is stirred; 2) The control ring excites the secondary magnetic field and increases the radial magnetic field near it. Therefore, the axial electromagnetic force on the metal melt in the area near the control ring is greatly increased, further increasing the flow of the metal melt. speed and disorder.

When the solenoid stirrer contains a weakened control ring, since the weakened control ring has excellent magnetic permeability, the control ring can have two benefits: 1) It weakens the axial magnetic field near the control ring, causing the area near the control ring to The electromagnetic force experienced by the metal melt is smaller than the area away from the control ring. Combined with the above analysis when the solenoid stirrer does not contain a control ring, it is known that the metal melt will have an inward flow trend. Due to the quality of the metal melt Conservation, the melt will eventually form a "double-loop" flow trajectory in which the area near the weakened control ring flows outward and other areas flow inward. This "double-loop" turbulent motion similar to mechanical stirring can effectively affect the entire melt. Stir; 2) The control ring increases the radial magnetic field near it, so the axial electromagnetic force on the metal melt in the area near the control ring is greatly increased, further increasing the speed and disorder of the metal melt flow.

Therefore, the solenoid electromagnetic stirrer provided by the present invention has the advantages of both a mechanical stirrer and a traditional electromagnetic stirrer.

In order to further explain the solenoid electromagnetic stirrer provided by the embodiment of the present invention, the details are as follows with reference to the accompanying drawings and specific examples:

First embodiment:

As shown in Figure 1, the solenoid stirrer with an enhanced control ring provided by the present invention includes an enhanced control ring 1, a shell 2, a shell upper cover 3, a solenoid coil 4, a crucible 5, Resistance wire heating unit 6, insulation layer 7. The enhanced control ring 1 is located between the thermal insulation layer and the inner wall of the shell, and its function is to control different stirring methods; the shell 2 plays the role of support, isolation and protection; the upper cover 3 of the shell plays the role of isolation and protection; the solenoid coil 4 Wound on the internal coil support wall of the shell 2; the crucible 5 is surrounded by a resistance wire and serves as a stirring container; the resistance wire heating unit 6 is composed of a resistance wire, a thermocouple and a temperature adjustment circuit (the thermocouple and temperature adjustment circuit are not shown in the diagram) The resistance wire is used to heat the crucible and maintain the molten state of the metal melt. The thermocouple is used to detect the temperature of the crucible and feedback the temperature to the temperature adjustment circuit. The temperature adjustment circuit can keep the crucible temperature at the user-set temperature based on the thermocouple feedback. ; The insulation layer 7 is located outside the resistance wire. Its function is to protect the solenoid coil and isolate the resistance wire from high temperatures. When the metal melting temperature is low, silica aerogel can be used as the insulation layer material. When the metal melting temperature is high, Hollow copper layers can be used for thermal insulation through water cooling.

As shown in Figure 5, the enhanced control ring 1 is located outside the middle part of the metal melt 8. Due to the electromagnetic induction effect, the control ring 1 excites the secondary magnetic field and increases the magnetic field near it. Therefore, the molten metal 8 in the crucible is subjected to The electromagnetic force is also distributed in a larger area near the control ring 1 and smaller in other areas. As shown in Figure 2(b), during an energization cycle of the solenoid coil 4, the coil 4 and the control ring 1 excite the alternating magnetic field B. This magnetic field is composed of a radial component and an axial component. This magnetic field is formed in the metal melt. The induced electric field E is excited in body 8. According to the law of electromagnetic induction, it can be seen that the phase of the induced electric field E lags behind the alternating magnetic field. Since the metal melt 8 is an inductive load, the phase of the induced current density J in the melt will lag behind the induced electric field/> According to Ampere's force formula, the electromagnetic force experienced by unit volume of metal melt/> Since the magnetic field has radial and axial components, the metal melt is subject to axial and radial electromagnetic forces. The axial electromagnetic force can accelerate the movement of the metal melt in the axial direction and increase the speed and disorder of the melt movement. For the radial electromagnetic force, the lagging phase α of the current density will cause the metal melt 8 to be acted upon by the radially inward electromagnetic force in one energization cycle. The action time and value are both greater than the radially outward electromagnetic force, as shown in the figure. As shown in 3(a),/> (Taking the radial outward direction as the positive direction), and because under the action of the control ring 1, the magnetic field in the middle of the metal melt is large, the magnetic field at both ends is small, and the mass is conserved, the metal melt in the middle will flow inward, and the metal melt at both ends will flow inward. The body flows outward, forming a complete circulation trajectory. As the working time increases, the flow rate of the metal melt continues to increase until the movement resistance and electromagnetic force reach a dynamic balance.

As shown in Figure 4, the metal melt in the middle is moved inward to near the axis by electromagnetic force and then flows upward and downward. This "double-loop" turbulent motion similar to mechanical stirring can efficiently stir the entire melt. Therefore, the solenoid electromagnetic stirrer provided by the present invention has the advantages of both a mechanical stirrer and a traditional electromagnetic stirrer.

This embodiment is suitable for metal continuous casting, semi-solid casting, etc., and is particularly suitable for particle reinforced metal matrix composite casting. The core step of the casting of particle-reinforced metal matrix composite materials is the mixing of metal melt and reinforced solid particles. The reinforced particles are sinking solid particles with a density slightly greater than that of the metal matrix. When static, the particles will fall at a slower speed. Shen. In this embodiment, the particles located in the upper half of the metal melt 8 are subject to the force of the upward circulation movement of the fluid, preventing them from sinking; the particles located in the lower half of the metal melt 8 are subject to the force of the downward circulation movement of the fluid. It first accelerates the sinking, and then moves to the middle of the metal melt 8 through cyclic movement. The circulation of the entire fluid causes the reinforced particles with a density slightly greater than that of the metal matrix to be evenly distributed in the metal melt 8 .

Second embodiment:

The difference between this embodiment and the first embodiment is that this embodiment uses an attenuated control loop 1 .

As shown in Figure 6, the weakened control ring 1 is located outside the middle part of the metal melt 8. Since the weakened control ring 1 has excellent magnetic permeability, it weakens the magnetic field near the control ring 1, so the electromagnetic field at both ends of the metal melt 8 is The force is larger, and the electromagnetic force in the middle is smaller. The metal melt at both ends flows inward, while the metal melt in the middle flows outward. The metal melt forms a complete circulation loop. The flow form is turbulent, and the circulation direction is the same as the first. Embodiment opposite.

This embodiment is suitable for metal continuous casting, semi-solid casting, etc., and is particularly suitable for particle reinforced metal matrix composite casting. The core step of the casting of particle-reinforced metal matrix composites is the mixing of metal melt and reinforced solid particles. The reinforced particles are floating solid particles with a density slightly smaller than that of the metal matrix. When static, the particles will float at a slower speed. In this embodiment, the particles located in the upper half of the metal melt 8 are subject to the force of the downward circulation movement of the fluid, preventing them from floating up; the particles located in the lower half area of the metal melt 8 are subject to the force of the upward circulation movement of the fluid. It accelerates to float to the middle of the metal melt 8 and then moves to the bottom of the metal melt 8 through circular motion. The circulation of the entire fluid causes the reinforced particles with a density slightly smaller than the metal matrix to be evenly distributed in the metal melt 8 .

Third embodiment:

The difference between this embodiment and the first embodiment is that the enhanced control ring 1 used in this embodiment is located outside the upper end of the metal melt 8 .

As shown in Figure 7, the enhanced control ring 1 is located outside the upper end of the metal melt 8. Therefore, the upper end of the metal melt 8 receives a larger electromagnetic force. The upper metal melt flows inward along the radial direction, and the lower metal melt flows radially inward. It flows outward to form a complete circulation loop, and the flow form is turbulent flow.

This embodiment is suitable for metal continuous casting, semi-solid casting, etc., and is particularly suitable for particle reinforced metal matrix composite casting. The core step of the casting of particle-reinforced metal matrix composites is the mixing of metal melt and reinforced solid particles. The reinforced particles are floating solid particles with a density smaller than that of the metal matrix, and the particles can float at a faster speed when static. In this embodiment, the downward flow of the metal melt 8 drives the particles to move toward the bottom of the crucible, and the floating reinforcing particles are evenly distributed in the metal melt 8 through circulating flow.

Fourth embodiment:

The difference between this embodiment and the third embodiment is that this embodiment uses an attenuated control loop 1 .

As shown in Figure 8, the weakened control ring 1 is located outside the upper end of the metal melt 8, so the electromagnetic force received by the upper end of the metal melt 8 is smaller. The upper metal melt flows outward along the radial direction, and the lower metal melt flows radially outward. It flows inward to form a complete circulation loop, the flow form is turbulent flow, and the flow direction is opposite to that of the third embodiment.

This embodiment is suitable for metal continuous casting, semi-solid casting, etc., and is particularly suitable for particle reinforced metal matrix composite casting. The core step of the casting of particle-reinforced metal matrix composite materials is the mixing of metal melt and reinforced solid particles. The reinforced particles are sinking solid particles with a density greater than that of the metal matrix, and the particles can sink at a faster speed when static. . In this embodiment, the upward flow of the metal melt 8 drives the particles to move toward the melt surface, and the sinking reinforced particles are evenly distributed in the metal melt 8 through circular flow.

Fifth embodiment:

The difference between this embodiment and the fourth embodiment is that this embodiment uses two control loops 1-1 and 1-2. The control ring 1-1 is a weakened control ring located outside the upper end of the metal melt 8; the control ring 1-2 is an enhanced control ring located outside the lower end of the metal melt 8.

As shown in Figure 9, the control rings 1-1 and 1-2 are located outside the upper end and the lower end of the metal melt 8 respectively. Therefore, the electromagnetic force received by the upper end of the metal melt 8 is smaller than when there is no control ring. The metal melt 8 The electromagnetic force received by the lower end is greater than when there is no control ring. The metal melt at the upper end flows radially outward and the metal melt at the lower end flows inward, forming an overall circulation loop with turbulent flow.

This embodiment is suitable for metal continuous casting, semi-solid casting, etc., and is particularly suitable for particle reinforced metal matrix composite casting. The core step of the casting of particle-reinforced metal matrix composite materials is the mixing of metal melt and reinforced solid particles. The reinforced particles are sinking solids with a density much greater than that of the metal matrix, and the particles can sink at a faster speed when static. Particles. In this embodiment, the upward flow of the metal melt 8 drives the particles to move toward the melt surface, and the sinking reinforced particles are evenly distributed in the metal melt 8 through circular flow.

Sixth embodiment:

The difference between this embodiment and the first embodiment is that the enhanced control ring 1 used in this embodiment is located between the lower end and the middle of the outside of the metal melt 8 .

As shown in Figure 10, the enhanced control ring 1 is located between the lower end and the middle of the outside of the metal melt 8. The metal melt in the area near the control ring 1 receives a large electromagnetic force and flows inward in the radial direction. The metal melt in other areas The electromagnetic force received by the melt is small and it flows outward in the radial direction. The "double loop" flow trajectory formed by the metal melt appears axially asymmetrically distributed. The range of the flow trajectory in the upper half is larger than that in the lower half. The form is turbulent flow.

This embodiment is suitable for metal continuous casting, semi-solid casting, etc., and is particularly suitable for particle reinforced metal matrix composite casting. The core step of casting the particle-reinforced metal matrix composite material is the mixing of the metal melt and the reinforced solid particles. The density of the floating reinforced particles applicable to this embodiment is between the second embodiment and the third embodiment.

Seventh embodiment:

The difference between this embodiment and the sixth embodiment is that this embodiment uses an attenuated control loop 1 .

As shown in Figure 11, the weakened control ring 1 is located between the lower end and the middle of the outside of the metal melt 8. The metal melt in the area near the control ring 1 receives a small electromagnetic force and flows outward in the radial direction. The metal melt in other areas The electromagnetic force received by the melt is small and it flows inward in the radial direction. The "double loop" flow trajectory formed by the metal melt appears axially asymmetrically distributed. The range of the flow trajectory in the upper half is larger than that in the lower half. The form is turbulent flow.

This embodiment is suitable for metal continuous casting, semi-solid casting, etc., and is particularly suitable for particle reinforced metal matrix composite casting. The core step of casting the particle-reinforced metal matrix composite material is the mixing of the metal melt and the reinforced solid particles. The density of the sunken reinforced particles applicable to this embodiment is between the first embodiment and the fourth embodiment.

In addition to the above embodiments, the control ring can have different combinations of forms, quantities, and positions to meet the requirements of various flow forms. Specifically, it can be matched according to different usage scenarios, metal matrices and reinforcing particles with different physical properties.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements, etc., made within the spirit and principles of the present invention, All should be included in the protection scope of the present invention.

Claims (9)

1. A solenoid electromagnetic stirrer with a control ring, characterized in that it includes: a control ring, a shell, a solenoid coil, a crucible, a resistance wire heating unit and an insulation layer; A coil support wall is provided in the housing, and the solenoid coil is wound around the coil support wall. When energized, the solenoid coil can provide radial and axial electromagnetic forces, and the electromagnetic force is mainly radial. ; The resistance wire heating unit is used to heat the crucible and maintain the molten state of the metal melt; The thermal insulation layer is used to isolate high temperature and protect the solenoid coil; The control loop is located between the insulation layer and the inner wall of the shell and is used to control different stirring modes; the control loop is an enhanced control loop or a weakened control loop, wherein the enhanced control loop activates two The secondary magnetic field increases the axial magnetic field near the enhanced control ring, so that the radial electromagnetic force experienced by the metal melt near the enhanced control ring is greater than the area far away from the enhanced control ring, thus forming the The "double loop" flow trajectory in which the melt in the area near the enhanced control ring flows inward and the melt in other areas flows outward; the weakened control ring weakens the axial magnetic field near the weakened control ring, So that the electromagnetic force experienced by the metal melt in the area near the weakened control ring is smaller than the area far away from the control ring, so that the melt in the area near the weakened control ring flows outward and the melt in other areas flows inward. The "double loop" flow trajectory. 2. The solenoid electromagnetic stirrer according to claim 1, characterized in that when the control ring is an enhanced control ring, it is arranged at the upper end outside the metal melt. During operation, the upper end of the metal melt is subjected to The electromagnetic force is greater than the electromagnetic force at the lower end. The metal melt at the upper end flows inward along the radial direction and the metal melt at the lower end flows outward. The metal melt forms an overall circulation loop, and the flow form is turbulent flow. 3. The solenoid type electromagnetic stirrer according to claim 1, characterized in that when the control ring is an enhanced control ring and is located outside half the height of the metal melt, the solenoid The magnetic field generated by the coil and the control ring is slightly smaller at the two ends in the middle of the metal melt, and the electromagnetic force received by the metal melt at the same time is also larger in the middle and smaller at the ends. 4. The solenoid electromagnetic stirrer according to claim 1, characterized in that when the control ring is an enhanced control ring, it is arranged between the lower end and the middle part outside the metal melt. When working, the metal The electromagnetic force received by the melt is larger near the height of the control ring, and the electromagnetic force received by other areas is smaller. The "double loop" flow trajectory formed by the metal melt has an axial asymmetric distribution, and the flow form is turbulent. 5. The solenoid type electromagnetic stirrer as claimed in claim 1, characterized in that when the control ring is a weakened control ring, it is arranged at the upper end outside the metal melt. During operation, the upper end of the metal melt is subjected to The electromagnetic force is small, and the electromagnetic force received by the lower end is larger. The metal melt at the upper end flows radially outward and the metal melt at the lower end flows inward. The metal melt forms an overall circulation loop, and the flow form is turbulent. 6. The solenoid electromagnetic stirrer according to claim 1, wherein when the control ring is a weakened control ring and is located outside half the height of the metal melt, the solenoid The magnetic field generated by the coil is slightly larger in the middle of the metal melt and is smaller at the two ends. The electromagnetic force received by the metal melt at the same time is also distributed in a smaller middle and larger at the ends. 7. The solenoid electromagnetic stirrer as claimed in claim 1, characterized in that when the control ring is of weakened type and is arranged between the lower end and the middle part outside the metal melt, during operation, the metal melt The electromagnetic force received near the height of the control ring is small, and the electromagnetic force received in other areas is relatively large. The "double loop" flow trajectory formed by the metal melt has an axial asymmetric distribution, and the flow form is turbulent. 8. The solenoid electromagnetic stirrer according to any one of claims 1 to 7, characterized in that the solenoid electromagnetic stirrer further includes: a frequency converter and a power supply, one end of the frequency converter is connected to The other end of the solenoid coil and the frequency converter is connected to the power supply. The frequency converter can arbitrarily change the frequency of the current flowing through the solenoid coil between 0 and 100 Hz. The power supply can be between 0 and 400 A. The effective value of the current flowing through the solenoid coil can be changed arbitrarily. 9. The solenoid electromagnetic stirrer according to any one of claims 1 to 7, wherein the resistance wire heating unit includes: a resistance wire, a thermocouple and a temperature adjustment circuit; The resistance wire is used to heat the crucible, and the thermocouple is used to detect the temperature of the crucible and feed the temperature back to the temperature adjustment circuit. The temperature adjustment circuit keeps the crucible temperature at the user-set temperature based on the thermocouple feedback.