Magnetic excitation homogenization solidification device

Abstract

The utility model relates to a magnetic excitation homogenization solidification device, which belongs to the technical field of non-ferrous metal solidification structure control, and comprises an integrated continuous casting crystallizer, a cooling chamber is arranged in the continuous casting crystallizer, a coil chamber surrounding the cooling chamber is arranged on the outer side of the cooling chamber, a coil is arranged in the coil chamber, and the upper end of the coil is higher than the top of the cooling chamber; the device further comprises a pulse power generator arranged outside the integrated continuous casting crystallizer, and the pulse power generator is connected with the coil through a cable. The electromagnetic stirring device can realize homogenization of components and solidification structures in a casting blank, and solves the problems that an existing electromagnetic stirring technology is poor in grain refinement effect when used in copper alloy continuous casting and cannot be applied to industrial production.

Description

TECHNICAL FIELD

[0001] The utility model belongs to non ferrous metal solidification organization control technical field, concretely relates to a magnetic excitation homogenization solidification device. BACKGROUND

[0002] It is the goal of metallurgical workers to realize the composition and organization homogenization of metal solidification billet. The composition and organization homogenization of billet has the remarkable benefit to the improvement of billet quality, the enhancement of mechanical properties and the improvement of product consistency. The basic method is: increase nucleation particles, reduce the crystal nucleus production speed to realize the large quantity, uniform equiaxed structure in unit volume, so as to obtain the composition and organization homogenization billet as far as possible. At present, the main methods are: control the pouring temperature and cooling intensity, inoculation treatment / modification treatment, mechanical or physical field treatment.

[0003] Inoculation treatment mainly adds a small amount of additives (called inoculant) in the metal melt to promote the formation of crystal nucleus in the melt and inhibit the crystal growth, so as to realize the refinement of grain, the improvement of solidification structure and the improvement of material mechanical properties. This technology is especially suitable for cast iron and other metal materials.

[0004] Mechanical or physical field treatment mainly has two types. (1) Mechanical stirring: through mechanical stirring, the convection and diffusion process in the melt can be accelerated, and the uniform distribution of solute can be promoted. Mechanical stirring can also break the dendritic structure in the solidification process, and promote the formation of equiaxed grains, so as to refine the grains. Physical field treatment: (2) electromagnetic stirring: the melt is stirred by the force generated by electromagnetic field, which can eliminate the composition segregation and grain coarsening phenomenon. The methods such as mechanical stirring and electromagnetic stirring can cause different degrees of relative motion between liquid and solid phases, that is, the convection of liquid metal, so as to break, crush and proliferate the dendrite arms, and achieve the purpose of refining grains. But for high melting point metals or the melting furnace is integrated with the crystallizer, mechanical stirring cannot be installed in the crystallizer. Electromagnetic stirring has the problems of complex equipment, low power efficiency, although the stirring in the secondary cooling zone can expand the equiaxed grain zone, but the effect of refining grains is not obvious, there is a trend of negative segregation, especially for the continuous casting process of copper alloy rod billet (copper rod diameter ≤ 40mm), the effect of refining grains is very limited. The force generated by electromagnetic field to stir the melt requires that the alloy liquid cavity in the crystallizer has enough free movement space. In the steel continuous casting, the crystallizer area affected by electromagnetic stirring has a solidification fraction (f) usually less than 10%, and the molten steel has enough movement space to realize the convection of the melt to break the dendrite arms. Then, in the continuous casting process of copper alloy rod billet (up-drawing continuous casting, horizontal continuous casting, down-drawing continuous casting), the small diameter of copper rod and the fast heat conduction of copper alloy cause high solidification fraction in the crystallizer, and the liquid cavity space is very small, so the effect of electromagnetic stirring is low. f s )Usually less than 10%, and the molten steel has enough movement space to realize the convection of the melt to break the dendrite arms. Then, in the continuous casting process of copper alloy rod billet (up-drawing continuous casting, horizontal continuous casting, down-drawing continuous casting), the small diameter of copper rod and the fast heat conduction of copper alloy cause high solidification fraction in the crystallizer, and the liquid cavity space is very small, so the effect of electromagnetic stirring is low. Utility Model Content

[0005] The purpose of this invention is to provide a magnetically excited homogenized solidification device to control the solidification process of continuously cast billets, achieve homogenization of the composition and solidification structure within the billets, and solve the problem that existing electromagnetic stirring technology has poor grain refinement effect in copper alloy continuous casting and cannot be applied in industrial production.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a magnetically excited homogenized solidification device, comprising an integrated continuous casting crystallizer, which has a cooling chamber inside, and a coil chamber surrounding the cooling chamber on the outside of the cooling chamber, wherein a coil is disposed in the coil chamber, and the upper end of the coil is higher than the top of the cooling chamber; it also includes a pulse power generator disposed outside the integrated continuous casting crystallizer, and the pulse power generator is connected to the coil via a cable.

[0007] Cooling water is supplied to the coil chamber, and the lower part of the coil chamber is provided with a coil chamber water inlet and a coil chamber water outlet.

[0008] The coil chamber is equipped with a cylindrical coil chamber guide plate. The lower end of the coil chamber guide plate is fixed to the bottom of the coil chamber. A water passage gap is left between the upper end of the coil chamber guide plate and the top of the coil chamber. The coil chamber inlet and the coil chamber outlet are located on both sides of the coil chamber guide plate.

[0009] The coil chamber guide plate divides the coil chamber into an inner space and an outer space, with the coil located in the inner space.

[0010] The coil chamber inlet is connected to the outer space, and the coil chamber outlet is connected to the inner space.

[0011] The coil is a spiral ring coil with 50 to 300 turns.

[0012] The coil is composed of multiple spiral ring coils connected in parallel, with the number of parallel layers ranging from 1 to 20.

[0013] The pulse current generator consists of a capacitor charging and discharging control system and multiple capacitors, with half of the capacitors connected in parallel to provide a positive pulse current to the coil and the other half of the capacitors connected in parallel to provide a negative pulse current to the coil.

[0014] The cooling chamber is equipped with a cylindrical cooling chamber guide plate. The lower end of the cooling chamber guide plate is fixed to the bottom of the cooling chamber, and a water passage gap is left between the upper end and the top of the cooling chamber. The cooling chamber inlet and cooling chamber outlet are located on both sides of the cooling chamber guide plate.

[0015] The cooling chamber guide vane divides the inner space of the cooling chamber into an inner side space and an outer side space, the cooling chamber water inlet communicates with the outer side space, the cooling chamber water outlet communicates with the inner side space, and the cooling chamber water outlet is inclined to the center of the crystallizer, so that the water outlet direction forms an angle of 15°-30° with the vertical direction.

[0016] The integrated continuous casting crystallizer has the advantages that the structure is simple, the distance between the coil and the cast blank is short, and the magnetic excitation effect is remarkable; and the upper end of the coil is higher than the cooling chamber, so that the melt can be excited in advance before entering the crystallizer and before solidification in the crystallizer is completed, and the solidification structure of the copper alloy rod blank can be refined significantly.

[0017] The cooling chamber is provided with a guide vane, the cooling water inlet and outlet can be arranged on the two sides of the guide vane respectively, and the solidification effect of the cast blank is improved.

[0018] The integrated continuous casting crystallizer has the advantages that the structure is simple, the distance between the coil and the cast blank is short, and the magnetic excitation effect is remarkable; and the upper end of the coil is higher than the cooling chamber, so that the melt can be excited in advance before entering the crystallizer and before solidification in the crystallizer is completed, and the solidification structure of the copper alloy rod blank can be refined significantly. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 It is a continuous solidification process schematic diagram of the magnetic excitation homogenization solidification device in the present application;

[0021] Figure 2 It is a structure schematic diagram of the integrated continuous casting crystallizer in the present application;

[0022] Figure 3 It is a principle schematic diagram of the pulse power generator;

[0023] Figure 4 It is a waveform diagram of the pulse current;

[0024] Figure 5 It is a SEM diagram of the Cu-10Fe alloy solidification structure without magnetic excitation treatment in the comparative example 1;

[0025] Figure 6SEM image of the solidification microstructure of Cu-10Fe alloy subjected to magnetic excitation treatment in Example 2;

[0026] Figure 7 This is a schematic diagram of the solidification process in the continuous casting of the crystallizer in Comparative Example 2.

[0027] The diagram shows the following markings: 1. Pulse power generator; 2. Cable; 3. Integrated continuous casting crystallizer; 4. Coil; 5. Continuous casting billet; 6. Liquid cavity; 7. Cooling chamber; 8. Coil chamber; 9. Cooling chamber guide plate; 10. Coil chamber guide plate; 11. Coil chamber inlet; 12. Coil chamber outlet; 13. Cooling chamber inlet; 14. Cooling chamber outlet; 15. Water passage gap; 16. Capacitor charging and discharging control system; 17. Capacitor; 18. Electromagnetic stirrer; 19. Crystallizer; 20. Crystallizer inlet; 21. Crystallizer outlet.

[0028] 100. Insulation furnace. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention in any way.

[0030] Example 1

[0031] like Figures 1-2 As shown, a magnetically excited homogenized solidification device includes a pulse power generator 1 and an integrated continuous casting crystallizer 3. The integrated continuous casting crystallizer 3 is used to be installed at the bottom gate of a smelting furnace or holding furnace 100 containing molten metal. The integrated continuous casting crystallizer 3 is provided with an annular cooling chamber 7 and an annular coil chamber 8. The cooling chamber 7 is located inside the coil chamber 8 and surrounds the formed continuous casting billet 5.

[0032] like Figure 2As shown, the cooling chamber 7 is provided with a cylindrical cooling chamber guide plate 9, the lower end of the cooling chamber guide plate 9 is fixed on the bottom of the cooling chamber 7, and a water gap 15 is left between the upper end of the cooling chamber guide plate 9 and the top of the cooling chamber 7, so that the space in the cooling chamber 7 is divided into two parts, an inner space and an outer space, by the cooling chamber guide plate 9. The cooling chamber inlet 13 and the cooling chamber outlet 14 of the cooling chamber 7 are both located on the bottom of the cooling chamber 7, and the cooling chamber inlet 13 and the cooling chamber outlet 14 are respectively located on the two sides of the cooling chamber guide plate 9. The cooling chamber inlet 13 communicates with the outer space, and the cooling chamber outlet 14 communicates with the inner space. The cooling chamber outlet 14 is inclined to the center of the crystallizer, so that the outlet direction forms an angle α with the vertical direction, and α = 15-30°. The cooling water enters the cooling chamber 7 from the cooling chamber inlet 13, first enters the outer space, then enters the inner space of the cooling chamber 7 through the water gap 15 at the top of the cooling chamber 7, and finally is discharged through the cooling chamber outlet 14 to become secondary cooling water for secondary cooling of the continuously cast billet 5.

[0033] Further, the cooling chamber inlet 13 and the cooling chamber outlet 14 can be provided in multiple, two of the multiple cooling chamber inlets 13 form a group and are oppositely arranged, and multiple groups of the cooling chamber inlets 13 are arranged in a circumferential direction at intervals. Two of the multiple cooling chamber outlets 14 form a group and are oppositely arranged, and multiple groups of the cooling chamber outlets 14 are arranged in a circumferential direction at intervals.

[0034] As shown, Figure 2 The upper end of the coil chamber 8 is higher than the upper end of the cooling chamber 7 by a height h of 20-50 mm. The coil chamber 8 is provided with a cylindrical coil chamber guide plate 10, the lower end of the coil chamber guide plate 10 is fixed on the bottom of the coil chamber 8, and a water gap 15 is left between the upper end of the coil chamber guide plate 10 and the top of the coil chamber 8, so that the space in the coil chamber 8 is divided into an inner space and an outer space by the coil chamber guide plate 15. The bottom of the outer periphery of the coil chamber 8 or the bottom end of the coil chamber 8 is provided with a coil chamber inlet 11 communicating with the outer space of the coil chamber 8, and the bottom end of the coil chamber 8 is provided with a coil chamber outlet 12 communicating with the inner space of the coil chamber 8. The inner space of the coil chamber 8 is provided with a coil 4, and the height of the coil 4 is equal to the height in the coil chamber 8, so that the upper end of the coil 4 is higher than the cooling chamber 7 by a distance h. The cooling water enters the coil chamber 8 from the coil chamber inlet 11, enters the inner space through the water gap 15, and surrounds the coil 4 to cool the coil 4, and is finally discharged through the coil chamber outlet 12.

[0035] The coil 4 is a spiral annular coil with a number of turns of 50-300, and can be composed of multiple spiral annular coils in parallel, and the number of parallel layers is 1-20. The shape of the coil 4 can be changed according to the shape of the continuously cast billet, and can be circular or rectangular. The coil 4 is made of solid copper conductor.Figure 3 As shown in the figure.

[0036] With reference to the Figure 3 As shown in the figure, the pulse power generator 1 is composed of a capacitor charging and discharging control system 16 and four capacitors 17, two sets of capacitors 17 are connected in parallel to provide positive pulse current, and two sets of capacitors 17 are connected in parallel to provide negative pulse current. The waveform of the pulse current is as shown in the figure. Figure 4 The pulse power generator 1 provides pulse current to the coil through the cable 2 to generate a pulse magnetic field. In other embodiments, the number of capacitors can be selected as needed.

[0037] Taking copper rod continuous casting as an example, the operation process of the device is as follows: the holding furnace 100 containing copper alloy liquid passes through the control rod to introduce copper liquid into the integrated continuous casting crystallizer 3, and the copper water solidifies under the forced cooling of the cooling chamber 7 to form a continuous casting billet 5 with a certain shell thickness, and continuously solidifies; the pulse current enters the coil 4 through the cable 2, and because the top end position of the coil 4 is higher than the top position of the cooling chamber 7, the excitation force is applied to the melt in advance, so that the melt can be fully excited before entering the integrated continuous casting crystallizer 3 and before solidification is completed in the integrated continuous casting crystallizer 3, and the continuous positive and negative pulse current will excite the square excitation magnetic field, which can produce positive and negative torsional force on the copper alloy dendrite arms nucleated and precipitated in the integrated continuous casting crystallizer 3, improve the dendrite fragmentation degree, form "crystallization rain", and achieve the purpose of composition and organization homogenization.

[0038] Example 2

[0039] The billet material is Cu-10Fe copper alloy, which is melted and refined in a melting furnace, and the melt temperature is uniform at 1400°C for 30 minutes to ensure uniform melt temperature before pouring. The integrated continuous casting crystallizer 3 is installed on the downward continuous casting machine, the cooling chamber 7 is 80mm high, the coil chamber 8 is 120mm high, and the coil 4 (30 turns, 2 layers) is fixed in the coil chamber 8. When starting pouring, start the dummy bar device of the continuous casting machine, set the continuous casting speed to 30mm / min, start the continuous casting machine at the same time, turn on the pulse power generator 1, adjust the processing parameters, and the parameters are: frequency 30Hz, current 100A. After pouring is completed, the power is cut off and the continuous casting machine is turned off.

[0040] Example 3

[0041] The billet material is Cu-6Ag copper alloy, which is melted and refined in a melting furnace and held at 1180℃ for 30 minutes to ensure uniform melt temperature before casting. An integrated continuous casting crystallizer 3 is installed on the lower-draw continuous casting machine. The cooling chamber 7 is 50mm high, the coil chamber 8 is 75mm high, and the coil 4 (25 turns, 3 layers) is fixed inside the coil chamber 8. At the start of casting, the dummy bar device of the continuous casting machine is activated, and the continuous casting speed is set to 35mm / min. Simultaneously with starting the continuous casting machine, the pulse power generator 1 is turned on, and the processing parameters are adjusted to: frequency 25Hz, current 150A. After casting is completed, the power is cut off, and the continuous casting machine is shut down.

[0042] Comparative Example 1

[0043] Comparative Example 1 was used for comparison with Example 2; therefore, its billet material was Cu-10Fe copper alloy, the crystallizer used had no coil chamber, the cooling chamber height of the crystallizer was 80 mm, and the casting speed was the same as in Example 2. When analyzing the copper rod billets prepared in Example 2 and Comparative Example 1, the middle section of the billet with a relatively stable casting speed was used. After grinding, polishing, and etching the copper rod billet samples, the macrostructure was observed. Figure 5 , 6 The image shows a SEM image of the solidification microstructure of the Cu-10Fe alloy. It can be seen from the image that in Comparative Example 1, the sample without magnetic excitation homogenization has coarse dendrites, long dendrite arms, and a grain size of 12. In Example 2, after applying this invention and performing magnetic excitation homogenization, the sample obtained fine dendrites with a grain size of 8, showing a very significant effect, as shown in Table 1.

[0044] Comparative Example 2

[0045] Comparative Example 2 was used for comparison with Example 3. The billet material was Cu-6Ag copper alloy. The crystallizer 19 used had no coil chamber inside, and an electromagnetic stirrer 18 was added externally to the crystallizer 19. See Figure 7 As shown, the electromagnetic stirrer 18 is powered by a sinusoidal current, and the pulling speed is the same as that in Example 3. When analyzing the copper rod billets prepared in Example 3 and Comparative Example 2, the middle section of the billet with a relatively stable pulling speed was used. After grinding, polishing, and etching the copper rod billet samples, the macrostructure was observed.

[0046] Table 1 lists the comparison results of grain size of the solidified structures in the examples and comparative examples. It can be seen that the samples using the traditional electromagnetic stirring installation method and current have a larger grain size. The samples homogenized by magnetic excitation using the device of this invention have a smaller grain size in their solidified structures, and the grain refinement effect is very obvious.

[0047]

[0048] The above examples are only used to illustrate the technical solutions of the present application and not to limit them, and those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by equivalents according to the above examples, and any modification or equivalent replacement that does not deviate from the spirit and scope of the present application is within the protection scope of the claims.

Claims

1. A magnetic oscillation homogenization solidification device comprising an integrated continuous casting crystallizer having a cooling chamber therein, characterized in that: The coil room is arranged outside the cooling chamber, and a coil is arranged in the coil room, with the upper end of the coil being higher than the top of the cooling chamber; a pulse power generator is arranged outside the integrated continuous casting crystallizer, and the pulse power generator is connected with the coil through a cable.

2. The magnetic vibration excitation homogenizing coagulation device according to claim 1, characterized in that: Cooling water is circulated in the coil room, and the lower part of the coil room is provided with a coil room water inlet and a coil room water outlet.

3. The magnetic vibration excitation homogenization solidification device according to claim 2, characterized in that: A cylindrical coil room flow guide plate is arranged in the coil room, with the lower end of the coil room flow guide plate being fixed to the bottom of the coil room, and a water passing gap being left between the upper end of the coil room flow guide plate and the top of the coil room, and the coil room water inlet and the coil room water outlet being respectively arranged on the two sides of the coil room flow guide plate.

4. The magnetic oscillation homogenizing coagulation device according to claim 3, characterized by: The coil room flow guide plate divides the coil room into an inner space and an outer space, and the coil is arranged in the inner space.

5. The magnetic vibration excitation homogenization coagulation device according to claim 4, characterized in that: The coil room water inlet is communicated with the outer space, and the coil room water outlet is communicated with the inner space.

6. The magnetic vibration excitation homogenization coagulation device according to claim 1, characterized in that: The coil is a spiral annular coil, with the number of turns being 50-300.

7. The magnetic vibration excitation homogenization coagulation device according to claim 1, characterized in that: The coil is composed of a plurality of spiral annular coils in parallel, with the number of parallel layers being 1-20.

8. The magnetic vibration excitation homogenization coagulation device according to claim 1, characterized in that: The pulse power generator is composed of a capacitor charging and discharging control system and a plurality of capacitors, with half of the number of the capacitors being connected in parallel to provide positive pulse current for the coil, and the other half of the number of the capacitors being connected in parallel to provide negative pulse current for the coil.

9. The magnetic vibration excitation homogenization coagulation device according to claim 1, characterized in that: A cylindrical cooling chamber flow guide plate is arranged in the cooling chamber, with the lower end of the cooling chamber flow guide plate being fixed to the bottom of the cooling chamber, and a water passing gap being left between the upper end of the cooling chamber flow guide plate and the top of the cooling chamber, and the cooling chamber water inlet and the cooling chamber water outlet of the cooling chamber being arranged on the two sides of the cooling chamber flow guide plate.

10. The magnetic vibration excitation homogenization coagulation device according to claim 9, characterized in that: The cooling chamber flow guide plate divides the space in the cooling chamber into an inner space and an outer space, the cooling chamber water inlet is communicated with the outer space, the cooling chamber water outlet is communicated with the inner space, and the cooling chamber water outlet is inclined to the center of the crystallizer, so that the water outlet direction forms an angle of 15°-30° with the vertical direction.

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