Ultrasonic-assisted method for preparing copper-iron alloy and continuous casting device for implementing method

Abstract

The invention belongs to the technical field of alloy preparation, and particularly relates to an ultrasonic-assisted method for preparing a copper-iron alloy and a continuous casting device for implementing the method. The ultrasonic-assisted method for preparing the copper-iron alloy comprises the following steps that corresponding raw materials are taken according to the composition of the designed copper-iron alloy to be smelted, and alloy melt is obtained; performing continuous casting on the alloy melt to obtain a copper-iron alloy casting blank; the continuous casting comprises the step that alloy melt is subjected to cooling crystallization under the action of an ultrasonic field, the cooling speed of cooling crystallization is 250-450 DEG C / s, and the copper-iron alloy is composed of 5-20 wt% of Fe and the balance Cu. An ultrasonic field is applied in the continuous casting process, the cooling speed during continuous casting is controlled, through the coupling effect of the ultrasonic field and the cooling speed, the refractory copper alloy is directly converted from a liquid phase to a solid phase in the solidification process, ultrasonic is assisted to further refine a Fe phase and crystal grains, meanwhile, component segregation and structure coarsening caused by liquid-liquid phase separation are avoided, and the quality of the refractory copper alloy is improved. And the strength and the conductivity performance of the copper-iron alloy are improved.

Description

Technical Field

[0001] The invention relates to the technical field of alloy preparation, and in particular to a method for preparing a copper-iron alloy with the assistance of ultrasound and a continuous casting device for implementing the method. Background Art

[0002] Copper alloys have good conductivity and mechanical properties and are widely used in key areas such as electronic information, new energy vehicles, high-speed railways, aerospace, national defense and military industries, as well as in harsh service environments. Among them, immiscible copper alloys are alloy elements that are very different from the matrix (melting point or density) and difficult to dissolve in each other, distributed on a copper matrix with good conductivity. The differences in the physical properties of these components give the alloy special mechanical and physicochemical properties, making it a copper alloy with special structure and function. Immiscible copper alloys often have special mechanical and physical properties, and have broad application prospects in self-lubrication, bearing materials, electrical contact materials, and electromagnetic shielding materials.

[0003] Immiscible copper alloys are a type of alloys with liquid phase separation characteristics. There is a stable or metastable immiscible zone on the phase diagram, that is, there is a metastable immiscible gap between the copper and iron liquid phases below the liquidus line, that is, when the alloy melt is supercooled to below the metastable solubility curve, the alloy supercooled melt will tend to undergo liquid phase separation. When the intersection of the composition and temperature of the supercooled melt is located inside it, the original alloy melt with uniform composition will spontaneously decompose into two liquid phases with different components. This type of alloy is very easy to form spatial liquid phase separation of the organization and severe segregation or even stratification of the organization during the conventional gravity field solidification process, and its potential excellent performance cannot be exerted. In order to solve this type of problem that occurs in the alloy casting of immiscible copper alloys, the preparation of immiscible copper alloys mostly adopts methods such as in-situ compounding, vacuum self-consumable and powder metallurgy. However, these methods have complicated procedures and high costs, and are not easy to achieve industrial continuous production.

[0004] With the increasingly higher performance requirements for inmiscible copper alloys and the continuous expansion of the market scale, there is an urgent need for a preparation method that can effectively inhibit the nucleation, coarsening, growth, aggregation, coagulation and collision of droplets during the liquid phase separation process during the smelting preparation of inmiscible copper alloys, so as to achieve homogenization of composition and refinement of structure, and provide high-quality inmiscible copper alloys for applications in electronic assembly, complex connectors in electrical systems, etc.

[0005] The Chinese invention patent with application publication number CN108842091A, which was applied for and published on November 20, 2018, discloses a method for preparing Cu-Cr alloy by magnetic field / ultrasonic field coupling. During the solidification process, a magnetic field and an ultrasonic field are simultaneously applied to control the solidification of the Cu-Cr alloy, which significantly refines the Cr dendrites and reduces Cr segregation, so that after subsequent cold deformation processing, the material has a uniformly distributed fine Cr fiber phase dispersed in the matrix, thereby greatly improving the strength of the material.

[0006] However, the liquid phase immiscible gap of Cu-Cr alloy is smaller than that of Cu-Fe alloy, that is, Cu-Fe alloy is more prone to liquid phase separation, thus forming a severely segregated structure. The above method cannot change the phase separation and composition segregation of Cu-Fe alloy during the solidification process, and Fe-rich dendrites or coarse Fe phase particles will still be formed, thereby affecting the subsequent processing performance, conductivity, mechanical properties and electromagnetic shielding performance. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing copper-iron alloy with the assistance of ultrasound, so as to solve the problems of coarse Fe phase dendrites and Fe phase segregation existing in the prior art when preparing copper-iron alloy.

[0008] The second object of the present invention is to provide a continuous casting device for implementing the ultrasonic-assisted method for preparing copper-iron alloy, so as to solve the problem of complex preparation method in the prior art when preparing high-performance copper-iron alloy.

[0009] In order to solve the above technical problems, the technical solution of the method for preparing copper-iron alloy with ultrasound assistance of the present invention is: A method for preparing a copper-iron alloy with the assistance of ultrasound comprises the following steps: taking corresponding raw materials according to the designed composition of the copper-iron alloy for smelting to obtain a molten alloy; the molten alloy is continuously cast to obtain a copper-iron alloy ingot; the continuous casting comprises cooling and crystallizing the molten alloy under the action of an ultrasonic field, the cooling rate of the cooling crystallization is 250-450°C / s, and the composition of the copper-iron alloy is as follows: 5-20wt% of Fe and the rest is Cu.

[0010] The present invention is an improvement on the prior art, and provides a method for preparing a copper-iron alloy with the assistance of ultrasound. By applying an ultrasonic field during the continuous casting process and controlling the cooling rate during the continuous casting, the coupling effect of the two allows the insoluble copper alloy to directly transform from a liquid phase to a solid phase during the solidification process, and the auxiliary ultrasonic system further refines the Fe phase and grains, while avoiding component segregation and structural coarsening caused by liquid-liquid phase separation; at the same time, the application of the ultrasonic field causes cavitation effect and acoustic streaming effect in the molten metal, which on the one hand promotes the nucleation of the second phase during the liquid-liquid phase separation process, and on the other hand effectively breaks up the second phase droplets with larger sizes and inhibits their mutual aggregation and coagulation behavior, so that a relatively uniform solidification structure can be obtained under the action of the ultrasonic field, and the strong shear force generated by the acoustic streaming effect can significantly inhibit the segregation and deposition of the solute, overcome the formation of alloy segregation or stratified structure under conventional gravity field casting conditions, and thus improve the strength, conductivity and electromagnetic shielding performance of the copper-iron alloy.

[0011] The method for preparing copper-iron alloy with ultrasound assistance provided by the present invention has simple process and low cost, and can prepare copper-iron alloy ingots with good comprehensive performance in the casting stage, which is beneficial to subsequent processing and forming, and at the same time obtains excellent conductivity, strength and electromagnetic shielding performance.

[0012] In order to further improve the cavitation effect and the acoustic streaming effect, preferably, the power of the ultrasonic field is 0.3-2 kW, and the frequency of the ultrasonic field is 20-22 kHz.

[0013] In order to further increase the cooling speed, preferably, the casting speed during continuous casting is 15-20 kg / min, and the casting temperature during continuous casting is 1300-1400° C.

[0014] In order to further improve the uniformity of the copper-iron alloy components, preferably, the smelting temperature is 1300-1600°C.

[0015] In order to further homogenize the alloy composition and remove impurities, preferably, the alloy melt is purified before continuous casting, and the purification is to keep the alloy melt at 1300-1400° C. for 20-40 minutes.

[0016] In order to further improve the strength and electrical conductivity of the alloy, preferably, after the continuous casting is completed, an ingot is obtained, and the ingot is subjected to homogenization annealing, hot rolling, cold deformation processing and aging treatment.

[0017] In order to further improve the strength and electrical conductivity of the alloy, preferably, the homogenization annealing is carried out at 900-950°C in an inert gas for 5-20 hours; the hot rolling temperature is 800-950°C, and the hot rolling deformation is 60-80%; the cold deformation deformation is 50-98%; the aging treatment temperature is 400-450°C, and the aging treatment time is 4-20 hours. After the cold deformation, a uniformly distributed and fine Fe fiber phase and a fine-grained Cu-Fe alloy are formed in the matrix, which can greatly improve the strength of the material.

[0018] The technical solution of the continuous casting device for implementing the ultrasonic-assisted method for preparing copper-iron alloy of the present invention is: A continuous casting device for implementing the method for preparing copper-iron alloy with ultrasound assistance, comprising a crystallizer, an ultrasonic system installed on the outside of the crystallizer, the crystallizer having a flow channel for alloy melt to pass through and a cooling channel arranged on the periphery of the flow channel, the cooling channels being multiple and extending along the length direction of the flow channel, the lower ends of the cooling channels being connected to form a water outlet channel, the water outlet channel being connected to a water outlet arranged on the crystallizer; a cooling water inner tube extending along the length direction of the cooling channel is arranged in the cooling channel, the cooling water inner tube having a water inlet located at the lower end and a water outlet hole near the top of the cooling channel, and a cooling water flow gap being provided between the cooling water inner tube and the cooling channel.

[0019] The continuous casting device for implementing the ultrasonic-assisted method for preparing copper-iron alloy provided by the present invention, by providing a cooling channel extending along the length direction of the flow channel and a cooling water inner tube in the cooling channel, a small-volume crystallizer can achieve efficient heat exchange, greatly improve the cooling rate of the alloy melt by the crystallizer, and combine with an ultrasonic system, and the joint coupling effect enables the difficult-to-mix copper alloy to directly transform from liquid phase to solid phase during the solidification process, and the ultrasonic system is assisted to further refine the Fe phase and grains, while avoiding component segregation and tissue coarsening caused by liquid-liquid phase separation, thereby obtaining a uniform solidified structure, greatly improving the strength and electrical conductivity of the copper-iron alloy, and obtaining a high-performance copper-iron alloy; compared with the high-cost and complex-operation processes for preparing high-performance copper-iron alloys such as in-situ compounding, vacuum self-consumption and powder metallurgy, the continuous casting device has a simple structure, is easy to use, and has a low production cost, and a high-performance copper-iron alloy can be obtained by a simple continuous casting method.

[0020] In order to further increase the heat dissipation area and improve the cooling efficiency, preferably, a plurality of grooves extending along the length direction of the cooling channel are provided on the inner wall of the cooling channel.

[0021] In order to further facilitate the continuous casting of the alloy, preferably, the continuous casting device also includes a smelting system, a pouring system and a spraying system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a crystallizer of Example 1 of a continuous casting device for implementing a method for preparing copper-iron alloy with ultrasound assistance according to the present invention; Figure 2 for Figure 1 AB section diagram; Figure 3 for Figure 1 Schematic diagram of the cooling channel structure; Figure 4 for Figure 3 CD cross-section diagram; Figure 5 The process flow chart of the method for preparing copper-iron alloy with ultrasound assistance of the present invention; Figure 6 It is a schematic diagram of the casting position of multiple casting channels; Figure 7 The microstructure morphology diagrams of the copper-iron alloys of Example 1 and Comparative Example 1 of the present invention; In the attached drawings: 1, crystallizer; 2, flow channel; 3, cooling channel; 31, cooling water inner tube; 311, groove; 4, water inlet; 5, water outlet; 6, water outlet channel. DETAILED DESCRIPTION

[0023] The technical concept of the method for preparing copper-iron alloy with ultrasound assistance of the present invention is as follows: A method for preparing a copper-iron alloy with the assistance of ultrasound comprises the following steps: taking corresponding raw materials according to the designed composition of the copper-iron alloy for smelting to obtain a molten alloy; the molten alloy is continuously cast to obtain a copper-iron alloy ingot; the continuous casting comprises cooling and crystallizing the molten alloy under the action of an ultrasonic field, the cooling rate of the cooling crystallization is 250-450°C / s, and the composition of the copper-iron alloy is as follows: 5-20wt% of Fe and the rest is Cu.

[0024] The ultrasonic-assisted method for preparing copper-iron alloy provided by the present invention applies an ultrasonic field during the continuous casting process and controls the cooling rate during the continuous casting. The coupling effect of the two enables the insoluble copper alloy to directly transform from the liquid phase to the solid phase during the solidification process, effectively inhibits the floating migration of the Fe phase due to the specific gravity difference, and assists the ultrasonic system to further refine the Fe phase and grains, while avoiding the component segregation and structure coarsening caused by liquid-liquid phase separation; at the same time, the application of the ultrasonic field causes cavitation effect and acoustic streaming effect in the molten metal, which on the one hand promotes the nucleation of the second phase during the liquid-liquid phase separation, and on the other hand effectively breaks up the second phase droplets with larger sizes and inhibits their mutual aggregation and coagulation behavior. Under the action of the ultrasonic field, a relatively uniform solidification structure can be obtained, and the strong shear force generated by the acoustic streaming effect can significantly inhibit the segregation and deposition of the solute, overcoming the formation of alloy segregation or stratified structure under conventional gravity field casting conditions.

[0025] The difference from the prior art lies in the rapid solidification. Instead of pouring them all into the crystallizer and then solidifying from bottom to top, the cooling rate is controlled to achieve similar "layer-by-layer solidification". The casting and solidification occur simultaneously, and the crystals are refined in the ultrasonic field while the liquid phase is directly transformed into the solid phase. This overcomes the formation of alloy segregation or stratified structure under conventional gravity field casting conditions, avoids component segregation, Fe phase coarsening and tree crystal formation, and significantly improves macro segregation.

[0026] The present invention adopts a copper crystallizer. Due to the excessively fast cooling rate of the alloy melt in the copper plate mold, the alloy solution is continuously poured, and the liquid-solid phase transition cannot be recorded by the traditional temperature measurement method. The crystallizer structure is complex, and under the action of the external field, observation and measurement are more difficult. Therefore, with the help of Curiotto et al. (Effect of cooling rate on the solidification of Cu 58 Co 42 ) is estimated using the empirical formula proposed in the study of copper alloy solidification, the formula is as follows: , where k and n are constants, z is the distance from the center of the crystallizer to the inner wall of the crystallizer, and the mold is not cooled. For the present invention, the casting speed and the inlet and outlet temperatures are controlled to achieve rapid solidification layer by layer; the k value is taken as 2042, the n value is -1.8, and the z value is replaced by the liquid level height. When the pouring thickness per second is 1mm / s~3mm / s, the cooling rate is 283℃ / s~2042℃ / s. The present invention is a continuous pouring. Considering factors such as the time required for the alloy liquid surface to spread and the heat conduction between the alloy liquid and the surrounding mold, there will be deviations in the cooling rate. The cooling rate range is determined by empirical formula calculation and organizational analysis.

[0027] In a specific implementation, the water temperature at the water inlet of the crystallizer is controlled to be 20-25°C, and the temperature difference between the water temperature at the inlet and outlet of the crystallizer is controlled to be 5-30°C; the cooling rate of the melt is controlled by cooling the cooling water of the crystallizer and the casting rate of the melt.

[0028] In a specific implementation manner, annealing is performed 1 to 2 times during the cold deformation process, the annealing temperature is 400 to 550° C., and the annealing time is 1 to 2 hours.

[0029] The implementation manner of the present invention is further described below in conjunction with specific examples.

[0030] 1. Specific embodiment of the continuous casting device for implementing the ultrasonic-assisted method for preparing copper-iron alloy of the present invention Example 1 The continuous casting device for implementing the ultrasonic-assisted method for preparing copper-iron alloy in this embodiment includes a crystallizer 1, and an ultrasonic system is installed outside the crystallizer 1. The specific structure of the crystallizer 1 is as follows: Figure 1-4As shown, the crystallizer 1 has a flow channel 2 for alloy melt to pass through and a cooling channel 3 arranged on the periphery of the flow channel 2. There are multiple cooling channels 3 and they extend along the length direction of the flow channel 2. The lower ends of the cooling channels 3 are connected to form a water outlet channel 6, and the water outlet channel 6 is connected to the water outlet 5 arranged on the crystallizer; a cooling water inner tube 31 extending along the length direction of the cooling channel 3 is arranged in the cooling channel 3, and the cooling water inner tube 31 has a water inlet 4 located at the lower end and a water outlet hole near the top of the cooling channel 3 (not shown in the figure), and a cooling water flow gap is provided between the cooling water inner tube 31 and the cooling channel 3.

[0031] by Figure 2 Taking the direction shown as an example, at this time, the lower temperature cooling water first contacts with the alloy melt that is being cast, and then flows downward after absorbing heat, contacting with the alloy melt that has been cooled down to absorb heat, which can greatly improve the cooling uniformity.

[0032] The inner wall of the cooling channel 3 is provided with a plurality of grooves 311 extending along the length direction of the cooling channel 3. The grooves 311 can further increase the contact area between the cooling water and the alloy melt, thereby improving the cooling efficiency. It is understandable that the grooves 311 can be arc grooves, V-shaped grooves or grooves of other shapes, as long as the contact area between the cooling water and the crystallizer can be increased.

[0033] When the crystallizer 1 is actually working, cooling water enters the cooling water inner tube 31 from the water inlet 4, flows into the cooling channel 3 through the water outlet hole of the cooling water inner tube 31 near the top of the cooling channel 3, and the cooling water exchanges heat with the crystallizer through the inner wall of the cooling channel 3, thereby cooling the alloy melt. The cooling water in each cooling channel 3 flows downward, and the outlet channel 6 formed by the lower end of the cooling channel 3 is connected. The outlet channel 6 is connected to the outlet 5 set on the crystallizer, and then flows out from the outlet 5. The water inlet 4 and the outlet 5 can be connected to an external water cooling system, and the cooling water flowing out of the outlet 5 is cooled and then flows into the water inlet 4 to realize a water cooling cycle. The continuous casting device also includes a smelting system, a pouring system and a spraying system.

[0034] 2. Specific embodiments of the method for preparing copper-iron alloy with ultrasound assistance of the present invention Example 2 The flowchart of the method for preparing copper-iron alloy with ultrasound assistance in this embodiment is as follows: Figure 5 As shown, the method for ultrasonic-assisted preparation of copper-iron alloy is as follows: (1) Smelting: The composition of the copper-iron alloy is as follows: 5wt% Fe, and the rest is Cu. According to the designed composition of the copper-iron alloy, the corresponding raw materials are taken in a smelting furnace for smelting, and the electrolytic copper and pure iron are heated to 1400°C to ensure that the raw materials are in a molten state. When the raw materials begin to melt and form a fluid, a covering agent is added to prevent the alloy melt from oxidation. After all the raw materials are melted, the heat is kept for 10 minutes. Under the protection of inert gas, the mixture is stirred evenly and then the slag is fully skimmed until the melt is clean and clear to obtain a copper-iron alloy melt.

[0035] (2) Purification of copper-iron alloy melt: Open the stopper rod between the smelting furnace and the holding furnace to transfer the copper-iron alloy melt in the smelting furnace to the holding furnace through the overflow tank. The copper-iron alloy melt is purified by keeping it at 1300°C for 40 minutes to further improve the uniformity of the alloy components and temporarily store the alloy melt. The smelting furnace can continue to smelt to achieve continuous preparation of copper-iron alloy.

[0036] (3) Casting: Open the stopper rod of the holding furnace to make the casting speed 18kg / min. Before casting, open the ultrasonic system and the cooling water circulation of the crystallizer. The power of the ultrasonic field is 0.3kw and the frequency is 20kHz. The water temperature at the water inlet of the crystallizer is controlled to be 20~25℃. The water temperature difference between the inlet and outlet of the crystallizer is controlled to be 30℃, so that the cooling rate during casting is 250~350℃ / s. The copper-iron alloy melt is cast at 1300℃. After the casting is completed, an inert gas argon is introduced between the runner and the crystallizer during the casting process to avoid oxidation and the introduction of impurities that affect the quality of the alloy. It can be understood that the casting channel of the holding furnace can be one or more, and the corresponding number of stopper rods are used to control the opening or closing of the casting channel. Opening multiple stopper rods can be used for casting at the same time. The casting positions of the three casting channels are as follows: Figure 6 shown.

[0037] (4) Homogenization annealing: The ingot is subjected to homogenization annealing treatment at 900°C in an inert gas for 20 h to obtain a homogenized ingot.

[0038] (5) Hot rolling: The homogenized ingot is hot rolled at 800°C with a deformation of 60%.

[0039] (6) Cold deformation processing: cold deformation processing is carried out after hot rolling. When the deformation amount of cold deformation processing is 25%, annealing is carried out once. The annealing temperature is 400℃ and the annealing time is 2h. After annealing is completed, cold deformation processing is continued to make the deformation amount reach 50%.

[0040] (7) Aging treatment: After cold deformation, aging treatment is carried out at 400°C for 20 hours.

[0041] Example 3 The method for preparing copper-iron alloy with ultrasound assistance in this embodiment is as follows: (1) Smelting: The composition of the copper-iron alloy is as follows: 10wt% Fe, and the rest is Cu. According to the designed composition of the copper-iron alloy, the corresponding raw materials are taken in a smelting furnace for smelting, and the electrolytic copper and pure iron are heated to 1500° C. to ensure that the raw materials are in a molten state. When the raw materials begin to melt and form a fluid, a covering agent is added to prevent the alloy melt from oxidation. After all the raw materials are melted, the heat is kept for 10 minutes. Under the protection of inert gas, the mixture is stirred evenly and then the slag is fully skimmed until the melt is clean and clear to obtain a copper-iron alloy melt.

[0042] (2) Purification of copper-iron alloy melt: Open the stopper rod between the smelting furnace and the holding furnace to transfer the copper-iron alloy melt in the smelting furnace to the holding furnace through the overflow tank. The copper-iron alloy melt is purified by keeping it at 1400°C for 20 minutes to further improve the uniformity of the alloy components and temporarily store the alloy melt. The smelting furnace can continue to smelt to achieve continuous preparation of copper-iron alloy.

[0043] (3) Casting: Open the stopper rod of the holding furnace to make the casting speed 20kg / min. Before casting, turn on the cooling water circulation of the ultrasonic system and the crystallizer. The power of the ultrasonic field is 1kw and the frequency is 21kHz. The water temperature at the water inlet of the crystallizer is controlled to be 20~25℃. The water temperature difference between the inlet and outlet of the crystallizer is controlled to be 10℃, so that the cooling rate during casting is 270~370℃ / s. The copper-iron alloy melt is cast at 1350℃. After the casting is completed, an ingot is obtained. During the casting process, inert gas argon is introduced between the runner and the crystallizer to avoid oxidation and the introduction of impurities that affect the quality of the alloy.

[0044] (4) Homogenization annealing: The ingot is subjected to homogenization annealing treatment at 930°C in an inert gas for 10 h to obtain a homogenized ingot.

[0045] (5) Hot rolling: The homogenized ingot is hot rolled at 900°C with a deformation of 70%.

[0046] (6) Cold deformation processing: cold deformation processing is carried out after hot rolling. When the deformation amount of cold deformation processing is 25%, annealing is carried out once. The annealing temperature is 550℃ and the annealing time is 1h. After annealing is completed, cold deformation processing is continued to make the deformation amount reach 60%.

[0047] (7) Aging treatment: After cold deformation, aging treatment is carried out at 430°C for 4 hours.

[0048] Example 4 The method for preparing copper-iron alloy with ultrasound assistance in this embodiment is as follows: (1) Smelting: The composition of the copper-iron alloy is as follows: 20wt% Fe, and the rest is Cu. According to the designed composition of the copper-iron alloy, the corresponding raw materials are taken in a smelting furnace for smelting, and the electrolytic copper and pure iron are heated to 1600°C to ensure that the raw materials are in a molten state. When the raw materials begin to melt and form a fluid, a covering agent is added to prevent the alloy melt from oxidation. After all the raw materials are melted, the heat is kept for 10 minutes. Under the protection of inert gas, the mixture is stirred evenly and then the slag is fully skimmed until the melt is clean and clear to obtain a copper-iron alloy melt.

[0049] (2) Purification of copper-iron alloy melt: Open the stopper rod between the smelting furnace and the holding furnace to transfer the copper-iron alloy melt in the smelting furnace to the holding furnace through the overflow tank. The copper-iron alloy melt is purified by keeping it at 1400°C for 20 minutes to further improve the uniformity of the alloy components and temporarily store the alloy melt. The smelting furnace can continue to smelt to achieve continuous preparation of copper-iron alloy.

[0050] (3) Casting: Open the stopper rod of the holding furnace to make the casting speed 15kg / min. Before casting, turn on the cooling water circulation of the ultrasonic system and the crystallizer. The power of the ultrasonic field is 2kw and the frequency is 22kHz. The water temperature at the inlet of the crystallizer is controlled to be 20-25℃. The temperature difference between the inlet and outlet of the crystallizer is controlled to be 5℃, so that the cooling rate during casting is 350-450℃ / s. The copper-iron alloy melt is cast at 1400℃. After the casting is completed, an ingot is obtained. During the casting process, inert gas argon is introduced between the runner and the crystallizer to avoid oxidation and the introduction of impurities that affect the quality of the alloy.

[0051] (4) Homogenization annealing: The ingot is subjected to homogenization annealing treatment at 950°C in an inert gas for 5 h to obtain a homogenized ingot.

[0052] (5) Hot rolling: The homogenized ingot is hot rolled at 950°C, and the deformation amount of hot rolling is 80%.

[0053] (6) Cold deformation processing: cold deformation processing is carried out after hot rolling. When the deformation amount of cold deformation processing is 25%, annealing is carried out once, and when the deformation amount is 60%, annealing is carried out again. The temperature of the two annealings is 550℃, and the annealing time is 1h. After annealing is completed, cold deformation processing is continued to make the deformation amount reach 98%.

[0054] (7) Aging treatment: After cold deformation, aging treatment is carried out at 400°C for 4 hours.

[0055] 2. Comparison Comparative Example 1 The method for preparing copper-iron alloy with ultrasound assistance in this comparative example is basically the same as that in Example 2, except that: (3) Casting: Open the stopper rod of the holding furnace to make the casting speed 5kg / min. Before casting, turn on the cooling water circulation of the ultrasonic system and the crystallizer. The power of the ultrasonic field is 0.3kw and the frequency is 20kHz. The water temperature at the inlet of the crystallizer is controlled to be 20-25℃. The temperature difference between the inlet and outlet of the crystallizer is controlled to be 50℃, so that the cooling rate during casting is 80-180℃ / s. The copper-iron alloy melt is cast at 1300℃. After the casting is completed, an ingot is obtained. During the casting process, inert gas argon is introduced between the runner and the crystallizer to avoid oxidation and the introduction of impurities that affect the quality of the alloy.

[0056] 3. Experimental Examples Experimental Example 1 In this experimental example, the microstructure morphology of the copper-iron alloy obtained in the embodiment and the comparative example is tested and observed. The microstructure morphology of the embodiment 1 (left) and the comparative example 1 (right) are shown in FIG. Figure 7 As shown, from Figure 7 It can be seen that the Fe phase in the copper-iron alloy prepared in Example 1 is fine and dispersed, while the Fe phase in the copper-iron alloy of Comparative Example 1 has coarse dendrites and uneven distribution of components, which indicates that the copper-iron alloy preparation method of the present invention can promote the uniform distribution of the Fe phase, significantly improve the macro-segregation, solve the problems of coarse primary Fe dendrites and severe segregation caused by liquid-liquid phase separation, make the Fe phase fine and evenly distributed in the copper matrix, and obtain a Cu-Fe alloy with fine grains.

[0057] Experimental Example 2 In this experimental example, the mechanical properties of the copper-iron alloy obtained in the embodiment and the comparative example were tested by a universal mechanical testing machine, and the electrical conductivity (%IACS) of the copper-iron alloy was tested by a metal eddy current conductivity meter. The test results are shown in Table 1.

[0058] Table 1 Test results of mechanical properties and electrical conductivity of copper-iron alloy Tensile strength (MPa) Electrical conductivity (%IACS) Example 2 630 61 Example 3 863 54 Example 4 1102 35 Comparative Example 1 495 49 As can be seen from Table 1, the tensile strength and electrical conductivity of the copper-iron alloy prepared in Example 2 are significantly higher than those in Comparative Example 1, indicating that the method for preparing the copper-iron alloy with the assistance of ultrasound provided by the present invention can greatly improve the tensile strength and electrical conductivity of the copper-iron alloy by controlling the cooling rate. In addition, the strength of the copper-iron alloy can be further improved by controlling the alloy composition, casting parameters and heat treatment conditions, but the electrical conductivity will be reduced.

[0059] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing copper-iron alloy with ultrasound assistance, characterized in that: The following steps are involved: According to the designed copper-iron alloy composition, corresponding raw materials are smelted to obtain alloy melt; the alloy melt is continuously cast to obtain copper-iron alloy ingot; the continuous casting includes cooling and crystallizing the alloy melt under the action of an ultrasonic field, and the cooling rate of the cooling crystallization is 250-450°C / s. The composition of the copper-iron alloy is as follows: Fe 5-20wt%, and the rest is Cu.

2. The method for preparing copper-iron alloy with ultrasound assistance according to claim 1, characterized in that: The power of the ultrasonic field is 0.3-2 kW, and the frequency of the ultrasonic field is 20-22 kHz.

3. The method for preparing copper-iron alloy with ultrasound assistance according to claim 1, characterized in that: The casting speed during continuous casting is 15-20 kg / min, and the casting temperature during continuous casting is 1300-1400° C.

4. The method for preparing copper-iron alloy with ultrasound assistance according to claim 1, characterized in that: The smelting temperature is 1300-1600°C.

5. The method for preparing copper-iron alloy with ultrasound assistance according to claim 1, characterized in that: The alloy melt is purified before continuous casting, and the purification is carried out by keeping the alloy melt at 1300-1400° C. for 20-40 minutes.

6. The method for preparing copper-iron alloy with ultrasound assistance according to claim 1, characterized in that: After the continuous casting is completed, an ingot is obtained, and the ingot is subjected to homogenization annealing, hot rolling, cold deformation processing and aging treatment.

7. The method for preparing copper-iron alloy with ultrasound assistance according to claim 6, characterized in that: The homogenization annealing is carried out in an inert gas at 900-950°C for 5-20h; the hot rolling temperature is 800-950°C, and the hot rolling deformation is 60-80%; the cold deformation is 50-98%; the aging treatment temperature is 400-450°C, and the aging treatment time is 4-20h.

8. A continuous casting device for implementing the method for preparing copper-iron alloy with ultrasound assistance according to any one of claims 1 to 7, comprising a crystallizer, an ultrasonic system is installed outside the crystallizer, the crystallizer has a flow channel for alloy melt to pass through and a cooling channel arranged on the periphery of the flow channel, characterized in that: There are multiple cooling channels and they extend along the length direction of the flow channel. The lower ends of the cooling channels are connected to form a water outlet channel, and the water outlet channel is connected to the water outlet arranged on the crystallizer. A cooling water inner tube extending along the length direction of the cooling channel is arranged in the cooling channel. The cooling water inner tube has a water inlet located at the lower end and a water outlet hole near the top of the cooling channel, and a cooling water flow gap is provided between the cooling water inner tube and the cooling channel.

9. The continuous casting device for implementing the method for preparing copper-iron alloy with ultrasound assistance according to claim 8, characterized in that: The inner wall of the cooling channel is provided with a plurality of grooves extending along the length direction of the cooling channel.

10. The continuous casting device for implementing the method for preparing copper-iron alloy with ultrasound assistance according to claim 8, characterized in that: The continuous casting device also includes a smelting system, a pouring system and a spraying system.

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