An intelligent processing system and control method for homogenizing and purifying an aluminum master alloy melt

Abstract

The present application belongs to the technical field of non-ferrous melt processing, and discloses an intelligent processing system and control method for homogenization and purification of aluminum intermediate alloy melt. The system comprises a heat preservation and heating device, a rotor degassing machine, mechanical stirring, an electromagnetic coil surrounding the outside of the heat preservation and heating device, a PLC core controller, and various sensors. The PLC performs online three-closed-loop linkage control: liquid level-stirring closed loop, rotating speed-frequency closed loop, and temperature-heating closed loop. The present application can automatically match the optimal parameters according to the alloy type and the organizational feature requirements of the alloy target core, and has self-learning optimization capability based on the alloy organization and performance requirements. The present application is applied to online rapid heating, heat preservation, melt purification, and homogenization processing of high-temperature and high-viscosity alloy melt, realizes the improvement of high-melting-point, easily-segregating, and not-easily-purified aluminum intermediate alloy melt and product quality, and meets the manufacturing requirements of high-performance aluminum alloy materials in the fields of aerospace, 3C electronics, etc.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal melt processing technology, specifically relating to an intelligent processing system and control method for homogenization and purification of aluminum master alloys (such as aluminum-titanium-boron, aluminum-strontium, and aluminum-titanium) and other alloys (such as magnesium alloys and zinc alloys) melts. Background Technology

[0002] As a key additive material for high-end cast and wrought aluminum alloys, the uniformity and purity of the aluminum master alloy's microstructure directly affect the quality and performance of the final products and components. However, due to the characteristics of aluminum master alloy melts, such as high melting point (750-1300℃), poor fluidity, and high slag content, the purification and homogenization of the melt has always been a challenge in the industry, presenting the following technical bottlenecks: Poor uniformity, poor intermelting properties, and severe segregation: Heavy alloying elements (such as Ti and B) tend to deposit in the melt, and traditional single stirring methods cannot form three-dimensional convection, resulting in uneven composition distribution.

[0003] Insufficient purification capacity: It is difficult to effectively remove hydrogen content, oxide inclusions and non-metallic inclusions in the melt, which directly affects the application performance of the material.

[0004] Slow online heating and low temperature control accuracy: Traditional equipment typically has a temperature control accuracy of ±10℃ or higher, poor heat preservation, and excessively fast melt cooling rate, resulting in coarse microstructure.

[0005] Limited control methods: Traditional equipment relies solely on mechanical stirring or manual operation, making it impossible to achieve multi-parameter coordinated control.

[0006] In existing technologies, such as CN104313339A, an online degassing device for molten aluminum is disclosed. This device uses permeable bricks at the bottom of the tank and is supplemented by electromagnetic stirring. However, its degassing principle relies on the foaming of the permeable bricks, which cannot generate microbubbles, resulting in low degassing efficiency and failing to address the problem of high-density element segregation. Another example is CN202387944U, which discloses a dual forced homogenization device that combines mechanical and electromagnetic stirring. However, this is primarily for preparing semi-solid slurries and does not integrate rotary degassing and purification functions, nor does it possess intelligent linkage control. Therefore, there is an urgent need for an integrated intelligent system capable of simultaneously achieving melt homogenization, efficient purification, and precise temperature control. Summary of the Invention

[0007] This invention aims to overcome the shortcomings of existing technologies and provide an intelligent processing system and control method for homogenizing and purifying aluminum master alloy melts. By deeply integrating electromagnetic stirring, mechanical stirring / rotary degassing, and intelligent control, a three-dimensional closed-loop linkage system of heat preservation / heating, stirring, and purification is formed, which significantly improves melt homogenization, purification efficiency, and temperature control accuracy, and can adaptively adjust process parameters according to the microstructure requirements of different alloys.

[0008] The technical solution adopted by this invention to solve the technical problem is: The first aspect of the present invention is to provide an intelligent processing system for homogenizing and purifying aluminum master alloy melt, including a heat preservation and heating device, a rotor degasser, a mechanical stirring and degassing rotor placed in the heat preservation and heating device, and an electromagnetic coil surrounding the outside of the heat preservation and heating device, and also includes a PLC core controller, and a liquid level sensor, a rotor speed sensor and a temperature sensor respectively connected to the PLC core controller. The PLC core controller is configured to perform the following three-closed-loop linkage control: (a) Liquid level-stirring closed loop: Based on the melt level height detected by the liquid level sensor, the input current of the electromagnetic coil is automatically adjusted, and the mechanical stirring and degassing rotor are stopped when the liquid level is lower than the safety threshold; (b) Rotation speed-frequency closed loop: Based on the rotor speed detected by the rotor speed sensor, the output frequency of the electromagnetic coil is automatically adjusted so that the ratio of the linear velocity of the melt surface generated by electromagnetic stirring to the linear velocity of the rotor periphery is kept within a preset range. (c) Temperature-Heating Closed Loop: Based on the melt temperature detected by the temperature sensor, the working mode of the electromagnetic coil is automatically switched. When the temperature is lower than the set value, the induction heating is enhanced. When the temperature is near the set value, the constant temperature is maintained. When the temperature is higher than the set value, the heating is weakened or the heating is stopped.

[0009] Furthermore, in the liquid level-stirring closed loop, the liquid level sensor is a high-temperature laser liquid level gauge with an accuracy of ±2mm; the safety threshold is a liquid level below 150mm. When the liquid level L≥300mm, the electromagnetic stirring current I = set value × 100%; When 150mm≤L<300mm, I=set value×(L / 300)×0.8+set value×0.2; When L < 150 mm, immediately stop the mechanical stirring and degassing rotor and issue an alarm.

[0010] Furthermore, in the aforementioned speed-frequency closed loop, the rotor peripheral linear velocity Vr = π·Dr·nr / 60, where Dr is the rotor outer diameter and nr is the rotor speed; The linear velocity of the melt surface generated by electromagnetic stirring is Ve = K × Vr, where K is the target coordination ratio and the preset coordination range is 0.85~1.15; the output frequency of the electromagnetic coil is f = Ve / kf, where kf is the electromagnetic conversion coefficient; when K < 0.85, f is increased in 1Hz increments, and when K > 1.15, f is decreased; if the rotor speed changes abruptly, the PLC first decreases f and then adjusts nr.

[0011] Further, in the temperature-heating closed loop, the temperature sensors are thermocouples arranged at multiple points, an average value Tavg is taken, Tset represents the target temperature, and the working modes include a heating mode, a stirring mode, a constant temperature mode and an alarm mode; When Tavg < Tset - 5°C, switch to the heating mode and increase the current; When Tset - 5°C ≤ Tavg < Tset - 2°C, switch to the heating mode; When Tavg is within Tset ± 2°C, switch to the constant temperature mode; When Tavg > Tset + 2°C, switch to the stirring mode and reduce the current; When Tavg > Tset + 5°C, stop the electromagnetic stirring and trigger an alarm.

[0012] A second aspect of the present invention provides an intelligent control method for the melt of the above-mentioned aluminum master alloy system, comprising the following steps: S1: Obtain the type of the target alloy and the structure requirement of the target core; S2: Match or generate a control parameter set from a pre-stored process formula library according to the information obtained in S1, wherein the control parameter set at least includes: target temperature and tolerance, electromagnetic stirring frequency and current, rotor rotation speed, argon flow rate, and treatment time; S3: The PLC core controller automatically executes the melt treatment process according to the control parameter set generated in S2; S4: During the treatment process, the PLC core controller performs three-closed-loop linkage adjustment on the electromagnetic stirring current, electromagnetic stirring frequency and rotor rotation speed based on the real-time feedback of the liquid level sensor, temperature sensor and rotation speed sensor, so as to control the deviation between the actual operating parameters and the target parameter set within a preset range.

[0013] Further, when the target alloy is an aluminum-titanium-boron alloy, the control parameter set includes: a target temperature of 700-1000°C, an electromagnetic stirring current of 250-350A, a rotor rotation speed of 300-800rpm, an argon flow rate of 10-60L / min, and the electromagnetic stirring is started in advance when the melt reaches 50-200°C before the liquidus temperature.

[0014] Further, when the target alloy is an aluminum-strontium alloy, the control parameter set includes: a target temperature of 850-1100°C, a rotor rotation speed of 400-600rpm, an argon flow rate of 10-30L / min; and during the treatment process, the furnace cover is kept fully sealed and a protective gas is introduced to maintain a slight positive pressure.

[0015] Furthermore, it also includes S5: receiving the metallographic test results of the alloy after the furnace treatment, and storing the metallographic test results in association with the control parameter set generated in S2; when the cumulative data of the microstructure requirements of the same alloy grade and target core reach a preset number, the system automatically updates the recommended control parameter set of the alloy.

[0016] The advantages and positive effects of this invention are: 1. This invention adopts a fully enclosed heat-insulating cover and a sealed device structure, combined with the high thermal efficiency of electromagnetic induction heating. Compared with open or semi-open structures, the melting heating rate is increased by more than 5 times, and the heat preservation deviation can be controlled within ±5℃, which greatly reduces heating power consumption and has a significant energy-saving effect.

[0017] 2. This invention utilizes the synergistic effect of global circulation from electromagnetic stirring and local shear flow from mechanical stirring / rotary degassing rotor to create strong three-dimensional turbulence within the entire melt, effectively suppressing the deposition and segregation of high-density alloying elements such as Ti and B. Actual measurements show that compositional fluctuations are controlled within 10%, meeting the requirements for uniformity of intermediate alloys in aerospace aluminum alloy materials.

[0018] 3. This invention utilizes a rotating degassing rotor to generate fine argon bubbles, which, combined with the strong convection of electromagnetic stirring, ensures more thorough contact between the bubbles and the melt. For high-temperature, high-viscosity aluminum alloy melts, the degassing efficiency and oxide inclusion removal capacity are far superior to permeable bricks or single-rotor degassing methods. After treatment, oxide inclusions are reduced by more than 30%.

[0019] 4. This invention linearly adjusts the electromagnetic stirring current in segments based on the liquid level, avoiding rotor idling damage and preventing melt splashing, while saving 15%~25% energy. Real-time matching of rotor speed and electromagnetic stirring frequency ensures the ratio of the melt surface linear velocity generated by electromagnetic stirring to the rotor's peripheral linear velocity is strictly maintained within a certain range. This synergistic ratio ensures that the two stirring methods work synergistically rather than interfere with each other, significantly improving component stability. Based on the difference between the measured average temperature and the target temperature, the invention automatically switches between the electromagnetic coil's heating mode, constant temperature mode, stirring mode, and protection alarm. Precise control of five temperature ranges avoids the large fluctuations or insufficient heating issues common in traditional equipment.

[0020] 5. This invention features a built-in process formula library. Operators only need to select the alloy type and target alloy's microstructure and performance requirements through the human-machine interface. The PLC automatically matches or generates the optimal set of control parameters, including target temperature, electromagnetic stirring current / frequency, rotor speed, argon flow rate, and processing efficiency. This eliminates reliance on experienced workers and ensures batch-to-batch consistency of material properties.

[0021] 6. The system of the present invention associates and stores the alloy composition and microstructure detection results of each processed heat with the corresponding control parameter set to form a database. When the accumulated data meeting the microstructure and performance requirements of the same alloy type and target alloy reaches a preset quantity, the system automatically updates and recommends formulas to realize intelligent management and control. Brief Description of the Drawings

[0022] Figure 1 is a schematic diagram of the overall structure of the system of the present invention; Figure 2 is an internal structural diagram of the apparatus; Figure 3 is a module block diagram of the control system of the present invention; Figure 4 is a metallographic structure diagram of the Al-Ti-B alloy in the embodiment of the present invention before treatment — oxides; Figure 5 is a metallographic structure diagram of the Al-Ti-B alloy in the embodiment of the present invention after treatment — oxides; Description of marks in the drawings: 1 — heat preservation heating device; 2 — fully enclosed heat preservation cover; 3 — electromagnetic coil; 4 — degassing rotor; 5 — thermocouple; 6 — high-temperature laser level gauge; 7 — rotor degasser. Detailed Description of the Embodiments

[0023] The present invention is further described in detail below through specific embodiments. The following embodiments are only descriptive, not restrictive, and shall not limit the protection scope of the present invention.

[0024] Embodiment 1: As shown in Figure 1 , an intelligent treatment system for homogenization and purification of aluminum master alloy melt comprises a heat preservation heating device 1 and a rotor degasser 7. An electromagnetic coil 3 is wound around the heat preservation heating device 1, a fully enclosed heat preservation cover 2 is arranged on the top of the heat preservation heating device 1, and a liftable degassing rotor 4 is mounted on the fully enclosed heat preservation cover 2. A thermocouple 5 is arranged inside the heat preservation heating device 1, and a high-temperature laser level gauge 6 is installed above the heat preservation heating device 1. The PLC controller is electrically connected to the electromagnetic coil 3, the rotor degasser 7, the thermocouple 5, the high-temperature laser level gauge 6 and the argon flow controller respectively.

[0025] Specific implementation of three-closed-loop linkage control: (1) Liquid level — stirring closed loop: The PLC controller reads the liquid level value L of the high-temperature laser level gauge 6 in real time. When L is less than the safe lower limit Lmin, the PLC issues an instruction to lift the degassing rotor 4 and cut off the power supply of the electromagnetic coil 3; when Lmin ≤ L ≤ Lmax, the PLC adjusts the current of the electromagnetic coil 3 according to the linear law as I=I0×(L / Lref); when L is greater than Lmax, the PLC issues an audible and visual alarm and stops feeding.

[0026] (2) Rotational speed-frequency closed loop: The PLC reads the rotor rotational speed nr in real time, and calculates the target equivalent rotational speed of electromagnetic stirring according to the formula ns=k×nr, where k is a preset coefficient of 0.8 to 1.2. The PLC adjusts the frequency f of the electromagnetic coil 3, so that the melt surface linear velocity ve generated by the actual electromagnetic stirring and the rotor peripheral linear velocity vr satisfy ve / vr∈[0.8, 1.2]. When the value is out of the range, the PLC adjusts f preferentially.

[0027] (3) Temperature-heating closed loop: The PLC reads the average value Tavg of the multi-point thermocouple 5. When Tavg<Tset-2℃, the frequency of the electromagnetic coil 3 is increased to 800-1000Hz in the heating mode, and the induced Joule heat is used for rapid supplementary heating; when Tavg>Tset+2℃, the coil frequency is reduced to 500-800Hz in the stirring mode to reduce heating and enhance convective heat dissipation; when Tavg is within Tset±2℃, the constant-temperature stirring mode is maintained.

[0028] Example 2: This example processes AlTi5B1 aluminum-titanium alloy, and the target core structure has oxides of <1000μm, a Ti content of 4.8%-5.2%, and no segregation blank zone.

[0029] Steps: The operator selects the alloy grade AlTi5B1 on the HMI for structure segregation prevention of the target core.

[0030] The PLC automatically calls the process formula: target temperature 750±5℃, electromagnetic stirring current 300A, frequency 900Hz, rotor rotational speed 400rpm, argon flow rate 10L / min, processing efficiency: 30Kg / min.

[0031] The PLC starts electromagnetic stirring in advance to prevent sedimentation of TiAl3 particles.

[0032] After casting is started, the PLC automatically executes: constant temperature 750℃→lower the rotor→start the rotor at 400rpm→introduce argon gas→maintain electromagnetic stirring at 300A→processing efficiency 30Kg / min→lift the rotor→stop electromagnetic stirring→shut down.

[0033] During the processing, the liquid level gauge feeds back in real time, and the PLC automatically adjusts the electromagnetic stirring current; the thermocouple 5 feeds back in real time, and the PLC automatically switches the mode of the electromagnetic coil 3 to maintain the temperature accuracy of ±2℃.

[0034] Sampling and testing after processing: the average oxide size is 745μm, while the average oxide size of conventional equipment is 947μm; the proportion of Ti content in 4.8%-5.2% is 90%, while that of conventional equipment is 72%, the segregation rate of blank zone is <5.8%, while that of conventional equipment is >30%.

[0035] Example 3: In this embodiment, AlSr10 aluminum-strontium alloy is processed, and the target core microstructure consists of AlSr4 particles <150μm, uniformly distributed.

[0036] step: The AlSr10 alloy was chosen because it produces fine and uniformly distributed target particles.

[0037] PLC-based formula settings: target temperature 900±5℃, electromagnetic stirring current 250A / frequency 500Hz, rotor speed 450rpm, argon flow rate 16L / min, processing efficiency: 16Kg / min.

[0038] During the process, the furnace cover is kept completely sealed and a protective gas is introduced to maintain a slight positive pressure.

[0039] Post-processing sampling and testing: 92% of the batches had AlSr4 particles <150μm, compared to less than 70% with traditional equipment, and no agglomeration was observed.

[0040] Example 4: After processing 50 heats of AlTi5B1 alloy, the metallographic data recorded by the system showed that when the rotor speed increased from 400 rpm to 450 rpm, the average oxide size decreased from 745 μm to 624 μm, the Ti content (4.8%–5.2%) increased from 90% to 92%, and the segregation rate of the blank band decreased from 5.8% to 4.9%. The system automatically updated the recommended formula for AlTi5B1: rotor speed 450 rpm, processing efficiency 33 kg / min. The new formula was used from the 51st heat onwards, further improving the quality.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.

Claims

1. A smart system for homogenizing and purifying aluminum master alloy melt, characterized in that, comprising a heat preservation and heating device (1), a rotor degasser (7), a mechanical stirring and degassing rotor (4) arranged inside the heat preservation and heating device (1), and an electromagnetic coil (3) surrounding the exterior of the heat preservation and heating device (1), further comprising a PLC core controller, as well as a liquid level sensor, a rotor rotational speed sensor and a temperature sensor respectively in signal connection with the PLC core controller; the top of the heat preservation and heating device (1) is provided with a fully enclosed heat preservation cover (2), and the mechanical stirring and degassing rotor (4) is mounted on the fully enclosed heat preservation cover (2) in a liftable manner; the rotor degasser (7) is configured to introduce argon gas into the melt through the mechanical stirring and degassing rotor (4) and generate fine bubbles; The liquid level sensor is a high-temperature laser liquid level gauge with an accuracy of ±2mm, and the safety threshold is that the liquid level is lower than 150mm; The PLC core controller is configured to execute the following three closed-loop linkage controls: (a) Liquid level-stirring closed loop: According to the melt liquid level height detected by the liquid level sensor, the input current I of the electromagnetic coil (3) is automatically adjusted. When the liquid level L≥300mm, I=set value×100%; when 150mm≤L<300mm, I=set value×(L / 300)×0.8+set value×0.2; when L<150mm, the mechanical stirring and degassing rotor (4) is stopped and an alarm is issued; (b) Rotational speed-frequency closed loop: According to the rotor rotational speed nr detected by the rotor rotational speed sensor, the output frequency f of the electromagnetic coil (3) is automatically adjusted, so that the ratio of the melt surface linear velocity Ve generated by electromagnetic stirring to the rotor peripheral linear velocity Vr is maintained within the preset coordination range of 0.85~1.15, where Vr=π·Dr·nr / 60, Dr is the outer diameter of the rotor, Ve=K×Vr, K is the target coordination ratio, f=Ve / kf, and kf is the electromagnetic conversion coefficient; when K<0.85, f is increased with a step size of 1Hz, and when K>1.15, f is decreased; if the rotor rotational speed changes abruptly, the PLC preferentially reduces f before adjusting nr; (c) Temperature-heating closed loop: According to the melt temperature detected by the temperature sensor, the working mode of the electromagnetic coil (3) is automatically switched. The temperature sensor is a thermocouple arranged at multiple points, the average value Tavg is taken, and Tset represents the target temperature, When Tavg<Tset-5℃, switch to the heating mode and increase the current; when Tset-5℃≤Tavg<Tset-2℃, switch to the heating mode; when Tavg is within Tset±2℃, switch to the constant temperature mode; when Tavg>Tset+2℃, switch to the stirring mode and reduce the current; when Tavg>Tset+5℃, stop the electromagnetic stirring and issue an alarm.

2. A method for intelligent control of aluminum master alloy melt according to claim 1, characterized in that, comprising the following steps: S1: Acquire the type of the target alloy and the microstructure requirement of the target core; S2: According to the information acquired in S1, match or generate a control parameter set from a pre-stored process parameter formula library, where the control parameter set at least includes: target temperature and allowable deviation, electromagnetic stirring frequency and current, rotor rotational speed, argon flow rate, and treatment time; S3: The PLC core controller automatically executes the melt treatment process according to the control parameter set generated in S2; S4: During the processing, the PLC core controller uses real-time feedback from the liquid level sensor, temperature sensor, and speed sensor to perform three-loop linkage adjustment of the electromagnetic stirring current, electromagnetic stirring frequency, and rotor speed, so that the deviation between the actual operating parameters and the target parameter set is controlled within the preset range.

3. The method according to claim 2, characterized in that, When the target alloy is an aluminum-titanium-boron alloy, the control parameter set includes: target temperature 700-1000℃, electromagnetic stirring current 250-350A, rotor speed 300-800rpm, argon flow rate 10-60L / min, and the electromagnetic stirring is started in advance when the melt reaches 50-200℃ above the liquidus temperature.

4. The method according to claim 2, characterized in that, When the target alloy is an aluminum-strontium alloy, the set of control parameters includes: target temperature 850-1100℃, rotor speed 400-600rpm, and argon flow rate 10-30L / min; and the furnace cover is kept completely sealed during the process and protective gas is introduced to maintain a slight positive pressure.

5. The method according to claim 2, characterized in that, It also includes S5: receiving the microstructure and property test results of the alloy after the furnace treatment, and storing the microstructure and property test results in association with the control parameter set generated in S2; when the cumulative data of the microstructure requirements of the same alloy grade and target core reaches a preset number, the system automatically updates the recommended control parameter set of the alloy.

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