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 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 multi-point arranged thermocouples, and an average value Tavg is obtained, Tset represents a target temperature, and working modes include a heating mode, a stirring mode, a constant temperature mode and an alarm; When Tavg < Tset-5°C, switching to the heating mode and increasing the current; When Tset-5°C ≤ Tavg < Tset-2°C, switching to the heating mode; When Tavg is within Tset±2°C, switching to the constant temperature mode; When Tavg > Tset+2°C, switching to the stirring mode and decreasing the current; When Tavg > Tset+5°C, stopping electromagnetic stirring and giving an alarm.

[0012] The second aspect of the present invention provides an intelligent control method for aluminum master alloy melt by using the above system, comprising the following steps: S1: acquiring the type of a target alloy and the structure requirements of a target core; S2: matching or generating a control parameter set from a pre-stored process formula library according to the information acquired in S1, wherein the control parameter set at least comprises: a target temperature and a tolerance, an electromagnetic stirring frequency and a current, a rotor rotation speed, an argon flow rate, and a treatment time; S3: automatically executing a melt treatment process by a PLC core controller according to the control parameter set generated in S2; S4: in the treatment process, performing three-closed-loop linkage adjustment on the electromagnetic stirring current, the electromagnetic stirring frequency and the rotor rotation speed by the PLC core controller according to real-time feedback from a liquid level sensor, a temperature sensor and a rotation speed sensor, so that the deviation between actual operating parameters and the target parameter set is controlled within a preset range.

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

[0014] Further, when the target alloy is an Al-Sr alloy, the control parameter set comprises: a target temperature of 850-1100°C, a rotor rotation speed of 400-600rpm, and an argon flow rate of 10-30L / min; and in the treatment process, a furnace cover keeps fully sealed and protective gas is introduced to maintain micro-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 interfering 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. In the system of the present invention, the alloy composition and microstructure detection results after each heat treatment are stored in association with the corresponding control parameter set to form a database. When the cumulative data meeting the requirements for the same alloy type and target alloy structure and performance reach a preset number, the system automatically updates and recommends the formula to realize intelligent management and control. Description of Drawings

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

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

[0024] Embodiment 1: as shown in Figure 1 , an intelligent homogenization and purification treatment system for aluminum master alloy melt, comprising an insulation heating device 1 and a rotor degasser 7, wherein an electromagnetic coil 3 is wound around the insulation heating device 1, a fully enclosed insulation cover 2 is arranged at the top of the insulation heating device 1, a liftable degassing rotor 4 is installed on the fully enclosed insulation cover 2, a thermocouple 5 is arranged inside the insulation heating device 1, and a high-temperature laser level gauge 6 is installed above the insulation heating device 1. A 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 an 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 < Lmin (safety lower limit), 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 a linear law: I = I0 × (L / Lref); when L > Lmax, the PLC issues an audible and visual alarm and stops feeding.

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

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

[0028] Example 2: In this example, AlTi5B1 aluminum-titanium alloy is processed, and the target structure of the core is oxides with size <1000um, Ti content of 4.8%-5.2%, and no segregation blank zone.

[0029] Steps: An operator selects the alloy grade AlTi5B1 on HMI, and sets the target as anti-segregation of core structure.

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

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

[0032] After casting is started, PLC automatically executes: constant temperature 750°C → lowering the rotor → starting the rotor at 400rpm → introducing argon → maintaining electromagnetic stirring at 300A → processing at efficiency of 30Kg / min → lifting the rotor → stopping electromagnetic stirring → shutting down.

[0033] During the processing, the liquid level gauge provides real-time feedback, and PLC automatically adjusts the electromagnetic stirring current; the thermocouple 5 provides real-time feedback, and PLC automatically switches the mode of electromagnetic coil 3 to maintain a temperature accuracy of ±2°C.

[0034] After processing, sampling detection shows that: the average size of oxides is 745um, and the average size of oxides of traditional equipment is 947um; the proportion of samples with Ti content of 4.8%-5.2% is 90%, and the proportion of traditional equipment is 72%; the segregation rate of blank zone is <5.8%, and the segregation rate of traditional 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, It includes a heat preservation and heating device (1), a rotor degasser (7), a mechanical stirring and degassing rotor (4) placed inside the heat preservation and heating device (1), and an electromagnetic coil (3) surrounding the outside of the heat preservation and heating device (1). It also includes a PLC core controller, and a liquid level sensor, a rotor speed sensor and a temperature sensor that are 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 liquid level height detected by the liquid level sensor, the input current of the electromagnetic coil (3) is automatically adjusted, and the mechanical stirring and degassing rotor (4) 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 (3) 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 the preset range. (c) Temperature-heating closed loop: Based on the melt temperature detected by the temperature sensor, the working mode of the electromagnetic coil (3) 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.

2. A method for intelligent control of aluminum master alloy melt according to claim 1, characterized in that, Includes the following steps: S1: Obtain the type of target alloy and the microstructure requirements of the target core; S2: Based on the information obtained in S1, match or generate a set of control parameters from the pre-stored process parameter formula library. The set of control parameters includes at least: target temperature and tolerance, electromagnetic stirring frequency and current, rotor speed, argon flow rate, and processing time. S3: The PLC core controller automatically executes the melt processing process according to the control parameter set generated by S2; S4: During the processing, the PLC core controller performs three-closed-loop linkage adjustment of electromagnetic stirring current, electromagnetic stirring frequency, and rotor speed based on real-time feedback from liquid level sensor, temperature sensor, and speed sensor, 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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