System and method for improving purity of light alloy through cryogenic nitrogen generation

Abstract

The invention relates to the technical field of life prediction, in particular to a system and method for improving the purity of light alloy through cryogenic nitrogen generation. Comprising a cryogenic nitrogen generation unit, an atomization forming unit, an oxygen content detection unit, a central control unit and a plurality of monitoring modules, the cryogenic nitrogen generation unit is used for preparing high-purity nitrogen through a cryogenic process, the atomization forming unit is used for atomizing alloy melt into powder, and the oxygen content detection unit is used for detecting the oxygen content of the powder in real time; the monitoring module comprises a cold trap frosting monitoring module, a nozzle wear monitoring module and a melt state monitoring module which are respectively used for acquiring the cold trap frosting thickness, the nozzle wear state and the alloy melt surface tension; and the central control unit is electrically connected with the cryogenic nitrogen generation unit, the atomization forming unit, the oxygen content detection unit and the monitoring module. According to the system, the purity stability and production reliability of the light alloy can be improved.

Description

Technical Field

[0001] This invention relates to the field of alloy preparation technology, and in particular to a system and method for improving the purity of lightweight alloys through cryogenic nitrogen production. Background Technology

[0002] In the production of lightweight alloys, cryogenic nitrogen production and atomization forming are key steps in improving product purity, and their process stability directly affects the oxygen content and powder quality of the alloy. In existing technologies, cryogenic nitrogen production, atomization forming, and oxygen content control are mostly independent operations, lacking coordinated parameter adjustments: the cryogenic nitrogen production unit controls nitrogen purity solely by fixing the cold trap temperature, without considering the attenuation effect of cold trap frost thickness on heat exchange efficiency, leading to nitrogen purity fluctuations of ±0.5N; the atomization forming unit operates based solely on preset pressure and temperature, without real-time monitoring of pressure field distortion caused by nozzle wear and changes in melt surface tension, resulting in powder adhesion rates often remaining between 8% and 12%; oxygen content control relies solely on nitrogen purity, neglecting the impact of powder adhesion rate on oxygen adsorption area, making it difficult to stably control oxygen content below 300 PPM. This independent control mode leads to a lag in parameter adjustment during the production process, making it impossible to address issues such as purity fluctuations and powder adhesion in a targeted manner. As a result, the produced lightweight alloys exhibit batch-to-batch variations in comprehensive properties such as strength and toughness, making it difficult to meet the stringent purity requirements of fields such as aerospace and high-end weapon systems.

[0003] Based on the above problems, there is an urgent need for a system that can coordinate and regulate the parameters of the entire process, including cryogenic nitrogen production, atomization forming, and oxygen content control, in order to improve the purity stability and production reliability of lightweight alloys. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and propose a system for improving the purity of lightweight alloys by cryogenic nitrogen production, including a cryogenic nitrogen production unit, an atomization forming unit, an oxygen content detection unit, a central control unit and multiple monitoring modules; The cryogenic nitrogen production unit is used to produce high-purity nitrogen gas through a cryogenic process; the atomization forming unit is used to atomize the alloy melt into powder; and the oxygen content detection unit is used to detect the oxygen content of the powder in real time. The monitoring module includes a cold trap frost monitoring module, a nozzle wear monitoring module, and a melt state monitoring module, which are used to obtain the cold trap frost thickness, nozzle wear state, and alloy melt surface tension, respectively. The central control unit is electrically connected to the cryogenic nitrogen generation unit, the atomization forming unit, the oxygen content detection unit, and the monitoring module. After receiving the detection signals from the cryogenic nitrogen generation unit, the atomization forming unit, the oxygen content detection unit, and the monitoring module, it dynamically adjusts the cryogenic nitrogen generation parameters based on the frost thickness of the cold trap to stabilize the nitrogen purity. It also optimizes the atomization parameters by combining the nozzle wear status and the surface tension of the melt to reduce the powder adhesion rate, and controls the oxygen content by linking the nitrogen purity and the powder adhesion rate.

[0005] Preferably, the cold trap frost monitoring module includes a millimeter-wave sensor and a temperature sensor. The millimeter-wave sensor is disposed on the outer wall of the cold trap of the cryogenic nitrogen generation unit and is used to transmit millimeter-wave signals and receive reflected signals, and to calculate the frost thickness of the cold trap by means of signal attenuation. The temperature sensor is embedded in the inner wall of the cold trap and is used to collect the real-time temperature of the cold trap. The output terminals of the millimeter-wave sensor and the temperature sensor are both electrically connected to the input terminal of the central control unit through an analog-to-digital converter. The central control unit filters the millimeter-wave reflected signal, removes environmental vibration interference signals, and then corrects the frost thickness calculation result by combining it with temperature data to ensure that the frost thickness detection error does not exceed 0.1mm.

[0006] More preferably, the central control unit includes a main processor and a coprocessor. The main processor is used to receive the raw signals from each monitoring module and perform data fusion, and the coprocessor is used to execute parameter control algorithms. When the purity of nitrogen output from the cryogenic nitrogen generator is lower than the preset threshold, the main processor sends a control command to the coprocessor. The coprocessor calculates the cold trap temperature compensation value based on the frost thickness of the cold trap, adjusts the cold trap temperature to the compensated target value by controlling the cooling power of the cryogenic nitrogen generator, and controls the opening of the airflow valve of the cryogenic nitrogen generator to adjust the airflow speed. When the powder adhesion rate of the atomization forming unit is higher than the preset threshold, the coprocessor sends a melt temperature adjustment signal and an atomization pressure correction signal to the atomization forming unit based on the nozzle wear status and melt surface tension. By increasing the melt temperature to increase the surface tension and correcting the atomization pressure to offset the pressure field distortion caused by nozzle wear, dynamic suppression of powder adhesion rate is achieved.

[0007] More preferably, the atomization forming unit includes a melt heating component, an atomizing nozzle, and a powder collecting component. The melt heating component is electrically connected to a central control unit and is used to adjust the alloy melt temperature according to a temperature control signal sent by the central control unit. A pressure sensor is installed at the inlet end of the atomizing nozzle, and a laser diameter gauge is installed at the outlet end. The pressure sensor is used to collect the real-time pressure of the nozzle, and the laser diameter gauge is used to detect the change in the nozzle outlet diameter to obtain the wear status. The pressure regulating valve of the atomizing nozzle is electrically connected to the central control unit, and the central control unit calculates a pressure compensation coefficient based on the change in the nozzle outlet diameter.

[0008] More preferably, the central control unit uses the nitrogen purity calculation formula: ; in, Nitrogen purity; The target temperature for the cold trap; This represents the temperature shift caused by the thickness of the frost layer, and ; This is the airflow drag coefficient; The nitrogen gas flow rate in the cryogenic nitrogen generation unit; This is the critical temperature of liquid nitrogen; This refers to the thickness of the frost formation on the cold trap. This is the attenuation coefficient of purity due to the thickness of the frosting.

[0009] More preferably, the central control unit calculates the powder adhesion rate using the powder adhesion rate calculation formula: ; in, This refers to the powder adhesion rate; Nozzle wear rate; This represents the cumulative number of sprays. The initial diameter of the nozzle; Atomization pressure; This refers to the melting temperature of the alloy. The surface tension of the alloy melt, and .

[0010] More preferably, the central control unit calculates the alloy oxygen content using the alloy oxygen content calculation formula: ; in, This refers to the oxygen content of the alloy. Nitrogen purity; This refers to the powder adhesion rate; This refers to the atomization time; This is the collaborative correction coefficient.

[0011] Further preferably, the system also includes a parameter adaptive optimization module, which is electrically connected to the central control unit and is used to store historical production data, including cold trap frost thickness, nozzle wear rate, melt surface tension and corresponding nitrogen purity, powder adhesion rate and oxygen content data for different alloy types; when switching alloy types, the parameter adaptive optimization module constructs a matching model based on historical data and outputs initial control parameters to the central control unit, which then makes fine adjustments based on real-time monitoring data to shorten the nitrogen purity stabilization time of the new alloy type to within 30 minutes.

[0012] More preferably, the atomization forming unit further includes a gas circulation module, which is electrically connected to the cryogenic nitrogen generation unit and the central control unit, respectively, for recovering nitrogen that was not fully utilized during the atomization process; the gas circulation module includes a gas purification component and a pressure regulating component, the gas purification component is used to remove dust and trace amounts of oxygen from the nitrogen, and the pressure regulating component is used to adjust the pressure of the recovered nitrogen to be consistent with the output pressure of the cryogenic nitrogen generation unit.

[0013] A method for improving the purity of lightweight alloys using cryogenic nitrogen production, applied to any of the above-described systems for improving the purity of lightweight alloys using cryogenic nitrogen production, comprising: S1: Start the system. The cryogenic nitrogen generation unit starts generating nitrogen. The atomization forming unit is preheated to the preset temperature. Each monitoring module starts and sends an initial detection signal to the central control unit. S2: The central control unit receives the initial frost thickness from the cold trap frost monitoring module, the initial wear status from the nozzle wear monitoring module, and the initial surface tension from the melt state monitoring module. It then calculates the initial nitrogen purity target value using the nitrogen purity calculation formula and controls the cryogenic nitrogen generator to adjust the cooling power and airflow speed. S3: When the nitrogen purity reaches 5N or above, the alloy melt enters the atomization forming unit. The central control unit predicts the powder adhesion rate based on the nozzle wear status and melt surface tension, combined with the powder adhesion rate calculation formula. If the predicted value is higher than 5%, the atomization pressure and melt temperature are adjusted. S4: During the atomization process, the oxygen content detection unit detects the oxygen content of the powder in real time. The central control unit calculates the theoretical oxygen content by combining the alloy oxygen content calculation formula. After comparing with the actual detection value, the nitrogen purity and atomization time are dynamically adjusted to keep the actual oxygen content stable below 200PPM. S5: After production is completed, the central control unit stores the parameters and results of this production to the parameter adaptive optimization module for parameter matching in subsequent production.

[0014] Technical effects: This invention features a central control unit that enables coordinated control of all parameters throughout the entire process, including cryogenic nitrogen generation, atomization forming, and multiple monitoring modules. This is the invention's innovative technical feature. This technology solves the problems of independent control and lack of parameter coordination in existing technologies. It stabilizes nitrogen purity, reduces powder adhesion, and improves oxygen content control accuracy, meeting the purity requirements of lightweight alloys in aerospace and other fields. Attached Figure Description

[0015] Figure 1 This is a system block diagram of a cryogenic nitrogen production method for improving the purity of lightweight alloys according to this application; Figure 2 This is a flowchart of a method for improving the purity of lightweight alloys using cryogenic nitrogen production, as described in this application. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] Traditional technologies for improving the purity of lightweight alloys through cryogenic nitrogen production have the following technical problems: poor nitrogen purity stability, with purity controlled solely by fixing the cold trap temperature without considering the impact of cold trap frost on heat exchange efficiency, resulting in large purity fluctuations; high powder adhesion rate during atomization molding due to lack of monitoring of nozzle wear and melt surface tension; and independent operation of nitrogen production, atomization, and oxygen content control without coordinated regulation, leading to insufficient precision in oxygen content control.

[0018] Based on this, please refer to Figure 1 This embodiment provides a system for improving the purity of lightweight alloys through cryogenic nitrogen production. The system includes a cryogenic nitrogen production unit, an atomization forming unit, an oxygen content detection unit, a central control unit, and multiple monitoring modules. The cryogenic nitrogen production unit is used to produce high-purity nitrogen through a cryogenic process. The atomization forming unit is used to atomize the alloy melt into powder. The oxygen content detection unit is used to detect the oxygen content of the powder in real time. The monitoring modules include a cold trap frost monitoring module, a nozzle wear monitoring module, and a melt state monitoring module, which are used to acquire the cold trap frost thickness, nozzle wear state, and alloy melt surface tension, respectively. The central control unit is electrically connected to the cryogenic nitrogen production unit, the atomization forming unit, the oxygen content detection unit, and the monitoring modules. After receiving the detection signals from each module, it dynamically adjusts the cryogenic nitrogen production parameters based on the cold trap frost thickness to stabilize nitrogen purity. It optimizes the atomization parameters based on the nozzle wear state and melt surface tension to reduce powder adhesion rate. Furthermore, it correlates nitrogen purity and powder adhesion rate to regulate oxygen content, achieving coordinated control of parameters throughout the entire process from nitrogen production to forming.

[0019] This solution solves the problem of parameter disconnect between different stages in the existing technology by constructing a closed-loop system for monitoring, control and feedback, linking the originally independent nitrogen generation, atomization and detection stages through a central control unit; the introduction of unconventional parameters such as cold trap frosting and nozzle wear breaks through the traditional control logic that relies only on single parameters of temperature and pressure, enabling the system to address core issues such as purity fluctuations and powder adhesion.

[0020] Traditional cold trap frost monitoring relies solely on temperature sensors to collect cold trap temperature and indirectly determine the frost status through temperature changes. This method suffers from significant lag – the temperature signal only shows a significant change when the frost thickness has already affected the heat exchange efficiency, leading to a delay in nitrogen purity control. Furthermore, the single temperature signal is easily affected by environmental interference, resulting in large errors in frost thickness calculation.

[0021] Based on this, the cold trap frost monitoring module includes a millimeter-wave sensor and a temperature sensor. The millimeter-wave sensor is installed on the outer wall of the cold trap in the cryogenic nitrogen generation unit to transmit millimeter-wave signals and receive reflected signals, and calculates the frost thickness of the cold trap by the signal attenuation. The temperature sensor is embedded in the inner wall of the cold trap to collect the real-time temperature of the cold trap. The output terminals of both the millimeter-wave sensor and the temperature sensor are electrically connected to the input terminal of the central control unit through an analog-to-digital converter. The central control unit filters the millimeter-wave reflected signals, removes environmental vibration interference signals, and then corrects the frost thickness calculation results by combining the temperature data to ensure that the frost thickness detection error does not exceed 0.1mm.

[0022] This innovative solution combines a millimeter-wave sensor with a temperature sensor. The millimeter-wave signal directly reflects the physical changes in frost thickness, avoiding the lag in indirect temperature-based judgments. The signal filtering and data fusion processing in the central control unit solves the problem of single-sensor susceptibility to interference, making frost thickness detection more accurate. This combination of non-contact monitoring and data correction provides reliable basic data for subsequent dynamic control of nitrogen purity, avoiding purity fluctuations caused by inaccurate frost determination.

[0023] Traditional central control units often use a single processor to process all signals, which leads to data processing delays. When real-time monitoring signals for cryogenic nitrogen generation and atomization are input simultaneously, the processor is prone to insufficient computing power, resulting in delayed control commands. Furthermore, the control logic does not clearly define the coordination rules for nitrogen generation and atomization parameters, and only independently controls a single link, making it impossible to achieve full-process optimization.

[0024] Based on this, the central control unit in this embodiment includes a main processor and a coprocessor. The main processor is used to receive the raw signals from each monitoring module and perform data fusion, while the coprocessor is used to execute parameter control algorithms. When the purity of nitrogen output from the cryogenic nitrogen generator is lower than a preset threshold, the main processor sends a control command to the coprocessor. The coprocessor calculates the cold trap temperature compensation value based on the frost thickness of the cold trap and adjusts the cold trap temperature to the compensated target value by controlling the cooling power of the cryogenic nitrogen generator. At the same time, it controls the opening of the airflow valve of the cryogenic nitrogen generator to adjust the airflow speed. When the powder adhesion rate of the atomization forming unit is higher than a preset threshold, the coprocessor sends a melt temperature adjustment signal and an atomization pressure correction signal to the atomization forming unit based on the nozzle wear status and melt surface tension. It increases the surface tension by increasing the melt temperature and corrects the atomization pressure to offset the pressure field distortion caused by nozzle wear.

[0025] This solution addresses the computational bottleneck of a single processor by dividing the work between the main processor and the coprocessor, ensuring the timeliness of real-time signal processing and control command output. More importantly, it clarifies the logic for coordinated temperature and airflow control when purity is insufficient and the logic for temperature and pressure linkage correction when viscosity is too high, replacing the traditional independent control mode. This makes parameter adjustments more targeted and can respond quickly to system changes.

[0026] Traditional atomization forming units do not monitor nozzle wear in real time and only maintain production by fixing the atomization pressure. After the nozzle wears down, the pressure field becomes distorted, leading to an increase in powder adhesion rate. Furthermore, they do not correlate melt surface tension with atomization parameters. When the surface tension is too low, powder adhesion is likely to occur, affecting product quality.

[0027] Based on this, the atomization forming unit in this embodiment includes a melt heating assembly, an atomizing nozzle, and a powder collecting assembly. The melt heating assembly is electrically connected to the central control unit and is used to adjust the temperature of the alloy melt according to the temperature control signal sent by the central control unit. A pressure sensor is installed at the inlet end of the atomizing nozzle, and a laser diameter gauge is installed at the outlet end. The pressure sensor is used to collect the real-time pressure of the nozzle, and the laser diameter gauge is used to detect the change in the nozzle outlet diameter to obtain the wear status. The pressure regulating valve of the atomizing nozzle is electrically connected to the central control unit. The central control unit calculates the pressure compensation coefficient based on the change in the nozzle outlet diameter, and corrects the actual atomization pressure to a combination of the reference pressure and the pressure compensation coefficient through the pressure regulating valve. At the same time, the melt heating assembly maintains the surface tension of the melt within the range of 80-120 mN / m.

[0028] This solution uses a laser diameter gauge to capture the nozzle wear status in real time and combines it with pressure sensor data to dynamically correct the atomization pressure, thus solving the problem of unstable pressure field caused by nozzle wear. The active control of melt surface tension avoids powder adhesion caused by excessively low surface tension. The combination of these two methods improves the atomization effect from two dimensions: pressure field stability and melt characteristic optimization, ensuring stable powder quality.

[0029] Traditional nitrogen purity calculations rely solely on the cold trap temperature as a single parameter, failing to consider the attenuation effect of cold trap frost thickness on heat transfer efficiency or the impact of airflow velocity on the temperature field. This results in significant discrepancies between the calculated and actual purity values, with noticeable purity fluctuations. Furthermore, the lack of a quantitative relationship between parameters such as frost formation and airflow and purity makes precise control impossible.

[0030] Based on this, the central control unit calculates the nitrogen purity using the following formula: ; in, Nitrogen purity; The target temperature for the cold trap; This represents the temperature shift caused by the thickness of the frost layer, and ; This is the airflow drag coefficient; The nitrogen gas flow rate in the cryogenic nitrogen generation unit; This is the critical temperature of liquid nitrogen; This refers to the thickness of the frost formation on the cold trap. This is the attenuation coefficient of purity due to the thickness of the frosting.

[0031] cold trap target temperature in the formula These are fundamental parameters for cryogenic nitrogen production processes. Their physical meaning is to control the internal temperature of the cold trap at the critical temperature of liquid nitrogen through a refrigeration system. The cold trap is located nearby to facilitate the condensation and separation of impurities in the air. However, in actual operation, frost formation on the outer wall of the cold trap leads to a decrease in heat exchange efficiency and an increase in frost thickness. Through the index term It has a degrading effect on purity—for every 1 mm increase in frost, the purity decreases by about 11.3%. This is because the thermal conductivity of the frost layer is only 1 / 100 that of metal, which significantly hinders the heat exchange between the cold trap and the airflow.

[0032] Temperature offset in the formula Using quadratic functions The description reflects the nonlinear relationship between frost thickness and temperature deviation.

[0033] For example, when the frost thickness increases from 1 mm to 2 mm, the temperature deviation increases from 0.85 K to 1.8 K. This non-linear increase is due to the exponential increase in thermal resistance caused by the increase in frost thickness.

[0034] airflow drag coefficient These are empirical parameters determined through wind tunnel experiments, and their physical meaning is the temperature disturbance value corresponding to the square of a unit airflow velocity.

[0035] Experiments show that when the airflow velocity exceeds 5 m / s, turbulence causes uneven temperature distribution inside the cold trap. The term can quantify the negative impact of this perturbation on purity.

[0036] The coefficient 4 in the formula is a proportionality constant obtained through dimensional analysis and experimental fitting. Its function is to convert the change in temperature parameter into a percentage change in purity.

[0037] For example, when the target temperature of the cold trap 80K, frosting thickness 1mm, airflow velocity The calculated nitrogen purity at a speed of 3 m / s The purity is approximately 99.997%, which is consistent with the results obtained by high-precision mass spectrometers in actual production. This formula breaks through the traditional control logic that relies solely on temperature as a single parameter. By introducing the quantitative relationship between frost thickness and airflow velocity, the calculation error of nitrogen purity is controlled within ±0.002%, meeting the quality requirements of high-purity nitrogen for aerospace applications.

[0038] This formula innovatively introduces an exponential decay term for the cold trap frost thickness and a quadratic term for the airflow velocity, quantifying the heat transfer efficiency reduction caused by frost and the impact of airflow disturbance on the temperature field as purity calculation parameters, thus solving the problem of traditional calculations neglecting key influencing factors; through The quadratic function relationship accurately reflects the nonlinear relationship between frost thickness and temperature deviation, making nitrogen purity calculation more consistent with actual production scenarios. This provides a precise quantitative basis for subsequent purity control and effectively reduces purity fluctuations.

[0039] In traditional technologies, the prediction of powder adhesion rate relies solely on single parameters such as atomization pressure or melt temperature, without considering pressure field distortion caused by nozzle wear or the relationship between alloy melt surface tension and powder morphology. This results in a large deviation between the predicted and actual adhesion rates. Furthermore, the lack of a quantitative relationship between the cumulative effects of wear and spraying times and adhesion rate makes it impossible to predict adhesion risks in advance. Parameters can only be passively adjusted after adhesion occurs, affecting production continuity.

[0040] Based on this, the central control unit calculates the powder adhesion rate using the following formula: ; in, This refers to the powder adhesion rate; Nozzle wear rate; This represents the cumulative number of sprays. The initial diameter of the nozzle; Atomization pressure; This refers to the melting temperature of the alloy. The surface tension of the alloy melt, and .

[0041] This formula innovatively integrates multiple factors such as the cumulative effect of nozzle wear, atomization pressure, melt temperature, and surface tension to establish a multi-parameter linkage prediction model for powder adhesion rate.

[0042] Nozzle wear rate The result was calculated by real-time monitoring of the nozzle outlet diameter change using a laser diameter gauge. Experiments show that when the nozzle has accumulated [number of sprays] times... More than 10 4 In this case, the wear rate will increase by 20%-30% due to material fatigue.

[0043] In the formula The term adopts a power function form, reflecting the nonlinear effect of pressure field distortion caused by wear on the adhesion rate—wear increases the nozzle outlet diameter, causes uneven atomization pressure distribution, reduces the dispersibility of powder particles in the airflow, and increases the probability of adhesion.

[0044] atomization pressure The 0.3 power indicates that its effect on adhesion rate has a diminishing marginal effect. For example, when the atomization pressure is increased from 0.5 MPa to 1.0 MPa, the adhesion rate only decreases by about 12%, because excessive pressure will cause the melt to break up excessively, which will increase the probability of collision between particles.

[0045] melt temperature The -0.5 power reflects the effect of temperature on melt viscosity—for every 100K increase in temperature, viscosity decreases by approximately 30%, and surface tension... Then through the quadratic term It has a significant inhibitory effect on adhesion rate.

[0046] Experimental data show that when the surface tension increases from 40 mN / m to 60 mN / m, the adhesion rate can be reduced by more than 60%. This is because high surface tension reduces droplet splitting during atomization, thus lowering the specific surface area. The coefficient 2.5 in the formula is a comprehensive correction factor determined through orthogonal experiments, and its function is to balance the dimensional differences of various parameters. For example, when the initial nozzle diameter... Sc element mass fraction At that time, the calculated surface tension Combined with melt temperature The surface tension can be calculated to be 65.5 mN / m, at which point the predicted adhesion rate is approximately 3.2%, with an error of less than 0.5% compared to the actual laser particle size analyzer results in production. This formula provides a precise mathematical basis for process optimization by establishing a quantitative relationship chain between alloy composition, atomization parameters, and powder quality.

[0047] This scheme uses a formula to account for the cumulative effect of nozzle wear. By integrating multiple factors such as atomization pressure, melt temperature, and surface tension, the influence of each factor on the adhesion rate is quantified. The pressure field distortion caused by wear is reflected by the power function term, and the inhibitory effect of surface tension on adhesion is reflected by the quadratic term, making the adhesion rate prediction more in line with the actual production scenario.

[0048] This multi-parameter linkage prediction method can predict risks in advance before obvious powder adhesion occurs, providing a basis for subsequent parameter adjustments and avoiding production interruptions caused by passive adjustments. At the same time, through the correlation formula between surface tension and composition, it can achieve full-chain optimization from alloy composition to atomization parameters.

[0049] In traditional techniques, the control of oxygen content in alloys relies solely on nitrogen purity as a single parameter, without considering the impact of powder adhesion rate on oxygen adsorption area or the cumulative effect of atomization time on oxygen contact amount. This results in insufficient precision in oxygen content control. Furthermore, the quantitative relationship between parameters such as nitrogen purity, adhesion rate, and atomization time and oxygen content has not been established, leaving a lack of clear basis for regulation. Adjustments can only be made through repeated experiments, which is inefficient.

[0050] Based on this, the central control unit calculates the oxygen content of the alloy using the following formula: ; in, This refers to the oxygen content of the alloy. Nitrogen purity; This refers to the powder adhesion rate; This refers to the atomization time; This is the synergistic correction coefficient. This scheme innovatively integrates the inhibitory effect of nitrogen purity, the cumulative effect of adhesion rate and time, and the synergistic regulatory effect of the two, clarifying the correlation logic between each parameter and oxygen content—nitrogen purity reduces oxygen content by inhibiting oxidation reaction, and adhered powder increases oxygen adsorption due to its large specific surface area. The synergistic correction of the two balances the limitations of single parameter regulation.

[0051] This formula integrates parameters across different stages, such as nitrogen purity, powder adhesion rate, and atomization time, and establishes a dynamic control model for oxygen content.

[0052] Nitrogen purity index term This reflects the inhibitory effect of purity on oxidation reactions—for every unit increase in purity, the oxygen content can decrease by approximately 22%.

[0053] For example, when the purity increases from 4N to 5N, the theoretical lower limit of oxygen content decreases from 298 PPM to 81 PPM, which is consistent with the Arrhenius equation law governing the relationship between oxygen partial pressure and oxidation rate in high-temperature oxidation experiments.

[0054] Powder adhesion rate With atomization time product term The oxygen adsorption effect brought about by the increased surface area of ​​the agglomerated powder was quantified. Experiments showed that the specific surface area of ​​the agglomerated powder was 2-3 times that of the normal powder. For every 1% increase in the agglomeration rate, the oxygen content would increase by about 3 PPM for every 1 minute increase in atomization time.

[0055] Cooperative correction coefficient ( The key parameter is determined by response surface methodology. Its physical meaning is to balance the antagonistic effect of nitrogen purity and viscosity on oxygen content.

[0056] For example, when purity Adhesion rate At that time, the correction item The predicted oxygen content can be lowered by 19.6 PPM to avoid overcompensation caused by adjusting a single parameter.

[0057] The constant term 800 PPM in the formula is the background oxygen content in an oxygen-free environment, reflecting unavoidable oxygen pollution sources such as equipment pipelines and alloy raw materials.

[0058] When atomization time Nitrogen purity Adhesion rate At that time, the calculated oxygen content The error between the actual pulse heating-infrared detection results and the actual production results is less than 5%. This formula, by referencing the calculation results of the preceding claims, forms a closed loop of parameters for nitrogen production, atomization, and oxygen content, improving the oxygen content control accuracy to ±10PPM, which meets the oxygen content control requirements of lightweight alloys for aerospace applications.

[0059] The formula references the calculation results of the preceding claims to form a parameter chain for nitrogen production, atomization, and oxygen content, providing a clear quantitative basis for oxygen content regulation. This avoids the blindness of traditional experimental adjustments and enables precise control of oxygen content by specifically improving nitrogen purity, reducing adhesion rate, or shortening atomization time.

[0060] In traditional technology, switching alloy models requires repeated manual adjustments to parameters such as cold trap temperature and atomization pressure, which relies on the operator's experience and has a long adjustment cycle. Furthermore, the lack of historical data support and unreasonable initial parameter settings for the new alloy can easily lead to problems such as substandard nitrogen purity or powder adhesion, resulting in a low product qualification rate in the initial stage of model changeover.

[0061] Based on this, the system also includes a parameter adaptive optimization module, which is electrically connected to the central control unit. This module stores historical production data, including cold trap frost thickness, nozzle wear rate, melt surface tension, and corresponding nitrogen purity, powder adhesion rate, and oxygen content data for different alloy types. When switching alloy types, the parameter adaptive optimization module builds a matching model based on historical data and outputs initial control parameters to the central control unit. The central control unit then fine-tunes these parameters using real-time monitoring data, reducing the nitrogen purity stabilization time for the new alloy type to within 30 minutes. This solution establishes a correlation between historical data and new alloy parameters through the parameter adaptive optimization module, using data matching to replace manual debugging and solving the problem of blind parameter setting during type change. The initial parameters output by the module have been historically verified and can quickly bring the system into a stable range. Further fine-tuning using real-time monitoring data further shortens the stabilization time.

[0062] This model, which combines historical data matching with real-time optimization, not only reduces reliance on human experience but also ensures the stability of nitrogen purity and powder quality during the changeover process, avoiding raw material waste and production stagnation caused by improper parameters during traditional changeovers.

[0063] In traditional technologies, nitrogen gas is often directly emitted during the atomization process, resulting in low utilization and increased production costs. Some recovery schemes fail to purify the recovered nitrogen, leading to dust or trace amounts of oxygen affecting the nitrogen purity. Furthermore, the lack of parameter coordination between the recovered nitrogen and the original nitrogen generation system makes it prone to fluctuations in nitrogen purity after mixing.

[0064] Based on this, the atomization forming unit also includes a gas circulation module, which is electrically connected to the cryogenic nitrogen generation unit and the central control unit, respectively, and is used to recover nitrogen that is not fully utilized during the atomization process. The gas circulation module includes a gas purification component and a pressure regulating component. The gas purification component is used to remove dust and trace amounts of oxygen from the nitrogen, and the pressure regulating component is used to adjust the pressure of the recovered nitrogen to be consistent with the output pressure of the cryogenic nitrogen generation unit. The central control unit adjusts the recovery flow rate of the gas circulation module in real time according to the nitrogen consumption of the atomization forming unit, so that the nitrogen utilization rate is increased to more than 90%, and at the same time, the influence of the recovered nitrogen on the purity is corrected by the formula of claim 5, ensuring that the purity of the mixed nitrogen remains stable above 5N.

[0065] This solution addresses the purity issue of recovered nitrogen through a gas purification component, while a pressure regulation component ensures stable mixing of the recovered gas and freshly produced nitrogen. The central control unit combines flow regulation with purity formula correction, improving nitrogen utilization while avoiding the impact of recovery on purity. This integrated recovery, purification, and control model reduces production costs while ensuring the stability of nitrogen purity during production, resolving the traditional problem of balancing recovery and purity control.

[0066] In traditional technologies, the operations of cryogenic nitrogen production and atomization molding are independent of each other and lack clear coordination logic. For example, atomization is started when the nitrogen purity does not meet the standard, resulting in excessive oxygen content in the powder. Furthermore, there is no feedback mechanism for oxygen content detection and preceding parameters, so it is impossible to dynamically adjust the nitrogen production or atomization parameters according to the real-time oxygen content. Production can only be carried out according to a fixed process, resulting in poor product quality consistency.

[0067] Based on this, please refer to Figure 2 This embodiment provides a method for improving the purity of lightweight alloys through cryogenic nitrogen production, applied to the above-mentioned system, and includes the following steps: S1: Start the system. The cryogenic nitrogen generation unit starts generating nitrogen. The atomization forming unit is preheated to the preset temperature. Each monitoring module starts and sends an initial detection signal to the central control unit. S2: The central control unit receives the initial frost thickness from the cold trap frost monitoring module, the initial wear status from the nozzle wear monitoring module, and the initial surface tension from the melt state monitoring module. It then calculates the initial nitrogen purity target value using the nitrogen purity calculation formula and controls the cryogenic nitrogen generator to adjust the cooling power and airflow speed. S3: When the nitrogen purity reaches 5N or above, the alloy melt enters the atomization forming unit. The central control unit predicts the powder adhesion rate based on the nozzle wear status and melt surface tension, combined with the powder adhesion rate calculation formula. If the predicted value is higher than 5%, the atomization pressure and melt temperature are adjusted. S4: During the atomization process, the oxygen content detection unit detects the oxygen content of the powder in real time. The central control unit calculates the theoretical oxygen content by combining the alloy oxygen content calculation formula. After comparing with the actual detection value, the nitrogen purity and atomization time are dynamically adjusted to keep the actual oxygen content stable below 200PPM. S5: After production is completed, the central control unit stores the parameters and results of this production to the parameter adaptive optimization module for parameter matching in subsequent production.

[0068] This solution addresses the poor coordination issues caused by independent steps in traditional methods by clearly defining the sequence of steps: first, nitrogen is generated to meet standards before atomization; second, adhesion is predicted before parameters are adjusted. It introduces a feedback mechanism of real-time detection and formula calculation, enabling parameter adjustments to respond quickly to changes in oxygen content and avoiding the limitations of fixed processes.

[0069] The historical data storage in step 5 provides support for subsequent production, forming a closed loop of production, optimization, and reproduction, thereby improving the overall consistency of product quality and production stability.

[0070] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A system for cryogenic nitrogen production to improve the purity of lightweight alloys, characterized in that, It includes a cryogenic nitrogen generation unit, an atomization forming unit, an oxygen content detection unit, a central control unit, and multiple monitoring modules; The cryogenic nitrogen production unit is used to produce high-purity nitrogen gas through a cryogenic process; the atomization forming unit is used to atomize the alloy melt into powder; and the oxygen content detection unit is used to detect the oxygen content of the powder in real time. The monitoring module includes a cold trap frost monitoring module, a nozzle wear monitoring module, and a melt state monitoring module, which are used to obtain the cold trap frost thickness, nozzle wear state, and alloy melt surface tension, respectively. The central control unit is electrically connected to the cryogenic nitrogen generation unit, the atomization forming unit, the oxygen content detection unit, and the monitoring module. After receiving the detection signals from the cryogenic nitrogen generation unit, the atomization forming unit, the oxygen content detection unit, and the monitoring module, it dynamically adjusts the cryogenic nitrogen generation parameters based on the frost thickness of the cold trap to stabilize the nitrogen purity. It also optimizes the atomization parameters by combining the nozzle wear status and the surface tension of the melt to reduce the powder adhesion rate, and controls the oxygen content by linking the nitrogen purity and the powder adhesion rate.

2. The system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The cold trap frost monitoring module includes a millimeter-wave sensor and a temperature sensor. The millimeter-wave sensor is installed on the outer wall of the cold trap of the cryogenic nitrogen generation unit and is used to transmit millimeter-wave signals and receive reflected signals. The thickness of the cold trap frost is calculated by the signal attenuation. The temperature sensor is embedded in the inner wall of the cold trap and is used to collect the real-time temperature of the cold trap. The output terminals of the millimeter-wave sensor and the temperature sensor are both electrically connected to the input terminal of the central control unit through an analog-to-digital converter. The central control unit filters the millimeter-wave reflected signal, removes environmental vibration interference signals, and then corrects the frost thickness calculation result by combining it with temperature data to ensure that the frost thickness detection error does not exceed 0.1mm.

3. The system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The central control unit includes a main processor and a coprocessor. The main processor is used to receive the raw signals from each monitoring module and perform data fusion. The coprocessor is used to execute parameter control algorithms. When the purity of nitrogen output from the cryogenic nitrogen generator is lower than the preset threshold, the main processor sends a control command to the coprocessor. The coprocessor calculates the cold trap temperature compensation value based on the frost thickness of the cold trap, adjusts the cold trap temperature to the compensated target value by controlling the cooling power of the cryogenic nitrogen generator, and controls the opening of the airflow valve of the cryogenic nitrogen generator to adjust the airflow speed. When the powder adhesion rate of the atomization forming unit is higher than the preset threshold, the coprocessor sends a melt temperature adjustment signal and an atomization pressure correction signal to the atomization forming unit based on the nozzle wear status and melt surface tension. By increasing the melt temperature to increase the surface tension and correcting the atomization pressure to offset the pressure field distortion caused by nozzle wear, dynamic suppression of powder adhesion rate is achieved.

4. The system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The atomization forming unit includes a melt heating assembly, an atomizing nozzle, and a powder collecting assembly. The melt heating assembly is electrically connected to a central control unit and is used to adjust the alloy melt temperature according to the temperature control signal sent by the central control unit. A pressure sensor is installed at the inlet end of the atomizing nozzle, and a laser diameter gauge is installed at the outlet end. The pressure sensor is used to collect the real-time pressure of the nozzle, and the laser diameter gauge is used to detect the change in the nozzle outlet diameter to obtain the wear status. The pressure regulating valve of the atomizing nozzle is electrically connected to the central control unit, and the central control unit calculates the pressure compensation coefficient based on the change in the nozzle outlet diameter.

5. The system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The central control unit uses the nitrogen purity calculation formula: ； in, Nitrogen purity; The target temperature for the cold trap; This represents the temperature shift caused by the thickness of the frost layer, and ; This is the airflow drag coefficient; The nitrogen gas flow rate in the cryogenic nitrogen generation unit; This is the critical temperature of liquid nitrogen; This refers to the thickness of the frost formation on the cold trap. This is the attenuation coefficient of purity due to the thickness of the frosting.

6. The system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The central control unit calculates the powder adhesion rate using the powder adhesion rate calculation formula: ； in, This refers to the powder adhesion rate; Nozzle wear rate; This represents the cumulative number of sprays. The initial diameter of the nozzle; Atomization pressure; This refers to the melting temperature of the alloy. The surface tension of the alloy melt, and .

7. The system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The central control unit calculates the oxygen content of the alloy using the alloy oxygen content calculation formula: ； in, This refers to the oxygen content of the alloy. Nitrogen purity; This refers to the powder adhesion rate; This refers to the atomization time; This is the collaborative correction coefficient.

8. The system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The system also includes a parameter adaptive optimization module, which is electrically connected to the central control unit and is used to store historical production data, including cold trap frost thickness, nozzle wear rate, melt surface tension and corresponding nitrogen purity, powder adhesion rate and oxygen content data for different alloy types. When switching alloy types, the parameter adaptive optimization module builds a matching model based on historical data and outputs initial control parameters to the central control unit. The central control unit makes fine adjustments based on real-time monitoring data to shorten the nitrogen purity stabilization time of the new alloy type to within 30 minutes.

9. A system for improving the purity of lightweight alloys through cryogenic nitrogen production according to claim 1, characterized in that, The atomization forming unit also includes a gas circulation module, which is electrically connected to the cryogenic nitrogen generation unit and the central control unit, respectively, and is used to recover nitrogen that is not fully utilized during the atomization process. The gas circulation module includes a gas purification component and a pressure regulating component. The gas purification component is used to remove dust and trace amounts of oxygen from the nitrogen, and the pressure regulating component is used to adjust the pressure of the recovered nitrogen to be consistent with the output pressure of the cryogenic nitrogen generation unit.

10. A method for improving the purity of lightweight alloys through cryogenic nitrogen production, applied to the system for improving the purity of lightweight alloys through cryogenic nitrogen production as described in any one of claims 1-9, characterized in that, include: S1: Start the system. The cryogenic nitrogen generation unit starts generating nitrogen. The atomization forming unit preheats to the preset temperature. Each monitoring module starts and sends an initial detection signal to the central control unit. S2: The central control unit receives the initial frost thickness from the cold trap frost monitoring module, the initial wear status from the nozzle wear monitoring module, and the initial surface tension from the melt state monitoring module. It then calculates the initial nitrogen purity target value using the nitrogen purity calculation formula and controls the cryogenic nitrogen generator to adjust the cooling power and airflow speed. S3: When the nitrogen purity reaches 5N or above, the alloy melt enters the atomization forming unit. The central control unit predicts the powder adhesion rate based on the nozzle wear status and melt surface tension, combined with the powder adhesion rate calculation formula. If the predicted value is higher than 5%, the atomization pressure and melt temperature are adjusted. S4: During the atomization process, the oxygen content detection unit detects the oxygen content of the powder in real time. The central control unit calculates the theoretical oxygen content by combining the alloy oxygen content calculation formula. After comparing with the actual detection value, the nitrogen purity and atomization time are dynamically adjusted to keep the actual oxygen content stable below 200PPM. S5: After production is completed, the central control unit stores the parameters and results of this production to the parameter adaptive optimization module for parameter matching in subsequent production.

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