Control method of wide hollow copper profile continuous extrusion device

Abstract

The invention relates to the technical field of copper material preparation, in particular to a control method of a wide-width hollow copper profile continuous extrusion device, which comprises the following steps: based on the section characteristics of a target wide-width hollow copper profile, cooperatively setting the rotating speed of double extrusion wheels, the feeding speed of multiple blanks and the temperatures of an expansion cavity and a forming die, and controlling the continuous extrusion of the wide-width hollow copper profile under the driving of the double extrusion wheels. The method comprises the steps that a copper blank generates plastic deformation in an expansion cavity and is transversely converged to form a metal cavity with preset hydrostatic pressure, a real-time feedback signal is obtained by monitoring the state of a welding interface of the metal cavity and the shape of a profile outlet, collaborative optimization control is carried out on the runner contour of the expansion cavity and a sizing belt of a forming die, and the forming yield is improved. And the corresponding process control parameter set is submitted to an off-line expert system for evaluation and correction until a preset requirement is met. Complete metallurgical bonding of internal welding seams of the wide-width hollow copper profile in the continuous extrusion preparation process is fundamentally guaranteed, and the mechanical property and compactness of the wide-width hollow copper profile are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper material preparation, and particularly to a control method of a wide hollow copper profile continuous extrusion device. BACKGROUND

[0002] In the continuous extrusion production of wide hollow copper profiles, ensuring the uniformity of the wall thickness, the compactness of the structure and the precision of the outer shape size is a core technical challenge, which is due to the complexity of metal flow and the strong coupling effect of thermal-mechanical parameters in the extrusion process. Although the traditional control method can perform preliminary parameter adjustment, the output result is often a "rough adjustment" scheme, which is difficult to accurately match the best process window at one time. Therefore, the currently recognized reliable method in the industry needs an offline expert correction link after trial production: that is, the parameter set calculated online based on the algorithm or model is converted into a specific process scheme, which is then evaluated and corrected by an offline expert system. This process relies on the deep knowledge base and rules embedded in the expert system to diagnose and fine-tune potential defects such as uneven metal flow field and unstable temperature field in the scheme, and then returns to the production line for trial production verification. Through multiple iterations of "scheme generation-offline correction-production verification", the satisfactory product is obtained. However, this mode which highly depends on the post-manual iterative correction is directly limited by the quality of the initial scheme. The initial scheme provided by the existing technology often deviates greatly from the optimal solution, resulting in a long expert correction period and high trial material cost. Therefore, the industry urgently needs a new control method that can independently generate an initial process scheme closer to the optimal solution, in order to greatly improve the starting point and efficiency of the expert correction link and compress the debugging period. SUMMARY

[0003] The present application overcomes the shortcomings of the prior art and provides a control method of a wide hollow copper profile continuous extrusion device.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: The present application discloses a control method of a wide hollow copper profile continuous extrusion device, comprising the following steps: Based on the cross-sectional characteristics of the target wide hollow copper profile, the rotational speed of the double extrusion wheels, the feeding speed of the multiple billets, and the temperature of the expansion cavity and the forming die are set in coordination; Under the drive of the double extrusion wheels, the multiple copper billets are plastically deformed and horizontally merged in the expansion cavity to form a metal cavity with a predetermined hydrostatic pressure; By monitoring the welding interface state of the metal cavity and the profile outlet shape, real-time feedback signals representing the welding quality and forming stability are obtained; According to the real-time feedback signals, the matching relationship between the extrusion wheel rotational speed and the feeding speed is adjusted, so that the welding interface is in a continuous compressive stress state and the profile size precision is optimized; Based on the adjusted process parameters, the flow channel profile of the expansion cavity and the sizing belt of the forming die are cooperatively optimized and controlled to realize the continuous extrusion of the wide-width hollow copper profile and the metallurgical combination of the internal weld.

[0005] Preferably, based on the cross-sectional characteristics of the target wide-width hollow copper profile, the rotational speed of the double extrusion wheel, the feeding speed of the multiple billets, and the temperatures of the expansion cavity and the forming die are cooperatively set, specifically: The cross-sectional characteristics of the target wide-width hollow copper profile are analyzed to obtain its width-thickness ratio and cross-sectional complexity coefficient, and the key geometric constraint conditions for profile forming are determined; Based on the key geometric constraint conditions, the flow resistance distribution of the metal in the expansion cavity is generated through virtual pre-filling analysis; According to the flow resistance distribution, the minimum hydrostatic pressure threshold required to achieve synchronous welding of multiple billets is determined; The minimum hydrostatic pressure threshold is converted into the basic load required by the extrusion system, thereby determining the basic rotational speed configuration of the double extrusion wheel and the basic feeding ratio of the multiple billets; Based on the plastic deformation heat and friction heat generated by the basic rotational speed configuration and the basic feeding ratio, the preheating temperature of the expansion cavity and the holding temperature of the forming die are determined through heat balance calculation to complete the cooperative setting of the process parameters.

[0006] Based on the key geometric constraint conditions, the flow resistance distribution of the metal in the expansion cavity is generated through virtual pre-filling analysis, specifically: A virtual three-dimensional flow channel model of the expansion cavity is established based on the key geometric constraint conditions, and the virtual three-dimensional flow channel model is subjected to grid discretization processing; Based on the discretized grid elements, the constitutive relationship of the metal material is constructed to determine the yield characteristics and strain hardening behavior of each grid element under the initial temperature condition; According to the yield characteristics and strain hardening behavior, the initial filling process of the multiple billet metals in the virtual three-dimensional flow channel of the expansion cavity is simulated to determine the velocity vector field at each grid element; Based on the velocity vector field, the grid elements with a velocity modulus below a predetermined threshold are identified and marked as low-speed flow regions; at the same time, adjacent groups of grid elements with a velocity gradient exceeding a predetermined critical value are identified and marked as strong shear action regions; According to the distribution characteristics of the low-speed flow regions and the strong shear action regions, a spatial distribution map of the metal flow resistance in the expansion cavity is generated.

[0007] Preferably, under the drive of the double extrusion wheel, the multiple copper billets are subjected to plastic deformation and lateral convergence in the expansion cavity to form a metal cavity with a predetermined hydrostatic pressure, specifically: Based on the coordinated setting of the rotating speed of the double extrusion wheels and the feeding speed of the multiple billets, the multiple copper billets are driven to enter the initial deformation zone of the expansion cavity synchronously, and the initial contact stress between the billets is generated according to the geometric constraint of the expansion cavity; The plastic flow behavior of the billets is triggered by the initial contact stress, and the material is softened and the atomic diffusion at the interface is promoted through the accumulation of plastic strain energy; Based on the atomic diffusion process, the interface migration rate when the billets converge laterally is controlled, and the welding front with preliminary metallurgical bonding is formed; By adjusting the extrusion wheel torque to maintain the pressure distribution at the welding front, it is ensured that the hydrostatic pressure reaches the preset pressure threshold; Under the continuous action of the hydrostatic pressure, the uniformity of the metal cavity is optimized.

[0008] Preferably, by monitoring the welding interface state of the metal cavity and the shape of the profile outlet, real-time feedback signals characterizing the welding quality and forming stability are obtained, specifically: The welding interface is scanned, the thermal radiation energy spectrum distribution at the welding interface is collected, and the isotherm distribution pattern of the welding interface region is calculated based on the thermal radiation energy spectrum distribution; The isotherm distribution pattern is analyzed in the time domain, the thermal oscillation frequency characteristics are extracted, and the activity index of interface lattice reconstruction is determined based on the thermal oscillation frequency characteristics; At the same time, the topological morphology of the profile outlet cross section is captured, the high frequency component of the surface fluctuation of the profile outlet cross section is analyzed, and the real-time warping vector is generated; The lattice reconstruction activity index and the warping vector are coupled to evaluate the diffusion kinetic conditions of the welding front; Based on the diffusion kinetic conditions and the plastic flow constitutive relation, real-time feedback signals characterizing the interface metallurgical bonding strength and the forming process stability are fused.

[0009] Preferably, according to the real-time feedback signals, the matching relationship between the extrusion wheel rotating speed and the feeding speed is adjusted, so that the welding interface is in a continuous compressive stress state and the profile size accuracy is optimized, specifically: The diffusion kinetic conditions in the real-time feedback signals are analyzed, and the energy barrier parameter characterizing the interface bonding strength is extracted; Based on the energy barrier parameter, the minimum strain rate threshold required to maintain stable bonding of the welding interface is determined by the critical strain rate; At the same time, according to the plastic flow constitutive relation in the real-time feedback signal, the strain rate sensitivity coefficient of the material at the welding front is derived; Based on the minimum strain rate threshold and the strain rate sensitivity coefficient, the coordinated adjustment amount of the double extrusion wheel rotating speed and the distribution ratio of the feeding speed of each billet are determined; According to the synergistic adjustment amount and the distribution ratio, the output torque of the extrusion wheel driving system and the displacement control instruction of the feeding mechanism are adjusted to realize the maintenance of the continuous stress state of the welding interface and the optimization of the profile size precision.

[0010] The synergistic adjustment amount of the double extrusion wheel speed and the distribution ratio of the feeding speed of each blank are determined based on the minimum strain rate threshold and the strain rate sensitivity coefficient, and specifically are: The equivalent strain rate increment is generated by difference operation between the minimum strain rate threshold and the actual strain rate of the current welding front; The equivalent stress correction amount required is obtained by product operation between the equivalent strain rate increment and the strain rate sensitivity coefficient; Based on the equivalent stress correction amount, the speed adjustment weight coefficient required by the upper and lower extrusion wheels to establish a stable welding environment is calculated by analyzing the mechanical relationship between the extrusion wheel torque and the strain rate; The synergistic adjustment amount of the double extrusion wheel speed is determined according to the speed adjustment weight coefficient and in combination with the symmetry constraint condition of the metal flow in the extended cavity; At the same time, the equivalent strain rate increment is proportionally distributed to each feeding channel based on the flow stress difference degree of each blank at the welding front, to generate the redistribution ratio of the feeding speed of each blank.

[0011] Preferably, based on the adjusted process parameters, the flow channel profile of the extended cavity and the sizing band of the forming die are synergistically optimized and controlled to realize the continuous extrusion of the wide-width hollow copper profile and the metallurgical bonding of the internal weld, and specifically are: The three-dimensional velocity field of the metal flow in the extended cavity is established according to the adjusted process parameters, and the metal flow velocity distribution data is obtained; Based on the metal flow velocity distribution data, the velocity gradient modulus of each position of the flow channel is determined, and the region where the velocity gradient modulus exceeds a preset value is identified and marked as a high gradient region; The spatial distribution characteristics of the high gradient region are analyzed, and a weight factor of the spatial distribution characteristics affecting the welding interface quality is extracted; Based on the weight factor, in combination with the critical shear strain rate of the metal flow, a key control region that needs to be preferentially regulated in the flow channel of the extended cavity is determined; and according to the distribution of the key control region, curvature optimization parameters of the flow guide surface of the extended cavity are generated; Based on the curvature optimization parameters, in combination with the stress state analysis at the sizing band of the forming die, a synergistic control strategy of the extended cavity and the forming die is established to realize the continuous and stable forming of the wide-width hollow copper profile and the complete metallurgical bonding of the internal weld.

[0012] According to the distribution of the key control region, the curvature optimization parameters of the flow guide surface of the extended cavity are generated, and specifically are: A normal distance mapping relationship between the center point of the key control area and the guide surface is established, and an area influence distance parameter is generated; Based on the area influence distance parameter, a geometric influence factor of each key control area on the guide surface is generated; The geometric influence factor is multiplied by the weight factor of the corresponding key control area to obtain a curvature adjustment intensity coefficient of each point of the guide surface; Based on the curvature adjustment intensity coefficient, the minimum curvature change gradient required by the guide surface is determined by a streamline envelope angle calculation method; According to the minimum curvature change gradient, the optimal curvature distribution parameter of the extended cavity guide surface is determined in combination with the wall attachment effect critical condition of metal flow.

[0013] The present application solves the technical defects in the background art, and has the following advantages: the present application realizes accurate maintenance and uniform distribution of the hydrostatic pressure of the weld interface during extrusion, fundamentally guarantees the complete metallurgical bonding of the internal weld, and improves the mechanical properties and density of the profile; at the same time, through real-time monitoring and feedback control, the stability of metal flow and the balance of the forming process are ensured, thereby improving the dimensional accuracy and surface quality of the profile, and finally ensuring the stability, efficiency and low scrap rate of the preparation of wide hollow copper profile while ensuring the high performance of the product. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings of embodiments according to these drawings without creative labor.

[0015] Figure 1 The control method principle flowchart of the present application; Figure 2 The structure schematic diagram of the weld interface in an embodiment of the present application; Figure 3 The structure schematic diagram of the forming blank in an embodiment of the present application; Figure 4 The structure schematic diagram of the double-wheel continuous extrusion device of the present application. DETAILED DESCRIPTION

[0016] In order to more clearly illustrate the above-mentioned purposes, features and advantages of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0017] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description.

[0018] As shown in Figure 1 , 4 The present application discloses a control method for a wide-width hollow copper profile continuous extrusion device, comprising the following steps: Based on the cross-sectional characteristics of the target wide-width hollow copper profile, the rotational speed of the double extrusion wheels, the multi-billet feeding speed, and the temperature of the expansion cavity and the forming die are set in coordination; Under the drive of the double extrusion wheels, the multiple copper billets are subjected to plastic deformation and transverse convergence in the expansion cavity to form a metal cavity with a predetermined hydrostatic pressure; By monitoring the state of the welded interface of the metal cavity and the shape of the profile outlet, real-time feedback signals representing the welding quality and forming stability are obtained; According to the real-time feedback signals, the matching relationship between the rotational speed of the extrusion wheels and the feeding speed is adjusted to keep the welded interface in a continuous compressive stress state and optimize the dimensional accuracy of the profile; Based on the adjusted process parameters, the flow channel profile of the expansion cavity and the sizing band of the forming die are controlled in coordination to realize the continuous extrusion of the wide-width hollow copper profile and the metallurgical bonding of the internal weld.

[0019] Preferably, based on the cross-sectional characteristics of the target wide-width hollow copper profile, the rotational speed of the double extrusion wheels, the multi-billet feeding speed, and the temperature of the expansion cavity and the forming die are set in coordination, specifically: The cross-sectional characteristics of the target wide-width hollow copper profile are analyzed to obtain its width-thickness ratio and cross-sectional complexity coefficient, and the key geometric constraint conditions for profile forming are determined; Based on the key geometric constraint conditions, the flow resistance distribution of the metal in the expansion cavity is generated through virtual pre-filling analysis; According to the flow resistance distribution, the minimum hydrostatic pressure threshold required for the synchronous welding of multiple billets is determined; Further, the specific spatial locations of the low-speed flow regions and the strong shear action regions marked in the flow resistance distribution map and their flow resistance intensity quantification values are identified. Then, based on the dynamic recrystallization critical condition of the material at the extrusion temperature and the diffusion welding theory, the minimum driving pressure required for each low-speed flow region to overcome the metal retention and the minimum constraint pressure required for each strong shear action region to inhibit the interface crack initiation are quantitatively calculated. Through the fluid pressure transmission model, these local pressure requirements are uniformly mapped to the welding cavity region, and the maximum value thereof is taken as the reference pressure value for ensuring the global reliable welding. Finally, a safety margin coefficient considering the material flow fluctuation and the temperature measurement error is added on this basis, and the minimum hydrostatic pressure threshold required for realizing the synchronous welding of multiple blanks is finally determined.

[0020] The minimum hydrostatic pressure threshold is converted into the basic load required to be provided by the extrusion system, so as to determine the basic rotation speed configuration of the double extrusion wheel and the basic feeding ratio of the multiple blanks. Based on the plastic deformation heat and the friction heat generated by the basic rotation speed configuration and the basic feeding ratio, the preheating temperature of the extension cavity and the holding temperature of the forming die are determined through heat balance calculation to complete the collaborative setting of the process parameters.

[0021] Based on the key geometric constraint conditions, the flow resistance distribution of the metal in the extension cavity is generated through virtual pre-filling analysis, specifically as follows: A virtual three-dimensional flow channel model of the extension cavity is established according to the key geometric constraint conditions, and the virtual three-dimensional flow channel model is subjected to grid discretization processing; The constitutive relation of the metal material is constructed based on the discretized grid elements, and the yield characteristics and strain hardening behavior of each grid element under the initial temperature condition are determined; According to the yield characteristics and strain hardening behavior, the initial filling process of the multiple blank metals in the virtual three-dimensional flow channel of the extension cavity is simulated, and the velocity vector field at each grid element is determined; Based on the velocity vector field, the grid elements with a velocity modulus lower than a predetermined threshold are identified and marked as low-speed flow regions, and the adjacent grid element groups with a velocity gradient exceeding a preset critical value are identified and marked as strong shear action regions; According to the distribution characteristics of the low-speed flow regions and the strong shear action regions, a spatial distribution map of the metal flow resistance in the extension cavity is generated.

[0022] As shown in Figure 2 , 3 The embodiment takes manufacturing a wide-width hollow copper profile for the power industry as an example, and the width-thickness ratio of the profile is 45, and the cross-section complexity coefficient is 3.5.

[0023] First, the exact cross-sectional drawing of the target profile is obtained by CAD software, and the drawing is parsed to extract two key geometric constraints: the width-thickness ratio (45) and the cross-sectional complexity coefficient (3.5). These conditions directly determine the space that the metal needs to fill in the expansion cavity and the difficulty of the metal flow. Then, according to the profile cross-section and the design of the expansion cavity, a virtual three-dimensional flow channel model of the expansion cavity is established in the finite element analysis software (such as Deform, Abaqus), and the mesh discretization processing is carried out, which is divided into millions of small tetrahedral or hexahedral grid units.

[0024] Next, virtual pre-filling analysis is performed to generate flow resistance distribution, i.e., to "anticipate" problems that may be encountered during the extrusion process by simulation. The grid units are assigned material properties of T2 copper alloy, including its yield strength at high temperature and strain hardening behavior (describing how the material's strength changes after plastic deformation), which are derived from the material library. At the set initial temperature (e.g., 400°C) and assumed feed speed, run the transient fluid dynamics or rigid-plastic finite element analysis. Simulate the filling process of multiple billet metals in the virtual three-dimensional flow channel, and finally output the velocity vector field at each grid unit to show the flow direction and speed of the metal at various places in the flow channel. Then, analyze the velocity vector field and mark the grid units with a velocity modulus less than 15% of the average velocity (i.e., a predetermined threshold) as "low-speed flow areas". These areas are usually where the metal is prone to stagnation, poor welding, or the risk of cold shut defects. For example, such low-speed areas often occur at sudden widening of the flow channel or corners. And calculate the velocity gradient (shear rate), mark the adjacent grid unit group with a velocity gradient exceeding 8 s -1 " as "strong shear action areas". These areas mean that there is a violent relative slip inside the metal, which will generate a large amount of shear heat, possibly leading to local overheating, grain coarsening, or even material tearing. By integrating the distribution of the above two areas, a visual spatial distribution map of the metal flow resistance in the expansion cavity is generated. In the figure, low-speed areas (high flow resistance areas) are marked with warm colors (such as red), and strong shear areas (high energy dissipation areas) are marked with specific patterns (such as grid lines).

[0025] According to the generated pressure distribution map, in particular to eliminate low speed flow area, ensure that the metal can fill the entire welding cavity and achieve atomic diffusion, the minimum threshold of hydrostatic pressure required to achieve reliable synchronous welding of multiple blanks is determined to be 85 MPa. This threshold is based on the diffusion welding theory and experimental data of copper alloy at a certain temperature. Then the minimum threshold of hydrostatic pressure of 85 MPa is converted into the basic load required to be provided by the extrusion system (mainly double extrusion wheel) through the mechanical model. According to the characteristic curve of the equipment, the basic speed configuration of the double extrusion wheel (for example, the upper wheel 55 RPM, the lower wheel 52 RPM) and the basic feeding ratio of multiple blanks (for example, 4 blanks are synchronously fed at a linear speed of 2.8 meters per minute) required to achieve the load are determined.

[0026] Based on the determined basic speed and feeding ratio, the heat generated by plastic deformation and friction in the stable extrusion state is calculated. Through heat balance calculation, the temperature rise of the system can be predicted. In order to ensure that the metal is in the best plastic state in the extension cavity and does not overheat, the following is determined: Preheating temperature of the extension cavity: for example, 380°C, to avoid too large temperature difference when the blank enters; Temperature of the forming die: for example, 420°C, to ensure that the size is stable and the microstructure and performance are uniform when the profile exits.

[0027] Preferably, under the drive of the double extrusion wheel, multiple copper blanks are plastically deformed in the extension cavity and transversely merged to form a metal cavity with a predetermined hydrostatic pressure, specifically: Based on the cooperatively set double extrusion wheel speed and multiple blank feeding speed, the multiple copper blanks are driven to synchronously enter the initial deformation zone of the extension cavity, and the initial contact stress between the blanks is generated according to the geometric constraints of the extension cavity; The plastic flow behavior of the blank is triggered by the initial contact stress, and the material is softened and the atomic diffusion at the interface is promoted by accumulating plastic strain energy; Based on the atomic diffusion process, the interface migration rate during the transverse merging of the blanks is controlled, and a preliminary metallurgical bonding welding front is formed; The pressure distribution at the welding front is maintained by adjusting the extrusion torque, to ensure that the hydrostatic pressure reaches the preset pressure threshold; Under the continuous action of the hydrostatic pressure, the uniformity of the metal cavity is optimized.

[0028] Specifically, first, based on the aforementioned synergistically set double extrusion wheel rotation speed (e.g., 55 RPM for the upper wheel and 52 RPM for the lower wheel) and multi-billet feeding speed (e.g., 4 billets fed synchronously), the multiple copper billets are driven into the entrance deformation zone of the expansion cavity in a highly synchronized manner. At this stage, the specific converging flow channel geometry of the expansion cavity exerts mechanical constraints on the billets, forcing them to come together and extrude, thereby generating initial contact stress between the billets, which lays the physical contact foundation for subsequent metallurgical bonding. Then, using this initial contact stress, combined with the strong friction driving force of the extrusion wheel, the copper billets undergo significant plastic flow behavior, during which the internal metal accumulates a large amount of plastic strain energy, on the one hand causing the material to undergo thermal softening effect, enhancing flowability, and on the other hand providing energy for the activation and migration of interface atoms, thereby effectively promoting atomic diffusion at the interface. Then, through real-time closed-loop control of the extrusion wheel driving motor torque (e.g., dynamically adjusting the output of the hydraulic or motor through a PID controller based on pressure sensor feedback signals), the pressure distribution at the bonding front is actively maintained, ensuring that the hydrostatic pressure in this area is stable above the preset pressure threshold (e.g., 85 MPa). Under this constant high pressure environment, the oxide film at the interface is broken and extruded out when the billets converge laterally, the fresh metal surfaces are in full contact, and atomic diffusion continues, thereby controlling the interface migration rate and forming a preliminary metallurgical bonding front. Finally, under the action of this continuous and uniform hydrostatic pressure, the density and composition distribution inside the metal cavity are optimized, and the flow tends to be stable, thereby completing the formation of a stable cavity with good homogeneity suitable for subsequent stable forming.

[0029] Preferably, by monitoring the bonding interface state of the metal cavity and the shape of the profile outlet, real-time feedback signals characterizing the bonding quality and forming stability are obtained, specifically: Scanning the bonding interface to collect the thermal radiation energy spectrum distribution at the bonding interface, and based on the thermal radiation energy spectrum distribution, calculating the isotherm distribution pattern of the bonding interface region; Performing time domain analysis on the isotherm distribution pattern, extracting the thermal oscillation frequency feature, and based on the thermal oscillation frequency feature, determining the activity index of interface lattice reconstruction; At the same time, capturing the topological morphology of the profile outlet cross section, analyzing the high frequency component of the surface fluctuation of the profile outlet cross section, and generating real-time warping vectors; Coupling the lattice reconstruction activity index and the warping vector to evaluate the diffusion kinetics conditions of the bonding front; Based on the diffusion kinetics conditions and the plastic flow constitutive relationship, the real-time feedback signals characterizing the interface metallurgical bonding strength and the forming process stability are fused.

[0030] In the implementation process, a multispectral infrared thermal imager is used to continuously scan the welding interface area, collect its thermal radiation spectrum distribution, and then convert the radiation spectrum data into temperature data through Planck's blackbody radiation law, and further generate an isotherm distribution pattern of the welding interface area. Time domain analysis is performed on the obtained isotherm distribution pattern, and the thermal oscillation frequency characteristics in the range of 0.5-3 Hz are extracted by using fast Fourier transform, which are directly related to the fluctuation behavior of atomic diffusion. Based on this, a quantitative index representing the activity degree of lattice reconstruction, i.e., the lattice reconstruction activity index, can be obtained. At the same time, a laser three-dimensional scanner is used to capture the topological morphology of the outlet section in real time, and a high-frequency component (usually with a wavelength less than 10 mm) caused by internal stress unevenness in the surface fluctuation is analyzed by using a spatial domain filtering technique, thereby generating a real-time warping vector containing warping direction and amplitude information. Then, the lattice reconstruction activity index reflecting the microscopic interface dynamics state and the real-time warping vector reflecting the macroscopic stress and strain state are coupled and analyzed by data fusion, so as to comprehensively evaluate whether the diffusion dynamics condition of the welding front is sufficient. The diffusion dynamics condition and the material plastic rheological constitutive relation obtained by experiment calibration are combined in a multi-parameter state evaluator to output a comprehensive and quantifiable real-time feedback signal, which not only represents the strength of the current interface metallurgical bonding, but also indicates the overall stability of the forming process.

[0031] Preferably, according to the real-time feedback signal, the matching relationship between the rotating speed of the extrusion wheel and the feeding speed is adjusted so that the welding interface is in a continuous compressive stress state and the profile size accuracy is optimized, specifically: The diffusion dynamics condition in the real-time feedback signal is analyzed to extract an energy barrier parameter representing the interface bonding strength; Based on the energy barrier parameter, a minimum strain rate threshold required to maintain stable bonding of the welding interface is determined by a critical strain rate; At the same time, according to the plastic rheological constitutive relation in the real-time feedback signal, the strain rate sensitivity coefficient of the material at the welding front is derived; Based on the minimum strain rate threshold and the strain rate sensitivity coefficient, the cooperative adjustment amount of the rotating speed of the double extrusion wheels and the distribution ratio of the feeding speed of each blank are determined; According to the cooperative adjustment amount and the distribution ratio, the output torque of the extrusion wheel driving system and the displacement control command of the feeding mechanism are adjusted to realize the maintenance of the continuous compressive stress state of the welding interface and the optimization of the profile size accuracy.

[0032] It should be noted that the diffusion kinetics condition in the signal is first analyzed. For example, when the lattice reconstruction activity index in the feedback signal is lower than the preset standard, it indicates that the interfacial atomic diffusion kinetic energy is insufficient, and the corresponding energy barrier parameter is extracted at this time. According to the Arrhenius type diffusion model in materials science, the minimum strain rate threshold required to maintain stable bonding of the welding interface is calculated by the formula Where A is a material constant, R is a gas constant, T is the absolute temperature, Q is the energy barrier parameter, and the minimum strain rate threshold required to maintain stable bonding of the welding interface is calculated At the same time, the plastic rheological constitutive relationship data in the real-time feedback signal is analyzed. By querying the curve slope of the material flow stress with the strain rate at the current deformation temperature and strain, the strain rate sensitivity coefficient of the material at the welding front is derived. For example, for T2 copper alloy at about 450°C, the strain rate sensitivity coefficient is 0.12. Finally, the calculated collaborative adjustment amount and the redistribution ratio are converted into specific output torque instructions of the extrusion wheel driving system and displacement control instructions of the feed mechanism servo motor, and are executed.

[0033] Based on the minimum strain rate threshold and the strain rate sensitivity coefficient, the collaborative adjustment amount of the double extrusion wheel speed and the distribution ratio of the feed speed of each blank are determined, specifically: The minimum strain rate threshold and the actual strain rate of the current welding front are operated by difference to generate an equivalent strain rate increment; The equivalent strain rate increment and the strain rate sensitivity coefficient are multiplied to obtain the required equivalent stress correction amount; Based on the equivalent stress correction amount, the mechanical relationship between the extrusion wheel torque and the strain rate is analyzed to calculate the speed adjustment weight coefficient required by the upper and lower extrusion wheels to establish a stable welding environment; According to the speed adjustment weight coefficient, combined with the symmetry constraint condition of metal flow in the extended cavity, the collaborative adjustment amount of the double extrusion wheel speed is determined; At the same time, based on the flow stress difference of each blank at the welding front, the equivalent strain rate increment is proportionally distributed to each feed channel to generate the redistribution ratio of the feed speed of each blank.

[0034] Specifically, first, a difference operation is performed: a determined minimum strain rate threshold is compared with a current actual strain rate of the welding front calculated by real-time monitoring and inversion, to generate an equivalent strain rate increment, to observe the increased deformation intensity required to achieve reliable welding. Then, stress correction calculation is performed: the equivalent strain rate increment is multiplied by the strain rate sensitivity coefficient obtained from the material constitutive relation to obtain the required equivalent stress correction, which is the increased stress level required to drive metal flow and achieve effective welding. Then, the speed adjustment amount is determined: based on the equivalent stress correction, the total driving torque required by the system is back calculated through the established mechanical balance model between the output torque of the extrusion wheel and the tensile stress at the profile outlet; and according to the feedback of the pressure sensors arranged on both sides of the expansion chamber, the speed adjustment weight coefficients required by the upper and lower extrusion wheels to balance the pressure distribution of the welding zone are calculated (for example, if the pressure on the upper wheel side is low, a weight of 0.6 is given to it, and a weight of 0.4 is given to the lower wheel). Finally, the total speed increase is distributed according to the weight based on the rigid constraint condition that the metal flow must be symmetric about the center line, to determine the specific coordinated adjustment amount of the double extrusion wheel speed (for example, the upper wheel increases by 3.0 RPM, and the lower wheel increases by 2.0 RPM). At the same time, the feeding speed is redistributed: based on the flow stress difference of each blank at the welding front (calculated by the thermocouple temperature measurement or pressure difference at the inlet of each blank), the equivalent strain rate increment is proportionally distributed to each feeding channel according to the degree of flow stress difference of each blank, to generate a redistribution ratio of the feeding speed of each blank (for example, the No. 1 and No. 3 blanks with low temperature and high flow stress are allocated a speed increase of 3.5%, and the No. 2 and No. 4 blanks are only allocated a speed increase of 1.5%).

[0035] Preferably, based on the adjusted process parameters, the flow channel profile of the expansion chamber and the sizing belt of the forming die are controlled in coordination to realize continuous extrusion of wide-width hollow copper profiles and metallurgical bonding of internal welds, specifically: A three-dimensional velocity field of metal flow in the expansion chamber is established based on the adjusted process parameters, and metal flow velocity distribution data is obtained; Based on the metal flow velocity distribution data, the velocity gradient modulus of each position of the flow channel is determined, and the region where the velocity gradient modulus exceeds a preset value is identified and marked as a high gradient region; The spatial distribution characteristics of the high gradient region are analyzed, and a weight factor of the spatial distribution characteristics affecting the quality of the welding interface is extracted; It needs to be explained that the plurality of spatial distribution characteristic parameters are quantitatively extracted from the identified high gradient area, including the area ratio of the high gradient area, the axial and radial position of the high gradient area in the flow channel, the geometric shape factor of the area, and the relative distance of the area to the preset welding line position, and then based on the historical process database or through the design of orthogonal test, the actual welding interface quality evaluation index (such as the mechanical strength of the weld and the metallographic structure rating) corresponding to different spatial distribution characteristic combinations is obtained. And using multivariate regression analysis or principal component analysis method, the mapping relationship model between the spatial distribution characteristic parameters and the welding interface quality evaluation index is established; finally, the contribution degree of each spatial distribution characteristic parameter to the welding quality is calculated from the mapping relationship model, that is, the weight factor.

[0036] Based on the weight factor, in combination with the critical shear strain rate of metal flow, the key control area in the extended cavity flow channel that needs to be preferentially regulated is determined; and according to the distribution of the key control area, the curvature optimization parameter of the extended cavity flow guide surface is generated; It needs to be explained that according to the distribution of the key control area, the curvature optimization parameter of the extended cavity flow guide surface is generated, specifically: the normal distance mapping relationship between the center point of the key control area and the flow guide surface is established to generate the area influence distance parameter; based on the area influence distance parameter, the geometric influence factor of each key control area on the flow guide surface is generated; the geometric influence factor is multiplied by the weight factor of the corresponding key control area to obtain the curvature adjustment intensity coefficient of each point of the flow guide surface; based on the curvature adjustment intensity coefficient, the minimum curvature change gradient required for the flow guide surface is determined through the streamline envelope angle calculation method; according to the minimum curvature change gradient, in combination with the critical condition of the wall attachment effect of metal flow, the optimal curvature distribution parameter of the extended cavity flow guide surface is determined.

[0037] Based on the curvature optimization parameter, in combination with the stress state analysis at the sizing belt of the forming die, the cooperative control strategy of the extended cavity and the forming die is established to realize the continuous and stable forming of the wide hollow copper profile and the complete metallurgical combination of the internal weld.

[0038] It should be noted that a three-dimensional velocity field model of metal flow in the extended cavity is established according to the adjusted process parameters (including extrusion temperature, speed and material properties, etc.), and the distribution data of metal flow velocity is obtained through numerical simulation. Based on the flow velocity distribution data, the velocity gradient modulus of each position in the flow channel is calculated, and the high gradient area with a velocity gradient modulus exceeding a preset threshold is identified, which usually corresponds to a flow instability or stress concentration point. The spatial distribution characteristics (such as position, shape and continuity) of the high gradient area are analyzed, and the weight factor (for example, the contribution of different characteristics to the weld strength is determined by regression analysis or empirical model) affecting the weld interface quality is extracted. On this basis, combined with the critical shear strain rate of metal flow (determined by the material constitutive relation), the key control area in the flow channel of the extended cavity that needs to be controlled is determined to ensure that the metal at the weld interface deforms plastically. Then, according to the distribution of the key control area, the curvature optimization parameters of the flow guide surface of the extended cavity are generated. Finally, based on the curvature optimization parameters, combined with the stress state analysis (including equivalent stress and strain rate distribution) at the sizing zone of the forming die, a coordinated control strategy of the extended cavity and the forming die is established (for example, by adjusting the extrusion ratio or the length of the sizing zone to match the flow channel optimization), so that the continuous and stable forming of wide hollow copper profiles is realized, and the internal weld is ensured to be fully metallurgical combined (i.e. continuous grain, defect-free interface fusion) in microstructure. Through the system integration of flow velocity field analysis, gradient identification and stress optimization, the forming quality and efficiency are effectively improved.

[0039] In addition, the control method can further include the following steps: Real-time acquisition of the active power fluctuation signal of the extrusion wheel driving motor and the transient acoustic emission signal of the specific measuring point of the extended cavity, and extraction of the feature band energy related to the plastic deformation energy release rate through wavelet analysis; Data fusion of the feature band energy and the isothermal line oscillation frequency obtained by the weld interface thermal imager to generate a recovery strength index representing the competition between dislocation multiplication and annihilation; The recovery strength index is used as an input parameter and substituted into the recrystallization kinetics equation to calculate the accumulated strain energy threshold offset required for the core area of the cavity to reach the critical recrystallization nucleation condition in real time; According to the direction and size of the accumulated strain energy threshold offset, the compensation value of the output power of the last group of induction heaters before the billet enters the extended cavity is mapped, the initial temperature gradient of the billet surface and core is changed, and the flow instability tendency of the billet after entering the weld zone is indirectly controlled, so as to stabilize the metallurgical bonding process.

[0040] Specifically, by collecting the active power fluctuation signal of the motor and the transient acoustic emission signal of the cavity in real time; and carrying out wavelet packet transform processing on the two types of signals, the specific characteristic band energy highly related to the dislocation slip, multiplication and recombination energy release rate in the plastic deformation process of the material is extracted. Then, the energy data is fused with the isotherm oscillation frequency obtained by the welding interface thermal imager to generate a "recovery strength index" that can quantitatively represent the dynamic competition relationship of dislocation multiplication and annihilation at the microscale. And taking the recovery strength index as the key input parameter, substitute it into the recrystallization kinetics model based on the Avrami equation, real-time inversion calculation of the real-time offset of the accumulated strain energy threshold required for the current cavity core area to reach the critical recrystallization nucleation condition, according to the direction (positive / negative) and size of the offset, through a pre-stored mapping relationship (such as a lookup table), it is converted into the compensation value of the last group of induction heaters output power before the billet enters the expansion cavity: if the offset is positive, it means that the recrystallization driving force is insufficient, then increase the heating power to increase the billet surface temperature and increase the core surface temperature difference; if the offset is negative, it means that the recrystallization is overheated, then reduce the power to reduce the temperature difference. By changing the initial temperature gradient of the billet surface and core in this forward-looking way, the yield behavior and dislocation motion characteristics of the material entering the welding area can be controlled, thereby indirectly and effectively suppressing the rheological instability tendency, stabilizing the metallurgical bonding process, and avoiding welding defects caused by uneven microstructure.

[0041] In addition, the control method can further include the following steps: By analyzing the time domain signal of the welding interface thermal radiation energy spectrum, the interface fluctuation amplitude characteristic spectrum and the lattice diffusion activity factor are extracted; Based on the interface fluctuation amplitude characteristic spectrum and the lattice diffusion activity factor, the critical turbulent intensity and the optimal turbulent frequency necessary for strengthening the interface atomic diffusion are calculated and obtained through turbulent field coupling analysis; Based on the critical turbulent intensity and the optimal turbulent frequency, combined with the real-time rheological stress state of the metal in the expansion cavity, the asymmetric torque pulse amplitude, duty cycle and phase lag angle required for the upper and lower extrusion wheels are determined through von Mises equivalent strain distribution inversion calculation; According to the asymmetric torque pulse parameters, a pulse envelope control signal with Lorentz distribution characteristics is generated to drive the double extrusion wheels to produce controlled periodic shear disturbance in the welding front area, promote interface recrystallization by optimizing dislocation density distribution, and thus realize substantial enhancement of metallurgical bonding.

[0042] It should be noted that in the continuous extrusion process of the wide hollow copper profile, the traditional control method mainly relies on the steady state control of the extrusion speed, temperature and other macro process parameters, often ignoring the dynamic characteristics of the micro diffusion process at the welding interface. Especially in the multi-billet transverse merging area, interface fluctuation and insufficient diffusion can easily lead to micro holes, unwelding and other defects, which seriously affect the mechanical properties and service life of the profile. In view of this, the embodiment collects the thermal radiation energy spectrum signal at the welding interface in real time, carries out wavelet transform analysis on the time domain signal, extracts the interface fluctuation amplitude characteristic spectrum which can represent the interface micro fluctuation state, and the lattice diffusion activity factor which reflects the atomic diffusion rate. Then, the above two key characteristic parameters are input into the turbulent field coupling analysis model based on computational fluid dynamics and diffusion theory, the model solves the coupled equation group of Navier-Stokes equation and Fick diffusion law, determines the critical turbulent intensity required to break the interface diffusion energy barrier, and the optimal turbulent frequency which can maximize the promotion of grain boundary migration.

[0043] Then, based on the calculated turbulent parameters, the von Mises equivalent strain distribution inversion calculation is carried out combined with the metal flow stress state in the extended cavity obtained by the real-time pressure sensor array. This calculation process determines the asymmetric torque pulse parameters required to achieve the ideal turbulent state by solving the stress-strain constitutive relationship in plastic mechanics, including the pulse amplitude of the upper and lower extrusion wheels, the accurate duty cycle and the key phase lag angle. The calculated torque parameters are converted into a pulse envelope control signal with Lorentz distribution characteristics, and the signal waveform can ensure the smooth transition and energy concentration of shear disturbance. The control system drives the double extrusion wheel actuator according to the signal to generate controlled periodic shear disturbance in the welding front area. Through the implementation of the embodiment, the microstate of the welding interface and the macro control parameters of the extrusion process are associated, the precise energy injection based on the interface diffusion dynamics is realized, and the problem of unstable internal weld quality of the wide hollow copper profile is effectively solved, and the comprehensive performance of the product is improved.

[0044] In summary, the present application solves the bottleneck problems of unstable welding quality and difficult size precision control in the continuous extrusion of wide hollow copper profile through the synergistic intelligent setting and optimization of process parameters, realizes the precise maintenance and uniform distribution of the welding interface hydrostatic pressure in the extrusion process, and fundamentally guarantees the complete metallurgical bonding of the internal weld, improves the mechanical properties and compactness of the profile. At the same time, through real-time monitoring and feedback control, the stability of metal flow and the balance of forming process are ensured, so as to improve the size precision and surface quality of the profile, and finally ensure the stability, efficiency and low scrap rate of the preparation of wide hollow copper profile while ensuring the high performance of the product.

[0045] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other manners. The described device embodiments are merely illustrative. For example, the division of the units is only a logical function division. There can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling, or direct coupling or communication connection between the components can be indirect coupling or communication connection through some interfaces, devices, or units, and can be electrical, mechanical, or in other forms.

[0046] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units; they can be located in one place, or distributed on multiple network units; and some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0047] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in the form of hardware or in the form of hardware plus software functional units.

[0048] Those of ordinary skill in the art can understand that all or part of the steps of the above-described method embodiments can be completed by a program instructing related hardware, and the foregoing program can be stored in a computer readable storage medium, and when the program is executed, the steps of the method embodiments are executed; and the foregoing storage medium includes mobile storage devices, read-only memories (ROMs), random access memories (RAMs), magnetic disks or optical disks, and various media that can store program codes.

[0049] Alternatively, the integrated units of the present application, if implemented in the form of software functional modules and sold or used as independent products, can also be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application can be embodied in the form of a software product, and the computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods of the embodiments of the present application. The foregoing storage medium includes mobile storage devices, ROMs, RAMs, magnetic disks or optical disks, and various media that can store program codes.

[0050] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A control method for a wide-width hollow copper profile continuous extrusion device, characterized in that, Includes the following steps: Based on the cross-sectional characteristics of the target wide hollow copper profile, the rotational speed of the dual extrusion rollers, the feed speed of multiple billets, and the temperature of the expansion cavity and forming die are set collaboratively. Driven by the dual extrusion rollers, multiple copper billets undergo plastic deformation within the expansion cavity and merge laterally to form a metal cavity with a predetermined hydrostatic pressure. By monitoring the welding interface state of the metal cavity and the profile exit shape, real-time feedback signals characterizing welding quality and forming stability are obtained. Based on the real-time feedback signal, the matching relationship between the extrusion roller speed and the feed speed is adjusted so that the welding interface is in a continuous compressive stress state and the profile dimensional accuracy is optimized. Based on the adjusted process parameters, the flow channel profile of the expansion cavity and the sizing zone of the forming die are coordinated and optimized to achieve continuous extrusion of wide hollow copper profiles and metallurgical bonding of internal welds.

2. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 1, characterized in that, Based on the cross-sectional characteristics of the target wide hollow copper profile, the rotational speed of the dual extrusion rollers, the feed rate of multiple billets, and the temperatures of the expansion cavity and forming die are set collaboratively, specifically as follows: The cross-sectional characteristics of the target wide hollow copper profile are analyzed to obtain its width-to-thickness ratio and cross-sectional complexity coefficient, and the key geometric constraints for profile forming are determined. Based on the aforementioned key geometric constraints, the flow resistance distribution of metal within the expansion cavity is generated through virtual pre-filling analysis. Based on the flow resistance distribution, the minimum hydrostatic pressure threshold required to achieve synchronous welding of multiple billets is determined; The minimum hydrostatic pressure threshold is converted into the basic load that the extrusion system needs to provide, thereby determining the basic speed configuration of the dual extrusion rollers and the basic feed ratio of multiple billets. Based on the plastic deformation heat and frictional heat generated by the basic rotational speed configuration and basic feed ratio, the preheating temperature of the expansion cavity and the heat preservation temperature of the forming mold are determined by thermal balance calculation, thus completing the coordinated setting of process parameters.

3. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 2, characterized in that, Based on the aforementioned key geometric constraints, the flow resistance distribution of the metal within the expansion cavity is generated through virtual pre-filling analysis, specifically as follows: A virtual three-dimensional flow channel model of the extended cavity is established based on the key geometric constraints, and the virtual three-dimensional flow channel model is subjected to mesh discretization. Constitutive relations of metallic materials are constructed based on discretized grid elements, and the yield characteristics and strain hardening behavior of each grid element under initial temperature conditions are determined. Based on the yield characteristics and strain hardening behavior, the initial filling process of multi-bulk metal in the virtual three-dimensional flow channel of the expanded cavity is simulated, and the velocity vector field at each grid unit is determined. Based on the velocity vector field, grid cells with velocity modulus below a predetermined threshold are identified and marked as low-speed flow regions; at the same time, adjacent grid cell groups with velocity gradients exceeding a preset critical value are identified and marked as strong shear regions. Based on the distribution characteristics of the low-speed flow region and the strong shear region, a spatial distribution map of the metal flow resistance in the extended cavity is generated.

4. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 1, characterized in that, Driven by the dual extrusion rollers, multiple copper billets undergo plastic deformation within the expansion cavity and converge laterally to form a metal cavity with a predetermined hydrostatic pressure, specifically: Based on the coordinated setting of the dual extrusion roller speed and the multiple billet feed speed, multiple copper billets are driven to enter the initial deformation zone of the expansion cavity simultaneously, and the initial contact stress between the billets is generated according to the geometric constraints of the expansion cavity. The initial contact stress is used to trigger the plastic flow behavior of the billet, and the material is softened and atomic diffusion at the interface is promoted by accumulating plastic strain energy. Based on the atomic diffusion process, the interface migration rate during the lateral convergence of the billet is controlled to form a welding front for preliminary metallurgical bonding. By adjusting the torque of the extrusion roller to maintain the pressure distribution at the welding front edge, the hydrostatic pressure is ensured to reach the preset pressure threshold. Optimize the uniformity of the metal cavity under continuous hydrostatic pressure.

5. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 1, characterized in that, By monitoring the welding interface state of the metal cavity and the profile exit shape, real-time feedback signals characterizing welding quality and forming stability are obtained, specifically: The weld interface is scanned, and the thermal radiation spectrum distribution at the weld interface is collected. Based on the thermal radiation spectrum distribution, the isotherm distribution morphology of the weld interface region is calculated. The isotherm distribution pattern is analyzed in the time domain to extract thermal oscillation frequency characteristics, and the activity index of interface lattice reconstruction is determined based on the thermal oscillation frequency characteristics. Simultaneously, the topological morphology of the profile exit section is captured, the high-frequency components of the surface fluctuation of the profile exit section are analyzed, and a real-time warping vector is generated. The lattice reconstruction activity index is coupled with the warpage vector to evaluate the diffusion kinetics conditions at the weld front. Based on the aforementioned diffusion kinetics conditions and plastic rheological constitutive relations, a real-time feedback signal characterizing the interfacial metallurgical bonding strength and the stability of the forming process is generated.

6. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 1, characterized in that, Based on the real-time feedback signal, the matching relationship between the extrusion roller speed and the feed speed is adjusted to ensure that the welding interface is under continuous compressive stress and to optimize the dimensional accuracy of the profile. Specifically: The diffusion dynamics conditions in the real-time feedback signal are analyzed, and the energy barrier parameters characterizing the interfacial bonding strength are extracted. Based on the energy barrier parameter, the minimum strain rate threshold required to maintain a stable bond at the weld interface is determined by the critical strain rate. Meanwhile, based on the plastic rheological constitutive relationship in the real-time feedback signal, the strain rate sensitivity coefficient of the material at the welding front is derived. Based on the minimum strain rate threshold and the strain rate sensitivity coefficient, the coordinated adjustment amount of the dual extrusion wheel speed and the distribution ratio of each billet feed speed are determined. Based on the aforementioned coordinated adjustment amount and distribution ratio, the output torque of the extrusion wheel drive system and the displacement control command of the feeding mechanism are adjusted to maintain the continuous compressive stress state of the welding interface and optimize the dimensional accuracy of the profile.

7. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 6, characterized in that, Based on the minimum strain rate threshold and the strain rate sensitivity coefficient, the coordinated adjustment amount of the dual extrusion roller speed and the distribution ratio of each billet feed speed are determined, specifically as follows: The difference between the minimum strain rate threshold and the actual strain rate at the current welding front is calculated to generate the equivalent strain rate increment. The equivalent stress correction amount is obtained by multiplying the equivalent strain rate increment with the strain rate sensitivity coefficient. Based on the equivalent stress correction, the mechanical relationship between the extrusion wheel torque and the strain rate is analyzed, and the speed adjustment weight coefficients required for the upper and lower extrusion wheels to establish a stable welding environment are calculated respectively. Based on the aforementioned rotational speed adjustment weighting coefficient and combined with the symmetry constraint condition of the metal flow in the extended cavity, the coordinated adjustment amount of the rotational speed of the two extrusion rollers is determined. Meanwhile, based on the difference in flow stress of each billet at the welding front, the equivalent strain rate increment is proportionally distributed to each feed channel to generate a redistribution ratio for the feed rate of each billet.

8. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 1, characterized in that, Based on the adjusted process parameters, the flow channel profile of the expansion cavity and the sizing zone of the forming die are synergistically optimized and controlled to achieve continuous extrusion of wide hollow copper profiles and metallurgical bonding of internal welds, specifically: A three-dimensional velocity field for metal flow within the extended cavity is established based on the adjusted process parameters to obtain metal flow velocity distribution data; Based on the metal flow velocity distribution data, the velocity gradient modulus at each location in the flow channel is determined, and regions where the velocity gradient modulus exceeds a preset value are identified and marked as high gradient regions. Analyze the spatial distribution characteristics of the high gradient region and extract the weighting factors of the influence of the spatial distribution characteristics on the weld interface quality; Based on the weighting factor and the critical shear strain rate of metal flow, the key control regions that need to be preferentially regulated in the extended cavity flow channel are determined; and the curvature optimization parameters of the extended cavity guide surface are generated according to the distribution of the key control regions. Based on the curvature optimization parameters and the stress state analysis at the sizing zone of the forming mold, a collaborative control strategy for the expansion cavity and the forming mold is established to achieve continuous and stable forming of wide hollow copper profiles and complete metallurgical bonding of internal welds.

9. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 8, characterized in that, Based on the distribution of the key control regions, the curvature optimization parameters of the extended cavity guide surface are generated, specifically: Establish the normal distance mapping relationship from the center point of the key control area to the guide surface, and generate regional influence distance parameters; Based on the regional influence distance parameter, the geometric influence factor of each key control area on the guide surface is generated; The curvature adjustment intensity coefficient of each point on the guide surface is obtained by multiplying the geometric influence factor with the weight factor of the corresponding key control area. Based on the curvature adjustment intensity coefficient, the minimum curvature change gradient required for the guide surface is determined by the streamline envelope angle calculation method. Based on the minimum curvature change gradient and the critical condition of the wall effect of metal flow, the optimal curvature distribution parameters of the extended cavity guide surface are determined.

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