A control method for a wide-width hollow copper profile continuous extrusion device

Abstract

This invention relates to the field of copper material preparation technology, specifically a control method for a continuous extrusion apparatus for wide-width hollow copper profiles. Based on the cross-sectional characteristics of the target wide-width hollow copper profile, the method collaboratively sets the rotational speed of the dual extrusion rollers, the feed rate of multiple billets, and the temperatures of the expansion cavity and the forming die. Driven by the dual extrusion rollers, the copper billets undergo plastic deformation within the expansion cavity and achieve lateral convergence to form a metal cavity with a predetermined hydrostatic pressure. By monitoring the weld interface state of the metal cavity and the profile exit shape, real-time feedback signals are obtained. The flow channel contour of the expansion cavity and the sizing zone of the forming die are then collaboratively optimized and controlled to obtain a corresponding set of process control parameters. These parameters are then evaluated and corrected by an offline expert system until the preset requirements are met. This invention fundamentally ensures the complete metallurgical bonding of the internal welds during the continuous extrusion process of wide-width hollow copper profiles, improving the mechanical properties and density of the wide-width hollow copper profiles.

Description

Technical Field

[0001] This invention relates to the field of copper material preparation technology, and in particular to a control method for a continuous extrusion device for wide-width hollow copper profiles. Background Technology

[0002] In the continuous extrusion production of wide-width hollow copper profiles, ensuring uniform wall thickness, dense microstructure, and dimensional accuracy are core technical challenges. This stems from the complexity of metal flow and the strong coupling effect of thermo-mechanical parameters during extrusion. While traditional control methods can perform preliminary parameter adjustments, their outputs are often still coarse-tuned solutions, making it difficult to precisely match the optimal process window in one go. Therefore, the currently recognized reliable method in the industry requires an offline expert correction stage after trial molding: the parameter set calculated online based on algorithms or models is converted into a clear process plan, which is then rigorously 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 in the plan, such as uneven metal flow field and unstable temperature field. The plan is then returned to the production line for trial production verification. Through multiple iterations of "plan generation - offline correction - production verification," a satisfactory finished product is obtained. However, this mode, which heavily relies on manual iterative correction in the later stages, is directly limited in efficiency and effectiveness by the quality of the initial plan. Existing technologies often provide initial solutions that deviate significantly from the optimal solution, leading to lengthy expert correction cycles and high sample costs. Therefore, the industry urgently needs a novel control method that can autonomously generate initial process solutions that more closely approximate the optimal solution, aiming to significantly improve the starting point and efficiency of the expert correction process and shorten the debugging cycle. Summary of the Invention

[0003] This invention overcomes the shortcomings of the prior art and provides a control method for a wide-width hollow copper profile continuous extrusion device.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] This invention discloses a control method for a continuous extrusion apparatus for wide-width hollow copper profiles, comprising the following steps:

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] Preferably, 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 the multiple blanks, and the temperatures of the expansion cavity and the forming die are set collaboratively, specifically as follows:

[0012] 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.

[0013] Based on the aforementioned key geometric constraints, the flow resistance distribution of metal within the expansion cavity is generated through virtual pre-filling analysis.

[0014] Based on the flow resistance distribution, the minimum hydrostatic pressure threshold required to achieve synchronous welding of multiple billets is determined;

[0015] 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.

[0016] 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.

[0017] Specifically, 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, as follows:

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] Preferably, 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:

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] Optimize the uniformity of the metal cavity under continuous hydrostatic pressure.

[0029] Preferably, by monitoring the welding interface state of the metal cavity and the profile exit shape, real-time feedback signals characterizing the welding quality and forming stability are obtained, specifically:

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The lattice reconstruction activity index is coupled with the warpage vector to evaluate the diffusion kinetics conditions at the weld front.

[0034] 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.

[0035] Preferably, 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:

[0036] The diffusion dynamics conditions in the real-time feedback signal are analyzed, and the energy barrier parameters characterizing the interfacial bonding strength are extracted.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Specifically, 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 as follows:

[0042] 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.

[0043] The equivalent stress correction amount is obtained by multiplying the equivalent strain rate increment with the strain rate sensitivity coefficient.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Preferably, 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:

[0048] 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;

[0049] 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.

[0050] 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;

[0051] 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.

[0052] 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.

[0053] Specifically, based on the distribution of the key control regions, the curvature optimization parameters of the extended cavity guide surface are generated as follows:

[0054] 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;

[0055] Based on the regional influence distance parameter, the geometric influence factor of each key control area on the guide surface is generated;

[0056] 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.

[0057] 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.

[0058] 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.

[0059] This invention addresses the technical deficiencies in the prior art and offers the following advantages: It achieves precise maintenance and uniform distribution of hydrostatic pressure at the welding interface during extrusion, fundamentally ensuring the complete metallurgical bond of the internal weld and improving the mechanical properties and density of the profile. Simultaneously, real-time monitoring and feedback control ensure stable metal flow and balanced forming process, thereby improving the dimensional accuracy and surface quality of the profile. Ultimately, while guaranteeing high product performance, it also ensures stable, efficient, and low-scrap-rate production of wide-width hollow copper profiles. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0061] Figure 1 This is a flowchart illustrating the principle of the control method of the present invention;

[0062] Figure 2 This is a schematic diagram of the welding interface structure in one embodiment of the present invention;

[0063] Figure 3 This is a schematic diagram of the structure of the forming blank in one embodiment of the present invention;

[0064] Figure 4 This is a simplified schematic diagram of the dual-wheel continuous extrusion device of the present invention. Detailed Implementation

[0065] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0066] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0067] like Figure 1 , 4 As shown, this invention discloses a control method for a wide-width hollow copper profile continuous extrusion device, comprising the following steps:

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] Preferably, 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 the multiple blanks, and the temperatures of the expansion cavity and the forming die are set collaboratively, specifically as follows:

[0074] 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.

[0075] Based on the aforementioned key geometric constraints, the flow resistance distribution of metal within the expansion cavity is generated through virtual pre-filling analysis.

[0076] Based on the flow resistance distribution, the minimum hydrostatic pressure threshold required to achieve synchronous welding of multiple billets is determined;

[0077] Further explanation is needed regarding the identification of the specific spatial locations and quantified flow resistance intensity of the low-speed flow regions and strong shear regions marked on the flow resistance distribution map. Then, based on the dynamic recrystallization critical condition of the material at extrusion temperature and diffusion welding theory, the minimum driving pressure required to overcome metal retention in each low-speed flow region and the minimum constraint pressure required to suppress interface crack initiation in each strong shear region are quantified. Using a fluid pressure transmission model, these local pressure requirements are uniformly mapped to the welding cavity region, and the maximum value is taken as the reference pressure value to ensure reliable welding across the entire region. Finally, a safety margin coefficient considering material flow fluctuations and temperature measurement errors is added to this, ultimately determining the minimum hydrostatic pressure threshold required for simultaneous welding of multiple billets.

[0078] 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.

[0079] 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.

[0080] Specifically, 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, as follows:

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] like Figure 2 , 3 As shown, this embodiment takes the manufacture of a wide hollow copper profile for the power industry as an example. The width-to-thickness ratio of the profile is 45, and the cross-sectional complexity coefficient is 3.5.

[0087] First, the precise cross-sectional drawing of the target profile is obtained through CAD software, and the drawing is analyzed to extract two key geometric constraints: the width-to-thickness ratio (45) and the cross-sectional complexity coefficient (3.5). These constraints directly determine the spatial shape and flow ease of the metal within the expansion cavity. Then, based on the design of the profile cross-section and the expansion cavity, a virtual three-dimensional flow channel model of the expansion cavity is established in finite element analysis software (such as Deform and Abaqus), and the mesh is discretized into millions of tiny tetrahedral or hexahedral mesh elements.

[0088] Next, a virtual pre-filling analysis is performed to generate the flow resistance distribution, essentially "anticipating" potential problems during the extrusion process through simulation. The mesh elements are assigned material properties of T2 copper alloy, including its high-temperature yield characteristics (such as yield strength) and strain hardening behavior (describing how the material's strength changes after plastic deformation), data sourced from a material library. Transient hydrodynamics or rigid-plastic finite element analysis is run at a set initial temperature (e.g., 400°C) and assumed feed rate. The filling process of multi-bulk metal in a virtual 3D flow channel is simulated, ultimately outputting the velocity vector field at each mesh element to show the flow direction and speed of the metal throughout the flow channel. Then, the velocity vector field is analyzed, marking mesh elements with velocity moduli below 15% of the average velocity (i.e., a predetermined threshold) as "low-speed flow regions." These regions are typically risk points where metal is prone to stagnation, poor welding, or cold shut defects. For example, such low-speed regions often appear at sudden widenings or corners of the flow channel. Furthermore, the velocity gradient (shear rate) is calculated, and velocity gradients exceeding 8 s are considered low-speed flow regions. -1 Adjacent grid cell groups (i.e., preset critical values) are marked as "strong shear regions." These regions indicate intense relative slip within the metal, generating significant shear heat that can lead to localized overheating, grain coarsening, or even material tearing. By combining the distributions of these two types of regions, a spatial distribution map of the metal flow resistance within the extended cavity is generated. In the map, low-velocity regions (high flow resistance regions) are indicated by warm colors (such as red), while strong shear regions (high energy dissipation regions) are indicated by specific patterns (such as grid lines).

[0089] Based on the generated resistance distribution map, and specifically to eliminate low-speed flow regions, ensure the metal fills the entire weld cavity, and achieve atomic-level diffusion, the minimum hydrostatic pressure threshold required for reliable synchronous welding of multiple billets was determined to be 85 MPa. This threshold was derived from diffusion welding theory and experimental data of copper alloys at specific temperatures. The minimum hydrostatic pressure threshold of 85 MPa was then converted into the basic load required by the extrusion system (primarily dual extrusion rollers) through a mechanical model. Based on the equipment characteristic curves, the basic rotational speed configuration of the dual extrusion rollers (e.g., 55 RPM for the upper roller and 52 RPM for the lower roller) and the basic feed ratio for multiple billets (e.g., four billets fed synchronously at a linear velocity of 2.8 meters per minute) were determined to achieve this load.

[0090] Based on a defined base rotation speed and feed ratio, the heat generated by plastic deformation and friction under stable extrusion conditions is calculated. The system temperature rise can be predicted through thermal balance calculations. To ensure the metal is in an optimal plastic state within the expansion cavity without overheating, the following is determined:

[0091] Preheating temperature of the expansion cavity: for example, 380°C, to avoid excessive temperature difference when the billet enters;

[0092] The molding die is kept at a temperature of, for example, 420°C, to ensure dimensional stability and uniform microstructure when the profile exits the mold.

[0093] Preferably, 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:

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] Optimize the uniformity of the metal cavity under continuous hydrostatic pressure.

[0099] Specifically, firstly, based on the aforementioned pre-set dual extrusion roller speeds (e.g., 55 RPM for the upper roller and 52 RPM for the lower roller) and multi-billet feed speeds (e.g., four billets fed simultaneously), multiple copper billets are driven into the inlet deformation zone of the expansion cavity in a highly synchronized manner. During this stage, the specific converging flow channel geometry of the expansion cavity applies mechanical constraints to the billets, forcing them to approach and compress each other, thereby generating initial contact stress between the billets. This lays the physical contact foundation for subsequent metallurgical welding. Next, utilizing this initial contact stress, combined with the powerful frictional driving force of the extrusion rollers, significant plastic flow behavior is triggered in the copper billets. During this process, a large amount of plastic strain energy accumulates within the metal, leading to a thermal softening effect and enhanced fluidity. Furthermore, it provides energy for the activation and migration of interface atoms, effectively promoting atomic diffusion at the interface. Then, through real-time closed-loop control of the extrusion wheel drive motor torque (e.g., dynamically adjusting the hydraulic or motor output based on pressure sensor feedback signals using a PID controller), the pressure distribution at the welding front is actively maintained, ensuring that the hydrostatic pressure in this area remains stable above a preset pressure threshold (e.g., 85 MPa). Under this constant high-pressure environment, the oxide film at the interface is broken and extruded when the billets merge laterally, allowing for full contact between fresh metal surfaces and continuous atomic diffusion, thereby controlling the interface migration rate and forming a preliminary metallurgical bonding welding front. Finally, under this continuous and uniform hydrostatic pressure, the density and composition distribution inside the metal cavity are optimized, and the flow tends to stabilize, thus completing the formation of a stable cavity with good homogeneity, suitable for subsequent stable molding.

[0100] Preferably, by monitoring the welding interface state of the metal cavity and the profile exit shape, real-time feedback signals characterizing the welding quality and forming stability are obtained, specifically:

[0101] 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.

[0102] 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.

[0103] 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.

[0104] The lattice reconstruction activity index is coupled with the warpage vector to evaluate the diffusion kinetics conditions at the weld front.

[0105] 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.

[0106] In the specific implementation process, a multispectral infrared thermal imager is used to continuously scan the welding interface region, acquiring its thermal radiation spectrum distribution. Then, using Planck's blackbody radiation law, the radiation spectrum data is converted into temperature data, thereby generating an isotherm distribution map of the welding interface region. Time-domain analysis is performed on the acquired isotherm distribution, and the thermal oscillation frequency characteristics in the 0.5-3Hz range are extracted using Fast Fourier Transform. These frequency characteristics are directly related to the fluctuation behavior of atomic diffusion, and based on this, a quantitative index characterizing the activity of interface atomic migration and lattice reconstruction, namely the lattice reconstruction activity index, can be obtained. Simultaneously, a laser 3D scanner is used to capture the topological morphology of the exit section in real time, and spatial domain filtering technology is used to resolve the high-frequency components (typically with wavelengths less than 10mm) caused by uneven internal stress in the surface fluctuations, thereby generating a real-time warp vector containing information on warp direction and amplitude. Then, the lattice reconstruction activity index, reflecting the microscopic interface dynamic state, and the real-time warp vector, reflecting the macroscopic stress and strain state, are fused and coupled for analysis to comprehensively evaluate whether the diffusion dynamic conditions at the welding front are sufficient. By combining diffusion kinetics conditions with the material plastic rheological constitutive relation obtained through experimental calibration, data fusion is performed in a multi-parameter state evaluator to output a comprehensive and quantifiable real-time feedback signal. The real-time feedback signal not only characterizes the current interfacial metallurgical bonding strength but also indicates the overall stability of the forming process.

[0107] Preferably, 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:

[0108] The diffusion dynamics conditions in the real-time feedback signal are analyzed, and the energy barrier parameters characterizing the interfacial bonding strength are extracted.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] It should be noted that the diffusion kinetics conditions in the signal are analyzed first. For example, when the lattice reconstruction activity index in the feedback signal is lower than a preset standard, it indicates insufficient kinetic energy for interfacial atomic diffusion; in this case, the corresponding energy barrier parameter is extracted. Then, based on the Arrhenius-type diffusion model in materials science, the energy barrier is determined using the formula... Where A is the material constant, R is the gas constant, T is the absolute temperature, and Q is the energy barrier parameter, the minimum strain rate threshold required to maintain a stable bond at the weld interface is calculated. Simultaneously, the plastic rheological constitutive relation data in the real-time feedback signal are analyzed. By querying the slope of the curve showing the change in material flow stress with 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 around 450°C, the strain rate sensitivity coefficient is 0.12. Finally, the calculated coordinated adjustment amount and redistribution ratio are converted into specific output torque commands for the extrusion wheel drive system and displacement control commands for the servo motor of the feeding mechanism, and then issued for execution.

[0114] Specifically, 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 as follows:

[0115] 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.

[0116] The equivalent stress correction amount is obtained by multiplying the equivalent strain rate increment with the strain rate sensitivity coefficient.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Specifically, firstly, an interpolation calculation is performed: the determined minimum strain rate threshold is compared with the actual strain rate at the current welding front obtained through real-time monitoring and inversion calculation, generating an equivalent strain rate increment to reflect the degree of deformation intensity required to achieve reliable welding. Then, a 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 amount, which is the increased stress level required to drive metal flow and achieve effective welding. Next, the rotational speed adjustment amount is determined: based on the equivalent stress correction amount, the total driving torque required by the system is derived from the established mechanical balance model between the extrusion wheel output torque and the tensile stress at the profile exit; and based on the feedback from pressure sensors arranged on both sides of the expansion cavity, the rotational speed adjustment weight coefficients required for the upper and lower extrusion wheels to balance the pressure distribution in the welding zone are calculated (for example, if the pressure on the upper wheel is low, it is assigned a weight of 0.6, and the lower wheel 0.4). Finally, considering the rigid constraint that the metal flow must be maintained symmetrical about the centerline, the total speed increase is weighted accordingly to determine the specific coordinated adjustment of the dual extrusion roller speeds (e.g., an increase of 3.0 RPM for the upper roller and 2.0 RPM for the lower roller). Simultaneously, the feed rate is redistributed: based on the difference in flow stress at the weld front of each billet (calculated by thermocouple temperature measurement or pressure difference at the inlet of each billet), the aforementioned equivalent rate increment is intelligently distributed to each feed channel according to the degree of flow stress difference among the billets, thereby generating a redistribution ratio for the feed rate of each billet (e.g., a 3.5% speed increase is allocated to billets 1 and 3, which have lower temperatures and higher flow stress, while only a 1.5% speed increase is allocated to billets 2 and 4).

[0121] Preferably, 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:

[0122] 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;

[0123] 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.

[0124] 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;

[0125] It is important to explain here that multiple spatial distribution characteristic parameters are quantitatively extracted from the identified high-gradient regions, including the area ratio of the high-gradient regions, their axial and radial positions in the flow channel, the geometric shape factor of the regions, and their relative distance to the preset weld line position. Then, based on historical process databases or through orthogonal experiments, the actual weld interface quality evaluation indicators (such as weld mechanical strength and metallographic structure rating) corresponding to different combinations of spatial distribution characteristics are obtained. Furthermore, multiple regression analysis or principal component analysis is used to establish a mapping relationship model between the spatial distribution characteristic parameters and the weld interface quality evaluation indicators. Finally, the contribution of each spatial distribution characteristic parameter to the weld quality, i.e., the weighting factor, is calculated from this mapping relationship model.

[0126] 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.

[0127] It should be noted that, based on the distribution of the key control regions, the curvature optimization parameters of the extended cavity guide surface are generated. Specifically, this involves: establishing a mapping relationship between the normal distance from the center point of the key control region to the guide surface, generating regional influence distance parameters; generating geometric influence factors of the effect of each key control region on the guide surface based on the regional influence distance parameters; multiplying the geometric influence factors with the weight factors of the corresponding key control regions to obtain the curvature adjustment intensity coefficients at each point of the guide surface; determining the minimum curvature change gradient required by the guide surface using the streamline envelope angle calculation method based on the minimum curvature change gradient; and determining the optimal curvature distribution parameters of the extended cavity guide surface based on the minimum curvature change gradient and the critical condition of the wall attachment effect of metal flow.

[0128] 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.

[0129] It should be noted that a three-dimensional velocity field model of metal flow within the expansion cavity is established based on the adjusted process parameters (including extrusion temperature, speed, and material properties), and the distribution data of metal flow velocity is obtained through numerical simulation. Based on this velocity distribution data, the velocity gradient modulus at various locations in the flow channel is calculated, identifying high-gradient regions where the velocity gradient modulus exceeds a preset threshold. These regions typically correspond to points of flow instability or stress concentration. The spatial distribution characteristics of high-gradient regions (such as location, shape, and continuity) are analyzed, and their weighting factors on the weld interface quality are extracted (e.g., determining the contribution of different characteristics to weld strength through regression analysis or empirical models). Based on this, and combined with the critical shear strain rate of metal flow (determined by the material constitutive relation), key control regions in the expansion cavity flow channel that require priority regulation are identified to ensure sufficient plastic deformation of the metal at the weld interface. Then, based on the distribution of the key control regions, curvature optimization parameters for the expansion cavity guide surface are generated. Finally, based on the curvature optimization parameters and combined with the stress state analysis at the sizing zone of the forming die (including equivalent stress and strain rate distribution), a collaborative control strategy for the expansion cavity and the forming die is established (e.g., by adjusting the extrusion ratio or the length of the sizing zone to match the flow channel optimization). This achieves continuous and stable forming of wide-width hollow copper profiles and ensures that the internal welds achieve complete metallurgical bonding in the microstructure (i.e., continuous grains and defect-free interface fusion). By systematically integrating flow field analysis, gradient identification, and stress optimization, the forming quality and efficiency are effectively improved.

[0130] In addition, the control method may also include the following steps:

[0131] Real-time acquisition of active power fluctuation signals of the extrusion wheel drive motor and transient acoustic emission signals of specific measurement points in the expansion cavity; and extraction of characteristic frequency band energy related to the plastic deformation energy release rate through wavelet analysis.

[0132] The characteristic frequency band energy is fused with the isothermal oscillation frequency obtained by the welding interface thermal imager to generate a recovery strength index characterizing the competition between micro-dislocation proliferation and annihilation.

[0133] The recovery strength index is used as an input parameter and substituted into the recrystallization kinetic equation to calculate the cumulative strain energy threshold offset required for the core region of the cavity to reach the critical recrystallization nucleation condition in real time.

[0134] Based on the direction and magnitude of the cumulative strain energy threshold offset, it is mapped to the compensation value of the output power of the last set of induction heaters before the billet enters the expansion cavity. By changing the initial temperature gradient between the surface and core of the billet, the rheological instability tendency after entering the welding zone is indirectly controlled, thereby stabilizing the metallurgical bonding process.

[0135] Specifically, by real-time acquisition of the active power fluctuation signal of the motor and the transient acoustic emission signal of the cavity, and by performing wavelet packet transform on these two types of signals, specific characteristic frequency band energies that are highly correlated with the energy release rate of dislocation slip, multiplication, and recombination during the plastic deformation of the material are extracted. Then, the energy data is fused with the isothermal oscillation frequency obtained by the welding interface thermal imager to generate a "recovery strength index" that can quantitatively characterize the dynamic competition relationship between dislocation multiplication and annihilation at the microscale. The recovery strength index is used as a key input parameter and substituted into the recrystallization kinetic model based on the Avrami equation. The real-time offset of the cumulative strain energy threshold required for the core region of the cavity to reach the critical recrystallization nucleation condition is calculated. Based on the direction (positive / negative) and magnitude of this offset, a pre-stored mapping relationship (such as a lookup table) is used to convert it into a compensation value for the output power of the last set of induction heaters before the billet enters the expansion cavity: if the offset is positive, it indicates insufficient recrystallization driving force, so the heating power is increased to raise the surface temperature of the billet and increase the temperature difference between the core and surface; if the offset is negative, it indicates a risk of recrystallization overheating, so the power is reduced to decrease the temperature difference. By proactively changing the initial temperature gradient between the surface and core of the billet, the yielding behavior and dislocation motion characteristics of the material after entering the welding zone can be controlled, thereby indirectly and effectively suppressing the tendency of rheological instability, stabilizing the metallurgical bonding process, and avoiding welding defects caused by microstructure inhomogeneity.

[0136] In addition, the control method may also include the following steps:

[0137] By analyzing the time-domain signal of the thermal radiation energy spectrum of the weld interface, the characteristic spectrum of its interface fluctuation amplitude and the lattice diffusion activity factor are extracted.

[0138] Based on the interface wave amplitude characteristic spectrum and the lattice diffusion activity factor, a turbulence field coupling analysis was performed to calculate the critical turbulence intensity and optimal turbulence frequency necessary for enhancing interface atomic diffusion.

[0139] Based on the critical turbulence intensity and optimal turbulence frequency, and combined with the real-time rheological stress state of the metal in the extended cavity, the asymmetric torque pulse amplitude, duty cycle and phase lag angle required by the upper and lower extrusion rollers are determined by von Mises equivalent strain distribution inversion calculation.

[0140] Based on the asymmetric torque pulse parameters, a pulse envelope control signal with Lorentz distribution characteristics is generated to drive the dual extrusion wheels to generate controlled periodic shear disturbances in the welding front region. By optimizing the dislocation density distribution, the interface recrystallization is promoted, thereby achieving substantial enhancement of the metallurgical bond.

[0141] It should be noted that in the continuous extrusion process of wide-width hollow copper profiles, traditional control methods mainly rely on steady-state control of macroscopic process parameters such as extrusion speed and temperature, often neglecting the dynamic characteristics of the microscopic diffusion process at the weld interface. Especially in the transverse convergence area of ​​multiple billets, insufficient interface fluctuations and diffusion can easily lead to defects such as microscopic voids and incomplete welding, seriously affecting the mechanical properties and service life of the profile. In view of this, this embodiment acquires the thermal radiation energy spectrum signal at the weld interface in real time, performs wavelet transform analysis on the time-domain signal, and extracts the interface fluctuation amplitude characteristic spectrum that can characterize the microscopic fluctuation state of the interface, as well as the lattice diffusion activity factor that reflects the atomic diffusion rate. Then, the above two key characteristic parameters are input into a turbulent field coupled analysis model based on computational fluid dynamics and diffusion theory. This model determines the critical turbulence intensity required to break the interface diffusion energy barrier and the optimal turbulence frequency that can maximize the promotion of grain boundary migration by solving the coupled equations of the Navier-Stokes equations and Fick's diffusion law.

[0142] Then, based on the calculated turbulence parameters and combined with the rheological stress state of the extended cavity metal obtained through a real-time pressure sensor array, a von Mises equivalent strain distribution inversion calculation is performed. This calculation process determines the asymmetric torque pulse parameters required to achieve the ideal turbulence state by solving the stress-strain constitutive relationship in plasticity, including the pulse amplitude of each of the upper and lower extrusion rollers, the precise duty cycle, and the key phase lag angle. The calculated torque parameters are converted into a pulse envelope control signal with Lorentz distribution characteristics, the waveform of which ensures a smooth transition and energy concentration of shear disturbance. The control system drives the dual extrusion roller actuators according to this signal to generate controlled periodic shear disturbances in the weld front region. Through the implementation of this embodiment, the microscopic state of the weld interface can be correlated with the macroscopic control parameters of the extrusion process, realizing precise energy injection based on interface diffusion dynamics, effectively solving the problem of unstable weld quality inside wide hollow copper profiles, and improving the overall performance of the product.

[0143] In summary, this invention effectively solves the bottleneck problems of unstable welding quality and difficulty in dimensional accuracy control during continuous extrusion of wide-width hollow copper profiles by intelligently setting and optimizing process parameters. It achieves precise maintenance and uniform distribution of hydrostatic pressure at the welding interface during extrusion, fundamentally ensuring the complete metallurgical bonding of the internal welds and improving the mechanical properties and density of the profiles. At the same time, through real-time monitoring and feedback control, it ensures the stability of metal flow and the balance of the forming process, thereby improving the dimensional accuracy and surface quality of the profiles. Ultimately, while ensuring high product performance, it also ensures stable, efficient, and low-scrap-rate production of wide-width hollow copper profiles.

[0144] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0145] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units. They may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs.

[0146] In addition, in the various embodiments of the present invention, each functional unit 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 hardware or in the form of hardware plus software functional units.

[0147] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0148] Alternatively, if the integrated units of this invention are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this invention, or the parts that contribute to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROM, RAM, magnetic disks, or optical disks.

[0149] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

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. 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. 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.

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, 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.

6. 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.

7. The control method for a wide-width hollow copper profile continuous extrusion device according to claim 6, 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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