Aluminum alloy bar constant-speed extrusion forming process energy consumption prediction model based on plane divergent die and establishment method thereof

Abstract

The invention relates to an aluminum alloy bar constant-speed extrusion forming process energy consumption prediction model based on a plane divergent die and an establishment method of the aluminum alloy bar constant-speed extrusion forming process energy consumption prediction model. An axial symmetry coordinate system is established, a speed field model of an aluminum alloy bar in a plastic deformation area is deduced based on a continuous speed field hypothesis, and then plastic deformation work is calculated; in combination with die design and tribology theories, friction work between the aluminum alloy and the extrusion container and friction work between the aluminum alloy and the die are deduced; a heat exchange energy model is established through a Stefan-Boltzmann law; finally, plastic deformation work, friction work and heat exchange energy are combined, the energy efficiency conversion efficiency of the servo system is considered, and a complete energy consumption prediction model is established. According to the model, the main energy loss in the aluminum alloy extrusion process can be quantified, the influence of a mold structure, process parameters and a friction state on energy consumption is comprehensively reflected, theoretical support can be provided for process optimization, energy conservation, consumption reduction and green manufacturing in aluminum alloy profile production, and the model has wide industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy material processing and modeling, and in particular to an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a plane splitter die and an establishment method thereof. Background Art

[0002] In recent years, with the deepening of the concept of green manufacturing, energy conservation and consumption reduction have become core concerns in the field of industrial metal processing. Aluminum alloys, due to their low density, high strength, strong corrosion resistance, and good recyclability, have been widely used in industries such as transportation, construction, electronics, power generation, and especially new energy vehicles. Aluminum alloy profiles, with their excellent mechanical properties and formability, are particularly critical in the field of lightweighting automobiles.

[0003] As the main means of forming aluminum alloy profiles, hot extrusion technology has the advantages of high material utilization, high product precision, and good surface quality. It is one of the most widely used extrusion forming methods in industrial production. However, this process generally has problems of high energy consumption and low thermal efficiency. In particular, when using complex mold structures such as flat diverter molds for profile extrusion, the energy consumption is more complex and uncontrollable, which has become an important factor limiting its promotion and application.

[0004] At present, in actual engineering, the prediction of energy consumption in the aluminum alloy extrusion process mainly relies on the following two methods:

[0005] Finite element simulation methods: By establishing a physical model, meshing, assigning material constitutive relationships, and setting boundary conditions, the extrusion force-stroke relationship is fitted, thereby estimating deformation work and related energy consumption. This method has high accuracy, but consumes large amounts of computing resources, takes a long time to simulate, and requires a high level of numerical simulation experience from the operator, making it unsuitable for routine rapid assessment and online decision-making.

[0006] Data-driven prediction methods: Leveraging big data analytics and machine learning models, energy consumption prediction models are developed through training and regression analysis of large amounts of historical extrusion process data. While these methods are effective when sufficient sample data is available, they suffer from poor interpretability, weak model robustness, and limited generalization capabilities. Prediction accuracy is particularly difficult to guarantee when the extrusion die structure or process parameters change.

[0007] In the above context, the existing technology lacks a unified, clear, and engineerable prediction model based on the thermal-mechanical-friction energy coupling mechanism in the aluminum alloy extrusion process, especially for the energy consumption modeling during uniform speed extrusion using a planar diverter die, and related research is relatively blank.

[0008] In summary, the following deficiencies generally exist in current technologies:

[0009] Extrusion energy consumption modeling relies on simulation or experience, and lacks analytical mathematical models with clear physical meanings; there is a lack of systematic analysis of the impact of mold structure on energy consumption, especially the local friction and energy loss caused by the diversion mold is difficult to quantify; the existing energy consumption estimation model ignores the heat exchange loss factor between the mold and the environment; there is a lack of a complete modeling framework that considers the synergistic effect of the three energy loss mechanisms of friction, plastic deformation and thermal radiation; it cannot meet the needs of enterprises for extrusion energy efficiency management, energy saving evaluation and process optimization.

[0010] Therefore, there is an urgent need for an aluminum alloy extrusion energy consumption modeling method that is oriented towards engineering practice and has high theoretical rigor and adaptability to support the realization of green manufacturing goals and provide guidance for lean extrusion processes. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a method for establishing an energy consumption prediction model for the uniform extrusion forming process of aluminum alloy bars based on a planar diverter die, so as to solve the problems existing in the prior art such as incomplete model structure, neglect of die structure factors, inability to simultaneously consider friction work and heat exchange loss, lack of analytical expression of energy consumption sources, low prediction accuracy and lack of engineering application capabilities.

[0012] To overcome the above-mentioned defects of the prior art, the present invention provides a method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die, comprising the following steps:

[0013] S1: Establish plastic deformation work W form Model: Based on the axisymmetric coordinate system, the velocity field model and stress distribution model of the aluminum alloy bar extrusion process are established, and the stress distribution in the plastic deformation zone and the plastic deformation work per unit time W are derived. form Model;

[0014] S2: Establish friction work model: Based on the die angle, dead zone structure length and extrusion stroke parameters of the plane diverter die, the friction work W between the aluminum alloy bar and the extrusion cylinder is obtained. cf and the friction work W in contact with the mold df The extrusion cylinder is the cavity structure where the aluminum alloy bar is located, and the friction work W cf and friction work W df The sum is the friction work model;

[0015] S3: Establish a thermal radiation heat transfer work model: Based on the Stefan-Boltzmann law, establish a thermal radiation heat transfer work model Q between the extrusion barrel and the die and the ambient air;

[0016] S4: Plastic deformation work W obtained by superimposing the steps S1, S2 and S3 formThe energy consumption prediction model is established by dividing the sum E of the three by the energy conversion efficiency η of the servo system.

[0017] In a possible embodiment, step S1 includes the following steps: first, establishing an axisymmetric coordinate system for describing the extrusion process of the aluminum alloy bar, which serves as a spatial basis for subsequent derivation of the velocity field and stress distribution;

[0018] Then, based on the assumption of continuous velocity field, a velocity distribution model of the metal in the radial direction in the plastic deformation zone is derived in the axisymmetric coordinate system to construct a velocity field model;

[0019] Selecting a tiny unit of unit volume in the plastic deformation zone, substituting its motion behavior into the axisymmetric coordinate system, and establishing a static equilibrium equation of the tiny unit in radial and circumferential directions;

[0020] Based on the velocity field model and the static equilibrium equation, combined with the Mises yield criterion, the stress distribution expression in the plastic deformation zone is derived;

[0021] Taking radial stress as the integral variable, substituting it into the stress distribution expression and integrating it along the metal flow path, the plastic deformation work W used to describe the energy consumption per unit time during the uniform extrusion process of aluminum alloy is obtained. form Model.

[0022] Compared with the existing technology, the method for establishing an energy consumption prediction model for the uniform speed extrusion forming process of aluminum alloy bars based on a planar diverter die in the present application has the following advantages: the establishment method of the present invention replaces the "black box" prediction method in the existing technology that relies on finite element simulation or empirical data fitting with an analytical energy consumption model derived based on physical mechanisms. This method establishes an energy consumption prediction structure that is clear, controllable, parameter-adjustable, and suitable for engineering applications through the coupling of plastic mechanics equations, friction theory, and thermal radiation heat transfer theory. The method of the present invention takes the mold structure characteristics as the modeling core, integrates key parameters such as mold angle, dead zone length, and slip distance, and accurately incorporates the friction path changes and power consumption differences caused by the "divergent mold" into the modeling range, significantly enhancing the model's adaptability to complex mold structures. By further introducing the thermal radiation heat exchange model, it comprehensively covers the explicit and implicit energy loss channels of the extrusion process, supplementing the problem of energy consumption errors caused by ignoring heat exchange in traditional modeling, and effectively improving the prediction accuracy and energy efficiency evaluation accuracy. In the establishment method of the present invention, each model sub-item constitutes a causal closed loop and logical association: the velocity field determines the stress field, and the stress distribution determines the plastic work; the mold structure The friction path and dead zone length are determined, and thus the friction energy consumption is determined; the process temperature determines the heat loss; the system efficiency reflects the conversion loss from the perspective of overall energy consumption. The various physical quantities interact with each other and jointly support the final energy consumption output value, thus constructing a complete energy analysis system. The present invention can provide theoretical support for the optimization of aluminum alloy profile extrusion process parameters, energy saving and consumption reduction evaluation, and energy efficiency comparative analysis in actual engineering. It can quantify the energy consumption change trend under different extrusion schemes and has good promotion value and industrial applicability. The method of the present invention comprehensively solves the problems mentioned in the prior art such as the lack of modeling structure, insufficient prediction accuracy, poor interpretability, and weak adaptability by establishing an energy consumption prediction model with a complete structure, a clear physical mechanism, and taking into account the influence of the actual structure of the mold. It provides theoretical support and application tools for the energy efficiency analysis of aluminum alloy extrusion in the context of green manufacturing.

[0023] In a possible implementation, in step S1, the plastic deformation work W form The model is:

[0024]

[0025] Among them, V J is the velocity of the metal particle when entering the plastic deformation zone, σ k is the deformation resistance of aluminum alloy, F t is the cross-sectional area of ​​the extrusion cylinder, ε e is the natural logarithm of the extrusion ratio, m z is the friction coefficient, t s is the plastic deformation time.

[0026] Compared with the existing technology, the above technical solution can accurately calculate the power consumption per unit time during the plastic deformation process of metal based on analytical methods, avoiding the problems of complex calculations, large errors, and strong data dependence in traditional finite element simulations or experimental estimates. In terms of technical principles, the model of the present invention adopts continuous velocity field theory to construct metal flow trajectories, combines the Mises yield criterion to derive the stress field distribution, and then obtains the total plastic power consumption expression through the energy superposition principle, which directly reflects the intrinsic relationship between material fluidity, friction state, extrusion ratio and plastic deformation work.

[0027] In a possible implementation, the σ k Calculated by the following formula:

[0028] σ k =C v σ s ;

[0029] Among them, C v is the coefficient of different strain rates compared to static state, σ s is the static tensile yield stress at the deformation temperature.

[0030] Compared with the existing technology, the above technical solution can introduce the influence of deformation rate on material resistance in the process of plastic work calculation, realize the correction of dynamic stress response, and overcome the problem of large calculation deviation caused by replacing actual deformation resistance with static yield stress at room temperature in traditional methods. The above technical solution is based on the strain rate sensitivity principle of aluminum alloy under thermal deformation conditions, and multiplies the correction coefficient C by v To reflect the improvement trend of the stress response of the material at different forming speeds, through the inductive results of material mechanics experimental data, it has good physical rationality and engineering practicality.

[0031] In a possible embodiment, the plastic deformation time t s Calculated by the following formula:

[0032]

[0033] Among them, D t is the diameter of the extrusion cylinder, d is the diameter of the circle of equal area of ​​the extrusion outlet, V j is the extrusion rod speed.

[0034] Compared with the existing technology, the above technical solution can accurately estimate the time required for the metal to undergo plastic deformation in the extrusion deformation zone through analytical expressions. Compared with the traditional method of estimating deformation time by finite element simulation or experimental means, it has significant advantages such as convenient calculation, high accuracy, and strong adaptability. The plastic deformation time t sThe formula is derived based on the principle of volume conservation and the uniform deformation assumption. By analyzing the volume difference between the inlet and outlet metal sections and combining it with the uniform advancement rate of the extrusion rod, the actual residence time of the metal in the die cavity is determined. The geometric variables (barrel and outlet dimensions) and motion variables (speed) are organically integrated, making the results both practical and easy to adjust.

[0035] In a possible embodiment, in step S2, the friction work W cf and friction work W df They are:

[0036]

[0037] Among them, the friction stress between the aluminum alloy billet and the extrusion cylinder is evenly distributed, k is the shear flow stress of the aluminum alloy material, m c is the friction coefficient, L t is the maximum sliding distance between the aluminum alloy and the extrusion cylinder, D t is the diameter of the extrusion cylinder;

[0038]

[0039] Among them, the friction stress between the aluminum alloy billet and the mold is evenly distributed and the interior of the mold is an ideal cylindrical surface, L d is the cylinder height, m d is the friction coefficient.

[0040] Compared with the existing technology, the above-mentioned technical scheme is adopted to accurately calculate the interface friction power consumption during the extrusion process in an analytical form, especially the energy consumption of two typical friction contact areas in the diverter die structure, which makes up for the problem that the existing model does not fully consider the contribution of friction work of the die structure. The above-mentioned technical scheme of the present invention is constructed based on the basic mechanical principle of interface friction work = friction stress × sliding distance × contact area. By simplifying it into a uniformly distributed and ideal contact model, a closed expression that can be used for engineering prediction is derived. At the same time, the sliding path and cylindrical height can be quantified through the die size and extrusion geometry, so that the model has strong geometric analyzability and measurability. The design of this friction work model not only improves the complete expression ability of the extrusion energy consumption composition, but also provides a quantitative basis for friction control, die selection and lubrication optimization of the extrusion system, effectively supporting the accuracy, practicality and engineering guidance value of the entire energy consumption prediction model.

[0041] In one possible implementation, the maximum sliding distance Lt between the aluminum alloy and the extrusion cylinder is calculated by the following formula:

[0042]

[0043] Where L is the length of the billet after extrusion filling, d is the diameter of the equal area circle of the extrusion outlet, α cr is the maximum dead zone free mode angle, u(α-α cr ) is a unit step function.

[0044] Compared with the existing technology, the above technical scheme can quantitatively calculate the influence of the dead zone length on the effective friction slip path, and accurately reflect the actual contribution of the die angle change to the interface power consumption in the friction work model, thereby improving the ability to finely characterize the energy consumption structure of the extrusion process. The geometric correction formula of the slip path Lt ensures the physical rationality and calculation accuracy of the friction work estimation, which helps to build a more accurate and engineering-applicable aluminum alloy extrusion energy consumption prediction model, and improve the robustness and reliability of the model under the working conditions of die structure changes.

[0045] In a possible implementation, in step S3, the calculation method of the thermal radiation heat transfer work model Q is:

[0046]

[0047] Where C0 is the blackbody radiation constant, T m 、T a is the temperature of the two materials in heat exchange, A is the contact area, t a The heat exchange time.

[0048] Compared with the existing technology, the above technical solution can accurately introduce the heat radiation loss between the mold and the environment in the energy consumption modeling, fill the theoretical gap in the traditional extrusion energy consumption model that ignores the heat dissipation link, and make the energy consumption estimation more in line with the actual high-temperature extrusion working conditions. The model of the present invention is based on the Stefan-Boltzmann law, and regards the heat exchange behavior between the mold and the air as a radiation heat exchange process. The heat flux density is accurately expressed by the fourth power relationship of the absolute temperature difference between the two, and the total heat dissipation per unit process is obtained by combining the heat exchange area and the action time. The calorific value can be converted into the Joule system through the unit conversion coefficient, which is convenient for superposition with plastic work and friction work in a unified dimension.

[0049] Another technical problem to be solved by the present invention is to provide an energy consumption prediction model for the uniform extrusion forming process of aluminum alloy bars based on a planar diverter die, so as to solve the problems existing in the prior art of incomplete expression of energy consumption composition, failure to consider the influence of die structure, lack of a unified mathematical model and inability to accurately respond to actual process changes.

[0050] In order to solve the above technical problems, the present invention provides an energy consumption prediction model for the uniform speed extrusion forming process of aluminum alloy bars based on a planar diverter die. The prediction model is established by the above method. The energy consumption prediction model is as follows:

[0051]

[0052] Among them, W form is the work done by plastic deformation, W cf is the friction work between the aluminum alloy bar and the extrusion cylinder, W df is the friction work between the aluminum alloy bar and the die, and Q is the heat transfer work due to thermal radiation.

[0053] Compared with the prior art, the energy consumption prediction model for the uniform extrusion forming process of aluminum alloy bars based on a plane diverter die in the present application has the following advantages: the model of the present invention starts from the nature of metal deformation and systematically considers four major energy consumption items based on the physical modeling principle, significantly improving the structural integrity and theoretical rigor of the model. The die structure parameters are introduced into the core formula of the model to achieve quantitative modeling of the influence of the diverter die structure. The friction work W in the model of the present invention is cf and friction work W df The die angle, dead zone, sliding length, die cylinder and other geometric parameters are clearly combined to truly reflect the interface friction behavior under different diversion die designs. This design fully reflects the present invention's profound understanding of the die structure-energy consumption response mechanism. In the present invention, W form Derived from the continuous velocity field assumption and yield criterion, W cf and W df It reflects the friction path and friction state, Q reflects the external heat loss, and η reflects the electrical-mechanical energy conversion efficiency; its overall structure is rigorous and the physical meaning is clear; the model parameters provided by the present invention have clear physical measurability and engineering applicability, and can be applied to rapid energy consumption prediction and comparative analysis under different equipment and different working conditions. It not only improves the integrity of the modeling dimension, but also realizes the direct linkage expression of process-structure-energy consumption, and solves the key problems raised in the background technology such as the inability to explain the mold influence, one-sided energy consumption estimation, and lack of universal adaptability, providing a theoretical basis and tool support for promoting green manufacturing of aluminum alloys and energy efficiency optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Schematic diagram of the stress-strain state during round rod extrusion. DETAILED DESCRIPTION

[0055] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of the present application and are not intended to limit the scope of protection of the embodiments of the present application. Those skilled in the art may adjust them as needed to suit specific application scenarios.

[0056] The present invention provides an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die and a method for establishing the model. The method comprises:

[0057] S1: Establish plastic deformation work W form Model: First, an axisymmetric coordinate system is established to describe the extrusion process of aluminum alloy bars, which serves as the spatial basis for the subsequent derivation of velocity field and stress distribution.

[0058] Subsequently, based on the continuous velocity field assumption, a velocity distribution model of the metal in the radial direction in the plastic deformation zone is derived in the axisymmetric coordinate system to construct a velocity field model; a tiny unit of unit volume is selected in the plastic deformation zone, and its motion behavior is substituted into the axisymmetric coordinate system to establish the static equilibrium equations of the tiny unit in the radial and circumferential directions; based on the velocity field model and the equilibrium equation, the stress distribution expression in the plastic deformation zone is derived in combination with the Mises yield criterion; the radial stress is used as the integral variable and integrated along the metal flow path to obtain the plastic deformation work W used to describe the energy consumption per unit time during the uniform extrusion process of aluminum alloy. form Model:

[0059]

[0060] Among them, V J is the velocity of the metal particle when entering the plastic deformation zone, σ k is the deformation resistance of aluminum alloy, F t is the cross-sectional area of ​​the extrusion cylinder, ε e is the natural logarithm of the extrusion ratio, m z is the friction coefficient, t s is the plastic deformation time.

[0061] S2: Based on the assumption that friction stress is uniformly distributed, the work model for overcoming friction in the extrusion barrel and the work model for overcoming friction in the plane diversion die are derived:

[0062]

[0063] Wherein, k is the shear flow stress of aluminum alloy material, m c is the friction coefficient, Lt is the maximum sliding distance between the aluminum alloy and the extrusion cylinder, D t is the diameter of the extrusion cylinder; L d is the cylinder height, m d is the friction coefficient.

[0064] S3: Based on the Stefan-Boltzmann law, a heat exchange energy model between the extrusion barrel, die and air was established:

[0065]

[0066] Where C0 is the blackbody radiation constant, T m 、T ais the temperature of the two materials in heat exchange, A is the contact area, t a The heat exchange time.

[0067] S4: The aluminum alloy bar plastic deformation work model, friction work model, and energy exchange model obtained in step S1 are integrated to obtain the sum E of the three models. The sum is divided by the energy conversion efficiency η to establish an energy consumption prediction model for the uniform speed extrusion forming process of aluminum alloy bars based on a plane split die:

[0068]

[0069] The specific steps of the method for establishing the mathematical prediction model of energy consumption of aluminum alloy uniform extrusion of the present invention are as follows:

[0070] Establishment of the work model of aluminum alloy extrusion plastic deformation, the work model of overcoming friction, and the energy model of heat exchange between the extrusion cylinder and the die and the air:

[0071] S1: Establishment of the work model of aluminum alloy extrusion plastic deformation:

[0072] The rod extrusion is an axisymmetric extrusion deformation, and the spherical coordinates are established as follows: Figure 1 As shown, the paper plane is The coordinates are represented by θ, and the direction perpendicular to the paper is represented by θ. It is assumed that the inlet and outlet surfaces of the plastic deformation zone are two concentric spheres, and the flow of metal in the plastic deformation zone obeys the B.Avitzur continuous velocity field:

[0073]

[0074] Where V j is the velocity of the metal particle when entering the plastic deformation zone, V r is the radial velocity of the metal particle in the plastic deformation zone, and r is the polar coordinate radius of the metal particle in the plastic deformation zone.

[0075] For the metal particle on the entrance surface of the plastic deformation zone, substituting r = r2 into formula (1) we get:

[0076]

[0077] Where V rc It is the metal flow velocity component of the metal particle along the radial direction at the inlet surface of the plastic deformation zone.

[0078] From the geometric projection relationship, the tangential velocity component of the metal particle on the entrance surface of the plastic deformation zone can be obtained as follows:

[0079]

[0080] Taking a tiny unit of volume in the metal plastic deformation zone, the Taylor expansion is retained to the first-order term, and the radial and circumferential column equilibrium equations are:

[0081]

[0082] Since the rod extrusion is an axisymmetric problem, we can get Simplifying the first equation in formula (4) yields:

[0083]

[0084] The Mises yield condition for a small unit cell of unit volume in spherical coordinates is as follows:

[0085]

[0086] Assuming that the friction stress in the plastic deformation zone is uniformly distributed, the magnitude of the friction stress can be obtained by simplifying Equation (6):

[0087]

[0088] Assuming that the shear stress in the plastic deformation zone is uniformly distributed and its magnitude obeys the following, τ z is the shear stress on the cone surface in the deformation zone:

[0089]

[0090] in, is the shear stress, τ z is the shear stress on the cone surface in the deformation zone, is the angle in spherical coordinates, σ k is the deformation resistance of aluminum alloy, m z is the friction coefficient.

[0091] The present invention adopts the above technical solution to introduce directional friction effect in the analytical modeling stage, truly reflecting the distribution characteristics of shear stress in the deformation zone with angle changes, breaking through the theoretical simplification deviation problem caused by the "constant shear stress assumption" in the traditional model; the stress distribution model is based on the law that the friction stress changes as a sine function along the angle of the spherical coordinate system, taking into account the force non-uniformity of the material in the complex angle area, and its derivation is based on the stress equilibrium condition and Mises yield criterion in the plasticity theory, and combined with the friction state parameter m z Reasonable assumptions are made, with a clear physical basis and verifiability. By introducing the stress distribution function, the plastic work model of the present invention is significantly improved in its ability to characterize actual deformation behavior, thereby enhancing the credibility and accuracy of the entire energy consumption prediction model in industrial applications.

[0092] Substituting equations (6) and (8) into equation (5), the simplified formula is as follows:

[0093]

[0094] Integrating Equation (9) from the inlet surface to the outlet surface of the plastic deformation zone, the normal stress on the inlet surface of the deformation zone is obtained as:

[0095]

[0096] In order to obtain the power of plastic deformation work, the normal stress is multiplied by the velocity and then integrated with time to obtain the work done by plastic deformation. Considering that the extrusion rod is at a uniform speed and the velocity is independent of time, the work done by plastic deformation W is form The model is:

[0097]

[0098] Where V J is the velocity of the metal particle when entering the plastic deformation zone, σ k is the deformation resistance of aluminum alloy, F t is the cross-sectional area of ​​the extrusion cylinder, ε e is the natural logarithm of the extrusion ratio, m z is the friction coefficient, t s is the plastic deformation time.

[0099] S2: Establishment of the work model to overcome friction:

[0100] Due to the existence of the dead zone, the maximum sliding distance between the aluminum alloy and the extrusion barrel is not the length of the billet after extrusion filling. The dead zone length is solved according to the geometric relationship as follows:

[0101]

[0102] Where D t is the diameter of the extrusion cylinder, d is the diameter of the circle of equal area of ​​the extrusion outlet, α cr is the maximum dead zone free mode angle, and u(α) is a step function.

[0103] Assuming L is the billet length after extrusion filling, the maximum sliding distance L of the friction between the aluminum alloy and the extrusion cylinder is t The solution is:

[0104]

[0105] Where L is the length of the billet after extrusion filling, d is the diameter of the equal area circle of the extrusion outlet, α cr is the maximum dead zone free mode angle, u(α-α cr ) is a unit step function.

[0106] Assuming that the friction stress between the aluminum alloy billet and the extrusion cylinder is uniformly distributed, the work W done to overcome the friction between the aluminum alloy and the extrusion cylinder is: cf The solution is as follows:

[0107]

[0108] Where, k is the shear flow stress of aluminum alloy material, m c is the friction coefficient, Lt is the maximum sliding distance between the aluminum alloy and the extrusion cylinder, D t is the diameter of the extrusion cylinder.

[0109] Assuming that the friction stress between the aluminum alloy billet and the die is uniformly distributed and the interior of the die is an ideal cylindrical surface, the work W done to overcome the friction between the aluminum alloy and the die is: df The solution is as follows:

[0110]

[0111] Where, L d is the cylinder height, m d is the friction coefficient.

[0112] S3: Establishment of the heat exchange energy model between the extrusion barrel and the die and the air:

[0113] Based on the Stefan-Boltzmann law, the heat exchange energy between the extrusion barrel and the die and the air is solved as follows:

[0114]

[0115] Where C0 is the blackbody radiation constant, T m 、T a is the temperature of the two materials in heat exchange, A is the contact area, t a The heat exchange time.

[0116] S4: An energy consumption prediction model for aluminum alloy extrusion forming based on a planar split die was established by integrating the plastic deformation work model, the friction overcoming model, the heat exchange model, and the conversion efficiency of electrical energy to extrusion work:

[0117] The energy consumption prediction model is as follows:

[0118]

[0119] The above-mentioned model of the present invention is based on the law of conservation of energy. By analyzing the energy transfer behavior in the hot extrusion process, a quantitative prediction model for extrusion energy consumption is established. On the one hand, the required energy consumption can be predicted according to the process parameters of extrusion production. On the other hand, the internal factors affecting energy consumption can be intuitively understood, providing theoretical guidance for enterprises to produce high-quality and low-energy profiles.

[0120] In order to verify the above-mentioned model and its technical effects of the present invention, the following provides specific embodiments combining the above-mentioned model and method of the present invention to further expand the present invention:

[0121] Example:

[0122] This embodiment provides an energy consumption prediction model for the uniform speed extrusion forming process of aluminum alloy bars based on a planar diverter die and a method for establishing the same. Specifically, a 6063 aluminum alloy automobile sunroof guide rail profile produced by a certain enterprise has a profile cross-section complexity conversion coefficient of 1.59. The profile is extruded on a hydraulic extruder using an extrusion barrel with a diameter of 187.5 mm. The equivalent circle diameter of the extrusion outlet area is 28 mm. The billet diameter is 178 mm, the length is 875 mm, the extrusion rod speed is 6 mm / s, and no lubricant is added during the extrusion process. The bar preheating temperature is 465°C, the extrusion barrel temperature is 420°C, and the die temperature is 480°C.

[0123] The following provides an energy consumption prediction model and calculation process for the uniform speed extrusion forming process of aluminum alloy bars based on a planar splitter die for the above-mentioned profile:

[0124] Calculation of the work done by aluminum alloy extrusion plastic deformation, the work done to overcome friction, and the heat exchange energy between the extrusion cylinder and the die and the air:

[0125] S1: Calculation of work done by plastic deformation of aluminum alloy extrusion:

[0126] Known V j =6×10 -3 , ε e =ln44.8487=3.8,m z =1.0, Determine the maximum sliding distance of the friction force between the aluminum alloy and the extrusion cylinder Solving for plastic deformation time Then the average strain velocity is obtained

[0127] The metal deformation resistance of aluminum alloy at different temperatures and different strain rates is solved as follows:

[0128] σ k =C v σ s (18) Where C v is the coefficient of different strain rates compared to static state, σ s is the static tensile yield stress at the deformation temperature.

[0129] Assuming that the extrusion temperature is the average of the bar preheating temperature and the extrusion barrel temperature, that is, 442.5℃. After consulting the data, when the extrusion temperature is 442.5℃, the static tensile yield stress of 6063 aluminum alloy is 17.5MPa; when the strain rate is 0.366s-1, C v =1.62; then we can get σ k =C v σ s =28.4MPa, Substituting the above parameters into formula 11, we get: W form =3.75387×10 5 J.

[0130] S2: Calculation of work done to overcome friction:

[0131] Known m t =1.0, Substituting the above parameters into formula 14, we get: W cf =

[0132] 5.318321×10 6 J.

[0133] Assuming that the cavity in the mold is an ideal cylinder, measure the circumference and height of the diversion hole section. Similarly, substitute the parameters into formula 15 to obtain: W df =W df1 +W df2 =9.1245×10 4 J.

[0134] S3: Calculation of heat exchange energy between extrusion barrel and die and air:

[0135] It is known that the air temperature is equal to the room temperature of 26℃.

[0136] Q = Q1 + Q2 = 8.32074 × 10 5 J.

[0137] S4: Through investigation, the efficiency of converting the servo motor's electrical energy into extrusion force during actual extrusion is about 70%. Substituting the above parameters into formula 17, we get: E all =9.452896MJ; by detecting the electrical energy of multiple extrusion cycles, the average extrusion forming energy consumption in the cycle is obtained to be 8.598803MJ; the relative error is 9.93%.

[0138] The above examples further demonstrate the effectiveness of the energy consumption prediction model and method for establishing the planar splitter die-based uniform extrusion process for aluminum alloy bars. In the examples, through precise energy consumption calculations, the main energy consumption factors in the aluminum alloy extrusion process, including plastic deformation work, friction work, and heat exchange energy, were successfully quantified, taking into account the influence of various process parameters and die structure during the extrusion process. Experimental results demonstrate that the relative error between the energy consumption prediction using the model of the present invention and the actual measured energy consumption data is only 9.93%, demonstrating high prediction accuracy and strong engineering practicality.

[0139] The technical principle of the present invention is based on physical mechanisms, combining the energy coupling model of plastic deformation, friction work and thermal radiation heat transfer, and comprehensively considering key factors such as mold design, process temperature, friction coefficient, etc., and can accurately reflect the energy consumption in the actual production process. Compared with the existing technology, the present invention not only improves the accuracy of energy consumption prediction, but also makes up for the shortcomings of traditional methods that ignore key factors such as mold structure, friction effect and heat exchange loss, and effectively solves the problems of large energy consumption estimation deviation, poor interpretability and insufficient adaptability in the existing technology.

[0140] In summary, the present invention not only provides a scientific basis for energy efficiency optimization of aluminum alloy extrusion process, but also provides an efficient and reliable tool for energy saving and consumption reduction, green manufacturing and process optimization, and has broad application prospects and industrial practical value.

[0141] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0142] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for establishing an energy consumption prediction model for the uniform speed extrusion forming process of aluminum alloy bars based on a plane splitter die, characterized in that: The following steps are involved: S1: Establish plastic deformation work W form Model: Based on the axisymmetric coordinate system, the velocity field model and stress distribution model of the aluminum alloy bar extrusion process are established, and the stress distribution in the plastic deformation zone and the plastic deformation work per unit time W are derived. form Model; S2: Establish friction work model: Based on the die angle, dead zone structure length and extrusion stroke parameters of the plane diverter die, the friction work W between the aluminum alloy bar and the extrusion cylinder is obtained. cf and the friction work W in contact with the mold df The extrusion cylinder is the cavity structure where the aluminum alloy bar is located, and the friction work W cf and friction work W df The sum is the friction work model; S3: Establish a thermal radiation heat transfer work model: Based on the Stefan-Boltzmann law, establish a thermal radiation heat transfer work model Q between the extrusion barrel and the die and the ambient air; S4: Plastic deformation work W obtained by superimposing the steps S1, S2 and S3 form The energy consumption prediction model is established by dividing the sum E of the three by the energy conversion efficiency η of the servo system.

2. The method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die according to claim 1, characterized in that: Said step S1 comprises the following steps: first, establishing an axisymmetric coordinate system for describing the extrusion process of the aluminum alloy bar, which serves as the spatial basis for the subsequent derivation of the velocity field and stress distribution; Then, based on the assumption of continuous velocity field, a velocity distribution model of the metal in the radial direction in the plastic deformation zone is derived in the axisymmetric coordinate system to construct a velocity field model; Selecting a tiny unit of unit volume in the plastic deformation zone, substituting its motion behavior into the axisymmetric coordinate system, and establishing a static equilibrium equation of the tiny unit in radial and circumferential directions; Based on the velocity field model and the static equilibrium equation, combined with the Mises yield criterion, the stress distribution expression in the plastic deformation zone is derived; Taking radial stress as the integral variable, substituting it into the stress distribution expression and integrating it along the metal flow path, the plastic deformation work W used to describe the energy consumption per unit time during the uniform extrusion process of aluminum alloy is obtained. form Model.

3. The method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die according to claim 1, characterized in that: In step S1, the plastic deformation work W form The model is: Among them, V j is the velocity of the metal particle when entering the plastic deformation zone, σ k is the deformation resistance of aluminum alloy, F t is the cross-sectional area of ​​the extrusion cylinder, ε e is the natural logarithm of the extrusion ratio, m z is the friction coefficient, t s is the plastic deformation time.

4. The method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die according to claim 3, characterized in that: The deformation resistance σ of the aluminum alloy k Calculated by the following formula: s k =C v s s ; Among them, C v is the coefficient of different strain rates compared to static state, σ s is the static tensile yield stress at the deformation temperature.

5. The method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die according to claim 3, characterized in that: The plastic deformation time t s Calculated by the following formula: Among them, D t is the diameter of the extrusion cylinder, d is the diameter of the circle of equal area of ​​the extrusion outlet, V j is the extrusion rod speed.

6. The method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die according to claim 1, characterized in that: In step S2, the friction work W cf and friction work W df They are: Wherein, k is the shear flow stress of aluminum alloy material, m c is the friction coefficient, Lt is the maximum sliding distance between the aluminum alloy and the extrusion cylinder, D t is the diameter of the extrusion cylinder; Among them, L d is the cylinder height, m d is the friction coefficient.

7. The method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die according to claim 6, characterized in that: The maximum sliding distance Lt between the aluminum alloy and the extrusion cylinder is calculated by the following formula: Where L is the length of the billet after extrusion filling, d is the diameter of the equal area circle of the extrusion outlet, α cr is the maximum dead zone free mode angle, u(α-α cr ) is a unit step function.

8. The method for establishing an energy consumption prediction model for a uniform speed extrusion forming process of an aluminum alloy bar based on a planar splitter die according to claim 1, characterized in that: In step S3, the calculation method of the thermal radiation heat transfer work model Q is: Where C0 is the blackbody radiation constant, T m 、T a is the temperature of the two materials in heat exchange, A is the contact area, t a The heat exchange time.

9. An energy consumption prediction model for the uniform speed extrusion process of aluminum alloy bars based on a planar splitter die, characterized in that: The prediction model is established by the establishment method according to any one of claims 1 to 8, wherein the energy consumption prediction model is as follows: Among them, W form is the work done by plastic deformation, W cf is the friction work between the aluminum alloy bar and the extrusion cylinder, W df is the friction work between the aluminum alloy bar and the die, and Q is the heat transfer work due to thermal radiation.

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