Aging control method and equipment for dimensional stability of zinc alloy die casting and medium

Abstract

The invention belongs to the field of metal material processing, particularly relates to an aging control method and equipment for the size stability of a zinc alloy die casting and a medium, and aims to solve the problems that a scheme for effectively stabilizing the size of the die casting is lacked, the period is too long and new deformation is easy to generate in the prior art. The method comprises the following steps: acquiring a physical signal for representing the internal residual stress of the die casting; synchronously applying mechanical vibration energy and first-stage heat energy to the die casting; second-stage heat energy is applied to the die casting, meanwhile, the change rate of the physical signals is continuously detected, and when the change rate is lower than a preset stability judgment threshold value within multiple continuous time intervals, it is determined that the internal phase change of the die casting reaches a stable state, and heating of the die casting is stopped; and after heating of the die casting is stopped, gradient cooling treatment is carried out on the die casting. The method can effectively shorten the period of the stress relieving stage, and meanwhile, new thermal stress and deformation generated in the final cooling stage are inhibited.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of metal material processing, and particularly relates to an aging control method, equipment and medium for size stability of zinc alloy pressure casting. BACKGROUND

[0002] Zinc alloy pressure casting is widely used in the automobile, electronic, hardware and other industries due to its good casting performance, high strength and low cost. However, residual stress generally exists in the zinc alloy pressure casting after pressure casting, which is caused by non-uniform cooling and solidification process of molten metal in the mold. The existence of residual stress easily leads to size deformation, warping and even cracking of the pressure casting during subsequent storage or use, which seriously affects the assembly accuracy and service life of the product.

[0003] At present, the related technology generally adopts natural aging or thermal aging (stress relief annealing) method to stabilize the size of the pressure casting. Among them, the natural aging is to store the pressure casting at room temperature for a long time (usually several weeks to several months), and the size is stabilized through extremely slow stress relaxation. This method has a long cycle and low efficiency, and cannot meet the rhythm demand of modern production. The thermal aging is to heat the pressure casting to a certain temperature (usually below the recrystallization temperature of zinc alloy), and then slowly cool after heat preservation for a period of time to accelerate stress release.

[0004] However, the above-mentioned thermal aging scheme still has defects, specifically, it has high energy consumption and a relatively long cycle. In order to fully eliminate stress, a long heat preservation time is often needed, which consumes a large amount of energy. Meanwhile, new deformation or performance degradation is easily caused in the process, and if the temperature or time is not properly controlled, the pressure casting may be over-annealed, causing grain coarsening, strength and hardness reduction, or new thermal stress due to uneven cooling rate of each part in the cooling process, leading to secondary deformation. SUMMARY

[0005] In order to solve the above-mentioned problems in the prior art, i.e., the related technology lacks an effective scheme to stabilize the size of the pressure casting, has a long cycle, and easily causes new deformation, the first aspect of the present application provides an aging control method for size stability of zinc alloy pressure casting, which comprises: acquiring a physical signal for representing residual stress in the pressure casting; synchronously applying mechanical vibration energy and first-order thermal energy to the pressure casting, and continuously detecting the change amount of the physical signal, and when the change amount of the physical signal reaches a predetermined preset value, stopping applying the mechanical vibration energy and the first-order thermal energy; applying second-order thermal energy to the die casting to drive the metastable phase transformation inside the die casting while continuously detecting the change rate of the physical signal, and determining that the phase transformation inside the die casting reaches a stable state when the change rate is lower than a preset stable determination threshold in a plurality of continuous time intervals, and stopping heating of the die casting; After stopping heating of the die casting, performing gradient cooling processing on the die casting, the gradient cooling processing being applying different cooling rates to different geometric feature regions of the die casting to compensate for shrinkage differences between the regions of the die casting.

[0006] In some preferred embodiments, the synchronously applying mechanical vibration energy and first-order thermal energy to the die casting comprises: applying mechanical vibration energy with a frequency set based on initial spectral characteristics of the physical signal while applying the first-order thermal energy to the die casting; After applying the mechanical vibration energy, dynamically adjusting the frequency of the mechanical vibration energy by continuously detecting frequency domain characteristics of the physical signal, so that the frequency of the mechanical vibration energy adapts to changes in dominant frequency components in the physical signal, and adaptively adjusting the amplitude of the mechanical vibration energy by continuously detecting the amplitude decay rate of the physical signal at the dominant frequency components.

[0007] In some preferred embodiments, the applying second-order thermal energy to the die casting comprises: determining a target temperature interval corresponding to the second-order thermal energy; heating the die casting to a preset intermediate platform at a first heating rate and holding for a preset time length to trigger initial transformation of metastable phases inside the die casting, the temperature of the intermediate platform being lower than the target temperature interval; continuing to heat the die casting to the target temperature interval at a second heating rate, the second heating rate being lower than the first heating rate; holding the die casting in the target temperature interval.

[0008] In some preferred embodiments, the continuously detecting the change rate of the physical signal comprises: continuously detecting the physical signal to obtain physical quantity-time sequence data; numerically differentiating the physical quantity-time sequence data and calculating the change rate in real time; continuously comparing the calculated change rate with the preset stable determination threshold; When the change rate is maintained below the stability determination threshold in a plurality of monitoring periods in quantity, it is determined that the phase change inside the die casting reaches a stable state.

[0009] In some preferred embodiments, the continuously detecting the change amount of the physical signal comprises: The physical signal is continuously detected, and the detected physical signal is preprocessed to extract a signal component directly related to stress release, the preprocessing comprising noise reduction and filtering processing; One or more characteristic values are extracted from the preprocessed physical signal, the characteristic values being energy integral values or envelope area of the signal in a specific frequency band; The cumulative relative change amount of the characteristic value is calculated in real time, and the cumulative relative change amount is compared with the predetermined value in real time.

[0010] In some preferred embodiments, the method further comprises: The die casting after the gradient cooling treatment is subjected to dimensional stability detection; All time sequence data in the current processing process are stored in association with the results of the dimensional stability detection, and a preset multivariate data analysis algorithm is used to determine an implicit mapping relationship between the aging control parameters of the die casting and the dimensional stability; According to the implicit mapping relationship, the aging control parameters of the die casting are optimized, the aging control parameters at least including the predetermined value and the stability determination threshold; The optimized aging control parameters are updated to a preset process database.

[0011] In some preferred embodiments, the gradient cooling treatment of the die casting comprises: A three-dimensional geometric model of the die casting is obtained, the three-dimensional geometric model being used to indicate the wall thickness difference of each part of the die casting; According to the three-dimensional geometric model of the die casting, the die casting is divided into a plurality of independent cooling control regions, wherein the cooling control regions include thick wall regions and thin wall regions of the die casting; Each cooling control region is set with an independent cooling rate control curve, wherein the cooling rate value of the cooling rate control curve corresponding to the thick wall region is lower than the cooling rate value of the cooling rate control curve corresponding to the thin wall region; According to the cooling rate control curves of each cooling control region, the cooling process of each part of the die casting is controlled to compensate for the shrinkage difference of each part inside the die casting.

[0012] In some preferred embodiments, the method further comprises; continuously detecting actual temperatures of the parts; comparing the detected actual temperatures with expected temperatures of the regions at the same time calculated based on the cooling rate control curves; when the deviation of the actual temperature of any region from the expected temperature exceeds a preset tolerance range, dynamically adjusting the cooling rate control curve of the region in the subsequent stage, and making the actual temperature change path of the region return to the cooling rate control curve by increasing or decreasing the cooling rate.

[0013] In a second aspect, the present application further provides an electronic device, comprising a memory and a processor, the memory being connected to the processor, the processor being configured to execute one or more computer programs stored in the memory, and the processor, when executing the one or more computer programs, causes the electronic device to implement the method according to any one of the first aspect.

[0014] In a third aspect, the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program comprises program instructions, and the program instructions, when executed by a processor, cause the processor to execute the method according to any one of the first aspect.

[0015] The present application has the following beneficial effects: Based on the method of the present application, the release process of residual stress is significantly accelerated by synchronously applying mechanical vibration energy and first-order thermal energy and utilizing the synergistic effect of the two. Compared with traditional natural aging (several weeks) or single thermal aging (several hours), the macro stress relief stage can be shortened to minutes, and the production efficiency is greatly improved. At the same time, the method takes the change amount and change rate of physical signals as the stopping condition, instead of the fixed time parameter, effectively avoids the excessive consumption of energy, and automatically stops once the target is reached, which has good energy-saving effect.

[0016] In addition, the method implements differentiated cooling strategies for different geometric features (such as thick walls and thin walls) of the die casting, actively compensates for the shrinkage difference between regions, and effectively suppresses the generation of new thermal stress and deformation in the final cooling stage. This is particularly beneficial for die castings with complex structures and uneven wall thicknesses, and solves the deformation problem that cannot be overcome by traditional uniform cooling. BRIEF DESCRIPTION OF DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings: Figure 1 is a flowchart of an aging control method for size stability of a zinc alloy die casting according to an embodiment of the present application; Figure 2 is a structural schematic diagram of a computer system according to an embodiment of the present application. DETAILED DESCRIPTION

[0018] The application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are intended to be illustrative only and not limiting of the application. In addition, it should be noted that for the sake of brevity, only the portions of the drawings that are necessary for an understanding of the relevant aspects of the present application will be discussed.

[0019] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below in conjunction with the drawings and embodiments.

[0020] Referring to Figure 1 The first embodiment of the present application provides an aging control method for size stability of a zinc alloy die casting, comprising: Step S10, acquiring a physical signal for representing residual stress inside the die casting; Step S20, synchronously applying mechanical vibration energy and first-order thermal energy to the die casting, while continuously detecting the change amount of the physical signal, and when the change amount of the physical signal reaches a preset predetermined value, stopping the application of the mechanical vibration energy and the first-order thermal energy; Step S30, after stopping the application of the mechanical vibration energy and the first-order thermal energy, applying second-order thermal energy to the die casting to drive the metastable phase transition inside the die casting, while continuously detecting the change rate of the physical signal, and when the change rate is lower than a preset stability determination threshold value in a plurality of continuous time intervals, determining that the phase change inside the die casting reaches a stable state, and stopping heating of the die casting; Step S40, after stopping heating of the die casting, performing gradient cooling processing on the die casting, the gradient cooling processing being: applying different cooling rates to different geometric feature regions of the die casting to compensate for the shrinkage difference between the regions of the die casting.

[0021] The method proposed in the embodiment aims to systematically solve the size stability problem of zinc alloy die castings through multi-stage, closed-loop control of physical field intervention, and the core is to decouple and accurately process the three targets of residual stress release, metastable phase stabilization and shrinkage stress control in time sequence.

[0022] In this embodiment, first, the resistance strain gauges are pasted on the key functional surfaces of the die casting or the areas with high theoretical residual stress (such as the thick-thin transition, the area near the ingate). For rapid detection on the production line, a non-contact laser speckle interferometer can also be used for full-field stress distribution scanning, etc. Through the dynamic signal acquisition instrument connected to the sensor, the initial value (such as the initial micro-strain or the initial resonance frequency) of the physical signal is collected and recorded before the process starts, which is used as the reference for the subsequent step judgment.

[0023] In this embodiment, the die casting can be installed on the workbench of the vibratory aging device through a special fixture. The control system determines the natural frequency of the workpiece through sweep analysis, and then sets it in the sub-resonance frequency area (usually 60%-80% of the natural frequency) to perform steady-state vibration at a certain fixed frequency and acceleration (such as 0.5g-1.5g). At the same time, the infrared heating array or forced convection hot air furnace is turned on synchronously to uniformly heat the workpiece in vibration and apply the first-order thermal energy.

[0024] Further, the mechanical vibration is used to provide energy to make the lattice dislocation escape from pinning, and the first-order thermal energy is used to enhance the diffusion ability of atoms, thereby reducing the energy barrier of dislocation movement and making the residual stress relax quickly.

[0025] It should be noted that the temperature range of the first-order thermal energy is strictly controlled at 70℃-120℃. This temperature is designed to reduce the rheological stress of the material and promote dislocation slip, but it is not enough to cause significant grain growth or overaging of the die casting.

[0026] In this embodiment, the mechanical vibration energy is applied through a full-automatic vibratory aging device (including a vibration exciter, a controller, and a fixture), the first-order thermal energy is applied through an infrared heating plate / array or a programmable temperature-controlled hot air oven, and the integrated control system is used to synchronously control the vibration and heating parameters.

[0027] Among them, the data acquisition system continuously records the signals from the strain gauges or acceleration sensors. For the acceleration signal, the system calculates the frequency offset in real time; for the strain signal, the cumulative strain release amount is calculated. When the offset or the cumulative strain release amount reaches the predetermined value (for example, the frequency offset is 3%-5%, or the strain release reaches a certain micro-strain threshold) determined through the previous process test, it indicates that the macro residual stress has been released to a stable and lower level. At this time, the integrated control system immediately issues an instruction to turn off the vibratory aging device and the first-order heat source.

[0028] In this embodiment, after step S20, the die casting is transferred to or kept in a precision program-controlled box-type resistance furnace (or other related heat source equipment) to apply the second-stage heat energy. Generally, the temperature range of the second-stage heat energy is controlled at 120°C - 180°C, which is the sensitive interval for the metastable phase (such as non-equilibrium eutectic structure) in the zinc alloy to transform into stable phase (such as η-Zn phase and β'-ZnAl phase).

[0029] In this step, by actively promoting the transformation of the metastable phase under controlled conditions, the dimensional natural aging change of the die casting caused by phase transformation during long-term use or storage can be effectively eliminated.

[0030] At the same time of applying the second-stage heat energy, the instantaneous change rate of the physical signal (such as strain signal) is continuously monitored. It is easy to understand that at the initial stage of phase transformation, the structure changes dramatically, at which time the instantaneous change rate is larger, and as the phase transformation tends to be completed, the structure tends to be stable, and the instantaneous change rate gradually decreases and tends to be zero.

[0031] In this embodiment, a stable judgment threshold K (for example, 0.1με / min) is preset. When the system detects that the instantaneous change rate is less than K in the continuous N (such as 5-10) sampling periods, it is determined that the internal phase transformation has reached a stable state, at which time the control system commands the heating furnace to stop heating.

[0032] Compared with the traditional fixed-time holding method, this embodiment can accurately capture the moment when the phase transformation is completed, avoiding the problems of insufficient holding (phase transformation not completed) or excessive holding (energy waste, performance degradation).

[0033] In this embodiment, when performing gradient cooling processing, first, based on the CAD model of the workpiece, the thick wall region (such as its thick section, hot spot region, etc.) and the thin wall region of the workpiece can be identified, and differential cooling is performed: For the thick wall region, a low cooling rate is used, such as covering by a closable heat shield, or using a low air volume temperature control air nozzle for slow cooling. This allows the region to shrink for a longer time to compensate for its larger solidification shrinkage.

[0034] And for the thin wall region, a high cooling rate is used, such as using high-flow room temperature air or atomized mist for forced cooling. This allows it to quickly set, limiting its over-shrinkage.

[0035] As a feasible implementation, thermocouples can be arranged in different regions to monitor the temperature in real time and ensure that the cooling curve meets the preset gradient.

[0036] Further, in this embodiment, the synchronous application of mechanical vibration energy and first-stage heat energy to the die casting comprises: applying mechanical vibration energy with a frequency set based on initial frequency spectrum characteristics of the physical signal, while applying the first-stage thermal energy to the die casting; After applying the mechanical vibration energy, dynamically adjusting the frequency of the mechanical vibration energy by continuously detecting frequency domain characteristics of the physical signal, so that the frequency of the mechanical vibration energy is adapted to changes in dominant frequency components in the physical signal, and adaptively adjusting the amplitude of the mechanical vibration energy by continuously detecting the amplitude decay rate of the physical signal at the dominant frequency components.

[0037] The embodiment dynamically adjusts vibration parameters (frequency and amplitude) by monitoring the response of the workpiece to vibration (physical signal) in real time, to ensure that vibration energy is always transmitted to the die casting with the highest efficiency for eliminating residual stress.

[0038] It is easy to understand that during the application of vibration and thermal energy, the release of residual stress will cause a slight change in the overall stiffness of the workpiece, and the natural frequency (resonance peak) will also drift accordingly. Therefore, in the embodiment, the dominant frequency component (i.e. the most important resonance peak) in the current frequency spectrum can be identified by performing FFT analysis on the real-time physical signal. If it is detected that the dominant frequency drifts from the initial F0 to F1, the frequency of the mechanical vibration energy should be adjusted from F0 to F1 at this time.

[0039] Correspondingly, the amplitude decay rate reflects the degree of change in the material damping characteristics and the intensity of the release of residual stress. If the decay is fast, it means that the dislocations inside the material are slipping a lot and the stress release is active. If the decay is slow, it means that the stress has been released to a certain extent and the process is tending to be smooth. Therefore, when the amplitude decay rate is detected to be very fast, the vibration amplitude should be maintained or appropriately increased, and when the amplitude decay rate is detected to be slower and below a certain threshold, the vibration amplitude should be actively reduced, which may cause over-vibration of the workpiece (such as the risk of micro-damage to the grain boundary).

[0040] Further, in the embodiment, the applying of the second-stage thermal energy to the die casting comprises: determining a target temperature interval corresponding to the second-stage thermal energy; heating the die casting to a preset intermediate platform at a first heating rate and performing heat preservation for a preset time length to trigger initial transformation of metastable phases in the die casting, the temperature of the intermediate platform being lower than the target temperature interval; continuing to heat the die casting to the target temperature interval at a second heating rate, the second heating rate being lower than the first heating rate; performing heat preservation of the die casting in the target temperature interval.

[0041] In this embodiment, by the strategy of stepwise heating, first set an intermediate preheating platform and reduce the subsequent heating rate, realize the fine guidance to the micro phase change process, ensure the sufficiency and uniformity of the organization transformation, and minimize the deformation caused by rapid and violent phase change.

[0042] Wherein, the target temperature range (for example 150℃ - 180℃) is accurately set based on the material grade of zinc alloy and the kinetic transformation curve of its metastable phase (such as non-equilibrium eutectic structure, transition phase) (usually determined by differential scanning calorimetry DSC), and the specific value is not limited in this embodiment.

[0043] In this embodiment, the die casting is first heated to a preset intermediate platform temperature at a first heating rate (a higher rate, for example 3-5℃ / min). The platform temperature is lower than the final target temperature range, for example, it can be set at 100℃-130℃. After reaching this temperature, the heat preservation is carried out for a preset time (for example 10-30 minutes); Then, after the end of the intermediate platform heat preservation, the die casting is continuously heated at a second heating rate until the lower limit of the target temperature range is reached, and the second heating rate is lower than the first heating rate (for example, slow heating at 1-2℃ / min); When the temperature enters the preset target temperature range (such as 150℃ - 180℃), long time heat preservation is carried out, and this stage is the main completion stage of the metastable phase transformation. Under the joint action of sufficient temperature and time, most of the metastable phase will decompose and transform into stable equilibrium phase.

[0044] Further, the rate of change of the physical signal is continuously detected, including: The physical signal is continuously detected to obtain physical parameter-time sequence data; the physical parameter-time sequence data is subjected to numerical differentiation, and its rate of change is calculated in real time; the calculated rate of change is continuously compared with the preset stability determination threshold value; when the rate of change is continuously maintained below the stability determination threshold value in a plurality of monitoring periods in quantity, it is determined that the internal phase change of the die casting reaches a stable state.

[0045] Wherein, the time sequence data obtained is first applied to the numerical differentiation algorithm to calculate the rate of change in real time, for example, the first order difference method can be used to calculate the instantaneous rate of change of the physical parameter in the latest time interval according to the physical parameter value of the current sampling point, the value of the last sampling point and the fixed sampling interval.

[0046] Wherein, the stability determination threshold value can be determined by a large number of process tests in advance, which is used to indicate the allowable small fluctuation rate of the physical parameter when the phase change basically stops.

[0047] Further, in the above embodiment, the continuously detecting the change amount of the physical signal comprises: continuously detecting the physical signal, pre-processing the detected physical signal to extract a signal component directly related to stress release, the pre-processing comprising noise reduction and filtering processing; extracting one or more characteristic values from the pre-processed physical signal, the characteristic value being an energy integral value or an envelope area of the signal in a specific frequency band; calculating a cumulative relative change amount of the characteristic value in real time, and comparing the cumulative relative change amount with the predetermined value in real time.

[0048] Further, the method in the above embodiment further comprises: detecting the dimensional stability of the die casting after the gradient cooling treatment; storing all time sequence data in the current treatment process in association with the result of the dimensional stability detection, and determining an implicit mapping relationship between the aging control parameters of the die casting and the dimensional stability by using a preset multivariate data analysis algorithm; optimizing the aging control parameters of the die casting according to the implicit mapping relationship, the aging control parameters at least including the predetermined value and the stability determination threshold; updating the optimized aging control parameters to a preset process database.

[0049] wherein the multivariate data analysis algorithm can be: multivariate linear / nonlinear regression analysis, which quantifies the contribution of process parameters to the dimensional result by establishing a mathematical model; principal component analysis (PCA), which finds the most critical process features affecting stability by dimensionality reduction.

[0050] Further, in the above embodiment, the performing gradient cooling treatment on the die casting comprises: obtaining a three-dimensional geometric model of the die casting, the three-dimensional geometric model being used to indicate the wall thickness difference of each part of the die casting; dividing the die casting into a plurality of independent cooling control regions according to the three-dimensional geometric model of the die casting, wherein the cooling control regions include thick wall regions and thin wall regions of the die casting; setting an independent cooling rate control curve for each cooling control region, wherein the cooling rate value of the cooling rate control curve corresponding to the thick wall region is lower than the cooling rate value of the cooling rate control curve corresponding to the thin wall region; controlling the cooling process of each part of the die casting according to the cooling rate control curve of each cooling control region to compensate for the shrinkage difference of each part of the die casting.

[0051] wherein the gradient cooling treatment further comprises: continuously detecting the actual temperature of each part while controlling the cooling process of each part of the die casting; comparing the detected actual temperature with the expected temperature of the region at the same time calculated based on the cooling rate control curve; when the deviation of the actual temperature of any region from the expected temperature exceeds a preset tolerance range, dynamically adjusting the cooling rate control curve of the region in the subsequent stage, and making the actual temperature change path of the region return to the cooling rate control curve by increasing or decreasing the cooling rate.

[0052] The second embodiment of the present application provides an electronic device, comprising a memory and a processor, the memory is connected to the processor, the processor is used for executing one or more computer programs stored in the memory, and the processor makes the electronic device implement the method according to the first embodiment when executing the one or more computer programs.

[0053] The third embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program comprises program instructions, and the program instructions make the processor execute the method according to the first embodiment when the processor executes the program instructions.

[0054] Reference will be made to the following description Figure 2 which shows the structural schematic diagram of a computer system of a server suitable for implementing the method and device embodiments of the present application. Figure 2 The server shown is only an example, and should not bring any limitation to the functions and use range of the embodiments of the present application.

[0055] As shown in Figure 2 , the computer system comprises a central processing unit (CPU) 301, which can perform various appropriate actions and processes according to the programs stored in a read-only memory (ROM) 302 or the programs loaded from a storage part 308 to a random access memory (RAM) 303. In the random access memory 303, various programs and data required for system operation are also stored. The central processing unit 301, the read-only memory 302 and the random access memory 303 are connected to each other through a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0056] The following components are connected to the input / output interface 305: an input section 306 including input devices such as a keyboard and a mouse; an output section 307 including output devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a speaker; a storage section 308 including a hard disk; and a communication section 309 including a network interface card such as a LAN (Local Area Network) card, a modem, and the like. The communication section 309 performs communication processing via a network such as the Internet. A drive 310 is also connected to the input / output interface 305 as necessary. A removable media 311 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, and the like is attached to the drive 310 as necessary, so that a computer program read therefrom is installed in the storage section 308 as necessary.

[0057] In particular, the processes described above with reference to the flowcharts can be implemented as a computer software program according to embodiments of the present application. For example, embodiments of the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing program code for executing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via the communication section 309, and / or installed from the removable media 311. When the computer program is executed by the central processing unit 301, the above-described functions defined in the methods of the present application are performed. It should be noted that the above-described computer readable medium of the present application can be a computer readable signal medium or a computer readable storage medium or any combination of the two. The computer readable storage medium may, for example, be - but is not limited to - an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, or any combination of the above.

[0058] More specific examples of the computer-readable storage medium can include but are not limited to the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the present disclosure, the computer-readable storage medium can be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. Also, in the present disclosure, the computer-readable storage medium can be any tangible medium that can be used to store or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code can be transmitted in a computer-readable signal medium using any suitable medium of modulation, including but not limited to wireless, wire line, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0059] Computer program code for carrying out operations of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0060] The computer program product of the present application can be a computer program implemented on one or more computers in one or more locations. The program instructions can be stored on a computer readable medium, such as a hard disk, CD-ROM, optical storage, or any other tangible medium. The program instructions can be downloaded over a network from a remote computer (e.g., a server computer) or to a remote computer (e.g., a client computer) with the assistance of one or more of the various above-mentioned network devices. The program instructions can be downloaded from the network or uploaded to the network.

[0061] The terms "first", "second", and the like, do not denote any ordinal, sequential, or temporal precedence or relationship, but are used solely to distinguish one element from another.

[0062] The term "comprising", or any of its derivatives, is intended to encompass the non-exclusive inclusion of one or more elements such that the process, method, article, or apparatus that comprises the elements is not necessarily limited to those elements.

[0063] The technical solutions of the present application have been described above in conjunction with the preferred embodiments shown in the drawings.

[0064] The above description is merely illustrative of the application, and is not intended to limit the application. The application can have various modifications and alterations without departing from the spirit and scope of the application. Any modifications, equivalent replacements, improvements, and the like within the spirit and principles of the application are intended to be included in the scope of the appended claims.

Claims

1. An aging control method for dimensional stability of a zinc alloy die casting, characterized by, The method comprises: acquiring a physical signal for characterizing residual stress inside the die casting; synchronously applying mechanical vibration energy and first-order thermal energy to the die casting while continuously detecting the change amount of the physical signal, and stopping the application of the mechanical vibration energy and first-order thermal energy when the change amount of the physical signal reaches a preset predetermined value; after stopping the application of the mechanical vibration energy and first-order thermal energy, applying second-order thermal energy to the die casting to drive the metastable phase transition inside the die casting, while continuously detecting the change rate of the physical signal, and determining that the phase transition inside the die casting reaches a stable state when the change rate is lower than a preset stable judgment threshold in a plurality of continuous time intervals, and stopping heating of the die casting; after stopping heating of the die casting, performing gradient cooling processing on the die casting, wherein the gradient cooling processing comprises applying different cooling rates to different geometric feature regions of the die casting to compensate for the shrinkage difference between the regions of the die casting.

2. The method of claim 1, wherein, The synchronous application of mechanical vibration energy and first-order thermal energy to the die casting comprises: applying mechanical vibration energy with a frequency set based on the initial frequency spectrum characteristics of the physical signal while applying the first-order thermal energy to the die casting; after applying the mechanical vibration energy, dynamically adjusting the frequency of the mechanical vibration energy by continuously detecting the frequency domain characteristics of the physical signal, so that the frequency of the mechanical vibration energy adapts to the change of the dominant frequency component in the physical signal, and adaptively adjusting the amplitude of the mechanical vibration energy by continuously detecting the amplitude decay rate of the physical signal at the dominant frequency component.

3. The method of claim 1, wherein, The application of second-order thermal energy to the die casting comprises: determining a target temperature interval corresponding to the second-order thermal energy; heating the die casting to a preset intermediate platform at a first heating rate and maintaining the temperature for a preset time period to trigger the initial transition of the metastable phase inside the die casting, wherein the temperature of the intermediate platform is lower than the target temperature interval; continuing to heat the die casting to the target temperature interval at a second heating rate, wherein the second heating rate is lower than the first heating rate; maintaining the temperature of the die casting in the target temperature interval.

4. The method of claim 1, wherein, The continuous detection of the change rate of the physical signal comprises: continuously detecting the physical signal to obtain physical parameter-time sequence data; performing numerical differentiation on the physical parameter-time sequence data and calculating the change rate in real time; continuously comparing the calculated change rate with the preset stable judgment threshold; when the change rate is maintained below the stable judgment threshold in a plurality of consecutive monitoring periods in quantity, it is determined that the phase transition inside the die casting reaches a stable state.

5. The method of claim 1, wherein, The continuous detection of the change amount of the physical signal comprises: continuously detecting the physical signal and pre-processing the detected physical signal to extract signal components directly related to stress release, wherein the pre-processing comprises noise reduction and filtering processing; extracting one or more characteristic values from the pre-processed physical signal, wherein the characteristic values are energy integral values or envelope area of the signal in a specific frequency band; The cumulative relative change of the characteristic value is calculated in real time, and the cumulative relative change is compared with the predetermined value in real time.

6. The method of claim 1, wherein, The method further comprises: detecting the dimensional stability of the die casting after the gradient cooling treatment; storing all time sequence data in the current treatment process in association with the result of the dimensional stability detection, and determining an implicit mapping relationship between the aging control parameters of the die casting and the dimensional stability by using a preset multivariate data analysis algorithm; optimizing the aging control parameters of the die casting according to the implicit mapping relationship, wherein the aging control parameters at least include the predetermined value and the stability determination threshold; updating the optimized aging control parameters to a preset process database.

7. The method of claim 1, wherein, The gradient cooling treatment of the die casting comprises: obtaining a three-dimensional geometric model of the die casting, wherein the three-dimensional geometric model is used to indicate the wall thickness difference of each part of the die casting; dividing the die casting into a plurality of independent cooling control regions according to the three-dimensional geometric model of the die casting, wherein the cooling control regions include thick wall regions and thin wall regions of the die casting; setting an independent cooling rate control curve for each cooling control region, wherein the cooling rate value of the cooling rate control curve corresponding to the thick wall region is lower than the cooling rate value of the cooling rate control curve corresponding to the thin wall region; controlling the cooling process of each part of the die casting according to the cooling rate control curve of each cooling control region, so as to compensate for the shrinkage difference of each part of the die casting.

8. The method of claim 7, wherein, The method further comprises: continuously detecting the actual temperature of each part while controlling the cooling process of each part of the die casting; comparing the detected actual temperature with the expected temperature of the region at the same time point calculated based on the cooling rate control curve; when the deviation between the actual temperature and the expected temperature of any region exceeds a preset tolerance range, dynamically adjusting the cooling rate control curve of the region in the subsequent stage by increasing or decreasing the cooling rate, so that the actual temperature change path of the region regresses to the cooling rate control curve.

9. An electronic device, comprising: The electronic device comprises a memory and a processor, the memory is connected to the processor, the processor is used to execute one or more computer programs stored in the memory, and the processor, when executing the one or more computer programs, causes the electronic device to implement the method of any one of claims 1-8.

10. A computer readable medium characterized by The computer readable storage medium stores a computer program, the computer program comprises program instructions, and the program instructions, when executed by a processor, cause the processor to execute the method of any one of claims 1-8.

Images