Nondestructive testing method and system for coarse grain layer on surface of aluminum alloy forge piece

Abstract

The invention provides a nondestructive testing method and system for a coarse grain layer on the surface of an aluminum alloy forge piece, and relates to the technical field of nondestructive testing. First surface temperature field time sequence data corresponding to a standard workpiece are collected, and according to the environment temperature, the workpiece heat conductivity, the workpiece specific heat capacity and detection environment parameters, the first surface temperature field time sequence data are obtained; generating a thermal response difference threshold calibration curve corresponding to the standard workpiece; performing eddy current induction heating on the to-be-detected workpiece at the same heating time as the standard workpiece and the preset workpiece interval, and collecting second surface temperature field time sequence data corresponding to the to-be-detected workpiece; comparing the temperature of each moment in the second surface temperature field time sequence data with the temperature of the moment corresponding to the thermal response difference threshold value calibration curve, and if the temperature difference value between the second surface temperature field time sequence data and the thermal response difference threshold value calibration curve exceeds a preset temperature threshold value, determining that the thermal response difference threshold value calibration curve does not exceed the preset temperature threshold value; and if so, determining that the coarse grain layer exists on the surface of the to-be-detected workpiece or the depth of the coarse grain layer on the surface of the to-be-detected workpiece exceeds the limit. According to the invention, the nondestructive detection precision of the metal workpiece can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to a nondestructive testing method and system for a coarse-grained layer on the surface of an aluminum alloy forging. Background Art

[0002] Aluminum alloys offer advantages such as low density, high specific strength, and high specific stiffness, making them ideal lightweight materials. Aluminum alloy forgings have become essential for mechanical parts across various industrial sectors and are widely used in aerospace, shipbuilding, and automotive manufacturing. However, excessive deformation rates during the manufacturing process or recrystallization during improper aging can lead to surface coarse grains, reducing the strength, corrosion resistance, fatigue resistance, and impact toughness of aluminum alloy forgings.

[0003] Chinese patent publication number CN105548258B discloses a method for rapid impact damage detection of composite materials based on infrared imaging. The method comprises: performing necessary cleaning on the surface of the material to be tested to remove stains and attachments; performing a low-emissivity detection on the surface of a metal surface; maintaining the infrared thermal imager, USB 3.0 data acquisition box, and computer analysis tools in normal working order, with the infrared thermal imager's optical axis substantially perpendicular to the plane of the material to be tested; using a hot air blower to heat the test area of ​​the material to be tested, and removing the hot air blower after a preset temporary heating time. The temporary heating time is determined by the thickness of the material to be tested and can be increased or decreased as appropriate; stopping the data acquisition time after the data acquisition time is reached, and saving the collected test data, thereby obtaining a series of time-ordered image sequences. However, the above-mentioned method uses a hot air blower to heat the sample, which has slow heat transfer and uneven temperature field, making it difficult to form a clear thermal response difference in a very short time, reducing sensitivity to damage or defects, and resulting in insufficient detection accuracy. Therefore, it is very necessary to provide a non-destructive detection method and system for the coarse-grained layer on the surface of aluminum alloy forgings to improve the accuracy of non-destructive detection of metal workpieces. Summary of the Invention

[0004] In light of this, this paper proposes a nondestructive testing method and system for the coarse-grained layer on the surface of aluminum alloy forgings. This method utilizes eddy current induction heating and infrared imaging to synchronously collect time-series data on the temperature field, eliminating the need for cutting or metallographic sample preparation. Parameters such as heating time and workpiece-coil spacing are maintained consistent between the reference workpiece and the workpiece being tested, ensuring reproducibility of the testing process and improving the accuracy of nondestructive testing of metal workpieces.

[0005] The present invention provides a non-destructive testing method for a coarse-grained layer on the surface of an aluminum alloy forging, the method comprising: Collecting time series data of a first surface temperature field corresponding to a standard workpiece, and generating a thermal response difference threshold calibration curve corresponding to the standard workpiece based on the ambient temperature, the thermal conductivity of the workpiece, the specific heat capacity of the workpiece, and the detection environment parameters, wherein the standard workpiece and the workpiece to be measured are made of the same material and have the same geometric shape; Performing eddy current induction heating on the workpiece to be measured with the same heating time and preset workpiece spacing as the standard workpiece, and collecting time series data of a second surface temperature field corresponding to the workpiece to be measured, wherein the preset workpiece spacing is the spacing between the eddy current coil and the standard workpiece; The temperature at each moment in the second surface temperature field time series data is compared with the temperature at the corresponding moment of the thermal response difference threshold calibration curve. If the temperature difference between the second surface temperature field time series data and the thermal response difference threshold calibration curve exceeds the preset temperature threshold, it is determined that there is a coarse-grained layer on the surface of the workpiece to be measured or the depth of the coarse-grained layer on the surface of the workpiece to be measured exceeds the limit.

[0006] On the basis of the above technical solution, preferably, the first surface temperature field time series data and the second surface temperature field time series data both select the area at the heating center position of the measured workpiece as the sampling area.

[0007] On the basis of the above technical solution, preferably, the number of the sampling areas is one or more. If the number of the sampling areas is multiple, the sampling temperature is the average temperature of the multiple sampling areas.

[0008] More preferably, the collecting of the second surface temperature field time series data corresponding to the workpiece to be measured specifically includes: The preset production rhythm of the conveyor belt speed sensor is read and input into the programmable controller to control the working frequency of the automatic adjustment induction heating device and the trigger timing of the infrared thermal imager, and the coil in the automatic adjustment induction heating device is made to move back and forth synchronously with the workpiece to be measured during the heating process to collect the second surface temperature field time series data corresponding to the workpiece to be measured.

[0009] More preferably, the induction heating time and data collection time corresponding to the workpiece to be measured can be dynamically adjusted according to a preset production rhythm.

[0010] More preferably, the method further comprises: If the preset production tact is less than or equal to the first production tact, the first preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured; If the preset production tact is greater than the first production tact and less than or equal to the second production tact, the second preset induction heating time is used as the induction heating time corresponding to the workpiece to be tested; If the preset production tact is greater than the second production tact, the third preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured.

[0011] More preferably, the first surface temperature field time series data is the temperature field time series data of the standard workpiece from the completion of heating to the cooling to room temperature.

[0012] In a second aspect of the present application, a nondestructive testing system for a coarse-grained layer on the surface of an aluminum alloy forging is provided. The nondestructive testing system includes a calibration curve generation module, a workpiece acquisition module, and an over-limit detection and evaluation module, wherein: The calibration curve generation module is used to collect time series data of the first surface temperature field corresponding to the standard workpiece, and generate a thermal response difference threshold calibration curve corresponding to the standard workpiece based on the ambient temperature, the thermal conductivity of the workpiece, the specific heat capacity of the workpiece, and the detection environment parameters, wherein the standard workpiece and the workpiece to be tested are made of the same material and have the same geometric shape; The workpiece acquisition module is used to perform eddy current induction heating on the workpiece to be measured with the same heating time and preset workpiece spacing as the standard workpiece, and to collect time series data of the second surface temperature field corresponding to the workpiece to be measured, wherein the preset workpiece spacing is the spacing between the eddy current coil and the standard workpiece; The over-limit detection and evaluation module is used to compare the temperature at each moment in the second surface temperature field time series data with the temperature at the corresponding moment of the thermal response difference threshold calibration curve. If the temperature difference between the second surface temperature field time series data and the thermal response difference threshold calibration curve exceeds the preset temperature threshold, it is determined that there is a coarse-grained layer on the surface of the workpiece to be measured or the depth of the coarse-grained layer on the surface of the workpiece to be measured exceeds the limit.

[0013] In a third aspect of the present application, an electronic device is provided, comprising a processor, a memory, a user interface and a network interface, wherein the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory.

[0014] In a fourth aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored. The computer program is executed by a processor to implement the steps of a non-destructive testing method for a coarse-grained layer on the surface of an aluminum alloy forging.

[0015] The present invention provides a nondestructive detection method and system for the coarse-grained layer on the surface of an aluminum alloy forging, which has the following beneficial effects compared with the prior art: (1) Eddy current induction heating and infrared imaging are used to synchronously collect temperature field time series data without cutting or metallographic sample preparation, which is suitable for rapid online detection on the production line. Standard workpieces of the same material and geometric shape are used, and factors such as ambient temperature, thermal conductivity, and specific heat capacity are combined to generate a difference threshold calibration curve, which effectively eliminates environmental disturbances and individual differences between workpieces and improves detection robustness. By comparing the temperature difference between the workpiece to be tested and the calibration curve at each moment, it can sensitively capture the thermal diffusion anomaly caused by the surface coarse grain layer, and can quantitatively evaluate whether the depth of the coarse grain layer exceeds the standard based on the degree of temperature overlimit. At the same time, parameters such as heating time and workpiece-coil spacing are kept consistent between the standard workpiece and the workpiece to be tested, ensuring the reproducibility of the detection process and improving the non-destructive detection accuracy of metal workpieces. The same set of calibration processes can be extended to different batches and the same model of aluminum alloy forgings, quickly giving qualified / unqualified judgment results, significantly shortening the detection cycle, and reducing the error caused by human experience judgment. There is no contact heating and imaging throughout the process, which reduces operational risks.

[0016] (2) The programmable controller automatically adjusts the operating frequency of the induction heating device according to the beat, ensuring that the ideal heating depth and uniformity can be obtained at different conveying speeds, and automatically controls the trigger timing of the infrared camera to avoid the acquisition time difference caused by speed fluctuations. The coil and the workpiece move back and forth synchronously, always maintaining a constant relative position, eliminating the thermal field disturbance or image blur caused by movement, thereby obtaining continuous and uniform time-series temperature field data. At the same time, through precise trigger timing and motion control, the temperature distribution at different positions on the workpiece surface can be captured at the best time, enhancing the sensitivity to thermal diffusion anomalies in the coarse-grained layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A schematic flow chart of a nondestructive testing method for a coarse-grained layer on the surface of an aluminum alloy forging provided by the present invention; Figure 2 This is an infrared thermal image of the sample after heating in Example 1; Figure 3 This is the infrared thermal imaging image of the sample after heating in Example 2; Figure 4 This is the thermal response difference calibration curve in Example 3; Figure 5 This is the thermal response difference calibration curve in Example 4; Figure 6 A schematic diagram of the structure of the real-time task scheduling system provided by the present invention; Figure 7 This is a schematic structural diagram of the electronic device provided by the present invention.

[0019] Explanation of the accompanying symbols: 1. Non-destructive testing system; 11. Calibration curve generation module; 12. Workpiece acquisition module to be tested; 13. Out-of-limit detection and evaluation module; 2. Electronic equipment; 21. Processor; 22. Communication bus; 23. User interface; 24. Network interface; 25. Memory. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] The present invention discloses a nondestructive detection method for the coarse-grained layer on the surface of an aluminum alloy forging, referring to Figure 1 , the steps of the method include S1~S3.

[0022] Step S1, collecting the first surface temperature field time series data corresponding to the standard workpiece, and generating a thermal response difference threshold calibration curve corresponding to the standard workpiece based on the ambient temperature, workpiece thermal conductivity, workpiece specific heat capacity and detection environment parameters, wherein the standard workpiece and the workpiece to be tested are made of the same material and have the same geometric shape.

[0023] In this step, the standard workpiece is placed on the inspection platform, thermally stimulated by an induction heating device, and an infrared thermal imaging device is used to collect real-time time-series data on the surface temperature field of the standard workpiece for calibration. The induction heating device is an eddy current induction heating device, which consists of components such as a high-frequency AC power supply, an induction coil, a magnetic conductor, and a moving device; the infrared thermal imaging device consists of components such as an infrared thermal imager, data acquisition software, a working machine, and a moving device. The induction heating device is built above the workpiece and can achieve the functions of up and down movement and periodic synchronous movement with the quasi-workpiece on the conveyor belt; the infrared thermal imaging device is built above the workpiece, perpendicular to the workpiece surface, and has the function of up and down movement. The infrared thermal imager collects workpiece surface temperature field data, which is data at a certain time within 0 to 10 seconds after the induction heating is completed. The first surface temperature field time-series data is the temperature field time-series data of the standard workpiece from the completion of heating to cooling to room temperature.

[0024] Furthermore, the standard workpiece is of the same type as the subsequent workpiece to be tested, the testing environment remains consistent, and includes a workpiece without a surface coarse-grained layer and at least one workpiece with a surface coarse-grained layer. The position of the workpiece inspection should focus on the area where coarse grains are prone to appear; the collected workpiece surface temperature field distribution data should at least include the area of ​​the heating center position, and the first surface temperature field time series data is the temperature field time series data of the standard workpiece from the completion of heating to cooling to room temperature.

[0025] The distance between the workpiece and the induction coil has a significant impact on the electromagnetic field distribution, eddy current distribution, heating structure, and coil efficiency of the induction heating device. Therefore, the distance between the coil and the workpiece surface to be tested during eddy current induction heating should be consistent with the subsequent detection process. The induction heating time is no less than 1s and can be adjusted according to the production cycle. After data acquisition, the temperature field time series data of the standard workpiece is used, combined with the workpiece material properties (such as thermal conductivity, specific heat capacity) and the detection environment parameters (such as temperature fluctuations and humidity) to create a thermal response difference calibration curve; the horizontal axis of the curve is the difference between the workpiece surface temperature and the ambient temperature after heating is completed (°C), and the vertical axis is the calibration value of the thermal response difference.

[0026] In step S2, eddy current induction heating is performed on the workpiece to be tested with the same heating time and preset workpiece spacing as the standard workpiece, and time series data of the second surface temperature field corresponding to the workpiece to be tested is collected, wherein the preset workpiece spacing is the spacing between the eddy current coil and the standard workpiece.

[0027] In this step, the preset production beat of the conveyor belt speed sensor is read and input into the programmable controller to control the operating frequency of the automatic adjustment induction heating device and the trigger timing of the infrared thermal imager. The coil in the automatic adjustment induction heating device is synchronized with the workpiece to reciprocate during the heating process to collect the time series data of the second surface temperature field corresponding to the workpiece to be measured. The programmable controller automatically adjusts the operating frequency of the induction heating device according to the beat to ensure that the ideal heating depth and uniformity can be achieved at different conveying speeds. The programmable controller also automatically controls the trigger timing of the infrared camera to avoid acquisition time differences caused by speed fluctuations. The coil and the workpiece reciprocate synchronously, always maintaining a constant relative position, eliminating thermal field disturbances or image blur caused by movement, thereby obtaining continuous and uniform time series temperature field data. At the same time, through precise trigger timing and motion control, the temperature distribution can be captured at the optimal time at different locations on the workpiece surface, enhancing sensitivity to thermal diffusion anomalies in the coarse-grained layer.

[0028] It is understandable that an eddy current heating device is used to perform induction heating on the workpiece to be measured on the production line, and an infrared thermal imager is used to collect the surface temperature field data of the workpiece; for induction heating and the collection of workpiece surface temperature field data, it is necessary to ensure that the distances from the coil and the infrared thermal imager to the workpiece surface are consistent with those in the calibration process. This can be achieved through manual adjustment or by integrating a ranging sensor on the induction coil to monitor the distance between the coil and the workpiece surface in real time. When the distance exceeds the preset threshold, a servo motor is used to drive the coil to move up and down to calibrate the distance. For induction heating and the collection of workpiece surface temperature field data, it is necessary to read the real-time beat parameters from the conveyor belt speed sensor, and automatically adjust the operating frequency of the induction heating device and the triggering timing of the infrared thermal imager through setting or a PLC control module; at the same time, determine the reciprocating movement speed of the coil to keep it moving synchronously with the workpiece during the heating process. The induction heating time for the workpiece to be measured is the same as the induction heating time during calibration with a standard workpiece; the infrared thermal imager is used to collect the surface temperature field data of the workpiece, which is the data at a certain moment within 0 - 10 s after the induction heating is completed.

[0029] Furthermore, both the first surface temperature field time series data and the second surface temperature field time series data select the area at the heating center position of the measured workpiece as the sampling area. The number of sampling areas is one or more. If the number of sampling areas is multiple, the sampling temperature is the average temperature of the multiple sampling areas. The induction heating time corresponding to the workpiece to be measured and the data collection time can be dynamically adjusted according to the preset production beat.

[0030] If the preset production beat is less than or equal to the first production beat, the first preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured; if the preset production beat is greater than the first production beat and less than or equal to the second production beat, the second preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured; if the preset production beat is greater than the second production beat, the third preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured.

[0031] In one example, the induction heating time t1 and the time t2 for collecting temperature data after the induction heating is completed can be adjusted according to the production beat P (seconds per piece).

[0032] When P ≤ 10 s, t1 = 1.0 s (rapid heating); When 10 s < P ≤ 30 s, t1 = 2.0 s (conventional heating); When P > 30 s, t1 = 5.0 s (deep heating); According to t1, dynamically allocate t2: t2 = (0.1 × t1) ~ (0.5 × t1), ensuring that the data collection is completed before the workpiece leaves the detection area.

[0033] Step S3, comparing the temperature at each moment in the second surface temperature field time series data with the temperature at the corresponding moment of the thermal response difference threshold calibration curve. If the temperature difference between the second surface temperature field time series data and the thermal response difference threshold calibration curve exceeds the preset temperature threshold, it is determined that there is a coarse grain layer on the surface of the workpiece to be measured or the depth of the coarse grain layer on the surface of the workpiece to be measured exceeds the limit.

[0034] In this step, the thermal response difference calibration curve is used to determine whether the workpiece under test has a surface coarse-grained layer or whether the depth of the surface coarse-grained layer meets the requirements. The determination of whether the workpiece under test has a surface coarse-grained layer is based on the thermal response of the workpiece under test. Specifically, the temperature data is obtained by calculating the difference between the temperature of the workpiece under test and the ambient temperature, as collected by the infrared thermal imager. The temperature data of the workpiece under test at a fixed moment after the induction heating is completed is compared with the temperature data of a standard workpiece at the same moment. The position of the workpiece under test in the thermal response difference calibration curve is determined based on the percentage difference in the temperature data and the temperature of the standard workpiece without coarse grains at that moment, thereby determining whether the workpiece under test has a surface coarse-grained layer or whether the depth of the surface coarse-grained layer meets the requirements.

[0035] See also Figure 2 , Figure 2 This is an infrared thermal imaging image of the sample after heating, corresponding to the non-destructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging proposed in Example 1.

[0036] In Example 1, an eddy current induction heating device and an infrared thermal imaging device were installed on the testing platform. The induction heating system, an eddy current induction heating device, includes a high-frequency AC power supply, an induction coil, a magnetic conductor, and a connection device. The infrared thermal imaging system includes an infrared thermal imager, data acquisition software, and a working machine. The coil is energized by a high-frequency AC power supply, while water circulation is used to cool the device. The infrared thermal imager is equipped with a tripod.

[0037] A standard workpiece without a coarse-grained surface layer is placed on the testing platform and heated using an eddy current induction heating device. Simultaneously, an infrared thermal imaging device is used to collect real-time time series data on the complete surface temperature field of the standard workpiece from the completion of heating to cooling to near room temperature. This standard workpiece is of the same type, size, and height as the subsequent workpieces to be tested. The distance between the coil and the workpiece surface to be tested during eddy current induction heating should remain the same throughout the subsequent testing process, and the induction heating time, t1, should be 4 seconds.

[0038] The workpiece to be tested is induction heated using an eddy current induction heating device, and the workpiece surface temperature field data is collected using an infrared thermal imager. The induction heating time of the workpiece to be tested is consistent with the induction heating time t1 when calibrating with a standard workpiece, which is 4s. The infrared thermal imager is used to collect data at time t2 (0~5s) after the induction heating is completed. Here, the temperature 0.5s after the heating is completed is selected as 50.63℃.

[0039] See also Figure 3 , Figure 3 This is an infrared thermal image of the sample after heating, corresponding to the non-destructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging proposed in Example 2. The testing platform construction and testing process of Example 2 are the same as those of Example 1, with the following differences: A standard sample without a coarse-grained surface layer and a sample to be tested were placed symmetrically on the testing platform, positioned around the induction coil and magnetic conductor. Eddy current induction heating was used, while an infrared thermal imaging system collected real-time surface temperature field data. The standard workpiece and the subsequent workpiece to be tested were at the same height, and the induction heating time was 1.5 seconds. To mitigate the effects of uneven magnetic field position or distribution, the two samples were swapped and tested twice.

[0040] The temperature data results for 0.5s after heating are selected are as follows Figure 5 As shown in the figure; before exchanging positions, the surface temperatures of the standard sample without coarse crystal layer on the surface and the sample to be tested are 27.86℃ and 26.71℃ respectively; after exchanging positions, the surface temperatures of the standard sample without coarse crystal layer on the surface and the sample to be tested are 28.64℃ and 27.88℃ respectively; it can be seen that under the same heating conditions, the temperature (or heating rate) of the sample without coarse crystal layer on the surface is higher than that of the sample with coarse crystal layer on the surface.

[0041] See also Figure 4 , Figure 4 This is a thermal response difference calibration curve corresponding to the non-destructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging proposed in Example 3. The testing platform construction and testing process of Example 3 are the same as those of Example 1, with the following differences: The standard workpieces with and without a coarse-grained layer on the surface are placed on the inspection platform respectively, and are induction heated for 10 seconds by an eddy current heating device. At the same time, an infrared thermal imaging system is used to collect the time series data of the surface temperature field of the standard workpiece in real time. The detection position is the center area of ​​the web of the die forging, and the collected workpiece surface temperature field distribution data includes a circular area with a radius of 10mm at the heating center position; the collected time series data of the surface temperature field of the standard workpiece is the complete temperature field time series data from the completion of heating to cooling to room temperature. During eddy current induction heating, the distance between the coil and the surface of the workpiece to be tested should be consistent with the subsequent inspection process. After data collection, a thermal response difference calibration curve is produced. The horizontal axis of the curve is the difference between the surface temperature of the workpiece and the ambient temperature after heating is completed (°C), and the vertical axis is the calibration value of the thermal response difference. The produced thermal response difference calibration curve is as follows: Figure 4 shown.

[0042] When P ≤ 10 s, t1 = 1.0 s (rapid heating); when 10 s < P ≤ 30 s, t1 = 2.0 s (conventional heating); when P > 30 s, t1 = 5.0 s (deep heating). Dynamically allocate t2 according to t1: t2 = (0.1 × t1) ~ (0.5 × t1) to ensure that data acquisition is completed before the workpiece leaves the detection area. For a production line with a production beat of 60 seconds per piece, a room temperature of 23 °C, a conveyor belt speed of 0.16 m / s, manually adjust the speed of the eddy current coil moving with the conveyor belt to 0.16 m / s, adjust the operating frequency of the induction heating system and the infrared thermal imager to 60 s / time. According to the time when the workpiece reaches below the induction heating system and the infrared thermal imager, set the start times of the heating system in each cycle to be the 12th s and the 17.5th s respectively. Use the eddy current induction heating device to perform induction heating on the workpiece to be tested for 5 s, and at the same time use the infrared thermal imager to collect the surface temperature field data of the workpiece; use the infrared thermal imager to collect the data at the time of 0.5 s after the induction heating is completed. The temperatures at the detection centers of the two workpieces collected are 56.73 °C and 57.63 °C.

[0043] Judge whether the surface coarse grain layer exists on the workpiece to be tested or whether the depth of the surface coarse grain layer meets the requirements through the thermal response difference calibration curve. Take the difference between the temperature collected by the infrared thermal imager and the ambient temperature to obtain the temperature rise values of the two workpieces A and B at 0.5 s after the induction heating is completed, which are 33.73 °C and 34.63 °C respectively. According to the temperature rise value of 35.85 °C corresponding to the non-coarse grain sample in the standard workpiece at 0.5 s after the heating is completed, obtain the thermal response difference calibration value of 5.5% from the thermal response difference calibration curve. Calculate the percentage differences between the temperature rise values of the two workpieces to be tested and the temperature rise of the non-coarse grain standard workpiece, which are 5.91% and 3.40% respectively. It can be considered that the depth of the surface coarse grain layer of workpiece A does not meet the requirements, and workpiece B has no surface coarse grain layer or the depth of the surface coarse grain layer meets the requirements.

[0044] Please refer to Figure 5 , Figure 5 the thermal response difference calibration curve corresponding to a non-destructive testing method for the surface coarse grain layer of an aluminum alloy forging proposed in Example 4. The detection platform construction and detection process in Example 4 are the same as those in Example 1, and the differences are as follows: Place standard workpieces with surface non-coarse crystal layers and surface coarse crystal layer depths of 1 mm, 2 mm, and 3 mm respectively on the detection platform, and perform induction heating for 10 s through an eddy current heating device. At the same time, use an infrared thermal imaging system to collect the time-series data of the surface temperature field of the standard workpiece in real time. The detection position is the center area of the web of the die forging. The collected data of the surface temperature field distribution of the workpiece includes a circular area with a radius of 10 mm centered on the heating center. The collected time-series data of the surface temperature field of the standard workpiece is the complete time-series data of the temperature field from the start of heating completion to cooling to room temperature. The distance between the coil and the surface of the workpiece to be measured during eddy current induction heating should be consistent with the subsequent detection process. After data collection, make a calibration curve of the thermal response difference. The horizontal axis of the curve is the difference (°C) between the surface temperature of the workpiece after heating completion and the ambient temperature, and the vertical axis is the calibrated value of the thermal response difference. The calibrated curve of the thermal response difference is as Figure 5 shown.

[0045] When P ≤ 10 s, t1 = 1.0 s (rapid heating); when 10 s < P ≤ 30 s, t1 = 2.0 s (conventional heating); when P > 30 s, t1 = 5.0 s (deep heating). Dynamically allocate t2 according to t1: t2 = (0.1 × t1) ~ (0.5 × t1) to ensure that data collection is completed before the workpiece leaves the detection area. For a production line with a production beat of 72 seconds per piece, a room temperature of 22 °C, a conveyor belt speed of 0.15 m / s, manually adjust the speed of the eddy current coil moving with the conveyor belt to 0.15 m / s, and adjust the operating frequencies of the induction heating system and the infrared thermal imager to 72 s / 次. According to the time when the workpiece arrives below the induction heating system and the infrared thermal imager, set the start times of the heating system in each cycle to the 13th s and the 19th s respectively. Use an eddy current induction heating device to perform induction heating on the workpiece to be measured for 5.5 s, and at the same time use an infrared thermal imager to collect the surface temperature field data of the workpiece; use the infrared thermal imager to collect the data at 0.5 s after the induction heating is completed. The temperatures at the detection centers of the two workpieces collected are 59.24 °C and 61.17 °C.

[0046] The thermal response difference calibration curve is used to determine whether the workpiece under test has a surface coarse-grained layer or whether the depth of the surface coarse-grained layer meets the requirements. The temperature collected by the infrared thermal imager is subtracted from the ambient temperature, and the temperature rise values ​​of workpieces A and B at 0.5s after the induction heating are obtained are 37.24℃ and 39.71℃, respectively. Based on the temperature rise value of 37.15℃ corresponding to the standard workpiece without coarse grains 0.5s after the heating is completed, the percentage difference between the temperature rise values ​​of the two workpieces under test and the temperature rise of the standard workpiece without coarse grains is calculated to be 0.24% and 6.89%, respectively. The position of workpiece A in the thermal response difference calibration curve is below the no-coarse-grained curve, and the position of workpiece B in the thermal response difference calibration curve is between 1mm and 2mm. Therefore, it is determined that the depth of the surface coarse-grained layer of workpiece A is close to 0mm, and the depth of the surface coarse-grained layer of workpiece B is 1-2mm.

[0047] In this embodiment, eddy current induction heating and infrared imaging are used to simultaneously collect temperature field time-series data, eliminating the need for cutting or metallographic sample preparation. This makes it suitable for rapid on-line testing on production lines. Using a standard workpiece of the same material and geometry, a difference threshold calibration curve is generated based on factors such as ambient temperature, thermal conductivity, and specific heat capacity. This effectively eliminates environmental disturbances and individual differences between workpieces, improving detection robustness. By comparing the temperature difference between the workpiece under test and the calibration curve at each moment, thermal diffusion anomalies caused by a surface coarse-grained layer can be sensitively detected, and the depth of the coarse-grained layer can be quantitatively assessed based on the degree of temperature overshoot. Parameters such as heating time and workpiece-to-coil spacing are maintained consistent between the standard and test workpieces, ensuring reproducible testing. The same calibration process can be applied to aluminum alloy forgings of the same model from different batches. Rapid pass / fail determination results are provided, significantly shortening the testing cycle and reducing errors caused by human judgment. The entire process involves contactless heating and imaging, minimizing operational risks.

[0048] Based on the above method, the embodiment of the present application discloses a non-destructive detection system for the coarse-grained layer on the surface of an aluminum alloy forging, referring to Figure 6 The nondestructive testing system 1 includes a calibration curve generation module 11, a workpiece acquisition module 12 and an over-limit detection and evaluation module 13, wherein: The calibration curve generation module 11 is used to collect time series data of the first surface temperature field corresponding to the standard workpiece, and generate a thermal response difference threshold calibration curve corresponding to the standard workpiece based on the ambient temperature, the thermal conductivity of the workpiece, the specific heat capacity of the workpiece, and the detection environment parameters, wherein the standard workpiece and the workpiece to be tested are made of the same material and have the same geometric shape; The workpiece acquisition module 12 is used to perform eddy current induction heating on the workpiece to be tested with the same heating time and preset workpiece spacing as the standard workpiece, and to collect time series data of the second surface temperature field corresponding to the workpiece to be tested, wherein the preset workpiece spacing is the spacing between the eddy current coil and the standard workpiece; The over-limit detection and evaluation module 13 is used to compare the temperature at each moment in the second surface temperature field time series data with the temperature at the corresponding moment of the thermal response difference threshold calibration curve. If the temperature difference between the second surface temperature field time series data and the thermal response difference threshold calibration curve exceeds the preset temperature threshold, it is determined that there is a coarse grain layer on the surface of the workpiece to be measured or the depth of the coarse grain layer on the surface of the workpiece to be measured exceeds the limit.

[0049] In one example, the first surface temperature field time series data and the second surface temperature field time series data both select the area at the heating center position of the measured workpiece as the sampling area.

[0050] In one example, the number of the sampling areas is one or more. If the number of the sampling areas is multiple, the sampled temperature is the average temperature of the multiple sampling areas.

[0051] In one example, the workpiece acquisition module 12 is used to read the preset production rhythm of the conveyor belt speed sensor, and input the preset production rhythm into the programmable controller to control the automatic adjustment of the working frequency of the induction heating device and the trigger timing of the infrared thermal imager, and make the coil in the automatic adjustment induction heating device move back and forth synchronously with the workpiece to be measured during the heating process to collect the second surface temperature field timing data corresponding to the workpiece to be measured.

[0052] In one example, the induction heating time and data collection time corresponding to the workpiece to be measured can be dynamically adjusted according to a preset production rhythm.

[0053] In one example, the method further includes: If the preset production cycle is less than or equal to the first production cycle, the first preset induction heating time is used as the induction heating time corresponding to the workpiece to be tested; If the preset production cycle is greater than the first production cycle and less than or equal to the second production cycle, the second preset induction heating time is used as the induction heating time corresponding to the workpiece to be tested; If the preset production cycle is greater than the second production cycle, the third preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured.

[0054] In one example, the first surface temperature field time series data is the temperature field time series data of the standard workpiece from the completion of heating to the cooling to room temperature.

[0055] See Figure 7 , is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 7 As shown, the electronic device 2 may include: at least one processor 21 , at least one network interface 24 , a user interface 23 , a memory 25 , and at least one communication bus 22 .

[0056] The communication bus 22 is used to realize the connection and communication between these components.

[0057] The user interface 23 may include a display screen (Display) and a camera (Camera). Optionally, the user interface 23 may also include a standard wired interface and a wireless interface.

[0058] The network interface 24 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0059] The processor 21 may include one or more processing cores. Using various interfaces and circuits, the processor 21 connects to various components within the server. It executes instructions, programs, code sets, or instruction sets stored in the memory 25, as well as accesses data stored in the memory 25, to perform various server functions and process data. Optionally, the processor 21 may be implemented using at least one of the following hardware forms: a digital signal processing (DSP), a field-programmable gate array (FPGA), or a programmable logic array (PLA). The processor 21 may integrate one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), and a modem. The CPU primarily processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing content displayed on the display; and the modem handles wireless communications. It is understood that the modem may not be integrated into the processor 21 but implemented as a separate chip.

[0060] Among them, the memory 25 may include a random access memory (Random Access Memory, RAM) and may also include a read-only memory (Read-Only Memory). Optionally, the memory 25 includes a non-transitory computer-readable storage medium. The memory 25 can be used to store instructions, programs, codes, code sets or instruction sets. The memory 25 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory 25 may also be optionally at least one storage device located away from the aforementioned processor 21. As Figure 7 As shown, the memory 25 as a computer storage medium may include an operating system, a network communication module, a user interface module and an application program for a non-destructive detection method for a coarse-grained layer on the surface of an aluminum alloy forging.

[0061] exist Figure 7 In the electronic device 2 shown, the user interface 23 is mainly used to provide an input interface for the user and obtain data input by the user; and the processor 21 can be used to call an application program stored in the memory 25 for a non-destructive testing method for a coarse-grained layer on the surface of an aluminum alloy forging. When executed by one or more processors, the electronic device executes one or more methods as in the above-mentioned embodiments.

[0062] A computer-readable storage medium stores instructions, which, when executed by one or more processors, cause the computer to execute one or more methods in the above-mentioned embodiments.

[0063] It should be noted that for the aforementioned method embodiments, for simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required for this application.

[0064] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0065] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely schematic, such as the division of units, which is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interface, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0066] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0067] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0068] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of this application, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the method of this application. The aforementioned memory includes various media that can store program code, such as USB flash drives, mobile hard drives, magnetic disks, or optical disks.

[0069] The above are merely exemplary embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. That is, any equivalent changes and modifications made in accordance with the teachings of the present disclosure are still within the scope of the present disclosure. After considering the disclosure of the specification and the truth of practice, those skilled in the art will easily think of other embodiments of the present disclosure. This application is intended to cover any variations, uses, or adaptive changes of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not described in the present disclosure.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nondestructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging, characterized in that: The method comprises: Collecting time series data of a first surface temperature field corresponding to a standard workpiece, and generating a thermal response difference threshold calibration curve corresponding to the standard workpiece based on the ambient temperature, the thermal conductivity of the workpiece, the specific heat capacity of the workpiece, and the detection environment parameters, wherein the standard workpiece and the workpiece to be measured are made of the same material and have the same geometric shape; Performing eddy current induction heating on the workpiece to be measured with the same heating time and preset workpiece spacing as the standard workpiece, and collecting time series data of a second surface temperature field corresponding to the workpiece to be measured, wherein the preset workpiece spacing is the spacing between the eddy current coil and the standard workpiece; The temperature at each moment in the second surface temperature field time series data is compared with the temperature at the corresponding moment of the thermal response difference threshold calibration curve. If the temperature difference between the second surface temperature field time series data and the thermal response difference threshold calibration curve exceeds the preset temperature threshold, it is determined that there is a coarse-grained layer on the surface of the workpiece to be measured or the depth of the coarse-grained layer on the surface of the workpiece to be measured exceeds the limit.

2. The nondestructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging according to claim 1, characterized in that: The first surface temperature field time series data and the second surface temperature field time series data both select the area at the heating center position of the measured workpiece as the sampling area.

3. The nondestructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging according to claim 2, characterized in that: The number of the sampling areas is one or more. If the number of the sampling areas is multiple, the sampling temperature is the average temperature of the multiple sampling areas.

4. The nondestructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging according to claim 1, wherein: The collecting of the second surface temperature field time series data corresponding to the workpiece to be measured specifically includes: The preset production rhythm of the conveyor belt speed sensor is read and input into the programmable controller to control the working frequency of the automatic adjustment induction heating device and the trigger timing of the infrared thermal imager, and the coil in the automatic adjustment induction heating device is made to move back and forth synchronously with the workpiece to be measured during the heating process to collect the second surface temperature field time series data corresponding to the workpiece to be measured.

5. The nondestructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging according to claim 4, characterized in that: The induction heating time and data collection time corresponding to the workpiece to be measured can be dynamically adjusted according to the preset production rhythm.

6. The nondestructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging according to claim 5, characterized in that: The method further comprises: If the preset production tact is less than or equal to the first production tact, the first preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured; If the preset production tact is greater than the first production tact and less than or equal to the second production tact, the second preset induction heating time is used as the induction heating time corresponding to the workpiece to be tested; If the preset production tact is greater than the second production tact, the third preset induction heating time is used as the induction heating time corresponding to the workpiece to be measured.

7. The nondestructive testing method for the coarse-grained layer on the surface of an aluminum alloy forging according to claim 1, characterized in that: The first surface temperature field time series data is the temperature field time series data of the standard workpiece from the completion of heating to the cooling to room temperature.

8. A nondestructive testing system for the coarse-grained layer on the surface of an aluminum alloy forging, characterized in that: The nondestructive testing system (1) comprises a calibration curve generating module (11), a workpiece acquisition module (12) and an over-limit detection and evaluation module (13), wherein: The calibration curve generation module (11) is used to collect time series data of a first surface temperature field corresponding to a standard workpiece, and generate a thermal response difference threshold calibration curve corresponding to the standard workpiece according to the ambient temperature, the thermal conductivity of the workpiece, the specific heat capacity of the workpiece, and the detection environment parameters, wherein the standard workpiece and the workpiece to be tested are made of the same material and have the same geometric shape; The workpiece acquisition module (12) is used to perform eddy current induction heating on the workpiece to be measured with the same heating time and preset workpiece spacing as the standard workpiece, and to collect time series data of the second surface temperature field corresponding to the workpiece to be measured, wherein the preset workpiece spacing is the spacing between the eddy current coil and the standard workpiece; The over-limit detection and evaluation module (13) is used to compare the temperature at each moment in the second surface temperature field time series data with the temperature at the corresponding moment of the thermal response difference threshold calibration curve; if the temperature difference between the second surface temperature field time series data and the thermal response difference threshold calibration curve exceeds a preset temperature threshold, it is determined that a coarse grain layer exists on the surface of the workpiece to be measured or the depth of the coarse grain layer on the surface of the workpiece to be measured exceeds the limit.

9. An electronic device, characterized in that: The electronic device (2) comprises a processor (21), a memory (25), a user interface (23) and a network interface (24), wherein the memory (25) is used to store instructions, the user interface (23) and the network interface (24) are used to communicate with other devices, and the processor (21) is used to execute the instructions stored in the memory (25) so that the electronic device (2) executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images