Method and device for simultaneously carrying out nondestructive testing by utilizing high-frequency heating treatment process

Abstract

The invention relates to the technical field of nondestructive testing, and discloses a method for synchronously carrying out high-frequency heating and nondestructive testing, which breaks through the traditional mode of carrying out heating and testing step by step, directly collects and transmits magnetic field signals when a high-frequency heater works, and utilizes self-excited induced eddy current in the high-frequency heating process as a detection excitation source to detect the high-frequency heating process. The method does not need extra independent excitation equipment, ensures that weak crack signals are extracted in a strong noise environment by tracking the working current frequency in real time, carrying out dynamic phase locking processing and generating detection reference signals strictly synchronous with the working current, and meanwhile, ensures that a crack-free workpiece can be accurately detected by presetting and constructing an impedance-temperature mapping relation of the crack-free workpiece. And interference of temperature on a detection result is eliminated. According to the invention, a high-frequency heater (interference source) is converted into a detection signal source, so as to realize heating and detection, and effectively solve the industrial problem of crack in-situ real-time detection in the high-frequency heat treatment process of the metal workpiece.

Description

Technical Field

[0001] The present invention relates to the technical field of non-destructive testing, and in particular to a method for performing non-destructive testing simultaneously by utilizing a high-frequency heating process. Background Art

[0002] High-frequency heating technology exists in many areas of modern industrial production. Among them, the use of high-frequency heating to treat the surface of metal parts with pressure, hardness, etc. is a conventional production process. Since high-frequency and high-power heating of metal materials may cause cracks on the surface and near the surface, it is necessary to monitor them in real time. Although existing infrared thermal imaging technology can monitor temperature in real time, it has many fundamental limitations in directly, reliably and highly sensitively detecting microcracks generated during heat treatment (strong background interference, insufficient resolution / sensitivity, interference from cooling media, and difficulty in data analysis), making it difficult to solve effective detection. Therefore, there is an urgent need to propose new solutions. Summary of the Invention

[0003] To solve the above problems, the present invention provides, and the present invention is achieved as follows:

[0004] A method for performing nondestructive testing simultaneously using a high-frequency heating process comprises the following steps:

[0005] S1. Use a high-frequency induction heater to heat the surface of the metal workpiece, so that an induced eddy current is generated on the surface of the metal workpiece and the temperature is raised to the target temperature;

[0006] S2. While the high-frequency induction heater is heating the metal workpiece, a reflected magnetic field signal from the surface of the metal workpiece is obtained in real time by at least one set of electromagnetic induction receivers;

[0007] S3, by real-time monitoring the working current frequency of the high-frequency induction heater and performing frequency division or frequency multiplication processing on the working current frequency, dynamically generating a detection reference signal that is strictly phase-locked with the working current of the high-frequency induction heater;

[0008] S4, inputting the reflected magnetic field signal obtained in step S2 and the detection reference signal generated in step S3 into a synchronous detector, extracting the in-phase component (I) and the quadrature component (Q) and constructing an impedance plane diagram;

[0009] S5. By monitoring the sudden deviation of the data points in the impedance plane diagram relative to the preset temperature drift trajectory, the generation of cracks on the surface of the metal workpiece is determined in real time.

[0010] Furthermore, the electromagnetic induction receiver is a magnetically shielded induction coil; when there are multiple groups of electromagnetic induction receivers, they cover the area to be detected of the metal workpiece in an array form.

[0011] Furthermore, the preset temperature drift trajectory in step S5 is established by any of the following methods:

[0012] a) The impedance-temperature mapping relationship of the metal workpiece without cracks under the same heat treatment process is stored;

[0013] b) The detection signal of the crack-free area of ​​the metal workpiece is used as a reference in real time.

[0014] Furthermore, the determination basis of the mutation deviation in step S5 is:

[0015] When the distance that the data point in the impedance plane graph deviates from the preset temperature drift trajectory exceeds a threshold and lasts longer than a preset period, it is determined to be a crack signal.

[0016] Furthermore, it also includes:

[0017] When a crack signal is detected in step S5, at least one of the following control actions is triggered in real time:

[0018] a) Stop the high-frequency heating process;

[0019] b) Adjust quenching cooling parameters;

[0020] c) Output defect alarm and location information.

[0021] The present invention also discloses a device for performing nondestructive testing simultaneously during a high-frequency heating process, which is used for real-time detection of cracks on the surface of a metal workpiece during a heating process, comprising:

[0022] A high-frequency induction heating unit, comprising a high-frequency power supply and an induction coil connected thereto, is used to excite eddy currents on the surface of the metal workpiece and heat it to a target temperature;

[0023] An electromagnetic induction receiving unit, composed of at least one set of electromagnetic induction receivers, for capturing the reflected magnetic field signal from the surface of the metal workpiece in real time;

[0024] A phase-locked reference signal generating unit is electrically connected to the output terminal of the high-frequency power supply, and includes a frequency tracking module and a programmable frequency division / multiplication circuit, and is used to generate a detection reference signal that is strictly synchronized with the heating current;

[0025] a synchronous detection unit, a first input end of which is connected to the electromagnetic induction receiving unit, a second input end of which is connected to the phase-locked reference signal generating unit, and extracts the in-phase component (I) and the quadrature component (Q) of the reflected signal through a multiplier and a low-pass filter;

[0026] The impedance analysis unit receives the in-phase component and the quadrature component, constructs an impedance plane diagram, and performs the following operations: a) calling a pre-stored temperature-impedance drift feature library; b) identifying a sudden deviation of a data point relative to a preset trajectory through a dynamic trajectory comparison algorithm;

[0027] The crack determination unit generates a crack alarm signal and position mark data when the sudden change deviation exceeds a preset threshold.

[0028] Furthermore, the sensors of the electromagnetic induction receiving unit are distributed in an equidistant ring shape, and the directions of their sensitive axes are orthogonal to the direction of the magnetic field of the induction coil.

[0029] Furthermore, the phase-locked reference signal generating unit realizes phase locking of the detection reference signal to the heating current frequency through a hardware phase-locked loop.

[0030] Furthermore, the impedance analysis unit has a built-in temperature compensation module for eliminating baseline impedance drift caused by workpiece temperature increase.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention breaks through the traditional model of separate heating and detection. When the high-frequency heater is working, it directly collects the emission magnetic field signal and uses the induced eddy currents excited by the high-frequency heating process itself as the detection excitation source, without the need for additional independent excitation equipment. In addition, by real-time tracking of the working current frequency, dynamic phase-locked processing is performed to generate a detection reference signal that is strictly synchronized with the working current, ensuring the extraction of weak crack signals in a strong noise environment. At the same time, by pre-setting the "impedance-temperature" mapping relationship of the crack-free workpiece, the interference of temperature on the detection results is eliminated. The present invention converts the high-frequency heater (interference source) into a detection signal source, realizing "heating is detection", effectively solving the industry problem of in-situ real-time detection of cracks during high-frequency heat treatment of metal workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the examples of the present invention or the technical solutions in the prior art or the drawings required for the description of the prior art, a brief introduction is given. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 Schematic diagram of the detection principle.

[0035] Figure 2 Schematic diagram of the detection process of the present invention. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0037] Traditional post-heating inspection methods, such as infrared testing or post-cooling eddy current testing, have inherent flaws. For example, cracks may close due to thermal stress during the cooling process, leading to missed detection; and the additional oxide layer introduced by secondary heating may mask tiny cracks. Furthermore, in eddy current testing methods that combine high-frequency heating with water spray cooling, the strong alternating magnetic field of the heating coil can couple into the eddy current probe, causing a sharp drop in the signal-to-noise ratio. In the water spray cooling method, the water film covers the surface of the workpiece, greatly affecting eddy current testing and potentially causing a short circuit in the eddy current test.

[0038] For example, in traditional online inspection of defects in precision metal workpieces with relatively smooth surfaces, a water-cooled array eddy current probe is typically used in conjunction with infrared temperature measurement and heating to detect surface cracks. However, this single device has a complex structure and poor detection integrity, making it difficult to accurately determine the detection timing and implement crack detection during the heating process.

[0039] Based on this, the production line was modified. This invention utilizes the heated eddy current itself as a signal source, combined with dynamic frequency optimization to generate a phase-locked detection reference signal. This allows for the capture of cracks at the instant they occur, thus avoiding the aforementioned issues. Artificial laser etching is used to create a pre-set crack in the metal workpiece to be tested. The workpiece is then subjected to high-temperature treatment to observe crack propagation at high temperatures.

[0040] Reference Attachment Figure 1-2 , configured with a device for performing non-destructive testing simultaneously using a high-frequency heating process, including a high-frequency induction heating unit, an electromagnetic induction receiving unit, a phase-locked reference signal generating unit, a synchronous detection unit, an impedance analysis unit, and a crack judgment unit.

[0041] In this embodiment, the high-frequency induction heating unit includes a high-frequency power supply and a multi-turn induction coil connected thereto, which is used to form a skin effect heating inside the metal workpiece to raise the temperature to the target temperature and generate induced eddy currents;

[0042] The electromagnetic induction receiving unit is composed of one, three or six groups of electromagnetic induction receivers, which are arranged on the periphery of the induction coil. Multiple groups of electromagnetic induction receivers are circularly and evenly spaced around the periphery of the induction coil, and are used to capture the reflected magnetic field signal of the surface of the metal workpiece to be tested in real time, normalize the acquired data, and realize non-destructive detection of cracks or residual stress on the surface and near-surface of the metal workpiece.

[0043] Furthermore, the electromagnetic induction receiver is a magnetically shielded induction coil, which covers the area to be detected of the metal workpiece in the form of an array.

[0044] a phase-locked reference signal generating unit, electrically connected to the output terminal of the high-frequency power supply, comprising a frequency tracking module and a programmable frequency division / multiplication circuit;

[0045] Specifically, the phase-locked reference signal generation unit includes a current transformer, a digital phase-locked loop (DPL), and a programmable frequency divider. The current transformer collects the output current waveform of the high-frequency power supply in real time. The DPL tracks the frequency of the current waveform and generates a reference signal with a phase error of less than 0.1°. The programmable frequency divider outputs a detection reference signal with a frequency that is N times or 1 / N times the heating circuit frequency, generating a detection reference signal that is strictly synchronized with the heating current.

[0046] a synchronous detection unit, a first input end of which is connected to the electromagnetic induction receiving unit, a second input end of which is connected to the phase-locked reference signal generating unit, and extracts the in-phase component (I) and the quadrature component (Q) of the reflected signal through a multiplier and a low-pass filter;

[0047] The impedance analysis unit receives the in-phase component and the quadrature component, constructs an impedance plane diagram, and performs the following operations: a) calling a pre-stored temperature-impedance drift feature library; b) identifying a sudden deviation of a data point relative to a preset trajectory through a dynamic trajectory comparison algorithm;

[0048] The crack determination unit generates a crack alarm signal and position mark data when the sudden change deviation exceeds a preset threshold.

[0049] Furthermore, the phase-locked reference signal generating unit realizes phase locking of the detection reference signal to the heating current frequency through a hardware phase-locked loop.

[0050] Furthermore, the impedance analysis unit has a built-in temperature compensation module, which pre-stores a high-temperature impedance ellipse parameter database and performs temperature compensation model training to eliminate baseline impedance drift caused by workpiece temperature rise.

[0051] The method of performing nondestructive testing simultaneously with a high-frequency heating process comprises the following steps:

[0052] S1, using a high-frequency induction heater to heat the surface of the metal workpiece to be tested, so that the surface of the metal workpiece to be tested generates induced eddy currents and the temperature is raised to the target temperature;

[0053] S2. While the high-frequency induction heater is heating the metal workpiece, a reflected magnetic field signal from the surface of the metal workpiece is obtained in real time through an electromagnetic induction receiver;

[0054] S3, by real-time monitoring the working current frequency of the high-frequency induction heater and performing frequency division or frequency multiplication processing on the working current frequency, dynamically generating a detection reference signal that is strictly phase-locked with the working current of the high-frequency induction heater;

[0055] S4, inputting the reflected magnetic field signal obtained in step S2 and the detection reference signal generated in step S3 into a synchronous detector, extracting the in-phase component I and the quadrature component Q and constructing an impedance plane diagram;

[0056] S5. By monitoring the sudden deviation of the data points in the impedance plane diagram relative to the preset temperature drift trajectory, the generation of cracks on the surface of the metal workpiece is determined in real time.

[0057] The preset temperature drift trajectory is achieved by pre-storing the impedance-temperature mapping relationship of the metal workpiece without cracks under the same heat treatment process; or by using the detection signal of the crack-free area of ​​the metal workpiece as a reference benchmark in real time.

[0058] The basis for determining the sudden deviation of the temperature drift trajectory is: when the distance that the data point in the impedance plane diagram deviates from the preset temperature drift trajectory exceeds a threshold and lasts longer than a preset period, it is determined to be a crack signal.

[0059] Furthermore, in step S5, when a crack signal is detected, at least one of the following control actions is triggered in real time:

[0060] a) Stop the high-frequency heating process;

[0061] b) Adjust quenching cooling parameters;

[0062] c) Output defect alarm and location information.

[0063] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for performing nondestructive testing simultaneously using a high-frequency heating process, characterized in that: The following steps are involved: S1, using a high-frequency induction heater (10) to perform surface heating treatment on a metal workpiece (30), so that an induced eddy current (40) is generated on the surface of the metal workpiece (30) and the temperature is raised to a target temperature; S2. While the high-frequency induction heater (10) is heating the metal workpiece (30), a reflected magnetic field signal on the surface of the metal workpiece (30) is acquired in real time by at least one set of electromagnetic induction receivers (20); S3, by real-time monitoring of the operating current frequency of the high-frequency induction heater (10), and performing frequency division or frequency multiplication processing on the operating current frequency, dynamically generating a detection reference signal that is strictly phase-locked with the operating current of the high-frequency induction heater (10); S4, inputting the reflected magnetic field signal obtained in step S2 and the detection reference signal generated in step S3 into a synchronous detector, extracting the in-phase component (I) and the quadrature component (Q) and constructing an impedance plane diagram; S5. By monitoring the sudden deviation of the data points in the impedance plane diagram relative to the preset temperature drift trajectory, the generation of cracks on the surface of the metal workpiece is determined in real time.

2. The method for performing nondestructive testing simultaneously using a high-frequency heating process according to claim 1, characterized in that: The electromagnetic induction receiver (20) is a magnetically shielded induction coil; when there are multiple groups of electromagnetic induction receivers (20), they cover the area to be detected of the metal workpiece in an array form.

3. The method for performing nondestructive testing simultaneously using a high-frequency heating process according to claim 1, characterized in that: The preset temperature drift trajectory in step S5 is established by any of the following methods: a) The impedance-temperature mapping relationship of the metal workpiece without cracks under the same heat treatment process is stored; b) The detection signal of the crack-free area of ​​the metal workpiece is used as a reference in real time.

4. The method for performing nondestructive testing simultaneously using a high-frequency heating process according to claim 1, wherein: The determination basis of the mutation deviation in step S5 is: When the distance that the data point in the impedance plane graph deviates from the preset temperature drift trajectory exceeds a threshold and lasts longer than a preset period, it is determined to be a crack signal.

5. The method for performing nondestructive testing simultaneously using a high-frequency heating process according to claim 1, characterized in that: The method further includes: in step S5, when a crack signal is detected, triggering at least one of the following control actions in real time: a) Stop the high-frequency heating process; b) Adjust quenching cooling parameters; c) Output defect alarm and location information.

6. A device for performing nondestructive testing simultaneously during high-frequency heating treatment, used for real-time detection of surface cracks in metal workpieces during heating treatment, characterized in that: include: A high-frequency induction heating unit, comprising a high-frequency power supply and an induction coil connected thereto, is used to excite eddy currents on the surface of the metal workpiece and heat it to a target temperature; An electromagnetic induction receiving unit, composed of at least one set of electromagnetic induction receivers, for capturing the reflected magnetic field signal from the surface of the metal workpiece in real time; A phase-locked reference signal generating unit is electrically connected to the output terminal of the high-frequency power supply, and includes a frequency tracking module and a programmable frequency division / multiplication circuit, and is used to generate a detection reference signal that is strictly synchronized with the heating current; a synchronous detection unit, a first input end of which is connected to the electromagnetic induction receiving unit, a second input end of which is connected to the phase-locked reference signal generating unit, and extracts the in-phase component (I) and the quadrature component (Q) of the reflected signal through a multiplier and a low-pass filter; The impedance analysis unit receives the in-phase component and the quadrature component, constructs an impedance plane diagram, and performs the following operations: a) calling a pre-stored temperature-impedance drift feature library; b) identifying a sudden deviation of a data point relative to a preset trajectory through a dynamic trajectory comparison algorithm; The crack determination unit generates a crack alarm signal and position mark data when the sudden change deviation exceeds a preset threshold.

7. The device for performing nondestructive testing simultaneously using a high-frequency heating process according to claim 6, characterized in that: The sensors of the electromagnetic induction receiving unit are distributed in a ring shape with equal intervals, and the directions of their sensitive axes are arranged orthogonally to the direction of the magnetic field of the induction coil.

8. The device for performing nondestructive testing simultaneously using a high-frequency heating process according to claim 6, characterized in that: The phase-locked reference signal generating unit realizes phase locking of the detection reference signal to the heating current frequency through a hardware phase-locked loop.

9. The device for performing nondestructive testing simultaneously using a high-frequency heating process according to claim 6, characterized in that: The impedance analysis unit has a built-in temperature compensation module for eliminating baseline impedance drift caused by workpiece temperature increase.

Images