Electromagnetic ultrasonic detection system

Abstract

The invention relates to the technical field of nondestructive testing, in particular to an electromagnetic ultrasonic testing system. The electromagnetic ultrasonic detection system comprises an excitation generation circuit, an electromagnetic ultrasonic transducer, a detection circuit and a duplexer, the excitation generation circuit is used for generating an excitation signal and outputting a target level signal, and the electromagnetic ultrasonic transducer is electrically connected with the excitation generation circuit. The ultrasonic transducer is used for being placed on a to-be-detected welding seam block, responding to the excitation signal and applying an alternating magnetic field to the to-be-detected welding seam block, receiving an ultrasonic signal excited by the to-be-detected welding seam block under the action of the alternating magnetic field, and detecting whether the to-be-detected welding seam block has a welding seam defect or not according to the ultrasonic signal; the duplexer is electrically connected with the excitation generation circuit, the electromagnetic ultrasonic transducer and the detection circuit and used for responding to the target level signal to prevent the excitation signal from entering the detection circuit and controlling the ultrasonic signal to be transmitted to the detection circuit from the electromagnetic ultrasonic transducer. According to the embodiment, weld defect detection can be automatically carried out on the to-be-detected weld block, and the detection efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, and more specifically to an electromagnetic ultrasonic testing system. Background Technology

[0002] With the rapid development of the new energy industry globally, the application scenarios of various special equipment are constantly expanding. Against this backdrop, the operational reliability of energy supply systems, as critical infrastructure, directly affects the safe and stable operation of equipment. Among these systems, welds, as core connecting components, have become a key factor restricting system reliability due to their defects. When welds contain defects such as porosity, cracks, or lack of fusion, serious consequences such as medium leakage and structural failure may occur. Especially under harsh conditions such as high pressure and high temperature, the risk of defect propagation increases significantly, threatening the safety of the entire energy system. To effectively manage weld defects in energy supply systems, non-destructive testing (NDT) technology has become an important means of assessing weld quality. Ultrasonic testing, with its strong penetration and high detection sensitivity, is widely used in weld defect detection. When ultrasonic waves propagate in a weld, they undergo reflection, refraction, and attenuation due to the presence of defects. By analyzing the characteristic parameters of the received signal, the location, qualitative, and quantitative analysis of defects can be achieved. However, the diversity of weld structures, the complexity of defect types, and interference factors in the detection signal under complex service environments pose significant challenges to traditional ultrasonic testing technology.

[0003] Ultrasonic testing is a non-destructive testing method. The main principle of ultrasonic testing is to utilize high-frequency sound waves propagating through the workpiece. When these waves encounter defects, they are reflected back to the probe, thus detecting defects in the weld. The advantages of ultrasonic testing are its ability to detect internal and near-surface defects, and its applicability to workpieces made of various materials, such as carbon steel, stainless steel, and aluminum alloys. The disadvantages are its relatively slow testing speed and the need for experienced inspectors to accurately determine the location and size of defects. Therefore, the current weld inspection methods have relatively low efficiency. Summary of the Invention

[0004] One object of the present invention is to provide an electromagnetic ultrasonic testing system that aims to improve the problem of low detection efficiency in existing weld inspection methods.

[0005] This invention provides an electromagnetic ultrasonic testing system, comprising: An excitation generation circuit is used to generate an excitation signal and output a target level signal. The target level signal includes a first level and a second level. When the excitation signal is generated, the target level signal is at the first level, and when the excitation signal ends, the target level signal is at the second level. An electromagnetic ultrasonic transducer, electrically connected to the excitation generating circuit, is used to be placed on the weld block to be tested and to apply an alternating magnetic field to the weld block to be tested in response to the excitation signal, and is used to receive the ultrasonic signal generated by the weld block to be tested under the action of the alternating magnetic field. A detection circuit is used to detect whether there are weld defects in the weld block to be tested based on the ultrasonic signal. A duplexer is electrically connected to the excitation generation circuit, the electromagnetic ultrasonic transducer, and the detection circuit, respectively. It is used to prevent the excitation signal from entering the detection circuit in response to the first level and to control the transmission of the ultrasonic signal from the electromagnetic ultrasonic transducer to the detection circuit in response to the second level.

[0006] Optionally, the excitation generation circuit includes: A signal generator, electrically connected to the duplexer, is used to generate sinusoidal and square wave signals modulated by a Hanning window and output the target level signal to the duplexer. A pulse amplifier is electrically connected to the signal generator, the electromagnetic ultrasonic transducer, and the duplexer, respectively, and is used to amplify the sine wave signal based on the square wave signal and output the excitation signal to the electromagnetic ultrasonic transducer.

[0007] Optionally, the electromagnetic ultrasonic transducer includes: The shell is cylindrical. A coil is disposed inside the housing with its surface perpendicular to the side of the housing. The coil is electrically connected to the excitation generation circuit and the duplexer, respectively, and is used to generate an alternating magnetic field perpendicular to the surface of the coil in response to the excitation signal, and to receive the ultrasonic signal, which is a longitudinal wave perpendicular to the surface of the coil. A permanent magnet is disposed inside the housing to enhance the magnetic field strength in a designated area; A matching circuit, located inside the housing, is used to bring the coil into a resonant state at the target frequency.

[0008] Optionally, the permanent magnet is a Heilbeck array magnet.

[0009] Optionally, the detection circuit includes: An ultrasonic preamplifier, electrically connected to the duplexer, is used to amplify the ultrasonic signal and output a first-stage amplified signal. An ultrasonic post-amplifier, electrically connected to the ultrasonic pre-amplifier, is used to amplify the first-stage amplified signal and output a second-stage amplified signal. The host computer is electrically connected to the ultrasonic post-amplifier and is used to detect whether there are weld defects in the weld block under test based on the secondary amplified signal.

[0010] Optionally, the host computer includes: The signal acquisition circuit is electrically connected to the ultrasonic post-amplifier and is used to acquire the secondary amplified signal to obtain a sampled signal. The signal processing circuit, electrically connected to the signal acquisition circuit, is used to filter the sampled signal to obtain a filtered signal, perform a Hilbert transform on the filtered signal to obtain a signal envelope, extract peak information and time-of-flight information from the signal envelope, and detect whether there are weld defects in the weld block to be tested based on the peak information and the time-of-flight information.

[0011] Optionally, an oscilloscope may also be included; The oscilloscope is electrically connected to the excitation generation circuit and the ultrasonic post-amplifier, respectively, and is used to display the excitation signal and the secondary amplified signal.

[0012] Optionally, the duplexer includes: The first switching circuit is electrically connected to the electromagnetic ultrasonic transducer. The second switching circuit is electrically connected to the electromagnetic ultrasonic transducer. The controller is electrically connected to the first switching circuit and the second switching circuit respectively. It is used to control the first switching circuit and the second switching circuit to be in the off state in response to the first level, so as to prevent the excitation signal from entering the detection circuit. In response to the second level, it controls the first switching circuit to be in the off state and controls the second switching circuit to be in the on state within a first preset time period to conduct the discharge circuit. After the first preset time period, it controls the first switching circuit to be in the on state and controls the second switching circuit to be in the off state within a second preset time period, so that the ultrasonic signal can enter the detection circuit through the first switching circuit. A limiting circuit is electrically connected to the first switching circuit and the detection circuit respectively, and is used to limit the signal amplitude of the ultrasonic signal entering the detection circuit; The discharge circuit is electrically connected to the second switching circuit and the electromagnetic ultrasonic transducer, respectively, and is used to consume the residual power of the excitation signal through the discharge circuit.

[0013] Optionally, the first switching circuit includes a first driving chip, a first resistor, a first diode, a first MOSFET, and a second MOSFET; The first driving chip is electrically connected to the controller, one end of the first resistor, the cathode of the first diode, the source of the first MOS transistor, and the source of the second MOS transistor. The other end of the first resistor is electrically connected to the anode of the first diode, the gate of the first MOS transistor, and the gate of the second MOS transistor. The drain of the first MOS transistor is electrically connected to the electromagnetic ultrasonic transducer. The drain of the second MOS transistor is electrically connected to the limiting circuit and the detection circuit.

[0014] Optionally, the second switching circuit includes a second driver chip, a second resistor, a second diode, a third MOSFET, and a fourth MOSFET; The second driving chip is electrically connected to the controller, one end of the second resistor, the cathode of the second diode, the source of the third MOS transistor, and the source of the fourth MOS transistor. The other end of the second resistor is electrically connected to the anode of the second diode, the gate of the third MOS transistor, and the gate of the fourth MOS transistor. The drain of the fourth MOS transistor is electrically connected to the electromagnetic ultrasonic transducer and the discharge circuit.

[0015] Compared with the prior art, the present invention provides an electromagnetic ultrasonic testing system, which includes an excitation generation circuit, an electromagnetic ultrasonic transducer, a detection circuit, and a duplexer. The excitation generation circuit generates an excitation signal and outputs a target level signal, which includes a first level and a second level. When the excitation signal is generated, the target level signal is at the first level, and when the excitation signal ends, the target level signal is at the second level. The electromagnetic ultrasonic transducer is electrically connected to the excitation generation circuit and is placed on the weld block to be tested. It applies an alternating magnetic field to the weld block to be tested in response to the excitation signal and receives the ultrasonic signal generated by the weld block under the action of the alternating magnetic field. It is used to detect whether there is a weld defect in the weld block to be tested based on the ultrasonic signal. The duplexer is electrically connected to the excitation generation circuit, the electromagnetic ultrasonic transducer, and the detection circuit respectively. It is used to prevent the excitation signal from entering the detection circuit in response to the first level signal and to control the transmission of the ultrasonic signal from the electromagnetic ultrasonic transducer to the detection circuit in response to the second level signal. On the one hand, this embodiment can perform non-destructive testing on the weld block under test and automatically detect whether there are weld defects in the weld block under test. There is no need for experienced testing personnel to manually judge the location and size of the defects, which helps to reduce the difficulty of testing and improve the testing efficiency. On the other hand, this embodiment uses a duplexer to prevent high-frequency excitation signals from entering the detection circuit when the excitation signal is generated, which can avoid the detection circuit being interfered with by the excitation signal. Furthermore, when the excitation signal ends, it controls the ultrasonic signal to be transmitted from the electromagnetic ultrasonic transducer to the detection circuit, so that the detection circuit can detect whether there are weld defects in the weld block under test according to the ultrasonic signal, thereby automatically detecting weld defects in the weld block under test. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an electromagnetic ultrasonic testing system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an electromagnetic ultrasonic testing system according to another embodiment of the present invention; Figure 3 This is a schematic diagram of a weld inspection scenario provided by an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an electromagnetic ultrasonic transducer provided in an embodiment of the present invention; Figure 5 A schematic diagram of an electromagnetic ultrasonic testing system provided in another embodiment of the present invention; Figure 6 A schematic diagram of a weld seam image provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the circuit structure of a duplexer provided in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0019] It should be noted that, unless otherwise specified, the various features in the embodiments of this invention can be combined with each other, all of which are within the protection scope of this invention. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this invention do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0020] In existing weld inspection technologies, in addition to ultrasonic testing mentioned in the background, there are also radiographic testing, magnetic particle testing, eddy current testing, etc.

[0021] Radiographic inspection is a commonly used method for inspecting welds. The principle is to use rays to penetrate the workpiece and record an image of the weld on film or digital imaging equipment, thereby detecting defects in the weld. Its advantages include the ability to visually display the shape and size of the weld, and its applicability to workpieces made of various materials, such as carbon steel, stainless steel, and aluminum alloys. Its disadvantages include a relatively slow inspection speed, the need for long exposure times and darkroom processing, and the potential for radiation exposure.

[0022] Magnetic particle inspection is a method that uses magnetic force to detect surface and near-surface defects in workpieces. Its main principle is to place the workpiece in a strong magnetic field; if defects or cracks exist, magnetic particles will accumulate on the surface, thus detecting the defects. The advantages of magnetic particle inspection are its ability to detect surface and near-surface defects and its suitability for ferromagnetic materials. Its disadvantages are that it is not suitable for non-ferromagnetic materials and for detecting internal defects.

[0023] Eddy current testing is a method that uses the principle of electromagnetic induction to detect internal defects in workpieces. Its main principle is to place the workpiece in an alternating magnetic field; if defects or cracks exist in the workpiece, eddy currents will form on the workpiece surface, thus detecting the defects. The advantages of eddy current testing are its ability to detect internal defects and its suitability for conductive materials. Its disadvantages are that it is not suitable for non-conductive materials and for detecting surface defects.

[0024] As mentioned above, existing weld inspection technologies often cannot balance inspection speed and comprehensiveness, thus hindering the development of weld inspection technology.

[0025] In view of this, the present invention improves existing ultrasonic testing technology, enabling automatic detection of internal and near-surface defects in workpieces of various materials, thus perfectly balancing detection speed and comprehensiveness.

[0026] Please see Figure 1 An electromagnetic ultrasonic testing system 100 provided in this embodiment of the invention includes an excitation generation circuit 101, an electromagnetic ultrasonic transducer 102, a detection circuit 103, and a duplexer 104.

[0027] The excitation generation circuit 101 is used to generate an excitation signal and output a target level signal. The target level signal includes a first level and a second level. When the excitation signal is generated, the target level signal is at the first level, and when the excitation signal ends, the target level signal is at the second level.

[0028] When an excitation signal is generated, the excitation generation circuit 101 can output an excitation signal; when the excitation signal ends, the excitation generation circuit 101 can stop outputting the excitation signal. Since the excitation generation circuit 101 is a circuit used to generate excitation signals, it can determine when the excitation signal is generated and when it ends, and decide when to output the first level and the second level. That is, it outputs the first level when the excitation signal is generated and outputs the second level when the excitation signal ends.

[0029] The excitation signal is used to excite the electromagnetic ultrasonic transducer to generate an alternating magnetic field. The excitation signal can be any waveform signal; in some embodiments, the excitation signal is a sine wave signal.

[0030] The target level signal is used to control the operation of the duplexer. The target level signal can be of any type; in some embodiments, it is a TTL (Transistor-Transistor Logic) level signal. TTL level is a voltage standard defined by transistor-transistor logic circuit technology. TTL level defines the voltage range for representing binary logic "0" and "1" in digital circuits. TTL level specifies that +5V is equivalent to logic "1", and 0V is equivalent to logic "0" (when using binary to represent data). The first level and the second level are the target level signals output by the excitation generation circuit 101 at different time points. The first level can be low ("0") or high ("1"), and the second level can be low or high. The first and second levels can be the same; for example, both the first and second levels can be "0", or both can be "1".

[0031] In some embodiments, please refer to Figure 2 The excitation generation circuit 101 includes a signal generator 1011 and a pulse amplifier 1012.

[0032] The signal generator 1011 is electrically connected to the duplexer 104 and is used to generate sinusoidal and square wave signals modulated by the Hanning window and output the target level signal to the duplexer 104.

[0033] The length of the Hanning window modulation can be set according to actual needs; in some embodiments, the length of the Hanning window modulation is 5. The center frequency, cycle period, and peak-to-peak amplitude of the sine wave signal can be set according to actual needs; in some embodiments, the center frequency of the sine wave signal is 0.4-2MHz, the cycle period is 40ms, and the peak-to-peak amplitude is 2V. The width, cycle period, and peak-to-peak amplitude of the square wave signal can be set according to actual needs; in some embodiments, the width of the square wave signal is 20μs, the cycle period is 40ms, and the peak-to-peak amplitude is 3V.

[0034] The pulse amplifier 1012 is electrically connected to the signal generator 1011, the electromagnetic ultrasonic transducer 102 and the duplexer 104 respectively, and is used to amplify the sine wave signal according to the square wave signal and output the excitation signal to the electromagnetic ultrasonic transducer 102.

[0035] A square wave signal is used to control whether a sine wave signal is amplified. When the square wave signal overlaps the sine wave signal in time, the sine wave signal is amplified. In some embodiments, the pulse amplifier 1012 is a high-energy gated RF (Radio Frequency) pulse amplifier. A high-energy gated RF pulse amplifier is a specialized electronic device capable of generating high-intensity, short-duration pulses of radio frequency power, and the on / off state of the radio frequency output can be precisely controlled by a gate signal.

[0036] Please combine Figure 1 and Figure 3 The electromagnetic ultrasonic transducer 102 is electrically connected to the excitation generation circuit 101. It is used to be placed on the weld block 200 to be tested and to apply an alternating magnetic field to the weld block 200 to be tested in response to the excitation signal. It is also used to receive the ultrasonic signal generated by the weld block 200 under the action of the alternating magnetic field.

[0037] The weld block 200 to be tested is a test block or workpiece with a weld. A weld refers to the joint area formed after two or more workpieces are connected by a welding process. When there are defects such as porosity, cracks, and lack of fusion in the weld, these weld defects are usually very subtle and difficult to observe with the naked eye.

[0038] When the weld block 200 to be tested is made of magnetostrictive materials such as ferromagnetic stainless steel, the magnetostrictive material will generate mechanical vibrations along the direction of the magnetic field under the action of an alternating magnetic field, forming ultrasonic waves.

[0039] During testing, it is necessary to confirm the relative position of the electromagnetic ultrasonic transducer 102 and the weld. The farther the electromagnetic ultrasonic transducer 102 is from the weld, the weaker the signal will be. If it is too close, the electromagnetic ultrasonic transducer 102 will be attracted to the weld and will not be easy to move. Therefore, the relative position can be set reasonably according to the actual situation.

[0040] If the weld is a weld between flat plates, the electromagnetic ultrasonic transducer 102 can be moved and scanned by a lead screw and a bracket. Figure 3 (The arrow shown indicates the scanning direction). If the weld is a pipe weld, a separate moving device suitable for a ring is needed to drive the electromagnetic ultrasonic transducer 102 to perform moving scanning.

[0041] In some embodiments, the electromagnetic ultrasonic transducer 102 is a self-transmitting and self-receiving transducer. Self-transmitting and self-receiving means that an electromagnetic ultrasonic transducer 102 integrates the functions of signal transmission and signal reception.

[0042] In some embodiments, please refer to Figure 4 The electromagnetic ultrasonic transducer 102 includes a housing 1021, a coil 1022, a permanent magnet 1023, and a matching circuit 1024.

[0043] The housing 1021 is cylindrical and is used to house the coil 1022, the permanent magnet 1023 and the matching circuit 1024.

[0044] The coil 1022 is disposed inside the housing 1021 and the surface of the coil is perpendicular to the side of the housing 1021. The coil 1022 is electrically connected to the excitation generation circuit 101 and the duplexer 104 respectively, and is used to generate an alternating magnetic field perpendicular to the surface of the coil in response to the excitation signal, and to receive ultrasonic signals.

[0045] The ultrasonic signal is a longitudinal wave perpendicular to the surface of the coil. When the ultrasonic signal is a longitudinal wave perpendicular to the surface of the coil, the ultrasonic signal that is excited and received at the point to be detected is the strongest.

[0046] like Figure 4 As shown, coil 1022 is ring-shaped, and the surface of coil 1022 refers to the plane formed by winding coil 1022, that is, the plane jointly formed by all the turns of wire in coil 1022. In some embodiments, coil 1022 is a double-layer coil. Compared with a single-layer coil, using a double-layer coil can make the signal generated by coil 1022 stronger; however, when the number of layers of coil 1022 is greater than 2, it is easy to cause the generated longitudinal wave to weaken.

[0047] The permanent magnet 1023 is disposed inside the housing 1021 to enhance the magnetic field strength of a designated area.

[0048] The permanent magnet 1023 can provide a signal generated by the Lorentz force, which is another source of longitudinal wave generation. This signal can be superimposed on the magnetostrictive signal, which significantly enhances the ultrasonic signal excited later. The coil 1022 can also more easily detect the reflected ultrasonic signal.

[0049] In some embodiments, the permanent magnet 1023 is a Hellbeck array magnet. A Hellbeck array magnet is a magnetic structure that enhances the magnetic field strength in a specific direction through a specially arranged arrangement of permanent magnets. The core principle of a Hellbeck array magnet is to achieve highly efficient magnetic field utilization by directionally arranging multiple magnets to significantly strengthen the magnetic field on one side and significantly weaken it on the other.

[0050] The matching circuit 1024 is located inside the housing 1021 and is used to bring the coil 1022 into a resonant state at the target frequency.

[0051] By bringing coil 1022 into a resonant state at the target frequency, the equivalent value of the load resistance can be increased at the resonant frequency.

[0052] Understandably, the matching circuit 1024 can also be used to eliminate the inductive effect of the coil 1022.

[0053] The detection circuit 103 is used to detect whether there are weld defects in the weld block 200 to be tested based on the ultrasonic signal.

[0054] In some embodiments, please continue reading Figure 2 The detection circuit 103 includes an ultrasonic preamplifier 1031, an ultrasonic postamplifier 1032, and a host computer 1033.

[0055] The ultrasonic preamplifier 1031 is electrically connected to the duplexer 104 and is used to amplify the ultrasonic signal and output a first-stage amplified signal. The ultrasonic preamplifier 1031 can amplify the ultrasonic signal by a first specified decibel and output a first-stage amplified signal. The first specified decibel can be set according to actual needs and is not limited here.

[0056] The ultrasonic postamplifier 1032 is electrically connected to the ultrasonic preamplifier 1031 and is used to amplify the first-stage amplified signal and output the second-stage amplified signal.

[0057] The ultrasonic post-amplifier 1032 can amplify the primary amplified signal to a second specified decibel and output a secondary amplified signal. The second specified decibel can be set according to actual needs and is not limited here.

[0058] In some embodiments, the second specified decibel is greater than the first specified decibel.

[0059] The host computer 1033 is electrically connected to the ultrasonic post-amplifier 1032 and is used to detect whether there are weld defects in the weld block 200 under test based on the secondary amplified signal.

[0060] The host computer 1033 is a computer device at the monitoring, management, and control level within the electromagnetic ultrasonic testing system 100. In the electromagnetic ultrasonic testing system 100, the host computer 1033 is used to acquire the secondary amplified signal output by the ultrasonic post-amplifier 1032 and automatically detect weld defects in the weld block 200 under test based on this signal. The host computer 1033 can be any suitable type of electronic device, including but not limited to general-purpose computers, dedicated industrial computers, mobile terminals, or other dedicated devices. General-purpose computers may include desktop computers, workstations, laptops, servers, etc.; dedicated industrial computers may include industrial PCs or industrial control computers, etc.; and mobile terminals may include smartphones, tablets, etc.

[0061] In some embodiments, please refer to Figure 5 The host computer 1033 includes a signal acquisition circuit 10331 and a signal processing circuit 10332.

[0062] The signal acquisition circuit 10331 is electrically connected to the ultrasonic post-amplifier 1032 and is used to acquire the secondary amplified signal to obtain the sampled signal.

[0063] Users can open the acquisition software on the host computer 1033 to control the signal acquisition circuit 10331 to acquire the secondary amplified signal and obtain the sampled signal.

[0064] The signal processing circuit 10332 is electrically connected to the signal acquisition circuit 10331. It is used to filter the sampled signal to obtain a filtered signal, perform a Hilbert transform on the filtered signal to obtain the signal envelope, extract peak information and time-of-flight information from the signal envelope, and detect whether there are weld defects in the weld block under test based on the peak information and time-of-flight information.

[0065] Because the electromagnetic ultrasonic transducer 102 has a low signal-to-noise ratio, the host computer 1033 can filter the sampled signal using a filter. This filter can be a bandpass filter, and the filtering range can be set according to the frequency of the electromagnetic ultrasonic transducer 102. For example, when the frequency of the electromagnetic ultrasonic transducer 102 is 1MHz, the filtering range can be 0.8 to 1.2MHz. The signal processing circuit 10332 can continuously sample 32 times within a preset time period, filter each signal using the bandpass filter, and then calculate the average value to obtain the filtered signal. The filtered signal obtained in this way can remove environmental noise and power supply noise, thereby improving signal quality.

[0066] Peak information may include all local peaks on the envelope of the signal envelope, and time-of-flight information includes the duration from the start of the transmitted pulse to the occurrence of each peak.

[0067] In some embodiments, the signal processing circuit 10332 can generate a weld image of the weld block under test based on peak information and time-of-flight information. The weld image is used to detect whether there are weld defects in the weld block under test.

[0068] In some embodiments, the signal processing circuit 10332 can perform normalized imaging processing on the peak information and time-of-flight information in a MATLAB program to obtain the weld image of the weld block to be tested.

[0069] Figure 6 This is a schematic diagram of a weld seam image provided as an embodiment of the present invention. For example... Figure 6 As shown, the weld image includes a local image of the defect with defect features. Figure 6 (The circled part of the image) When there is a weld defect in the weld block to be tested, the weld image will show obvious defect features. The inspector only needs to determine whether there is a weld defect in the weld block to be tested based on whether there are defect features in the weld image. There is no need for experienced inspectors to manually judge the location and size of the defect, which can reduce the difficulty of inspection and improve the inspection efficiency.

[0070] In some embodiments, a similar test can be performed on the weld sample to be tested first, and the peak information and time-of-flight information of all acquired signal envelopes can be extracted as sample data to establish a sample database. When testing the weld block 200 to be tested, the peak information and time-of-flight information of the signal envelope are also extracted, and these data are compared with the data in the sample database. The similarity between the two data is given by deviation calculation, and the weld block 200 to be tested is used to detect whether there are weld defects.

[0071] Understandably, this weld inspection method can also automatically detect weld defects in the weld block 200 under test, eliminating the need for experienced inspectors to manually determine the location and size of defects, thereby reducing the difficulty of inspection and improving inspection efficiency.

[0072] The duplexer 104 is electrically connected to the excitation generation circuit 101, the electromagnetic ultrasonic transducer 102 and the detection circuit 103 respectively. It is used to prevent the excitation signal from entering the detection circuit 103 in response to the first level and to control the ultrasonic signal to be transmitted from the electromagnetic ultrasonic transducer 102 to the detection circuit 103 in response to the second level.

[0073] Therefore, in this embodiment, the duplexer 104 prevents the high-frequency excitation signal from entering the detection circuit 103 when the excitation signal is generated, thus avoiding interference from the excitation signal to the detection circuit 103. Furthermore, when the excitation signal ends, the ultrasonic signal is controlled to be transmitted from the electromagnetic ultrasonic transducer 102 to the detection circuit 103. The signal transmission and reception do not affect each other, which is beneficial to achieve self-transmission and self-reception using only one electromagnetic ultrasonic transducer.

[0074] In summary, on the one hand, this embodiment can perform non-destructive testing on the weld block under test and automatically detect whether there are weld defects in the weld block under test, without requiring experienced inspectors to manually judge the location and size of defects, which helps to reduce the difficulty of testing and improve the efficiency of testing. On the other hand, this embodiment uses a duplexer to prevent high-frequency excitation signals from entering the detection circuit when the excitation signal is generated, which can avoid the detection circuit being interfered with by the excitation signal. Furthermore, when the excitation signal ends, it controls the ultrasonic signal to be transmitted from the electromagnetic ultrasonic transducer to the detection circuit, so that the detection circuit can detect whether there are weld defects in the weld block under test according to the ultrasonic signal, thereby automatically detecting weld defects in the weld block under test.

[0075] In some embodiments, please continue reading Figure 2 The electromagnetic ultrasonic testing system 100 also includes an oscilloscope 105.

[0076] The oscilloscope 105 is electrically connected to the excitation generation circuit 101 and the ultrasonic post-amplifier 1032, respectively, and is used to display the excitation signal and the secondary amplified signal.

[0077] The oscilloscope 105 includes two channels. One channel is electrically connected to the excitation generation circuit 101 and is used to display the signal after the excitation signal is attenuated by the excitation generation circuit 101, so that users can intuitively observe the waveform changes of the excitation signal. The other channel is electrically connected to the ultrasonic post-amplifier 1032 and is used to display the secondary amplified signal, so that users can intuitively observe the waveform changes of the ultrasonic signal.

[0078] In some embodiments, such as Figure 2 As shown, the duplexer 104 includes a first switching circuit 1041, a second switching circuit 1042, a controller 1043, a limiting circuit 1044, and a discharge circuit 1045.

[0079] The first switching circuit 1041 is electrically connected to the electromagnetic ultrasonic transducer 102, the controller 1043, and the limiting circuit 1044, respectively, and is used to be in a conducting state or a disconnected state under the control of the controller 1043. The first switching circuit 1041 is used on the one hand to prevent the excitation signal of the electromagnetic ultrasonic transducer 102 from interfering with the detection circuit 103, and on the other hand to transmit the ultrasonic signal received by the electromagnetic ultrasonic transducer 102 to the detection circuit 103 so that the detection circuit 103 can perform weld defect detection based on the ultrasonic signal.

[0080] The second switching circuit 1042 is electrically connected to the electromagnetic ultrasonic transducer 102, the controller 1043, and the discharge circuit 1045, respectively, and is used to be in a conducting or disconnected state under the control of the controller 1043. The second switching circuit 1042 serves two purposes: firstly, to prevent the excitation signal of the electromagnetic ultrasonic transducer 102 from interfering with the detection circuit 103; and secondly, to open the residual discharge path of the excitation signal of the electromagnetic ultrasonic transducer 102, so as to discharge the residual electricity at the end of the excitation signal, which is beneficial for the electromagnetic ultrasonic transducer 102 to receive ultrasonic signals more reliably subsequently, thereby improving the reliability of weld detection.

[0081] The controller 1043 is electrically connected to the excitation generation circuit 101, the first switching circuit 1041, and the second switching circuit 1042, respectively. It is used to respond to a first level to control the first switching circuit 1041 and the second switching circuit 1042 to be in a turned-off state, preventing the excitation signal from entering the detection circuit 103. Responding to a second level, it controls the first switching circuit 1041 to be in a turned-off state and the second switching circuit 1042 to be in a turned-on state for a first preset time period, thus opening the discharge circuit. After the first preset time period, it controls the first switching circuit 1041 to be in a turned-on state and the second switching circuit 1042 to be in a turned-off state for a second preset time period, allowing the ultrasonic signal to pass through the first switching circuit 1041 and the limiting circuit 1044 into the detection circuit 103. The first and second preset time periods can be set according to actual needs and are not limited here.

[0082] The limiting circuit 1044 is electrically connected to the first switching circuit 1041 and the detection circuit 103 respectively, and is used to limit the signal amplitude of the ultrasonic signal entering the detection circuit 103.

[0083] As mentioned above, when the ultrasonic signal enters the detection circuit 103 through the first switching circuit 1041 and the limiting circuit 1044, the limiting circuit 1044 can limit the amplitude of the ultrasonic signal, thereby preventing the ultrasonic signal amplitude entering the detection circuit 103 from being too large.

[0084] The discharge circuit 1045 is electrically connected to the second switching circuit 1042 and the electromagnetic ultrasonic transducer 102, respectively, and is used to consume the residual power of the excitation signal through the discharge circuit.

[0085] In some embodiments, please refer to Figure 7 The first switching circuit 1041 includes a first driving chip U1, a first resistor R1, a first diode D1, a first MOSFET Q1, and a second MOSFET Q2.

[0086] The first driving chip U1 is electrically connected to the controller 1043, one end of the first resistor R1, the cathode of the first diode D1, the source of the first MOSFET Q1, and the source of the second MOSFET Q2. The other end of the first resistor R1 is electrically connected to the anode of the first diode D1, the gate of the first MOSFET Q1, and the gate of the second MOSFET Q2. The drain of the first MOSFET Q1 is electrically connected to the electromagnetic ultrasonic transducer 102, and the drain of the second MOSFET Q2 is electrically connected to the limiting circuit 1044.

[0087] like Figure 7 As shown, the second switching circuit 1042 includes a second driving chip U2, a second resistor R2, a second diode D2, a third MOSFET Q3, and a fourth MOSFET Q4.

[0088] The second driver chip U2 is electrically connected to the controller 1043, one end of the second resistor R2, the cathode of the second diode D2, the source of the third MOSFET Q3, and the source of the fourth MOSFET Q4. The other end of the second resistor R2 is electrically connected to the anode of the second diode D2, the gate of the third MOSFET Q3, and the gate of the fourth MOSFET Q4. The drain of the fourth MOSFET Q4 is electrically connected to the electromagnetic ultrasonic transducer 102, and the drain of the fourth MOSFET Q4 is electrically connected to the discharge circuit 1045.

[0089] like Figure 7 As shown, the limiting circuit 1044 includes a third diode D3 and a fourth diode D4.

[0090] The cathode of the third diode D3 and the anode of the fourth diode D4 are electrically connected to the first switching circuit 1041 and the detection circuit 103, respectively, and the anode of the third diode D3 and the cathode of the fourth diode D4 are electrically connected to the detection circuit 103.

[0091] like Figure 7 As shown, the discharge circuit 1045 includes a third resistor R3.

[0092] One end of the third resistor R3 is electrically connected to the second switching circuit 1042, and the other end of the third resistor R3 is electrically connected to the electromagnetic ultrasonic transducer 102.

[0093] The following is combined Figure 7 The working process of the duplexer in the embodiments of the present invention is described in detail.

[0094] First, the controller 1043 responds to the first level by outputting a first drive signal to the first drive chip U1 and a second drive signal to the second drive chip U2. The first drive chip U1 responds to the first drive signal by driving the first MOSFET Q1 and the second MOSFET Q2 to be in the off state. The second drive chip U2 responds to the second drive signal by driving the third MOSFET Q3 and the fourth MOSFET Q4 to be in the off state. This prevents the excitation signal from entering the detection circuit 103 through the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3 and the fourth MOSFET Q4 when the excitation signal is generated, thus avoiding interference from the excitation signal to the detection circuit 103.

[0095] Next, the controller 1043 responds to the second level and outputs a third driving signal to the first driving chip U1 and a fourth driving signal to the second driving chip U2 within a first preset time period. The first driving chip U1 responds to the third driving signal and drives the first MOSFET Q1 and the second MOSFET Q2 to be in the off state. The second driving chip U2 responds to the fourth driving signal and drives the third MOSFET Q3 and the fourth MOSFET Q4 to be in the on state, so that the residual power of the excitation signal is quickly consumed through the third resistor R3 when the excitation signal ends.

[0096] Finally, within a second preset time period after the first preset time period, the controller 1043 outputs a fifth driving signal to the first driving chip U1 and a sixth driving signal to the second driving chip U2. The first driving chip U1 responds to the fifth driving signal and drives the first MOSFET Q1 and the second MOSFET Q2 to be in the conducting state. The second driving chip U2 responds to the sixth driving signal and drives the third MOSFET Q3 and the fourth MOSFET Q4 to be in the de-energized state, thereby transmitting the ultrasonic signal received by the electromagnetic ultrasonic transducer 102 to the detection circuit 103.

[0097] Finally, it should be noted that the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to impose additional limitations on the content of the present invention; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of the present invention. Furthermore, within the framework of the present invention, the above-described technical features can be combined with each other, and many other variations of different aspects of the present invention as described above exist, all of which are considered to be within the scope of the present invention specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An electromagnetic ultrasonic testing system, characterized in that, include: An excitation generation circuit is used to generate an excitation signal and output a target level signal. The target level signal includes a first level and a second level. When the excitation signal is generated, the target level signal is at the first level, and when the excitation signal ends, the target level signal is at the second level. An electromagnetic ultrasonic transducer, electrically connected to the excitation generating circuit, is used to be placed on the weld block to be tested and to apply an alternating magnetic field to the weld block to be tested in response to the excitation signal, and is used to receive the ultrasonic signal generated by the weld block to be tested under the action of the alternating magnetic field. A detection circuit is used to detect whether there are weld defects in the weld block to be tested based on the ultrasonic signal. A duplexer is electrically connected to the excitation generation circuit, the electromagnetic ultrasonic transducer, and the detection circuit, respectively. It is used to prevent the excitation signal from entering the detection circuit in response to the first level and to control the transmission of the ultrasonic signal from the electromagnetic ultrasonic transducer to the detection circuit in response to the second level.

2. The electromagnetic ultrasonic testing system according to claim 1, characterized in that, The excitation generation circuit includes: A signal generator, electrically connected to the duplexer, is used to generate sinusoidal and square wave signals modulated by a Hanning window and output the target level signal to the duplexer. A pulse amplifier is electrically connected to the signal generator, the electromagnetic ultrasonic transducer, and the duplexer, respectively, and is used to amplify the sine wave signal based on the square wave signal and output the excitation signal to the electromagnetic ultrasonic transducer.

3. The electromagnetic ultrasonic testing system according to claim 1, characterized in that, The electromagnetic ultrasonic transducer includes: The shell is cylindrical. A coil is disposed inside the housing with its surface perpendicular to the side of the housing. The coil is electrically connected to the excitation generation circuit and the duplexer, respectively, and is used to generate an alternating magnetic field perpendicular to the surface of the coil in response to the excitation signal, and to receive the ultrasonic signal, which is a longitudinal wave perpendicular to the surface of the coil. A permanent magnet is disposed inside the housing to enhance the magnetic field strength in a designated area; A matching circuit, located inside the housing, is used to bring the coil into a resonant state at the target frequency.

4. The electromagnetic ultrasonic testing system according to claim 3, characterized in that, The permanent magnet is a Heilbeck array magnet.

5. The electromagnetic ultrasonic testing system according to claim 1, characterized in that, The detection circuit includes: An ultrasonic preamplifier, electrically connected to the duplexer, is used to amplify the ultrasonic signal and output a first-stage amplified signal. An ultrasonic post-amplifier, electrically connected to the ultrasonic pre-amplifier, is used to amplify the first-stage amplified signal and output a second-stage amplified signal. The host computer is electrically connected to the ultrasonic post-amplifier and is used to detect whether there are weld defects in the weld block under test based on the secondary amplified signal.

6. The electromagnetic ultrasonic testing system according to claim 5, characterized in that, The host computer includes: The signal acquisition circuit is electrically connected to the ultrasonic post-amplifier and is used to acquire the secondary amplified signal to obtain a sampled signal. The signal processing circuit, electrically connected to the signal acquisition circuit, is used to filter the sampled signal to obtain a filtered signal, perform a Hilbert transform on the filtered signal to obtain a signal envelope, extract peak information and time-of-flight information from the signal envelope, and detect whether there are weld defects in the weld block to be tested based on the peak information and the time-of-flight information.

7. The electromagnetic ultrasonic testing system according to claim 5, characterized in that, It also includes oscilloscopes; The oscilloscope is electrically connected to the excitation generation circuit and the ultrasonic post-amplifier, respectively, and is used to display the excitation signal and the secondary amplified signal.

8. The electromagnetic ultrasonic testing system according to any one of claims 1 to 7, characterized in that, The duplexer includes: The first switching circuit is electrically connected to the electromagnetic ultrasonic transducer. The second switching circuit is electrically connected to the electromagnetic ultrasonic transducer. The controller is electrically connected to the first switching circuit and the second switching circuit respectively. It is used to control the first switching circuit and the second switching circuit to be in the off state in response to the first level, so as to prevent the excitation signal from entering the detection circuit. In response to the second level, it controls the first switching circuit to be in the off state and controls the second switching circuit to be in the on state within a first preset time period to conduct the discharge circuit. After the first preset time period, it controls the first switching circuit to be in the on state and controls the second switching circuit to be in the off state within a second preset time period, so that the ultrasonic signal can enter the detection circuit through the first switching circuit. A limiting circuit is electrically connected to the first switching circuit and the detection circuit respectively, and is used to limit the signal amplitude of the ultrasonic signal entering the detection circuit; The discharge circuit is electrically connected to the second switching circuit and the electromagnetic ultrasonic transducer, respectively, and is used to consume the residual power of the excitation signal through the discharge circuit.

9. The electromagnetic ultrasonic testing system according to claim 8, characterized in that, The first switching circuit includes a first driver chip, a first resistor, a first diode, a first MOSFET, and a second MOSFET; The first driving chip is electrically connected to the controller, one end of the first resistor, the cathode of the first diode, the source of the first MOS transistor, and the source of the second MOS transistor. The other end of the first resistor is electrically connected to the anode of the first diode, the gate of the first MOS transistor, and the gate of the second MOS transistor. The drain of the first MOS transistor is electrically connected to the electromagnetic ultrasonic transducer, and the drain of the second MOS transistor is electrically connected to the limiting circuit.

10. The electromagnetic ultrasonic testing system according to claim 8, characterized in that, The second switching circuit includes a second driver chip, a second resistor, a second diode, a third MOSFET, and a fourth MOSFET; The second driving chip is electrically connected to the controller, one end of the second resistor, the cathode of the second diode, the source of the third MOS transistor, and the source of the fourth MOS transistor. The other end of the second resistor is electrically connected to the anode of the second diode, the gate of the third MOS transistor, and the gate of the fourth MOS transistor. The drain of the fourth MOS transistor is electrically connected to the electromagnetic ultrasonic transducer and the discharge circuit.

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