CN117607202A - Welding quality detection device and method for converter transformer oil tank based on electromagnetic induction principle - Google Patents

Abstract

The invention discloses a welding quality detection device and method for a converter transformer oil tank based on an electromagnetic induction principle. The detection method comprises the following steps: the signal excitation module in the device generates an alternating magnetic field, so that induced voltage generated in the signal induction module forms eddy current at the welding position of the oil tank to be tested; the signal detection module obtains the resistivity information of the detected metal through induced voltage, and the welding quality judgment module judges the welding quality through the resistivity information; the infrared thermal imaging module is used for detecting the temperature distribution of the surface of the metal to be detected, and judging the welding quality according to the principle that the eddy current density distribution can influence the surface to present different temperature distribution due to the fact that the eddy current generates Joule heat. The detection method is simple, high in accuracy and easy to operate.

Description

A converter oil tank welding quality detection device based on the principle of electromagnetic induction and method

Technical field

The invention belongs to the technical field of non-destructive testing, and particularly relates to a device and method for detecting the welding quality of a converter oil tank based on the principle of electromagnetic induction.

Background technique

Welding technology is widely used and plays an important role in heavy industry, automobile industry, energy and power equipment manufacturing and other fields. Welding operations on large equipment put forward higher requirements for welding quality. Post-weld quality inspection after welding is an important part of ensuring the safe and normal operation of large equipment. Welding quality testing includes radiographic testing, penetrant testing, magnetic particle testing, ultrasonic testing, and eddy current testing. The conventional welding process is generally used for the oil tank welding of converter transformers. The welding material matches the base metal of the copper plate. The welding method uses MIG pure argon gas shielded semi-automatic welding. However, there may be some welding defects after welding by traditional processes, such as uneven welding appearance, internal pores, incomplete welding, etc. It is necessary to conduct quality inspection of the welds to eliminate potential hidden dangers and avoid major safety accidents.

Although the current penetrant testing method for detecting welds is simple and reliable, it can only be applied to open-type defects and the surface of the fuel tank weld to be tested must be kept clean. For magnetic particle testing, the testing material must be ferromagnetic, and the weld surface smoothness also has high requirements. Therefore, these methods in the prior art are not very suitable for weld inspection of converter oil tanks.

Purpose of invention

The purpose of the present invention is to solve the problems existing in the prior art and provide a method and device for detecting the welding quality of a converter oil tank based on the principle of electromagnetic induction. It uses eddy current thermal imaging to detect the difference in temperature distribution at the weld. Determine the type of welding defects to complete the quality inspection of the fuel tank welds, which has the advantages of non-destructive, fast and accurate.

Contents of the invention

According to one aspect of the present invention, a converter oil tank welding quality detection device based on the principle of electromagnetic induction is provided, including: an AC voltage excitation module, a detection probe, a signal conditioning module, an infrared thermal imager (10) and an analysis and calculation module (11);

The detection probe is composed of an excitation coil (1), an induction coil (2), a shield (3) and a magnetic core (4); the AC voltage excitation module includes an AC signal generator (5) and a power amplifier (6) ; The signal conditioning module consists of a preamplifier (7), an adjustable gain amplifier (8) and a signal collector (9).

Preferably, the AC signal generator (5) emits sinusoidal AC voltages of different frequencies according to actual engineering requirements, thereby changing the frequency of the alternating magnetic field according to the law of electromagnetic induction to achieve quality detection at different depths of the weld; the power amplifier ( 6) Make the AC voltage excitation module have enough power to drive subsequent modules;

The excitation coil (1) is connected to the AC voltage excitation module and generates a changing magnetic field under the excitation of AC signals of different frequencies. The changing magnetic field generates eddy currents inside the converter oil tank plate, and the eddy currents generate a new induced magnetic field. And is received by the induction coil (2); the shielding cover ( 3 4) shields the interference from the external environment;

The signal conditioning module is used to amplify the detection signal and obtain the real and imaginary components, and convert the signal transmitted from the detection probe into a standard signal;

The infrared thermal imager (10) is connected to the AC signal generator (5), synchronously receives the excitation signal of the AC voltage excitation module, scans the measured weld and transmits the temperature distribution data to the analysis and calculation module ( 11) Perform imaging and determine the type and location of welding defects by observing the local temperature on the image;

The analysis and calculation module (11) inputs the standard signal conditioned by the signal conditioning module into the computer, obtains the resistivity information of the measured location, conducts comparative analysis with the calibration value, and determines whether there are defects, defect shapes, and defects at the point. position to complete the inspection of welding quality.

According to another aspect of the present invention, a method for detecting the welding quality of a converter oil tank using the above device is provided. The excitation coil (1), the induction coil (2) and the electromagnetic induction of the welding joint are used to collect the measured welding seam. The resistivity and temperature distribution information caused by Joule heat are analyzed to determine the welding quality, including the following steps:

Step 1. Place the detection probe and the infrared thermal imager (10) on the surface of the weld with good welding quality, calibrate its resistance value, set a feasible weld resistance calibration value, and observe and record the temperature distribution of good welding;

Step 2. Use the detection probe to conduct corresponding detection on other welds of the converter oil tank to obtain the actual resistance value at that position. At the same time, use an infrared thermal imager (10) to photograph the welds and place the infrared thermal imager The captured image data is sent to the analysis calculation module (11);

Step 3. The analysis and calculation module (11) compares the actual resistance value with the calibrated value. When the actual value is greater than the calibrated value, it is considered that the welding quality here does not meet the required standard. When the actual value is less than the calibrated value, the welding quality is considered to be up to standard; at the same time , by observing the infrared thermal imaging image and analyzing the temperature distribution at the weld to determine the welding quality.

Preferably, in step 1, the detection probe and the infrared thermal imager (10) are placed on the surface of the weld with good welding quality. When calibrating its resistance value, the positional relationship between the detection probe and the place with good welding quality is adjusted so that the excitation coil The axial directions of (1) and induction coil (2) are in contact with the weld and are vertical.

Preferably, step 2 further includes:

Step S21: Use the signal generator (5) to send out an alternating current signal, which passes through the power amplifier (6) to cause the excitation coil (1) to generate a corresponding alternating magnetic field. At the same time, it also sends out excitation to the infrared imager (10) to synchronize it. start working;

Step S22: The alternating magnetic field is guided by the magnetic core (4) and enters the weld to form an eddy current. The eddy current generates a new magnetic field, and the new magnetic field energy is obtained by the induction coil (2) through the magnetic core (4);

Step S23, the signal obtained by the induction coil (2) is processed into a standard signal through the preamplifier (7), the adjustable gain amplifier (8) and the signal collector (9);

Step S24: Transmit the standard signal to the analysis and calculation module (11) for calculation to obtain the resistance calibration value of the weld;

Step S25: Transfer the image signal formed by the infrared imager (10) to the analysis and calculation module (11) for analysis to obtain the temperature distribution at the location with good welding quality;

Step S26: Repeat steps S21-S24 at the weld where the welding quality needs to be judged, compare the calculated resistance value with the calibrated value and refer to the temperature distribution at the weld to judge the welding quality.

Description of drawings

Figure 1 is a structural module diagram of the welding quality detection device of the converter oil tank according to the present invention.

Figure 2 is an overall structural diagram of the welding quality detection device of the converter oil tank according to the present invention.

Figure 3 is a cross-sectional view of the detection probe of the welding quality detection device of the converter oil tank according to the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

Those skilled in the art should understand that the step numbers used herein are only for convenience of description and are not intended to limit the order in which the steps are performed. The terminology used in the description of the present invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an" and "the" may include plural referents unless the context clearly dictates otherwise. The term "and/or" refers to any and all possible combinations of one or more of the associated listed items and includes such combinations. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

Figure 1 is a structural module diagram of the welding quality detection device of the converter oil tank according to the present invention. As shown in the figure, the converter oil tank welding quality detection device includes an AC voltage excitation module, a detection probe, a signal conditioning module, an infrared thermal imager (10) and an analysis and calculation module (11).

Figure 2 is an overall structural diagram of the welding quality detection device of the converter oil tank according to the present invention. As shown in the figure, the AC voltage excitation module includes an AC signal generator (5) and a power amplifier (6). The detection probe includes an excitation coil and an induction coil; the signal conditioning module consists of a preamplifier (7), an adjustable gain amplifier (8) and a signal collector (9). The infrared thermal imager (10) is connected to the AC signal generator (5), synchronously receives the excitation signal of the AC voltage excitation module, and transmits the acquired data to the analysis and calculation module (11).

Figure 3 is a cross-sectional view of the detection probe of the welding quality detection device of the converter oil tank according to the present invention. As shown in the figure, the detection probe consists of an excitation coil (1), an induction coil (2), a shield (3) and a magnetic core (4). The excitation coil (1) is connected to the AC voltage excitation module and generates a changing magnetic field under the excitation of AC signals of different frequencies. The changing magnetic field generates eddy currents inside the converter oil tank plate, and the eddy currents generate a new induced magnetic field. and is received by the induction coil (2). The shielding cover ( 3 4) shields the interference from the external environment.

In the device, the AC signal generator (5) of the AC voltage excitation module emits sinusoidal AC voltages of different frequencies according to actual engineering requirements, thereby changing the frequency of the alternating magnetic field according to the law of electromagnetic induction to achieve different depths of the weld. Quality inspection; the power amplifier (6) enables the AC voltage excitation module to have enough power to drive subsequent modules. The signal conditioning module is used to amplify the detection signal and obtain the real and imaginary components, and convert the signal transmitted from the detection probe into a standard signal. The infrared thermal imager (10) is connected to the AC signal generator (5), synchronously receives the excitation signal of the AC voltage excitation module, scans the measured weld and transmits the temperature distribution data to the analysis and calculation module (11) Perform imaging and determine the type and location of welding defects by observing the local temperature on the image. The analysis and calculation module (11) inputs the standard signal conditioned by the signal conditioning module into the computer, obtains the resistivity information of the measured location, conducts comparative analysis with the calibration value, and determines whether there are defects, defect shapes, and defects at the point. position to complete the inspection of welding quality.

Example

In a specific example of welding quality inspection of converter oil tank, the specific process is as follows:

Step a. Adjust the positional relationship between the detection probe and the place with good welding quality, so that the axial direction of the excitation coil (1) and induction coil (2) is in contact with the weld and is perpendicular.

Step b. The signal generator (5) starts to emit an alternating current signal and passes through the power amplifier (6) to cause the excitation coil (1) to generate a corresponding alternating magnetic field. At the same time, it also excites the infrared imager (10) to start it synchronously. Work.

Step c. The alternating magnetic field is guided by the magnetic core (4) and enters the weld to form an eddy current. The eddy current will generate a new magnetic field, and the new magnetic field energy is obtained by the induction coil (2) through the magnetic core.

Step d. The signal obtained by the induction coil (2) is processed into a standard signal through the preamplifier (7), the adjustable gain amplifier (8) and the signal collector (9).

Step e. The processed standard signal is transmitted to the analysis and calculation module (11) for calculation, and the resistance calibration value here is obtained.

Step f. The infrared imager (10) transmits the formed image signal to the analysis and calculation module (11) for analysis to obtain the temperature distribution at the location with good welding quality.

Step g. Repeat the above steps at the weld where the welding quality needs to be judged, compare the calculated resistance value with the calibrated value and refer to the temperature distribution at the weld to judge the welding quality.

Claims (5)

1. A converter oil tank welding quality detection device based on the principle of electromagnetic induction, characterized by including: an AC voltage excitation module, a detection probe, a signal conditioning module, an infrared thermal imager (10) and an analysis and calculation module (11) ; The detection probe is composed of an excitation coil (1), an induction coil (2), a shield (3) and a magnetic core (4); the AC voltage excitation module includes an AC signal generator (5) and a power amplifier (6) ; The signal conditioning module consists of a preamplifier (7), an adjustable gain amplifier (8) and a signal collector (9). 2. A converter oil tank welding quality detection device based on the principle of electromagnetic induction according to claim 1, characterized in that the AC signal generator (5) emits sinusoidal AC voltages of different frequencies according to actual engineering requirements, thereby The frequency of the alternating magnetic field is changed according to the law of electromagnetic induction to achieve quality detection at different depths of the weld; the power amplifier (6) enables the AC voltage excitation module to have enough power to drive subsequent modules; The excitation coil (1) is connected to the AC voltage excitation module and generates a changing magnetic field under the excitation of AC signals of different frequencies. The changing magnetic field generates eddy currents inside the converter tank plate, and the eddy currents generate a new induced magnetic field. And is received by the induction coil (2); the shielding cover (3) shields the interference from the external environment; The signal conditioning module is used to amplify the detection signal and obtain the real and imaginary components, and convert the signal transmitted from the detection probe into a standard signal; The infrared thermal imager (10) is connected to the AC signal generator (5), synchronously receives the excitation signal of the AC voltage excitation module, scans the measured weld and transmits the temperature distribution data to the analysis and calculation module ( 11) Perform imaging and determine the type and location of welding defects by observing the local temperature on the image; The analysis and calculation module (11) inputs the standard signal conditioned by the signal conditioning module into the computer, obtains the resistivity information of the measured location, conducts comparative analysis with the calibration value, and determines whether there are defects, defect shapes, and defects at the point. position to complete the inspection of welding quality. 3. A method for detecting the welding quality of a converter oil tank using the detection device of claim 1 or 2, which utilizes the electromagnetic induction of the excitation coil (1), the induction coil (2) and the welding joint to collect the measured weld joints. The resistivity and temperature distribution information caused by Joule heat are analyzed to determine the welding quality, which is characterized by including the following steps: Step 1. Place the detection probe and the infrared thermal imager (10) on the surface of the weld with good welding quality, calibrate its resistance value, set a feasible weld resistance calibration value, and observe and record the temperature distribution of good welding; Step 2. Use the detection probe to conduct corresponding detection on other welds of the converter oil tank to obtain the actual resistance value at that position. At the same time, use an infrared thermal imager (10) to photograph the welds and place the infrared thermal imager The captured image data is sent to the analysis calculation module (11); Step 3. The analysis and calculation module (11) compares the actual resistance value with the calibrated value. When the actual value is greater than the calibrated value, it is considered that the welding quality here does not meet the required standard. When the actual value is less than the calibrated value, the welding quality is considered to be up to standard; at the same time , by observing the infrared thermal imaging image and analyzing the temperature distribution at the weld to determine the welding quality. 4. The welding quality detection method of the converter oil tank according to claim 3, characterized in that in step 1, the detection probe and the infrared thermal imager (10) are placed on the surface of the weld with good welding quality, and the resistance value is When calibrating, adjust the positional relationship between the detection probe and the place with good welding quality so that the axial direction of the excitation coil (1) and induction coil (2) is in contact with the weld and is perpendicular. 5. The converter oil tank welding quality detection method according to claim 4, characterized in that step 2 further includes the following sub-steps: Step S21: Use the signal generator (5) to send out an alternating current signal, which passes through the power amplifier (6) to cause the excitation coil (1) to generate a corresponding alternating magnetic field. At the same time, it also sends out excitation to the infrared imager (10) to synchronize it. start working; Step S22: The alternating magnetic field is guided by the magnetic core (4) and enters the weld to form an eddy current. The eddy current generates a new magnetic field, and the new magnetic field energy is obtained by the induction coil (2) through the magnetic core (4); Step S23, the signal obtained by the induction coil (2) is processed into a standard signal through the preamplifier (7), the adjustable gain amplifier (8) and the signal collector (9); Step S24: Transmit the standard signal to the analysis and calculation module (11) for calculation to obtain the resistance calibration value of the weld; Step S25: Transfer the image signal formed by the infrared imager (10) to the analysis and calculation module (11) for analysis to obtain the temperature distribution at the location with good welding quality; Step S26: Repeat steps S21-S24 at the weld where the welding quality needs to be judged, compare the calculated resistance value with the calibrated value and refer to the temperature distribution at the weld to judge the welding quality.