Phased array detection method for reheater fixture block weld crack defects

Abstract

The invention relates to the technical field of boiler reheater ultrasonic phased array detection, and provides a phased array detection method for reheater fixture block weld crack defects, which comprises the following steps: adjusting the sensitivity of a phased array probe by using a reference block; the phased array probe is controlled to be perpendicular to the weld joint and move from one side of the reheater tube to one side of the clamping block, the moving track of the phased array probe is a sawtooth-shaped moving track, and the moving track sequentially passes through the first detection point, the second detection point and the third detection point; acquiring a first echo value of the first detection point, a second echo value of the second detection point and a third echo value of the third detection point; positioning a detection path of the phased array probe according to the first echo value and the third echo value; and judging whether the weld joint has crack defects or not according to the second echo value. The first detection point A, the second detection point B and the third detection point C are arranged for spatial positioning, the crack defects are judged according to echo values, and the weld crack detection rate is increased.

Description

Technical Field

[0001] This application relates to the field of ultrasonic phased array testing technology for boiler reheaters, and more specifically, to a phased array testing method for weld crack defects in reheater block welds. Background Technology

[0002] Currently, the detection of dissimilar steel weld cracks in reheater blocks typically relies on conventional ultrasonic or radiographic methods. However, because the cracks originate at the weld root between the block and the reheater tube and extend inwards, conventional non-destructive testing methods cannot effectively detect these cracks, resulting in insufficient detection rates. Furthermore, existing standard test blocks cannot simulate actual crack morphology, probe sensitivity settings rely on experience, leading to a high false positive rate and stringent requirements for operator experience, making it difficult to meet the rapid maintenance needs of thermal power units. Summary of the Invention

[0003] This application aims to at least address the technical problem in the related art that conventional non-destructive testing methods cannot effectively detect weld cracks in dissimilar steel in reheater blocks, resulting in insufficient detection rate.

[0004] To solve the above-mentioned technical problems, this application is implemented as follows:

[0005] This application provides a phased array detection method for weld crack defects in reheater chucks, used to detect weld cracks between reheater tubes and chucks. Along the direction from the reheater tube to the chuck, a first detection point, a second detection point, and a third detection point are sequentially arranged. The first detection point is located on the reheater tube, the second detection point is located on the weld, and the third detection point is located on the chuck. The phased array detection method for reheater chuck weld crack defects includes: adjusting the sensitivity of the phased array probe using a comparison test block; controlling the phased array probe to be perpendicular to the weld and moving it from one side of the reheater tube towards the side of the chuck, with the moving trajectory of the phased array probe being a sawtooth-shaped trajectory, and the moving trajectory sequentially passing through the first detection point, the second detection point, and the third detection point; acquiring the first echo value of the first detection point, the second echo value of the second detection point, and the third echo value of the third detection point; locating the detection path of the phased array probe based on the first echo value and the third echo value; and determining whether a weld crack defect exists based on the second echo value.

[0006] The phased array detection method for reheater block weld crack defects provided in this application eliminates blind spots by setting a first detection point A, a second detection point B, and a third detection point C for spatial positioning, and judges crack defects based on echo values. This effectively solves the problem of insufficient detection rate caused by the inability of conventional non-destructive testing methods to effectively detect weld cracks. At the same time, the PL-DZ series reheater block comparison test blocks are developed to simulate the actual crack morphology and improve the detection sensitivity of the phased array probe, solving the problem of inaccurate sensitivity calibration.

[0007] This application provides a phased array detection method for weld crack defects in reheater jacks. The method detects weld cracks between the reheater tube and the jack. Three detection points—a first detection point A, a second detection point B, and a third detection point C—are sequentially positioned along the direction from the reheater tube to the jack. These three points are used to spatially locate the detection path of the phased array probe, eliminating blind spots. The presence of weld crack defects is determined based on the echo values ​​from these three detection points. This method solves the problem of insufficient detection rate caused by the inability of conventional non-destructive testing methods to effectively detect weld cracks. Furthermore, this application develops the PL-DZ series of reheater jack comparison test blocks to simulate actual crack morphology, improving the detection sensitivity of the phased array probe and addressing the issue of inaccurate sensitivity calibration of the phased array probe.

[0008] Additional aspects and advantages of this application will become apparent in the following description or may be learned by practice of this application. Attached Figure Description

[0009] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0010] Figure 1 This is a schematic diagram of the reheater card block according to one embodiment of this application;

[0011] Figure 2 This is one of the structural schematic diagrams of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application;

[0012] Figure 3 This is a second schematic diagram of the structure of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application;

[0013] Figure 4 This is the third schematic diagram of the structure of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application;

[0014] Figure 5 This is the fourth schematic diagram of the structure of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application;

[0015] Figure 6 This is a schematic diagram of the movement path of a phased array probe during detection according to an embodiment of this application;

[0016] Figure 7 This is a schematic diagram of the movement trajectory of a phased array probe during detection according to an embodiment of this application;

[0017] Figure 8 This is a schematic diagram of the detection spectrum of a phased array probe at the first detection point according to an embodiment of this application;

[0018] Figure 9 This is a schematic diagram of a defect detection spectrum at the second detection point using a phased array probe according to an embodiment of this application.

[0019] Figure 10 This is a schematic diagram of the defect-free detection spectrum of a phased array probe at the second detection point according to an embodiment of this application;

[0020] Figure 11 This is a schematic diagram of the detection spectrum of a phased array probe at a third detection point according to an embodiment of this application;

[0021] Figure 12 This is one of the flowcharts for a phased array detection method for weld crack defects in reheater block according to an embodiment of this application;

[0022] Figure 13 This is the second flowchart of a phased array detection method for weld crack defects in reheater block according to an embodiment of this application.

[0023] in, Figures 1 to 7 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0024] 100 reheater block, 110 reheater tube, 120 block, 130 weld, 140 crack, 200 phased array probe. Detailed Implementation

[0025] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0027] The following reference Figures 1 to 13 This application describes a phased array method for detecting weld crack defects in reheater block according to some embodiments.

[0028] like Figures 1 to 13 As shown, Figure 1 This is a schematic diagram of the reheater card block according to one embodiment of this application; Figure 2 This is one of the structural schematic diagrams of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application; Figure 3 This is a second schematic diagram of the structure of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application; Figure 4 This is the third schematic diagram of the structure of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application; Figure 5 This is the fourth schematic diagram of the structure of a comparative test block for detecting weld crack defects in a reheater block according to an embodiment of this application; Figure 6 This is a schematic diagram of the movement path of a phased array probe during detection according to an embodiment of this application; Figure 7 This is a schematic diagram of the movement trajectory of a phased array probe during detection according to an embodiment of this application; Figure 8 This is a schematic diagram of the detection spectrum of a phased array probe at the first detection point according to an embodiment of this application; Figure 9 This is a schematic diagram of a defect detection spectrum at the second detection point using a phased array probe according to an embodiment of this application. Figure 10 This is a schematic diagram of the defect-free detection spectrum of a phased array probe at the second detection point according to an embodiment of this application; Figure 11 This is a schematic diagram of the detection spectrum of a phased array probe at a third detection point according to an embodiment of this application; Figure 12 This is one of the flowcharts for a phased array detection method for weld crack defects in reheater block according to an embodiment of this application; Figure 13 This is the second flowchart of a phased array detection method for weld crack defects in reheater block according to an embodiment of this application.

[0029] like Figure 1 , Figure 6 and Figure 7 As shown in the figure, one embodiment of this application provides a phased array detection method for weld crack defects in a reheater block. This method is used to detect weld cracks between the reheater tube and the block. Along the direction from the reheater tube to the block, a first detection point, a second detection point, and a third detection point are sequentially arranged. The first detection point is located on the reheater tube, the second detection point is located on the weld, and the third detection point is located on the block. The phased array detection method for weld crack defects in the reheater block includes: adjusting the sensitivity of the phased array probe using a comparison test block; controlling the phased array probe to be perpendicular to the weld and moving it from one side of the reheater tube towards the side of the block, with the probe's movement trajectory being a sawtooth-shaped trajectory, and the trajectory sequentially passing through the first, second, and third detection points; acquiring the first echo value of the first detection point, the second echo value of the second detection point, and the third echo value of the third detection point; locating the detection path of the phased array probe based on the first and third echo values; and determining whether a weld crack defect exists based on the second echo value.

[0030] This application provides a phased array detection method for weld crack defects in reheater jacks. The method detects weld cracks between the reheater tube and the jack. Three detection points—a first detection point A, a second detection point B, and a third detection point C—are sequentially positioned along the direction from the reheater tube to the jack. These three points are used to spatially locate the detection path of the phased array probe, eliminating blind spots. The presence of weld crack defects is determined based on the echo values ​​from these three detection points. This method solves the problem of insufficient detection rate caused by the inability of conventional non-destructive testing methods to effectively detect weld cracks. Furthermore, this application develops the PL-DZ series of reheater jack comparison test blocks to simulate actual crack morphology, improving the detection sensitivity of the phased array probe and resolving the issue of inaccurate sensitivity calibration of the phased array probe.

[0031] Specifically, in recent years, with the deepening of peak shaving in thermal power units, the units have frequently been subjected to alternating thermal stress, leading to an increase in four-tube failure cases. Several power plants within the service area have experienced reheater block failures in recent years, seriously threatening the safe and stable operation of these power plants. Power plants urgently need to solve the technical challenges of detecting such defects. Traditional detection of reheater block weld cracks relies on conventional ultrasonic or radiographic methods. However, because the cracks originate at the weld root between the block and the reheater tube and extend inwards, conventional non-destructive testing methods cannot effectively detect these cracks, resulting in insufficient detection rates. Furthermore, the structure of these blocks means that there are currently no well-designed comparative test blocks or corresponding testing processes to detect these defects. Therefore, existing standard test blocks cannot simulate actual crack morphology, sensitivity settings rely on experience, have a high false positive rate, and require highly experienced operators, making it difficult to meet the rapid maintenance needs of thermal power units.

[0032] To address the shortcomings of existing technologies, such as Figure 1 , Figure 6 , Figure 7 and Figure 12As shown, this application proposes a phased array detection method for weld crack defects in reheater chucks, used to detect weld cracks between reheater tubes and chucks. Specifically, along the direction from the reheater tube to the chuck, a first detection point, a second detection point, and a third detection point are sequentially set. The first detection point is located on the reheater tube, the second detection point is located on the weld, and the third detection point is located on the chuck. These three locations are used to spatially locate the detection path of the phased array probe. That is, the detection process sequentially passes through the first, second, and third detection points. This is mainly because the weld between the reheater tube and the chuck is difficult to locate. By measuring the normal echo values ​​at the first and third detection points, it can be determined that 100% detection of the weld between the reheater tube and the chuck in the vertical direction has been completed during the detection process, achieving spatial positioning of the detection path of the phased array probe. Then, based on the echo value at the second detection point, it is determined whether a weld crack defect exists. The specific steps of the phased array detection method for reheater chuck weld crack defects are as follows:

[0033] S202, the sensitivity of the phased array probe is adjusted using a comparison test block;

[0034] S204, control the phased array probe to be perpendicular to the weld and move from the reheater tube side to the block side. The movement trajectory of the phased array probe is a sawtooth movement trajectory, and the movement trajectory passes through the first detection point, the second detection point and the third detection point in sequence.

[0035] S206, acquire the first echo value of the first detection point, the second echo value of the second detection point, and the third echo value of the third detection point;

[0036] S208, locate the detection path of the phased array probe based on the first echo value and the third echo value;

[0037] S210, determine whether there are crack defects in the weld based on the second echo value.

[0038] Specifically, such as Figure 1 As shown, the reheater clamp 100 includes a reheater tube 110 and a clamp 120. The reheater tube 110 and the clamp 120 are connected by a weld 130. A crack 140 in the weld between the reheater tube 110 and the clamp 120 is located at the weld between the clamp 120 and the outer wall of the reheater tube 110 and extends into the reheater tube. To improve the detection rate of crack 140, this application first uses a comparison test block to adjust the sensitivity of the phased array probe 200. The sensitivity of the phased array probe 200 is adjusted to the baseline level and the final detection level through gain compensation. After adjusting the sensitivity of the phased array probe 200, the reheater clamp 100 that actually needs to be tested is then tested.

[0039] First, along the direction from the reheater tube to the clamping block, three detection points are sequentially set: a first detection point A, a second detection point B, and a third detection point C. Detection point A is located on the reheater tube, detection point B is located on the weld, and detection point C is located on the clamping block. These three points are used to spatially locate the detection path of the phased array probe. The detection process involves sequentially passing through the first, second, and third detection points. This is primarily because the weld between the reheater tube and the clamping block is difficult to locate. By measuring the normal echo values ​​at the first and third detection points, it can be determined that 100% of the vertical direction of the weld between the reheater tube and the clamping block has been inspected, thus achieving spatial positioning of the phased array probe's detection path. Then, based on the echo value at the second detection point, it is determined whether there are cracks or defects in the weld.

[0040] By setting up three detection points (A, B, and C) for spatial positioning, blind spots in the scanning are eliminated, and crack defects are identified based on echo values. This effectively solves the problem of insufficient detection rate caused by the inability of conventional non-destructive testing methods to effectively detect weld cracks. Simultaneously, the PL-DZ series reheater block comparison test block was developed to simulate actual crack morphology, improving the detection sensitivity of the phased array probe and resolving the issue of inaccurate sensitivity calibration.

[0041] In specific applications, the phased array detection method for weld crack defects in reheater block can be specifically a method for phased array detection of weld defects in dissimilar steels in reheater block. The outer diameter of the reheater tube can be 52mm to 76mm, the wall thickness of the reheater tube can be 3.5mm to 11mm, and the wall thickness of the block can be 4mm to 11mm. The specific selection can be made according to the actual application conditions, and will not be listed here.

[0042] In some embodiments, optionally, such as Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 13 As shown, the sensitivity of the phased array probe is adjusted using a comparison test block. Specifically, this includes: controlling the phased array probe to detect the grooves on the comparison test block and adjusting the full-amplitude waveform height of the scan display to 60%–80%; performing a first gain compensation on the phased array probe to adjust its sensitivity to the reference level; and performing a second gain compensation on the phased array probe to adjust its sensitivity to the final detection level.

[0043] Specifically, such as Figure 13 As shown, in the phased array detection method for weld crack defects in reheater blocks, a comparison test block is used to adjust the sensitivity of the phased array probe, specifically including:

[0044] S302, control the phased array probe to detect the grooves on the comparison test block, and adjust the full-amplitude wave height of the scanning display to 60% to 80%;

[0045] S304 performs the first gain compensation on the phased array probe, adjusting the sensitivity of the phased array probe to the reference level;

[0046] S306 performs a second gain compensation on the phased array probe, adjusting the sensitivity of the phased array probe to the final detection level;

[0047] Specifically, taking a reheater clamp with an outer diameter of 57mm, an inner diameter of 49mm, and a wall thickness of 5.5mm as an example, let's illustrate this further. Figures 2 to 5 As shown, in order to adjust the sensitivity of the phased array probe, this application designed a detection comparison test block for weld crack defects in the reheater block. The reheater tube in the test block has an outer diameter of 57 mm and an inner diameter of 49 mm. The block wall thickness is 5.5 mm, and the block and reheater tube form a weld structure. Rectangular grooves are used to simulate crack defects. This detection comparison test block is a series of four blocks with groove depths of 1 mm, 2 mm, 3 mm, and 4 mm, respectively. Figure 2 As shown, the length of the rectangular groove in the test comparison block is 4mm. Figure 3 As shown, the length of the rectangular groove in the test comparison block is 3mm. Figure 4 As shown, the rectangular groove length in the test comparison block is 2mm. Figure 5 As shown, the rectangular groove length in the test comparison block is 1mm. The main function of the test comparison block is to detect and adjust the sensitivity of the phased array probe. The specific method for detecting and adjusting the sensitivity of the phased array probe is as follows: Taking a test comparison block with a groove depth of 1mm as an example, the test comparison block is scanned by the phased array probe to detect the maximum reflected wave of the 1mm deep rectangular groove at the corresponding position of the test block. The sensitivity is adjusted to 60% to 80% of the full-amplitude wave height displayed in the A-scan, and a gain of 6dB to 12dB for defect surface characteristic compensation is used as the reference sensitivity. At this time, the sensitivity of the phased array probe is adjusted to the reference level, and then the gain is adjusted by 6dB to 12dB as the detection sensitivity. At this time, the sensitivity of the phased array probe is adjusted to the final detection level. After the adjustment is completed, the actual reheater card block to be tested can be tested.

[0048] Furthermore, the specific steps of the phased array detection method for weld crack defects in the reheater block to be inspected are as follows:

[0049] S308 controls the phased array probe to be perpendicular to the weld and to move from one side of the reheater tube to the side of the clamping block. The movement trajectory of the phased array probe is a sawtooth-shaped movement trajectory, and the movement trajectory passes through the first detection point, the second detection point and the third detection point in sequence.

[0050] S310, acquire the first echo value of the first detection point, the second echo value of the second detection point, and the third echo value of the third detection point;

[0051] S312, locate the detection path of the phased array probe based on the first echo value and the third echo value;

[0052] S314, determine whether there are crack defects in the weld based on the second echo value.

[0053] By setting up three detection points (A, B, and C) for spatial positioning, blind spots in the scanning are eliminated, and crack defects are identified based on echo values. This effectively solves the problem of insufficient detection rate caused by the inability of conventional non-destructive testing methods to effectively detect weld cracks. Simultaneously, the PL-DZ series reheater block comparison test block was developed to simulate actual crack morphology, improving the detection sensitivity of the phased array probe and resolving the issue of inaccurate sensitivity calibration.

[0054] In specific applications, the test block for comparison is the PL-DZ test block. There are four types of PL-DZ test blocks: PL-DZ1, PL-DZ2, PL-DZ3, and PL-DZ4. The specific type can be selected according to the actual application, and will not be listed here.

[0055] In some embodiments, optionally, the groove depth h satisfies 1mm≤h≤4mm, and the first gain compensation and the second gain compensation are 6dB~12dB.

[0056] Specifically, by setting up a first detection point A, a second detection point B, and a third detection point C for spatial positioning to eliminate blind spots in the inspection, and combining this with a sawtooth-shaped moving trajectory to ensure 100% coverage of the weld in the vertical direction, and accurately judging crack defects based on the echo value of the second detection point, the problem of insufficient crack detection rate caused by structural limitations in conventional non-destructive testing methods is effectively solved. Simultaneously, by developing the PL-DZ series reheater card block comparison test block, specifically including grooves with a depth of 1mm to 4mm and employing two-stage gain compensation of 6dB to 12dB, the sensitivity is accurately calibrated from the baseline level to the final detection level, significantly improving the simulation accuracy of actual crack morphology, solving the problem of sensitivity calibration relying on experience and having a high misjudgment rate, and meeting the rapid maintenance needs of thermal power units.

[0057] In specific applications, the groove depth h can be set to 1mm, 2mm, 3mm, or 4mm, and the first gain compensation and second gain compensation can be set to 6dB, 7dB, 8dB, 9dB, 10dB, 11dB, or 12dB. These can be selected according to the actual usage and will not be listed here.

[0058] In some embodiments, optionally, such as Figure 1, Figure 6 and Figure 7 As shown, the wall thickness of the reheater tube is d, the wall thickness of the card block is H, the first echo value is DA1, the second echo value is DA2, and the third echo value is DA3. After locating the detection path of the phased array probe based on the first echo value and the third echo value, the method further includes: if the first echo value satisfies (d-0.2)mm≤DA1≤(d+0.2)mm and the third echo value satisfies (H-0.2)mm≤DA3≤(H+0.2)mm, then the spatial positioning of the detection path of the phased array probe is determined to be correct.

[0059] Specifically, such as Figure 1 , Figure 6 and Figure 7 As shown, the wall thickness of the reheater tube is set to d, the wall thickness of the clamp is H, the first echo value is DA1, the second echo value is DA2, and the third echo value is DA3. After locating the detection path of the phased array probe based on the first and third echo values, the phased array detection method for weld crack defects in the reheater clamp also includes: if the first echo value satisfies (d-0.2)mm≤DA1≤(d+0.2)mm, and the third echo value satisfies (H-0.2)mm≤DA3≤(H+0.2)mm, then the spatial positioning of the detection path of the phased array probe is determined to be correct. That is, the detection process must sequentially pass through the first, second, and third detection points. This is mainly because the weld between the reheater tube and the clamp is difficult to locate. By measuring the normal echo values ​​at the first and third detection points, it can be determined that 100% detection of the vertical direction of the weld between the reheater tube and the clamp has been completed during the detection process, thus achieving spatial positioning of the detection path of the phased array probe. Then, based on the echo value of the second detection point, it is determined whether there are cracks or defects in the weld.

[0060] In some embodiments, optionally, such as Figures 8 to 11 As shown, after determining that the spatial positioning of the phased array probe's detection path is correct, the following steps are also included: if the second echo value satisfies (2d-0.3)mm≤DA2≤(2d+0.3)mm, then it is determined that there are no crack defects in the weld; if the second echo value satisfies... If so, it is determined that the weld has a crack defect.

[0061] Specifically, after determining that the spatial positioning of the phased array probe's detection path is correct, the phased array detection method for weld crack defects in the reheater block also includes: if the second echo value satisfies (2d-0.3)mm≤DA2≤(2d+0.3)mm, then it is determined that there are no crack defects in the weld; if the second echo value satisfies... If so, it is determined that the weld has a crack defect.

[0062] Specifically, taking a reheater clamp with an outer diameter of 57mm, an inner diameter of 49mm, and a wall thickness of 5.5mm as an example, the wall thickness d of the reheater tube is 4mm, the wall thickness H of the clamp is 5.5mm, the first echo value DA1 is 4±0.2mm, the second echo value DA2 is 8±0.3mm or 6±0.3mm, and the third echo value DA3 is 5.5±0.2mm. For example... Figures 6 to 10 As shown,

[0063] After adjusting the instrument using the PL-DZ series comparison test block, place the phased array probe as follows: Figure 6 and Figure 7 At the indicated location, a small-angle line scan is performed perpendicular to the weld. The phased array probe moves horizontally from the reheater tube position to the clamping block position, constituting one scan. During the scan, it sequentially passes through the first detection point A, the second detection point B, and the third detection point C, and performs a sawtooth scan perpendicular to the weld. During the sawtooth scan, the phased array probe movement trajectories overlap by 10%. The detection process involves sequentially passing through positions A, B, and C, mainly because the weld between the reheater tube and the clamping block is difficult to locate. By measuring the normal echo values ​​at A and C, it can be determined that 100% vertical detection of the weld between the reheater tube and the clamping block has been completed during the detection process. During the detection process, the instrument value changes from the characteristic echo value at position A to the value at position B, and then to the characteristic echo value at position C. Completing one cycle of this process constitutes one defect scan.

[0064] like Figure 8 As shown, the phased array probe at the first detection point A has a corresponding waveform. When the phased array probe passes the first detection point A, the actual detection value of the first detection point A is 4±0.2mm, which is the characteristic echo depth of the first echo DA1. This is a normal waveform of the reheater tube, indicating that the phased array probe is in contact with the first detection point A.

[0065] like Figure 9 As shown, the phased array probe at the second detection point B corresponds to the phased array probe's waveform. When the phased array probe passes the second detection point B, if the instrument displays a value (the second echo value) of DA2 of 6 ± 0.3 mm, it indicates the presence of a crack defect at that location, and the probe is considered unqualified.

[0066] like Figure 10 As shown, the phased array probe at the second detection point B corresponds to the spectrum. When the phased array probe passes the second detection point B, the actual measured echo depth at this location, i.e., the second echo value DA2, is 8 ± 0.3 mm. If the instrument displays a value that meets the above requirements, then there is no crack defect at this location.

[0067] like Figure 11As shown, the corresponding spectrum of the phased array probe at the third detection point C is displayed. When the phased array probe passes the third detection point C, the actual detection value at the third detection point C is DA3, which is 5.5±0.2mm. This is a normal echo waveform of the card block. When the value displayed by the instrument meets the above requirements, it indicates that the phased array probe is in contact at the third detection point C.

[0068] By setting a first detection point A, a second detection point B, and a third detection point C on the reheater block, spatial positioning is used to eliminate blind spots in the scanning process. Combined with a sawtooth-shaped moving trajectory, 100% coverage of the weld in the vertical direction is ensured. The positioning is determined based on the echo depth, i.e., the echo value. When the first echo value DA1 meets (d±0.2) mm and the third echo value DA3 meets (H±0.2) mm, the positioning is considered correct, providing a quantitative verification basis for the spatial positioning of the detection path and significantly improving the positioning reliability. Furthermore, the crack defect is accurately determined based on the detection value of the second echo value DA2 of the second detection point, effectively solving the problem of insufficient crack detection rate caused by structural limitations in conventional non-destructive testing methods.

[0069] In specific applications, the outer diameter of the reheater tube can be 52mm to 76mm, the wall thickness d of the reheater tube can be 3.5mm to 11mm, and the wall thickness H of the clamp can be 4mm to 11mm. The specific selection can be made according to the actual application conditions, and will not be listed here.

[0070] In some embodiments, the phased array probe may optionally be in a depth focusing mode, where the focusing depth S satisfies: S = 1.5(d + H).

[0071] Specifically, a depth-focusing mode is adopted, with a specific focusing depth S = 1.5(d+H) to optimize the concentration of sound beam energy, significantly improving the signal-to-noise ratio of microcracks; finally, the crack defect is accurately judged based on the echo value of the second detection point, effectively solving the problem of insufficient crack detection rate caused by structural limitations in conventional non-destructive testing methods.

[0072] In some embodiments, optionally, the phased array probe's movement trajectory is a sawtooth movement trajectory, specifically including: controlling the phased array probe to scan with a sawtooth movement trajectory, wherein the overlap rate between adjacent movement trajectories is greater than or equal to 10%.

[0073] Specifically, such as Figure 6 and Figure 7 As shown, Figure 6This is a schematic diagram of the horizontal movement path or direction of the phased array probe along the first detection point A, the second detection point B, and the third detection point C during the detection process. The probe must pass through positions A, B, and C in sequence during the detection process, mainly because the weld between the reheater tube and the clamp block is difficult to locate. By measuring the normal echo values ​​at A and C, it can be determined whether 100% detection of the vertical direction of the weld between the reheater tube and the clamp block has been completed during the detection process. Figure 7 This diagram illustrates the zigzag scanning trajectory of a phased array probe along a vertical weld during inspection. The phased array probe is moved sequentially through three locations (A, B, and C) on the reheater block and weld, while simultaneously performing a zigzag scan along the vertical weld. During the zigzag scan, the phased array probe's movement trajectories overlap by 10%, thus completing a full-coverage inspection of weld crack defects in the reheater block.

[0074] Spatial positioning is achieved by setting up a first detection point A, a second detection point B, and a third detection point C to eliminate blind spots in the inspection. Combined with a sawtooth-shaped movement trajectory and an overlap rate of ≥10%, the weld area is ensured to be completely covered. The accuracy of the detection path positioning is quantified and verified using the first and second echo values. Furthermore, a depth-focusing mode is employed to enhance the sound beam penetration and the ability to identify minute cracks. Finally, the second echo value from the second detection point is used to accurately determine crack defects, completely resolving the problem of missed detections caused by complex structures. Simultaneously, the PL-DZ series comparison test blocks, featuring 1mm–4mm grooves and two-stage gain compensation of 6dB–12dB, achieve precise sensitivity calibration, significantly reducing the false positive rate and meeting the needs of efficient maintenance of thermal power units.

[0075] In specific applications, the overlap rate between adjacent movement trajectories can be set to 12%, 15%, or 20%, depending on the actual usage, and will not be listed here.

[0076] In some embodiments, optionally, the phased array detection method for weld crack defects in reheater block further includes: the scanning angle θ of the phased array probe satisfies: 0°≤θ≤10°.

[0077] Specifically, by setting the scanning angle θ of the phased array probe to satisfy: 0°≤θ≤10°, the intensity of the reflected signal is maximized by ensuring that the sound beam is incident perpendicularly, thereby improving the accuracy of the phased array probe in detecting crack defects.

[0078] In practical applications, the scanning angle of the phased array probe can be set to 0°, 3°, 5°, 8° or 10°, which can be selected according to the actual use situation, and will not be listed here.

[0079] In some embodiments, the parameters of the phased array probe may optionally satisfy the following: the element step is set to 1 to 3.

[0080] Specifically, by limiting the array element step size to 1 to 3, the detection resolution and efficiency are improved, thereby enhancing the accuracy of the phased array probe in detecting crack defects.

[0081] In some embodiments, the coupling agent may optionally be a sound-permeable material, including engine oil, chemical paste, glycerin, or water.

[0082] Specifically, the coupling agent should be one with good sound transmission properties and without damaging the surface of the workpiece being inspected, such as machine oil, chemical paste, glycerin, and water, to ensure efficient sound energy transmission and signal stability, and improve the accuracy of phased array probes in detecting crack defects.

[0083] Specifically, the phased array detection method for weld crack defects in reheater block according to this application has the following specific operating procedure: Taking a reheater block with an outer diameter of 57mm, an inner diameter of 49mm, and a wall thickness of 5.5mm as an example, the wall thickness d of the reheater tube is 4mm, the wall thickness H of the block is 5.5mm, the first echo value DA1 is 4±0.2mm, the second echo value DA2 is 8±0.3mm or 6±0.3mm, and the third echo value DA3 is 5.5±0.2mm. For example... Figures 6 to 10 As shown,

[0084] First, the PL-DZ series of comparison test blocks were designed. There are four types of comparison test blocks: PL-DZ1, PL-DZ2, PL-DZ3, and PL-DZ4. The rectangular groove lengths of these test blocks are 1mm, 2mm, 3mm, and 4mm. The main function of these test blocks is for detection and sensitivity adjustment. The method for sensitivity adjustment is as follows: Taking a comparison test block with a groove depth of 1mm as an example, the test block is scanned using a phased array probe. The maximum reflected wave of the 1mm deep rectangular groove at the corresponding position of the test block is detected. The sensitivity is adjusted to 60%–80% of the full-amplitude wave height displayed on the A-scan. A gain of 6dB–12dB for defect surface characteristic compensation is used as the baseline sensitivity. At this point, the sensitivity of the phased array probe is adjusted to the baseline level, and then a gain of 6dB–12dB is used as the detection sensitivity. Finally, the sensitivity of the phased array probe is adjusted to the final detection level. After adjustment, the actual reheater block to be tested can be inspected.

[0085] To ensure penetration, select a phased array probe with the smallest possible active aperture; to ensure sufficient detection sensitivity (signal-to-noise ratio), select a phased array probe with the highest possible frequency; thin-film wedges or flat wedges should be used during detection; for phased array detection of dissimilar steel weld defects in reheater blocks, line scanning is recommended, with a minimum angle range of 0°–10° and an element step of 1–3; phased array ultrasonic testing uses depth focusing, with the focusing depth set to 1.5 times the sum of the reheater tube thickness d and the M-type block thickness H. The coupling agent should have good sound transmission properties and not damage the surface of the inspected workpiece, such as machine oil, chemical paste, glycerin, and water. Defect assessment is performed as follows:

[0086] If the defect is determined to be a crack, it is rated as Level III and is unacceptable; if the defect is located between the weld and the pipe and its maximum reflected wave amplitude is greater than or equal to the reference sensitivity, it is rated as Level III and is unacceptable; for smaller signals that are not sufficient to be determined as cracks, they should be recorded and their locations should be recorded and tracked for easy review.

[0087] After adjusting the instrument using the PL-DZ series comparison test block, place the phased array probe as follows: Figure 6 At the indicated location, a small-angle line scan is performed perpendicular to the weld. The phased array probe moves from the reheater tube position to the clamping block position, constituting one scan. During the scan, it sequentially passes through the first detection point A, the second detection point B, and the third detection point C, and performs a sawtooth scan perpendicular to the weld. During the sawtooth scan, the phased array probe movement trajectories overlap by 10%. The detection process involves sequentially passing through positions A, B, and C, mainly because the weld between the reheater tube and the clamping block is difficult to locate. By measuring the normal echo values ​​at A and C, it can be determined that 100% detection of the vertical direction of the weld between the reheater tube and the clamping block has been completed during the detection process. During the detection process, the instrument value changes from the characteristic echo value at position A to the value at position B, and then to the characteristic echo value at position C. Completing one cycle of this process constitutes one defect scan.

[0088] like Figure 8 As shown, the phased array probe at the first detection point A has a corresponding waveform. When the phased array probe passes the first detection point A, the actual detection value of the first detection point A is 4±0.2mm, which is the characteristic echo depth of the first echo DA1. This is a normal waveform of the reheater tube, indicating that the phased array probe is in contact with the first detection point A.

[0089] like Figure 9 As shown, the phased array probe at the second detection point B corresponds to the phased array probe's waveform. When the phased array probe passes the second detection point B, if the instrument displays a value (the second echo value) of DA2 of 6 ± 0.3 mm, it indicates the presence of a crack defect at that location, and the probe is considered unqualified.

[0090] like Figure 10 As shown, the phased array probe at the second detection point B corresponds to the spectrum. When the phased array probe passes the second detection point B, the actual measured echo depth at this location, i.e., the second echo value DA2, is 8 ± 0.3 mm. If the instrument displays a value that meets the above requirements, then there is no crack defect at this location.

[0091] like Figure 11 As shown, the corresponding spectrum of the phased array probe at the third detection point C is displayed. When the phased array probe passes the third detection point C, the actual detection value at the third detection point C is DA3, which is 5.5±0.2mm. This is a normal echo waveform of the card block. When the value displayed by the instrument meets the above requirements, it indicates that the phased array probe is in contact at the third detection point C.

[0092] By setting a first detection point A, a second detection point B, and a third detection point C on the reheater block, spatial positioning is used to eliminate blind spots in the scanning process. Combined with a sawtooth-shaped moving trajectory, 100% coverage of the weld in the vertical direction is ensured. The positioning is determined based on the echo depth, i.e., the echo value. When the first echo value DA1 meets (d±0.2) mm and the third echo value DA3 meets (H±0.2) mm, the positioning is considered correct, providing a quantitative verification basis for the spatial positioning of the detection path and significantly improving the positioning reliability. Furthermore, the crack defect is accurately determined based on the detection value of the second echo value DA2 of the second detection point, effectively solving the problem of insufficient crack detection rate caused by structural limitations in conventional non-destructive testing methods.

[0093] In the description of this application, the term "multiple" refers to two or more. Unless otherwise expressly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0094] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0095] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A phased array detection method for weld crack defects in reheater block, characterized in that, For detecting weld cracks between a reheater tube and a retaining block, a first detection point, a second detection point, and a third detection point are sequentially arranged along the direction from the reheater tube to the retaining block. The first detection point is located on the reheater tube, the second detection point is located on the weld, and the third detection point is located on the retaining block. The phased array detection method for weld crack defects in the reheater retaining block includes: The sensitivity of the phased array probe was adjusted using a comparison test block; The phased array probe is controlled to be perpendicular to the weld and move from one side of the reheater tube to the side of the clamping block. The moving trajectory of the phased array probe is a sawtooth moving trajectory, and the moving trajectory passes through the first detection point, the second detection point and the third detection point in sequence. Obtain the first echo value of the first detection point, the second echo value of the second detection point, and the third echo value of the third detection point; The detection path of the phased array probe is located based on the first echo value and the third echo value; The presence of cracks or defects in the weld is determined based on the second echo value.

2. The phased array detection method for weld crack defects in reheater block according to claim 1, characterized in that, The adjustment of the sensitivity of the phased array probe using a comparison test block specifically includes: The phased array probe is controlled to detect the grooves on the comparison test block, and the full-amplitude wave height of the scanning display is adjusted to 60% to 80%. Perform first gain compensation on the phased array probe to adjust the sensitivity of the phased array probe to the reference level; A second gain compensation is performed on the phased array probe to adjust its sensitivity to the final detection level.

3. The phased array detection method for weld crack defects in reheater blocks according to claim 2, characterized in that, The depth h of the groove satisfies 1mm≤h≤4mm, and the first gain compensation and the second gain compensation are 6dB~12dB.

4. The phased array detection method for weld crack defects in reheater block according to claim 1, characterized in that, The wall thickness of the reheater tube is d, the wall thickness of the card block is H, the first echo value is DA1, the second echo value is DA2, and the third echo value is DA3. After locating the detection path of the phased array probe based on the first echo value and the third echo value, the method further includes: If the first echo value satisfies (d-0.2)mm≤DA1≤(d+0.2)mm and the third echo value satisfies (H-0.2)mm≤DA3≤(H+0.2)mm, then the spatial positioning of the detection path of the phased array probe is determined to be correct.

5. The phased array detection method for weld crack defects in reheater block according to claim 4, characterized in that, After determining that the spatial positioning of the detection path of the phased array probe is correct, the method further includes: If the second echo value satisfies (2d-0.3)mm≤DA2≤(2d+0.3)mm, then the weld is determined to be free of crack defects. The weld is then determined to have a crack defect.

6. The phased array detection method for weld crack defects in reheater block according to claim 4, characterized in that, The phased array probe has a depth focusing mode, and the focusing depth S satisfies: S = 1.5(d + H).

7. The phased array detection method for reheater block weld crack defects according to any one of claims 1 to 6, characterized in that, The phased array probe's movement trajectory is a sawtooth-shaped trajectory, specifically including: The phased array probe is controlled to scan in a sawtooth-shaped movement trajectory, with an overlap rate of greater than or equal to 10% between adjacent movement trajectories.

8. The phased array detection method for reheater block weld crack defects according to any one of claims 1 to 6, characterized in that, The phased array detection method for weld crack defects in the reheater block also includes: The scanning angle θ of the phased array probe satisfies: 0°≤θ≤10°.

9. The phased array detection method for reheater block weld crack defects according to any one of claims 1 to 6, characterized in that, The parameters of the phased array probe satisfy the following: the array element step is set to 1 to 3.

10. The phased array detection method for weld crack defects in reheater block according to any one of claims 1 to 6, characterized in that, The coupling agent is made of a sound-permeable material, including engine oil, chemical paste, glycerin, or water.

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