A kind of tank weld X-ray digitization nondestructive testing system

Abstract

The present application belongs to the technical field of storage tank weld detection, and provides a kind of storage tank weld X ray digitization nondestructive testing system, comprising: detection area identification module: obtain storage tank weld design data and combine weld appearance features, judge whether the area to be detected is multi-layer weld interlayer transition area;Angle interval determination module: if so, then extract the physical parameters of weld, combine the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the physical parameters of weld, and the relationship between the relationship between the relationship between the relationship between the relationship between the relationship between the angle of inclination and the physical parameters is constructed by combining the penetration thickness ratio, and the angle of inclination interval is obtained;Wherein, the physical parameters of weld include: the number of weld layers and weld thickness. The problem that false image is formed by X ray scattering caused by irregular interface in multi-layer weld interlayer transition zone, which easily leads to defect misjudgment, and the problem that the detection efficiency is unbalanced due to the low defect detection rate caused by the subjective risk assessment and the blind angle selection in traditional detection is optimized, finally the accuracy and reliability of storage tank weld X ray detection are improved, and the safety evaluation effect of storage tank is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of storage tank weld inspection technology, specifically a storage tank weld X-ray digital non-destructive testing system. Background Technology

[0002] Weld inspection of storage tanks is a key link in ensuring the safe operation of storage tanks in the petroleum, chemical and other fields. The core is to check for defects such as weld cracks, porosity and incomplete penetration to prevent media leakage. It needs to cover the entire range of the welded joint, and can also avoid safety risks in advance and extend the service life of the storage tank.

[0003] Typically, image sensors are used for surface inspection of tank welds. However, when image sensors cannot acquire deep images due to the specific characteristics of the weld, X-ray inspection is required to correct or supplement the data. Multimodal fusion of image sensors and X-ray inspection can improve the defect detection rate and reduce the risk of missed detection.

[0004] However, when using X-rays for inspection, because multi-layer welds are welded layer by layer, the transition zone between layers is not a smooth interface. Instead, it contains irregular fusion lines, tiny unfused gaps, and weld slag residue. When X-rays pass through these areas, they will be scattered in a non-direct manner due to the unevenness of the interface (for example, the rays originally travel in a straight line, but turn in other directions after encountering a raised fusion line). These scattered rays do not carry defect information, but they will be captured by the detector, forming blurry "cloud-like" or "strip-like" artifacts. These artifacts on the image may be misjudged as defects, thereby reducing the overall inspection efficiency and affecting the safety assessment of the storage tank.

[0005] Therefore, the present invention provides a digital non-destructive testing system for X-ray welds of storage tanks. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by this invention to solve its technical problem is: a digital non-destructive testing system for X-ray welds of storage tanks, comprising:

[0008] Detection area identification module: acquires tank weld design data and combines weld appearance features to determine whether the area to be detected is a transition area between multiple weld layers;

[0009] Angle range determination module: If so, extract the physical parameters of the weld, combine the radiographic thickness ratio to construct the relationship between the tilt angle and the physical parameters, and obtain the tilt angle range;

[0010] The physical parameters of the weld include: the number of weld layers and the weld thickness;

[0011] Regional Risk Analysis Module: Acquires historical defect occurrence data and historical defect omission data for the area to be inspected. Combines the analysis of defect occurrence and defect omission to assess the defect risk level of the area to be inspected. Based on the defect risk level results, selects the upper or lower limit of the tilt angle range as the final tilt angle.

[0012] As a further aspect of the present invention: the process of determining whether the area to be detected is a transition area between layers of a multi-layer weld is as follows:

[0013] The design data of the tank weld is used to determine whether there is a potential multi-layer weld area. If so, the weld appearance feature identification process is executed.

[0014] If at least 3 consecutive fusion lines with a length of at least 8 mm are observed within a 1-meter weld length, and there is a tendency for delamination along the thickness direction, then the macroscopic characteristics meet the standard.

[0015] If at least two out of the three locations observe a continuous stepped structure, and the number of steps matches the number of layers in the design, then the microscopic features meet the requirements.

[0016] If both macroscopic and microscopic characteristics meet the standards, it is determined to be a transition zone between layers of multi-layer welds.

[0017] As a further aspect of the present invention: the process for determining whether there is a potential multi-layer weld area is as follows:

[0018] Extract the number of weld layers in the area to be inspected. If the number of weld layers is greater than or equal to 2, it is determined to be a potential multi-layer weld area. If the number of weld layers is equal to 1, it is determined to be a non-multi-layer weld area.

[0019] As a further aspect of the present invention: the process of obtaining the tilt angle range is as follows:

[0020] Five measuring points in a quincunx pattern were selected in the area to be inspected using an ultrasonic thickness gauge to measure the weld thickness. The average thickness of the five measuring points was then calculated as the effective weld thickness.

[0021] An equivalent penetration thickness calculation formula is introduced, and the lower limit of the tilt angle is determined based on the number of weld layers, thus obtaining the calculation method for the lower limit of the tilt angle.

[0022] The calculation method for the upper limit of the tilt angle is derived by substituting the maximum value of the radiographic thickness ratio into the equivalent penetration thickness formula.

[0023] Substituting the number of weld layers and the effective weld thickness into the formula for calculating the lower limit of the tilt angle, the lower limit of the tilt angle is obtained. Substituting the maximum value of the radiographic thickness ratio into the formula for calculating the upper limit of the tilt angle, the upper limit of the tilt angle is obtained.

[0024] As a further aspect of this invention: the process of analyzing both defect occurrence and defect missed detection is as follows:

[0025] Obtain the defect occurrence assessment coefficient and the defect missed detection assessment coefficient;

[0026] If the defect occurrence assessment coefficient does not exceed the standard, the defect occurrence is judged to be of low risk; if the defect occurrence assessment coefficient exceeds the standard, the defect occurrence is judged to be of high risk.

[0027] If the defect omission assessment coefficient does not exceed the standard, the defect omission risk is determined to be low; if the defect omission assessment coefficient exceeds the standard, the defect omission risk is determined to be high.

[0028] As a further aspect of the present invention: the calculation process of the defect occurrence evaluation coefficient is as follows:

[0029] The number of defects per unit length and the number of defect recurrences per unit length are calculated using historical defect data.

[0030] The defect occurrence assessment coefficient is obtained by multiplying the number of defects per unit length by the number of defect recurrences per unit length.

[0031] As a further aspect of the present invention: the calculation process for the defect omission evaluation coefficient is as follows:

[0032] Calculate the number of missed defects per unit length and the number of recurrences of missed defects per unit length using historical defect missed detection data;

[0033] The defect omission evaluation coefficient is obtained by multiplying the number of missed inspections per unit length with the number of recurrences of missed inspections per unit length.

[0034] As a further aspect of the present invention: the calculation process for the number of defects per unit length and the number of defect recurrences per unit length is as follows:

[0035] Historical defect data includes the number of times defects occurred in the area to be inspected within a historical period and the location of the defects.

[0036] The total number of defects that have occurred in the area to be inspected throughout history is counted. The ratio of the total number of defects that have occurred throughout history to the effective length of the area to be inspected is calculated to obtain the number of defects per unit length.

[0037] The number of historical defects occurring in the same location within the area to be inspected is counted as the defect recurrence count. The maximum defect recurrence count is extracted, and the ratio of the maximum defect recurrence count to the effective length of the area to be inspected is calculated to obtain the defect recurrence count per unit length.

[0038] As a further aspect of the present invention: the calculation process for the number of missed detections per unit length and the number of recurrences of missed detections per unit length is as follows:

[0039] Historical defect omission data includes the number of times the area to be inspected was not detected during the initial inspection within a historical period, the number of times it was detected during subsequent re-inspections, and the location of the missed defects;

[0040] The total number of historical missed detections in the area to be detected is counted, and the ratio of the total number of historical missed detections to the effective length of the area to be detected is calculated to obtain the number of missed detections per unit length.

[0041] The number of times the detection area is missed in the same position is counted as the number of missed recurrences. The maximum value of the number of missed recurrences is extracted, and the ratio of the maximum value of the number of missed recurrences to the effective length of the detection area is calculated to obtain the number of missed recurrences per unit length.

[0042] As a further aspect of the present invention, the process of determining the final tilt angle is as follows:

[0043] If the defect is determined to have a high risk of occurrence or a high risk of missed detection, then the defect risk level of the area to be inspected is high, and the upper limit of the tilt angle range is selected.

[0044] If the risk of defect occurrence is determined to be low and the risk of defect failure is determined to be low, then the defect risk level of the area to be inspected is low, and the lower limit of the tilt angle range is selected.

[0045] The beneficial effects of this invention are as follows:

[0046] This invention combines design data with appearance feature recognition to distinguish between the transition area and non-transition area of ​​multi-layer welds, reducing the problem of misjudgment based solely on the number of layers, improving the recognition accuracy of the transition area between multi-layer welds, effectively eliminating areas without the risk of scattering artifacts, and reducing subsequent invalid inspection operations.

[0047] This invention calculates the angle range by combining the physical parameters of the weld with the radiographic thickness ratio, ensuring that the tilt angle within the range can effectively avoid the irregular interface between the layers of the multi-layer weld transition zone, reduce cloud-like and strip-like artifacts caused by scattered rays, reduce misjudgment of defects, and meet the X-ray penetration requirements to prevent imaging blurring or insufficient penetration due to improper angle.

[0048] This invention prioritizes detection targets based on risk levels. For high-risk areas, the upper limit of the angle range is selected to maximize the suppression of scattered ray artifacts, improve the defect detection rate, and avoid safety hazards caused by missed detections. For low-risk areas, the lower limit of the angle range is selected to reduce radiation energy consumption and detection time while meeting the basic detection rate, thus balancing detection efficiency.

[0049] This invention optimizes the problem of X-ray scattering artifacts caused by irregular interfaces in the transition zone between layers of multi-layer welds, which easily leads to misjudgment of defects. It also addresses the problem of low defect detection rate and imbalance between detection efficiency caused by blind angle selection and subjective risk assessment in traditional detection. Ultimately, it improves the accuracy and reliability of X-ray detection of tank welds and ensures the effectiveness of tank safety assessment. Attached Figure Description

[0050] The invention will now be further described with reference to the accompanying drawings.

[0051] Figure 1 This is an architecture diagram of a digital non-destructive testing system for X-ray welds of a storage tank according to the present invention;

[0052] Figure 2 This is a flowchart of the steps of a digital non-destructive testing method for X-ray welds of a storage tank according to the present invention. Detailed Implementation

[0053] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0054] Example 1

[0055] Please see Figure 1 As shown in the figure, an X-ray digital non-destructive testing system for tank welds according to an embodiment of the present invention includes:

[0056] Detection area identification module: acquires tank weld design data and combines weld appearance features to determine whether the area to be detected is a transition area between multiple weld layers;

[0057] In this module, the design data of the tank weld is obtained, which is retrieved from the basic weld database of the tank to be inspected.

[0058] Extract the number of weld layers in the area to be inspected. If the number of weld layers is greater than or equal to 2, it is determined to be a potential multi-layer weld area. If the number of weld layers is equal to 1, it is determined to be a non-multi-layer weld area.

[0059] If the area is determined to be a potential multi-layer weld area, then the weld appearance feature recognition process is executed.

[0060] Specifically, the weld appearance feature identification process includes:

[0061] A high-definition industrial camera (resolution ≥ 1080P) was used to perform a full-length scan of the potential multi-layer weld area to observe the interlayer fusion line;

[0062] Take a close-up photo (magnified 5-8 times) every 100mm along the length of the weld, focusing on whether there are discontinuous dark gray linear traces (fusion lines are the interface marks of incomplete fusion when multiple weld layers overlap, and single-layer welds do not have this feature).

[0063] Within a 1-meter weld length, if ≥3 consecutive fusion lines with a length ≥8mm are observed, and there is a tendency for delamination along the thickness direction (e.g., 1-2 lines on the top and bottom), then the macroscopic characteristics meet the standard; otherwise, the macroscopic characteristics do not meet the standard.

[0064] Using a portable endoscope, one can penetrate into the tiny grooves on the weld surface (1-3 mm deep) to observe the interlayer lap staircase.

[0065] In areas where macroscopic features meet the standards, three points are randomly selected (one at the center of the weld and one on each side). The endoscope probe is inserted at a 45° angle to the weld surface to observe whether there are stepped protrusions (the 0.3-1mm height difference formed by the accumulation at the edge of each weld layer is direct evidence of multiple layers).

[0066] If at least two out of the three locations show a continuous stepped structure, and the number of steps matches the number of designed layers (e.g., if the design has four layers, observe three to four steps), then the microscopic features meet the standard; otherwise, the microscopic features do not meet the standard.

[0067] If both macroscopic and microscopic characteristics meet the standards, it is determined to be a multi-layer weld transition zone.

[0068] If the macroscopic or microscopic characteristics do not meet the standards, it is determined to be a non-multilayer weld interlayer transition area.

[0069] In this embodiment, the detection and identification module first retrieves the weld design data from the weld base database of the storage tank to be inspected, extracts the number of weld layers in the area to be inspected, and if the number of layers is ≥2, it is determined to be a potential multi-layer weld area. Then, the weld appearance feature identification process is executed. First, a high-definition industrial camera with a resolution ≥1080P is used to scan the entire length of the potential area. The macroscopic feature standard is to observe ≥3 continuous fusion lines with a length ≥8mm and a layering trend along the thickness direction within 1 meter. Then, a portable endoscope is used to penetrate into the micro grooves 1-3mm deep on the weld surface. Three points are randomly selected in the macroscopic standard area, including the weld center and both sides. If there are ≥2 points with a stepped protrusion of 0.3-1mm in height and the number of steps matches the design layer number, it is a microscopic feature standard. Finally, it is determined to be a multi-layer weld interlayer transition area only when both macroscopic and microscopic features meet the standard. If any feature does not meet the standard, it is determined to be a non-multi-layer weld interlayer transition area.

[0070] It has the following functions: by combining design data with appearance feature recognition, it can distinguish between the transition area and non-transition area of ​​multi-layer welds, reduce the problem of misjudgment based solely on the number of layers, improve the recognition accuracy of the transition area between multi-layer welds, effectively eliminate areas without the risk of scattering artifacts, and reduce subsequent invalid inspection operations.

[0071] Based on the identification results of the detection area, the subsequent physical parameter extraction and tilt angle calculation process is only triggered when the module determines that it is a transition area between layers of multi-layer welds. If it is determined to be a non-transition area, there is no need to start tilt angle optimization. The detection is directly performed according to the conventional multi-layer weld parameters, which reduces the mismatch of angle calculation caused by misjudgment of the area (such as adjusting the angle of the non-transition area as a transition area, which will increase the detection cost or generate new interference), and ensures the relevance and rationality of the angle range determination.

[0072] Angle range determination module: If so, extract the physical parameters of the weld, combine the radiographic thickness ratio to construct the relationship between the tilt angle and the physical parameters, and obtain the tilt angle range;

[0073] The physical parameters of the weld include: the number of weld layers and the weld thickness;

[0074] In this module, the number of weld layers in the area to be inspected is used;

[0075] Five measuring points in a quincunx pattern were selected in the area to be inspected using an ultrasonic thickness gauge to measure the weld thickness. The average thickness of the five measuring points was then calculated as the effective weld thickness.

[0076] Based on industry standards for X-ray inspection of tank welds and in combination with the inspection scenario and the performance of the inspection equipment, those skilled in the art have determined the maximum value of the transmission thickness ratio in a single-wall X-ray inspection scenario, wherein the transmission thickness ratio is the ratio of the equivalent penetration thickness to the effective thickness of the weld.

[0077] Introducing the formula for calculating equivalent penetration thickness, ,in, The tilt angle of the X-ray;

[0078] The lower limit of the tilt angle is determined based on the number of weld layers. The more weld layers there are, the stronger the interlayer scattering, requiring a larger angle to suppress artifacts. The formula for calculating the lower limit of the tilt angle is: Where N is the number of weld layers and T is the effective weld thickness. This is the lower limit of the tilt angle;

[0079] Based on the maximum transmission thickness ratio, and by substituting this maximum value into the equivalent penetration thickness formula, the formula for calculating the upper limit of the tilt angle is as follows: ,in, This is the upper limit of the tilt angle. This represents the maximum value of the transmission thickness ratio;

[0080] Substituting the number of weld layers and the effective weld thickness into the formula for calculating the lower limit of the tilt angle, the lower limit of the tilt angle is obtained. Substituting the maximum value of the radiographic thickness ratio into the formula for calculating the upper limit of the tilt angle, the upper limit of the tilt angle is obtained.

[0081] In this embodiment, the angle interval determination module first extracts the number of weld layers in the area to be inspected from the weld basic database and calculates the average thickness as the effective weld thickness. Then, based on the industry standard for X-ray inspection of tank welds, it determines the maximum value of the radiographic thickness ratio in combination with the inspection scenario and equipment performance. Subsequently, it calculates the upper and lower limits of the angle using formulas. The lower limit is combined with the number of weld layers and the effective thickness (the more layers and the greater the thickness, the larger the lower limit angle, in order to initially suppress interlayer scattering). The upper limit is derived from the maximum value of the radiographic thickness ratio (combined with the equivalent penetration thickness formula to ensure penetration compliance). Finally, the calculated upper and lower limits of the angle are integrated to form the tilt angle interval.

[0082] It has the following functions: by combining the physical parameters of the weld and the ratio of the radiographic thickness to calculate the angle range, it ensures that the tilt angle within the range can effectively avoid the irregular interface between the layers of the multi-layer weld transition zone, reduce the "cloud-like" and "strip-like" artifacts caused by scattered rays, reduce the misjudgment of defects, and meet the X-ray penetration requirements to prevent imaging blurring or insufficient penetration caused by improper angle.

[0083] The output tilt angle range is a calculated reasonable angle range, which reduces the subjective arbitrariness when subsequent modules select angles and lays a data foundation for the regional risk analysis module to determine the final tilt angle in combination with the risk level.

[0084] Regional Risk Analysis Module: Obtain historical defect occurrence data and historical defect omission data for the area to be inspected. Combining the two dimensions of defect occurrence and defect omission, assess the defect risk level of the area to be inspected. Based on the defect risk level results, select the upper or lower limit of the tilt angle range as the final tilt angle.

[0085] It should be noted that the reason for selecting the upper and lower limits of the tilt angle range based on the defect risk level is that the defect risk level determines the priority of the detection target, the target priority matches the core function of the tilt angle, the essence of the tilt angle is to balance the defect detection rate and the detection efficiency, and the risk level defines these two targets. Ultimately, the higher the risk, the higher the priority is to ensure the detection rate (select the upper limit), and the lower the risk, the higher the priority is to balance efficiency (select the lower limit).

[0086] In this module, historical defect data and historical missed defect data of the area to be inspected are retrieved from the weld base database of the storage tank to be inspected.

[0087] Among them, historical defect data includes the number of defects and the location of defects in the area to be inspected within a historical period (3-5 years);

[0088] The total number of defects that have occurred in the area to be inspected throughout history is counted. The ratio of the total number of defects that have occurred throughout history to the effective length of the area to be inspected is calculated to obtain the number of defects per unit length.

[0089] The number of historical defects occurring in the same location in the area to be inspected is counted as the defect recurrence count. The maximum defect recurrence count is extracted, and the ratio of the maximum defect recurrence count to the effective length of the area to be inspected is calculated to obtain the defect recurrence count per unit length.

[0090] The defect occurrence assessment coefficient is obtained by multiplying the number of defects per unit length by the number of defect recurrences per unit length.

[0091] It should be noted that the number of defects per unit length is the ratio of the total number of defects that have occurred in the area to be inspected to the effective length of the area. Its physical meaning is to quantitatively characterize the density of defects occurring within a unit length of weld, directly reflecting the overall defect distribution level of the area to be inspected. The number of defect recurrences per unit length is the ratio of the maximum number of times defects recur at the same location within the area to the effective length of the area. Its physical meaning is to quantitatively characterize the severity of defects recurring at the same location within a unit length of weld, reflecting the stubbornness of defects at local high-risk points.

[0092] The defect occurrence assessment coefficient is the product of the number of defects per unit length and the number of defect recurrences per unit length. Its physical meaning is to comprehensively and quantitatively characterize the superimposed risk of the overall defect density and local defect persistence in the area to be tested. It reflects both the overall defect occurrence level of the area and highlights the high-risk characteristics of repeated defects in local areas.

[0093] The defect occurrence assessment coefficient is compared with the corresponding preset threshold. If the defect occurrence assessment coefficient is less than or equal to the corresponding preset threshold, the defect occurrence risk is determined to be low. If the defect occurrence assessment coefficient is greater than the preset threshold, the defect occurrence risk is determined to be high.

[0094] The preset threshold corresponding to the defect occurrence assessment coefficient is set by those skilled in the art based on historical data and statistical analysis methods.

[0095] Historical defect omission data includes the number of omissions that were not detected in the initial inspection of the area to be inspected within a historical period (3-5 years), the number of omissions that were detected in subsequent re-inspections, and the location of the omission defects;

[0096] The total number of historical missed detections in the area to be detected is counted, and the ratio of the total number of historical missed detections to the effective length of the area to be detected is calculated to obtain the number of missed detections per unit length.

[0097] The number of times the detection area is missed in the same position is counted as the number of missed recurrences. The maximum value of the number of missed recurrences is extracted, and the ratio of the maximum value of the number of missed recurrences to the effective length of the detection area is calculated to obtain the number of missed recurrences per unit length.

[0098] The defect omission evaluation coefficient is obtained by multiplying the number of missed inspections per unit length with the number of recurrences of missed inspections per unit length.

[0099] It should be noted that the number of missed inspections per unit length is the ratio of the total number of missed inspections in the historical period of the area to be inspected to the effective length of the area. Its core physical meaning is to quantitatively characterize the overall distribution density of missed defects within a unit length of weld, eliminating the interference of different area length differences on the judgment of missed inspection frequency. The higher the value, the more defects are missed in the initial inspection and only discovered in the re-inspection in the historical period of the area per meter of weld, and the higher the probability of failing to identify defects in time during the overall inspection process. The number of repeated missed inspections per unit length is the ratio of the maximum number of missed inspections at the same location in the area to the effective length of the area. Its core physical meaning is to quantitatively characterize the severity of repeated missed inspections at local high-risk points within a unit length of weld, focusing on the stubborn locality of missed inspection risk, reflecting the local missed inspection hidden dangers in the area to be inspected. Missed inspections at the same location mean that there may be problems such as blind spots or special defect morphology at that location, resulting in missed inspections in multiple inspections. The maximum value identifies the local point with the most frequent missed inspections.

[0100] The defect omission assessment coefficient is the product of the number of omissions per unit length and the number of recurrences of omissions per unit length. Its core physical meaning is to comprehensively and quantitatively characterize the overall density and local stubbornness superposition effect of omission risk in the area to be tested. It avoids ignoring local high-risk points by only looking at the overall omissions, and also avoids misjudging the overall risk by only looking at local omissions. It achieves a comprehensive quantification of omission risk and reflects the superposition intensity of omission risk. The higher the value, the more it means that the area not only has a high overall omission density, but also has repeated omissions at local points. After the two are superimposed, the probability of omissions leading to undetected defects causing safety hazards increases significantly.

[0101] The defect omission assessment coefficient is compared with the corresponding preset threshold. If the defect omission assessment coefficient is less than or equal to the corresponding preset threshold, the defect omission risk is determined to be low. If the defect omission assessment coefficient is greater than the preset threshold, the defect omission risk is determined to be high.

[0102] The preset threshold for the defect omission evaluation coefficient is set by those skilled in the art based on historical data and statistical analysis methods.

[0103] If the defect is determined to have a high risk of occurrence or a high risk of missed detection, then the defect risk level of the area to be inspected is high, and the upper limit of the tilt angle range is selected.

[0104] If the risk of defect occurrence is determined to be low and the risk of defect failure is determined to be low, then the defect risk level of the area to be inspected is low, and the lower limit of the tilt angle range is selected.

[0105] In this embodiment, the regional risk analysis module first retrieves historical defect data and historical missed defect data for the past 3-5 years from the weld base database of the tank to be inspected. It calculates the number of defects per unit length by dividing the total number of historical defects by the effective length of the area to be inspected, and calculates the number of defect recurrences per unit length by dividing the maximum number of recurrences at the same location by the effective length. The product of these two values ​​is the defect occurrence assessment coefficient, which is compared with a preset threshold to determine the defect occurrence risk level. Simultaneously, it calculates the number of missed defects per unit length by dividing the total number of missed defects by the effective length, and calculates the number of missed defects recurring per unit length by dividing the maximum number of missed defects at the same location by the effective length. The product of these two values ​​is the defect missed detection assessment coefficient. Finally, combining the risk levels of both defect occurrence and defect missed detection, and based on the logic of prioritizing detection rate for higher risks and balancing efficiency for lower risks, it selects the upper or lower limit from the tilt angle range output by the angle range determination module as the final tilt angle.

[0106] It has the following functions: based on the risk level, it clarifies the priority of detection targets; for high-risk areas, it selects the upper limit of the angle range to maximize the suppression of scattered ray artifacts, improve the defect detection rate, and avoid missed detections that may cause safety hazards; for low-risk areas, it selects the lower limit of the angle range to reduce radiation energy consumption and detection time while meeting the basic detection rate, thus balancing detection efficiency.

[0107] This embodiment optimizes the problem of X-ray scattering artifacts caused by irregular interfaces in the transition zone between layers of multi-layer welds, which easily leads to misjudgment of defects. It also addresses the problem of low defect detection rate and imbalance between detection efficiency caused by blind angle selection and subjective risk assessment in traditional detection. Ultimately, it improves the accuracy and reliability of X-ray inspection of tank welds and ensures the effectiveness of tank safety assessment.

[0108] Optimizing artifacts by changing the tilt angle is essentially about adjusting the X-ray penetration path to better match the actual interface morphology of the interlayer transition zone. The tilt angle calculated by combining physical parameters such as the number and thickness of weld layers and the transmission thickness ratio (e.g., a reasonable value within an angle range) allows X-rays to avoid scattering sources such as irregular protrusions and gaps between layers, reducing unnecessary collisions between X-rays and the interface, thereby reducing the amount of scattered rays generated. Simultaneously, a suitable tilt angle (especially the upper / lower limit of the range selected based on risk level) ensures that X-rays penetrate the weld with a better path, reducing interference from scattered signals to the detector, ultimately optimizing artifacts and reducing defect misjudgments caused by artifacts.

[0109] Example 2

[0110] Based on the same inventive concept as the X-ray digital non-destructive testing system for tank welds in the foregoing embodiments, such as Figure 2 As shown, this application provides a digital non-destructive testing method for X-ray welds in storage tanks, which specifically includes the following steps:

[0111] Step 1: Obtain the design data of the tank weld and, in conjunction with the appearance characteristics of the weld, determine whether the area to be inspected is a transition area between multiple weld layers;

[0112] Step 2: If so, extract the physical parameters of the weld, combine the radiographic thickness ratio to construct the relationship between the tilt angle and the physical parameters, and obtain the tilt angle range;

[0113] The physical parameters of the weld include: the number of weld layers and the weld thickness;

[0114] Step 3: Obtain historical defect occurrence data and historical defect miss data for the area to be inspected. Combine the two dimensions of defect occurrence and defect miss to assess the defect risk level of the area to be inspected. Based on the defect risk level results, select the upper or lower limit of the tilt angle range as the final tilt angle.

[0115] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A digital non-destructive testing system for X-ray welds in storage tanks, characterized in that: include: Detection area identification module: acquires tank weld design data and combines weld appearance features to determine whether the area to be detected is a transition area between multiple weld layers; Angle range determination module: If so, extract the physical parameters of the weld, combine the radiographic thickness ratio to construct the relationship between the tilt angle and the physical parameters, and obtain the tilt angle range; The physical parameters of the weld include: the number of weld layers and the weld thickness; Regional Risk Analysis Module: Acquires historical defect occurrence data and historical defect omission data for the area to be inspected. Combines the analysis of defect occurrence and defect omission to assess the defect risk level of the area to be inspected. Based on the defect risk level results, selects the upper or lower limit of the tilt angle range as the final tilt angle.

2. The X-ray digital non-destructive testing system for tank welds according to claim 1, characterized in that: The process of determining whether the area to be inspected is a transition area between layers of a multi-layer weld is as follows: The design data of the tank weld is used to determine whether there is a potential multi-layer weld area. If so, the weld appearance feature identification process is executed. If at least 3 consecutive fusion lines with a length of at least 8 mm are observed within a 1-meter weld length, and there is a tendency for delamination along the thickness direction, then the macroscopic characteristics meet the standard. If at least two out of the three locations observe a continuous stepped structure, and the number of steps matches the number of layers in the design, then the microscopic features meet the requirements. If both macroscopic and microscopic characteristics meet the standards, it is determined to be a transition zone between layers of multi-layer welds.

3. The X-ray digital non-destructive testing system for tank welds according to claim 2, characterized in that: The process for determining whether there is a potential multi-layer weld area is as follows: Extract the number of weld layers in the area to be inspected. If the number of weld layers is greater than or equal to 2, it is determined to be a potential multi-layer weld area. If the number of weld layers is equal to 1, it is determined to be a non-multi-layer weld area.

4. The X-ray digital non-destructive testing system for tank welds according to claim 1, characterized in that: The process of obtaining the tilt angle range is as follows: Five measuring points in a quincunx pattern were selected in the area to be inspected using an ultrasonic thickness gauge to measure the weld thickness. The average thickness of the five measuring points was then calculated as the effective weld thickness. An equivalent penetration thickness calculation formula is introduced, and the lower limit of the tilt angle is determined based on the number of weld layers, thus obtaining the calculation method for the lower limit of the tilt angle. The calculation method for the upper limit of the tilt angle is derived by substituting the maximum value of the radiographic thickness ratio into the equivalent penetration thickness formula. Substituting the number of weld layers and the effective weld thickness into the formula for calculating the lower limit of the tilt angle, the lower limit of the tilt angle is obtained. Substituting the maximum value of the radiographic thickness ratio into the formula for calculating the upper limit of the tilt angle, the upper limit of the tilt angle is obtained.

5. The X-ray digital non-destructive testing system for tank welds according to claim 1, characterized in that: The process of analyzing both defect occurrence and defect missed detection is as follows: Obtain the defect occurrence assessment coefficient and the defect missed detection assessment coefficient; If the defect occurrence assessment coefficient does not exceed the standard, the defect occurrence is judged to be of low risk; if the defect occurrence assessment coefficient exceeds the standard, the defect occurrence is judged to be of high risk. If the defect omission assessment coefficient does not exceed the standard, the defect omission risk is determined to be low; if the defect omission assessment coefficient exceeds the standard, the defect omission risk is determined to be high.

6. The X-ray digital non-destructive testing system for tank welds according to claim 5, characterized in that: The calculation process for the defect occurrence assessment coefficient is as follows: The number of defects per unit length and the number of defect recurrences per unit length are calculated using historical defect data. The defect occurrence assessment coefficient is obtained by multiplying the number of defects per unit length by the number of defect recurrences per unit length.

7. The X-ray digital non-destructive testing system for tank welds according to claim 5, characterized in that: The calculation process for the defect omission evaluation coefficient is as follows: Calculate the number of missed defects per unit length and the number of recurrences of missed defects per unit length using historical defect missed detection data; The defect omission evaluation coefficient is obtained by multiplying the number of missed inspections per unit length with the number of recurrences of missed inspections per unit length.

8. The X-ray digital non-destructive testing system for tank welds according to claim 6, characterized in that: The calculation process for the number of defects per unit length and the number of defect recurrences per unit length is as follows: Historical defect data includes the number of times defects occurred in the area to be inspected within a historical period and the location of the defects. The total number of defects that have occurred in the area to be inspected throughout history is counted. The ratio of the total number of defects that have occurred throughout history to the effective length of the area to be inspected is calculated to obtain the number of defects per unit length. The number of historical defects occurring in the same location within the area to be inspected is counted as the defect recurrence count. The maximum defect recurrence count is extracted, and the ratio of the maximum defect recurrence count to the effective length of the area to be inspected is calculated to obtain the defect recurrence count per unit length.

9. The X-ray digital non-destructive testing system for tank welds according to claim 7, characterized in that: The calculation process for the number of missed detections per unit length and the number of recurrences of missed detections per unit length is as follows: Historical defect omission data includes the number of times the area to be inspected was not detected during the initial inspection within a historical period, the number of times it was detected during subsequent re-inspections, and the location of the missed defects; The total number of historical missed detections in the area to be detected is counted, and the ratio of the total number of historical missed detections to the effective length of the area to be detected is calculated to obtain the number of missed detections per unit length. The number of times the detection area is missed in the same position is counted as the number of missed recurrences. The maximum value of the number of missed recurrences is extracted, and the ratio of the maximum value of the number of missed recurrences to the effective length of the detection area is calculated to obtain the number of missed recurrences per unit length.

10. The X-ray digital non-destructive testing system for tank welds according to claim 1, characterized in that: The process of determining the final tilt angle is as follows: If the defect is determined to have a high risk of occurrence or a high risk of missed detection, then the defect risk level of the area to be inspected is high, and the upper limit of the tilt angle range is selected. If the risk of defect occurrence is determined to be low and the risk of defect failure is determined to be low, then the defect risk level of the area to be inspected is low, and the lower limit of the tilt angle range is selected.

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