A method for evaluating the feasibility of weld eddy current testing and a detection device thereof

Abstract

This invention discloses a method and apparatus for feasibility assessment of eddy current testing of weld seams. The apparatus (2) is used for eddy current testing of the weld seam (11) surface of welded components on large facilities and equipment such as civil aviation terminal buildings, high-speed rail waiting halls, and large metal frame buildings. It is electrically connected to a multi-channel orthogonal eddy current testing instrument (3). The apparatus includes a housing (21) and a pair of cross-shaped vertical orthogonal eddy current testing coils (22a, 22b). The invention is characterized by the inclusion of an absolute testing coil (23), which is horizontally and vertically arranged on the end side (221) of the orthogonal eddy current testing coils (22a, 22b) near the testing surface of the inspected component. This invention is applicable to the feasibility assessment of testing on metal surfaces under complex working conditions, particularly weld seams.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, specifically to an eddy current testing and evaluation method for weld surfaces of welded components on large facilities and equipment, and particularly to a feasibility evaluation method and testing device for eddy current testing of welds. Background Technology

[0002] In modern society, there are numerous large-scale civilian facilities and equipment, such as civil aviation terminals, high-speed rail waiting halls, large metal frame buildings, tunnel boring machines, and large track-laying vehicles. These large facilities and equipment contain many components welded from different metal materials, and the welding processes vary greatly. Post-weld quality inspection and in-service inspection are crucial to ensuring the safe operation of these large facilities and equipment. Currently available non-destructive testing methods, such as ultrasonic testing, magnetic particle testing, radiographic testing, and penetrant testing, are extremely difficult to use in such complex conditions, especially for welds with coatings and those requiring high-altitude operations. Therefore, after weighing the pros and cons, most of these testing needs can only be addressed using eddy current testing. To date, although the International Organization for Standardization (ISO) and the National Standardization Administration of China (NSC) have issued some standards for eddy current testing of welds, such as the EN1711 standard issued by Europe / the UK on November 11, 1999, and my country's GB / T26954-2011 national standard, the current eddy current testing method for welds remains in place. However, these standards share a common problem: the rough surface of the weld caused by weld spatter and slag significantly impacts eddy current testing. Most welds in welding equipment and engineering projects are done manually, resulting in highly irregular weld surfaces with varying widths and unevenness, especially in in-service facilities and equipment with non-uniform protective layers. This introduces a second problem beyond the impact of weld surface roughness on eddy current testing: whether these weld surfaces require pretreatment, such as grinding or removing the protective layer. Therefore, assessing the surface condition of such welds becomes a prerequisite for the successful and reliable implementation of eddy current testing.

[0003] Regarding the assessment of weld surface roughness, currently available roughness testing instruments, whether optical or mechanical, cannot assess the roughness of coated metals (including welds). While the conventional stylus method can assess whether weld surfaces require grinding or removal of the protective layer, it is inconvenient for field use. This is especially true for assessing hand-welded welds of varying widths or those with painted coatings, as the lack of a reference surface makes it unsuitable for projects where eddy current testing is planned. This is particularly true for large metal components.

[0004] To address the above problems, the present invention adopts the following technical solution for further improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for feasibility assessment of eddy current testing of welds. The disclosed technical solution is as follows: A feasibility assessment method for eddy current testing of welds is disclosed. This method is used for eddy current testing and feasibility assessment of weld surfaces on large facilities and equipment such as civil aviation terminal buildings, high-speed rail waiting halls, and large metal frame buildings. The method is characterized by using a non-directional eddy current testing device composed of cross-shaped orthogonal coils for testing, and using an absolute detection coil perpendicularly positioned near the detection surface of the cross-shaped non-directional coils as the detection reference. The specific testing and assessment analysis steps are as follows: a. Calibrate the weld detection signal parameters of the absolute detection coil in the detection device and set the calibration value for weld feasibility; b. The eddy current detection device is attached to the surface of the metal to be tested for scanning and detection. The non-directional cross-shaped detection coil is alternately excited and detected by high-frequency AC signal, the detection data is extracted and sent to the detection instrument for analysis and processing. c. In data evaluation and analysis, when the non-directional cross-shaped detection coil, subjected to alternating excitation and detection, detects defect data, the signal parameter values ​​detected by the absolute detection coil are extracted. If the signal parameter value is less than the calibrated value for weld feasibility, the weld eddy current detection is deemed feasible; if the signal parameter value is greater than the calibrated value, the weld eddy current detection is deemed infeasible. Generally, when abrupt abnormal signals exist, this value should be corrected, such as by removing the highest value, to obtain a more effective and feasible evaluation and analysis.

[0006] For workpieces with welds deemed unfeasible, engineering operations such as grinding and repair are performed. A cross-shaped omnidirectional eddy current testing probe consists of two orthogonally perpendicular eddy current coils that are alternately excited and detected by a high-frequency AC power signal. This allows for omnidirectional scanning and detection at various angles, making it ideal for inspecting rough metal surfaces with welds. However, because welds are often uneven, lift-off during scanning affects the eddy current detection signal, especially on coated metal surfaces where the skin effect of the eddy current signal often makes it insensitive to defects. In this invention, while the orthogonal eddy current coils are detecting, a separate absolute detection coil, perpendicularly positioned to the orthogonal eddy current coils, acquires the detection signal as a standard for analysis and judgment. This significantly improves the accuracy of the omnidirectional eddy current testing probe, allowing for more precise analysis and judgment of the weld's specific condition, thus providing a reference for engineering operations.

[0007] Furthermore, the aforementioned detection and evaluation method using an absolute detection coil as a detection reference also includes a method for calibrating the absolute detection coil as a reference surface for the orthogonal eddy current detection coil. This involves comparing and extracting the signal value of the absolute detection coil at its maximum parameter value, which is then used as the detection value when the orthogonal eddy current detection coil is perpendicular to the surface of the metal part being inspected. Due to the unevenness of the weld inspection surface, the rough surface caused by weld spatter and slag, and the fact that many welding equipment and engineering projects rely primarily on manual welding, the weld surface often exhibits highly irregularities, with varying widths and unevenness. This is especially true for welds on in-service facilities and equipment with uneven protective layers. During eddy current testing, it is difficult for the detection device to achieve a perfectly flat fit against the surface of the metal being inspected, or it may be skewed, affecting the sensitivity of the orthogonal eddy current detection coil and potentially leading to misjudgments or missed detections. Therefore, a horizontal reference surface is essential to ensure the orthogonal eddy current detection coil is perpendicular to the surface of the inspected part. A vertical absolute detection coil is set on the side of the orthogonal eddy current coil. When the absolute detection coil is horizontal to the surface of the workpiece, the magnetic flux formed is at its maximum value. Therefore, when the detected electrical signal parameter value is at its peak value, it serves as the reference for the orthogonal eddy current detection coil perpendicular to the surface of the workpiece.

[0008] Furthermore, the detection signal extracted by the absolute detection coil is the electromagnetic eddy current signal excited by the orthogonal eddy current detection coil. While the cross-shaped orthogonal eddy current detection coil alternately excites and detects, the absolute detection coil detects the corresponding electromagnetic eddy current signal. This detection method ensures that both the orthogonal eddy current coil and the absolute eddy current detection sensor operate at high frequencies simultaneously. When the orthogonal eddy current detection coil detects a defect signal, the absolute detection coil, serving as a reference perpendicular to the surface of the inspected workpiece, also serves as a criterion for determining the feasibility of the weld. That is, when the signal value detected by the absolute detection coil is at its maximum value, it is determined that the orthogonal eddy current detection coil is perpendicular to the surface of the inspected workpiece, and the signal data detected by the orthogonal eddy current detection coil at this time is a valid detection signal value. If, at the same time the orthogonal eddy current detection coil detects a defect signal, the peak value of the signal detected by the absolute detection coil is less than the reference value amplitude calibrated for the weld of the metal device, it can be determined that the weld of the metal device does not need grinding; otherwise, grinding is necessary. This achieves the requirement of rapid and accurate detection.

[0009] The present invention also discloses a weld eddy current testing feasibility assessment device, which is used for eddy current testing of the weld surface (11) of welded parts (1) on large facilities and equipment such as civil aviation terminal buildings, high-speed train waiting halls, and large metal frame buildings. It is electrically connected to a multi-channel orthogonal eddy current testing instrument (3), including a housing (21) and a pair of cross-shaped vertical orthogonal eddy current testing coils (22a, 22b). The feature is that it also includes an absolute testing coil (23), which is horizontally and vertically arranged on the end side (221) of the orthogonal eddy current testing coils (22a, 22b) near the testing surface of the tested part.

[0010] Furthermore, the absolute detection coil (23) is a planar spiral coil disposed near the end face of the metal being detected by the orthogonal eddy current detection coil (22a, 22b).

[0011] Furthermore, the absolute detection coil of the planar helical coil is configured as a square planar helical coil (231).

[0012] Furthermore, the side length of the square planar spiral coil (231) is greater than the end face side length of the orthogonal eddy current detection coils (22a, 22b). To avoid shielding interference of the detection signal, i.e. to avoid the absolute detection coil shielding the orthogonal eddy current detection coil signal, the side length of the square planar spiral coil is greater than the end face side length of the orthogonal eddy current detection coil, thus avoiding the transmission of the detection signal.

[0013] Furthermore, the absolute detection coil of the planar helical coil is configured as a circular planar helical coil (232).

[0014] Furthermore, the diameter of the circular planar spiral coil (232) is greater than the end face side length of the orthogonal eddy current detection coils (22a, 22b).

[0015] Furthermore, it also includes a magnetic core (24) disposed within the orthogonal eddy current detection coils (22a, 22b), the orthogonal eddy current detection coils (22a, 22b) being wound around the outside of the magnetic core (24), and the diameter of the circular planar spiral coil (232) being larger than the side length of the end face of the orthogonal eddy current detection coils (22a, 22b), wherein the circular planar spiral coil (232) is etched on the end face of the magnetic core (24) near the detection surface. Generally, the magnetic core (24) is a rectangular prism, and a pair of cross-shaped perpendicular orthogonal eddy current detection coils are respectively wound around the two intersecting perpendicular surfaces of the rectangular prism magnetic core (24).

[0016] Based on the above technical solution, the present invention has the following beneficial effects: The present invention is applicable to the feasibility assessment of metal surfaces under complex working conditions, especially weld surfaces. The present invention utilizes a highly sensitive orthogonal non-directional eddy current detection coil, plus an absolute multi-frequency eddy current detection coil set on the end face as calibration and reference, to assess the roughness of pre-service or in-service metal surfaces, especially welds with anti-corrosion coatings. This achieves a feasibility assessment of using electromagnetic eddy current detection. Based on the physical phenomenon of eddy current lift-off effect affecting crack detection sensitivity (and also solving factors affecting eddy current detection signals such as excessively thick coatings or excessive roughness), it determines whether the weld inspection object meets quality requirements, whether surface grinding treatment is necessary, or, based on the calibrated reference value, lowering the required detection sensitivity reference value. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the detection device in use according to the preferred embodiment of the present invention; Figure 2 This is a schematic diagram of the detection coil for the feasibility assessment method of the preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the front of the detection coil in the feasibility assessment method of the preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the detection device structure according to the preferred embodiment of the present invention; Figure 5 A schematic diagram of the detection device structure according to another embodiment of the preferred embodiment of the present invention; Figure 6 A schematic diagram of the detection device structure according to another embodiment of the preferred embodiment of the present invention; Figure 7 This is a schematic diagram of the detection device structure, representing another preferred embodiment of the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] like Figures 1 to 3 As shown, a feasibility assessment method for eddy current testing of welds is provided. This method is used for flow detection and feasibility assessment of the weld surface 11 of welded parts 1 in large facilities and equipment such as civil aviation terminal buildings, high-speed rail waiting halls, and large metal frame buildings. The method is characterized by using a non-directional eddy current testing device composed of cross-shaped orthogonal coils for detection, and using an absolute detection coil vertically positioned near the detection surface of the cross-shaped non-directional coils as the detection reference. The specific detection and assessment analysis steps are as follows: a. Calibrate the weld detection signal parameters of the absolute detection coil in the detection device and set the calibration value for weld feasibility; b. The eddy current detection device is attached to the surface of the metal to be tested for scanning and detection. The non-directional cross-shaped detection coil is alternately excited and detected by high-frequency AC signal, the detection data is extracted and sent to the detection instrument for analysis and processing. c. In data evaluation and analysis, when the non-directional cross-shaped detection coil of alternating excitation and detection detects defect data, the signal parameter value of the absolute detection coil is extracted. When the signal parameter value is less than the calibration value of weld feasibility, the weld eddy current detection is determined to be feasible. When the signal parameter value is greater than the calibration value of weld feasibility, the weld eddy current detection is determined to be infeasible.

[0020] Using the above evaluation methods, workpieces corresponding to welds deemed infeasible undergo engineering operations such as grinding and repair. The cross-shaped omnidirectional eddy current detection probe consists of two orthogonally perpendicular eddy current coils that are alternately excited and detected by a high-frequency AC power signal. This allows for omnidirectional scanning and detection at various angles, making it ideal for detecting rough metal surfaces with welds. However, because welds are often uneven structures, the lift-off during scanning affects the eddy current detection signal, especially on coated metal surfaces, where the skin effect of the eddy current signal often makes it insensitive to defects. In this invention, while the orthogonal eddy current coils are detecting, a separate absolute detection coil, vertically positioned above the orthogonal eddy current coils, acquires the detection signal as a standard for analysis and judgment, greatly improving the accuracy of the omnidirectional eddy current detection probe and enabling more precise analysis and judgment of the specific condition of the weld, thus providing a reference for engineering operations.

[0021] like Figure 2 and Figure 3As shown, the detection evaluation method using the absolute detection coil 23 as the detection reference also includes a method for calibrating the absolute detection coil 23 as the reference surface for the orthogonal eddy current detection coils 22a and 22b. This involves comparing and extracting the signal value of the absolute detection coil when it reaches its maximum parameter value, which is then used as the detection value when the orthogonal eddy current detection coils 22a and 22b are perpendicular to the surface of the metal part being inspected. Due to the unevenness of the weld inspection surface and the rough surface caused by weld spatter and slag, and because many welding equipment and engineering projects rely heavily on manual welding, the weld surface often exhibits highly irregularities, with varying widths and unevenness. This is especially true for welds on in-service facilities and equipment with uneven protective layers. During eddy current testing, it is difficult for the detection device to achieve a perfectly flat fit against the surface of the metal being inspected, or it may be skewed, affecting the sensitivity of the orthogonal eddy current detection coil and potentially leading to misjudgments or missed detections. Therefore, a horizontal reference surface is essential to assist in ensuring the orthogonal eddy current detection coils are perpendicular to the surface of the inspected part. A vertical absolute detection coil is set on the side of the orthogonal eddy current coil. When the absolute detection coil is horizontal to the surface of the workpiece, the magnetic flux formed is at its maximum value. Therefore, when the detected electrical signal parameter value is at its peak value, it serves as the reference for the orthogonal eddy current detection coil perpendicular to the surface of the workpiece.

[0022] like Figure 2 and Figure 3 As shown, the detection signal extracted by the absolute detection coil 23 is the electromagnetic eddy current signal excited by the orthogonal eddy current detection coils 22a and 22b. While the cross-shaped orthogonal eddy current detection coils 22a and 22b alternately excite and detect, the absolute detection coil 23 detects the corresponding electromagnetic eddy current signal. This detection method ensures that both the orthogonal eddy current coils and the absolute eddy current detection sensor operate at high frequencies simultaneously. When the orthogonal eddy current detection coils detect defect signals, the absolute detection coil, serving as a reference perpendicular to the surface of the inspected workpiece, also acts as a criterion for determining the feasibility of the weld. Specifically, when the signal value detected by the absolute detection coil is at its maximum, it is determined that the orthogonal eddy current detection coil is perpendicular to the surface of the inspected workpiece, and the signal data detected by the orthogonal eddy current detection coil at this time is a valid detection signal value. If, at the same time the orthogonal eddy current detection coil detects a defect signal, the peak value of the signal detected by the absolute detection coil is less than the reference value amplitude calibrated for the weld of the metal device, it can be determined that the weld of the metal device does not require grinding; otherwise, grinding is necessary. This achieves the requirement of rapid and accurate detection.

[0023] like Figures 4 to 7As shown, the present invention also discloses a weld eddy current testing feasibility assessment device, which is used for eddy current testing of the weld surface 11 of welded parts 1 on large facilities and equipment such as civil aviation terminal buildings, high-speed train waiting halls, and large metal frame buildings. It is electrically connected to a multi-channel orthogonal eddy current testing instrument 3, including a housing 21 and a pair of cross-shaped vertical orthogonal eddy current testing coils 22a and 22b. The feature is that it also includes an absolute testing coil 23, which is horizontally and vertically arranged on the end side 221 of the orthogonal eddy current testing coils 22a and 22b near the testing surface of the tested part.

[0024] like Figures 4 to 7 As shown, the absolute detection coil 23 is a planar spiral coil disposed near the end face of the metal being detected on the orthogonal eddy current detection coils 22a and 22b.

[0025] like Figure 4 and Figure 6 As shown, the absolute detection coil of the planar helical coil is set as a square planar helical coil 231.

[0026] like Figure 4 As shown, the side length of the square planar spiral coil 231 is greater than the end face side length of the orthogonal eddy current detection coils 22a and 22b. To avoid shielding interference of the detection signal, that is, to avoid the absolute detection coil shielding the signal of the orthogonal eddy current detection coil, the side length of the square planar spiral coil is greater than the end face side length of the orthogonal eddy current detection coil, thus avoiding the transmission of the detection signal.

[0027] like Figure 5 and Figure 7 As shown, the absolute detection coil of the planar helical coil is set as a circular planar helical coil 232.

[0028] like Figure 5 As shown, the diameter of the circular planar spiral coil 232 is greater than the side length of the end face of the orthogonal eddy current detection coils 22a and 22b.

[0029] And, such as Figures 4 to 7 As shown, the magnetic core 24 is also included within the orthogonal eddy current detection coils 22a and 22b. The orthogonal eddy current detection coils 22a and 22b are wound around the outside of the magnetic core 24. The diameter of the circular planar spiral coil 232 is larger than the side length of the end face of the orthogonal eddy current detection coils 22a and 22b. The circular planar spiral coil 232 is etched on the end face of the magnetic core 24 near the detection surface. Generally, the magnetic core 24 is a rectangular prism, and a pair of cross-shaped perpendicular orthogonal eddy current detection coils are wound around the two intersecting perpendicular surfaces of the rectangular prism magnetic core 24.

[0030] The above is one embodiment of the present invention. Furthermore, it should be noted that any equivalent or simple variations made to the structure, features, and principles described in this patent concept are included within the scope of protection of this patent.

Claims

1. A method for feasibility assessment of eddy current testing of welds, characterized in that... A non-directional eddy current detection device composed of cross-shaped orthogonal coils is used for detection, and an absolute detection coil perpendicularly positioned near the detection surface of the cross-shaped non-directional coils is used as the detection reference for the detection evaluation method. The specific detection evaluation and analysis steps are as follows: a. Calibrate the weld detection signal parameters of the absolute detection coil in the detection device and set the calibration value for weld feasibility; b. The eddy current detection device is attached to the surface of the metal to be tested for scanning and detection. The non-directional cross-shaped detection coil is alternately excited and detected by high-frequency AC signal, the detection data is extracted and sent to the detection instrument for analysis and processing. c. In data evaluation and analysis, when the non-directional cross-shaped detection coil of alternating excitation and detection detects defect data, the signal parameter value of the absolute detection coil is extracted. When the signal parameter value is less than the calibration value of weld feasibility, the weld eddy current detection is determined to be feasible. When the signal parameter value is greater than the calibration value of weld feasibility, the weld eddy current detection is determined to be infeasible.

2. The feasibility assessment method for eddy current testing of welds according to claim 1, characterized in that... The detection and evaluation method using the absolute detection coil as the detection reference also includes a method for calibrating the absolute detection coil as the reference surface of the orthogonal eddy current detection coil. The method uses the maximum parameter value of the absolute detection coil as the detection value when the orthogonal eddy current detection coil is perpendicular to the surface of the metal part being tested.

3. The feasibility assessment method for eddy current testing of welds according to claim 2, characterized in that... The detection signal extracted by the absolute detection coil is the electromagnetic eddy current signal excited by the orthogonal eddy current detection coil. While the cross-shaped orthogonal eddy current detection coil is alternately excited and detected, the absolute detection coil detects the corresponding electromagnetic eddy current signal.

4. A feasibility assessment device for weld eddy current testing, employing the feasibility assessment method for weld eddy current testing as described in any one of claims 1-3, comprising a housing (21) and a pair of cross-shaped vertical orthogonal eddy current detection coils (22a, 22b), characterized in that... It also includes an absolute detection coil (23), which is arranged laterally and vertically on the end side (221) of the orthogonal eddy current detection coil (22a, 22b) near the detection surface of the workpiece.

5. The feasibility assessment and testing device for weld eddy current testing according to claim 4, characterized in that... The absolute detection coil (23) is a planar spiral coil located near the end face of the metal being detected on the orthogonal eddy current detection coil (22a, 22b).

6. The feasibility assessment and testing device for weld eddy current testing according to claim 5, characterized in that... The absolute detection coil of the planar spiral coil is configured as a square planar spiral coil (231).

7. The feasibility assessment and testing device for eddy current testing of welds according to claim 6, characterized in that... The side length of the square planar spiral coil (231) is greater than the end face side length of the orthogonal eddy current detection coils (22a, 22b).

8. The feasibility assessment and testing device for eddy current testing of welds according to claim 5, characterized in that... The absolute detection coil of the planar helical coil is configured as a circular planar helical coil (232).

9. The feasibility assessment and testing device for eddy current testing of welds according to claim 8, characterized in that... The diameter of the circular planar spiral coil (232) is greater than the side length of the end face of the orthogonal eddy current detection coils (22a, 22b).

10. The feasibility assessment and testing device for eddy current testing of welds according to claim 8, characterized in that... It also includes a magnetic core (24) disposed within the orthogonal eddy current detection coils (22a, 22b), the orthogonal eddy current detection coils (22a, 22b) being wound around the outside of the magnetic core (24), and the diameter of the circular planar spiral coil (232) being greater than the side length of the end face of the orthogonal eddy current detection coils (22a, 22b), wherein the circular planar spiral coil (232) is etched on the end face of the magnetic core (24) near the detection surface.

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