Calibration test piece for eddy current detection

Abstract

This application proposes a calibration test piece for eddy current detection, comprising: a metal substrate; metal corrugated fins welded to the metal substrate, wherein the metal corrugated fins include a plurality of metal crests and a plurality of metal troughs, and the plurality of metal crests and a plurality of metal troughs extend parallel to an extension direction parallel to the metal substrate; and a calibration test pattern formed between the metal corrugated fins and the metal substrate, wherein in the region of the calibration test pattern, the metal corrugated fins and the metal substrate are in an abnormal welding state; wherein the calibration test pattern has a beveled edge, and the beveled edge forms an angle with the extension direction. Therefore, the calibration test piece can be applied to eddy current detection procedures and solves the problem of ineffective adjustment of parameter settings of the detection equipment.

Description

Technical Field

[0001] This application relates to a calibration test piece for eddy current detection. Prior Technology

[0002] In conventional reheat exchangers, to achieve heat exchange, metal corrugated fins are typically arranged between the two metal substrates. The structure of the metal corrugated fins forms multiple channels between the two metal substrates, and heat exchange is then carried out using the medium (e.g., water) in the channels.

[0003] Regarding the metal substrates, the two metal substrates in the heat exchanger can be referred to as a first metal substrate (e.g., top plate) and a second metal substrate (e.g., bottom plate), and these two metal substrates can specifically be, for example, thin plates of 2 mm or other thicknesses.

[0004] Regarding the metal corrugated fin, it is a corrugated metal plate. More specifically, the metal corrugated fin has a plurality of metal crests and a plurality of metal troughs, and each of the plurality of metal crests and each of the plurality of metal troughs extends parallel to each other along the same direction (e.g., a direction parallel to the surface where the metal substrate and the metal corrugated fin contact), so as to form respective parallel and continuous metal crests and respective parallel and continuous metal troughs. Furthermore, the respective metal crests of the metal corrugated fin can be welded to, for example, a first metal substrate, and the respective metal troughs of the metal corrugated fin can be welded to, for example, a second metal substrate, so as to form the aforementioned plurality of ramps.

[0005] To ensure the proper functioning of the corrugated metal fins in a heat exchanger, practical inspection is often required on the finished product, specifically the welds between the corrugated metal fins and the metal substrate. Since these welds are located inside the heat exchanger and cannot be directly inspected by the naked eye, and must be inspected without damaging the surface, non-destructive testing methods such as X-ray imaging, ultrasonic testing, magnetic particle testing, and eddy current testing are necessary to determine the proper welding condition of the welds without damaging the finished heat exchanger. Summary of the Invention

[0006] Looking at various non-destructive testing methods, not all are suitable for inspecting the weld joints between metal corrugated fins and the metal substrate. For example, X-ray imaging is difficult to interpret due to the small gaps in the image; ultrasonic testing is unsuitable for surface and / or subsurface inspection; and magnetic particle testing is unsuitable for non-ferromagnetic materials. To effectively inspect these weld joints, eddy current testing is often used to determine if they are properly welded.

[0007] Regarding eddy current testing, while it is more suitable for inspecting the welds between the aforementioned metal corrugated fins and the metal substrate due to its sensitivity to minute defects, testing equipment involving eddy current testing technology often requires pre-setting corresponding parameter values ​​for various finished products to be tested in order to effectively perform subsequent testing operations. More specifically, since the finished products of regenerators can be configured differently according to actual needs, in practice, it is necessary to pre-set the corresponding parameter values ​​for the testing equipment for finished products with different configurations, so that the testing equipment can effectively perform subsequent testing operations for finished products with different regenerator configurations.

[0008] However, in practice, the parameter values ​​are often set by the experience of the testing personnel before the testing operation. In this case, it is impossible to effectively adjust the parameter values ​​based on some objective standard, and thus it is impossible to carry out the subsequent testing operation effectively.

[0009] Therefore, how to solve the above-mentioned problems encountered by conventional techniques and effectively improve the efficiency of parameter value adjustment, thereby improving the subsequent detection speed and accuracy, has become an urgent problem that this technical field hopes to solve.

[0010] To address the aforementioned problems, this application provides a calibration test piece for eddy current detection, comprising: a metal substrate; a metal corrugated fin soldered to the metal substrate, wherein the metal corrugated fin includes a plurality of metal peaks and a plurality of metal troughs, and the plurality of metal peaks and the plurality of metal troughs extend parallel to each other along an extension direction parallel to the metal substrate; and a calibration test pattern formed between the metal corrugated fin and the metal substrate, wherein in the region of the calibration test pattern, the metal corrugated fin and the metal substrate are in an abnormal soldering state; wherein the calibration test pattern has a beveled edge, and the beveled edge forms an angle with the extension direction.

[0011] In some embodiments, the calibration test pattern further has a first side and a second side, the first side being parallel to the extension direction and the second side being perpendicular to the extension direction.

[0012] In some embodiments, the calibration test pattern is in the shape of a triangle.

[0013] In some embodiments, the metal substrate is a metal plate or a metal bent plate.

[0014] In some embodiments, the calibration test piece is used in an eddy current detection procedure for a regenerator.

[0015] Therefore, the technical means provided in this application can produce advantages that were not possible with prior art. Specifically, one advantage that this application can achieve is that it can effectively improve the adjustment efficiency of parameter value setting of the detection equipment, thereby effectively completing the parameter value setting before the detection operation, which helps to effectively improve the subsequent detection speed and detection accuracy. Simple Explanation of the Diagram

[0016] Figure 1A is a top view illustrating a calibration test piece for eddy current detection according to one embodiment of this application. Figure 1B is a side view illustrating the calibration test piece used for eddy current detection, as shown in Figure 1A. Figure 1C is a partially enlarged schematic diagram illustrating the calibration test piece used for eddy current detection, as shown in Figure 1A. Figure 2A is a waveform diagram illustrating the detection signal of a calibration test piece for eddy current detection according to one embodiment of this application. Figure 2B is a waveform diagram illustrating the detection signal of a test object in one embodiment of this application. Figure 3A is a waveform diagram illustrating the detection signal of a calibration test piece for eddy current detection according to another embodiment of this application. Figure 3B is a waveform diagram illustrating the detection signal of a test object in another embodiment of this application. Implementation

[0017] This application will be described in detail through the embodiments described below and the accompanying drawings, so as to help those skilled in the art to which this application pertains to understand the purpose, features and effects of this application.

[0018] It should be noted that in the description of this application, terms such as "first," "second," and "third" are used to distinguish between elements, not to limit the elements themselves or to indicate a specific order of elements. Furthermore, in the description below, the same elements or steps may be represented by the same number.

[0019] Please refer to Figures 1A, 1B and 1C. Figure 1A is a top view illustrating a calibration test piece 50 for eddy current detection according to one embodiment of this application. Figure 1B is a side view illustrating the calibration test piece 50 for eddy current detection as shown in Figure 1A. Figure 1C is a partially enlarged schematic diagram illustrating the calibration test piece 50 for eddy current detection as shown in Figure 1A.

[0020] As shown in Figure 1A, the calibration test piece 50 for eddy current detection includes a metal substrate 100, a metal corrugated fin 200, and a calibration test pattern 300. The following will describe each component in more detail.

[0021] Regarding the metal substrate 100, it can specifically be a thin plate, for example, 2 mm or other thicknesses. In some embodiments, the material and / or thickness of the metal substrate 100 may vary depending on the actual finished product of the regenerator to be tested. For example, when the metal substrate of the regenerator to be tested is made of Alloy 800, the metal substrate 100 of the calibration test piece 50 is also made of Alloy 800; and when the metal substrate of the regenerator to be tested is made of Alloy 625, the metal substrate 100 of the calibration test piece 50 is also made of Alloy 625. In other words, the material of the metal substrate 100 of the calibration test piece 50 is the same as the material of the metal substrate of the regenerator to be tested. Similarly, the thickness of the metal substrate 100 of the calibration test piece 50 is also the same as the thickness of the metal substrate of the regenerator to be tested. In some embodiments, the metal substrate 100 may be a flat metal plate; in other embodiments, the metal substrate 100 may be a curved metal plate.

[0022] Regarding the metal corrugated fin 200, it is soldered onto the metal substrate 100. More specifically, as shown in FIG1B, the metal corrugated fin 200 includes a plurality of metal crests 210 and a plurality of metal troughs 220, wherein each of the plurality of metal crests 210 and each of the plurality of metal troughs 220 extends parallel to an extension direction parallel to the metal substrate 100, so as to form respective parallel and continuous metal crests 210 and parallel and continuous metal troughs 220. Taking FIG1A as an example, the aforementioned extension direction is a horizontal line direction from left to right or from right to left. In addition, the aforementioned extension direction can also be a straight line direction from top to bottom or from bottom to top. In other words, the aforementioned extension direction can be a direction parallel to the surface in contact with the metal substrate 100 and the metal corrugated fin 200. As shown in Figures 1A and 1B, each parallel and continuous metal trough 220 in the metal wave fin 200 will be welded to the metal substrate 100 of the calibration test piece 50.

[0023] Regarding the calibration test pattern 300, it is formed between the metal corrugated fin 200 and the metal substrate 100. More specifically, the calibration test pattern 300 is formed between a plurality of metal troughs 220 of the metal corrugated fin 200 and the metal substrate 100. It should be noted that, in order to present the calibration test pattern 300 more clearly in the figures, the metal corrugated fin 200 corresponding to the area of ​​the calibration test pattern 300 shown in FIG1A has been specially blurred. In other words, the metal corrugated fin 200 is still present in the area of ​​the calibration test pattern 300 shown in FIG1A.

[0024] Furthermore, in the area of ​​the calibration test pattern 300, the plurality of metal troughs 220 of the metal corrugated fin 200 are in an abnormal welding state with the metal substrate 100; while in areas other than the calibration test pattern 300, the plurality of metal troughs 220 of the metal corrugated fin 200 are in a normal welding state with the metal substrate 100. More specifically, the aforementioned normal welding state refers to a state where the weld is solid, that is, the metal troughs 220 can be reliably welded to the metal substrate 100 through welding; in contrast, the aforementioned abnormal welding state refers to a state where the metal troughs 220 cannot be reliably welded to the metal substrate 100 through welding, specifically such as a state of cold solder joint, false solder joint, missing solder joint, or no solder joint. When the plurality of metal troughs 220 of the metal corrugated fin 200 are in an abnormal welding state with the metal substrate 100, two adjacent ramps cannot be effectively separated because the welding point is in an abnormal welding state; while when the plurality of metal troughs 220 of the metal corrugated fin 200 are in a normal welding state with the metal substrate 100, two adjacent ramps will be effectively separated, which prevents the medium (e.g., water) between two adjacent ramps from flowing between each other.

[0025] As shown in Figure 1C, the calibration test pattern 300 has a hypotenuse 330, and the hypotenuse 330 forms an angle θ with the aforementioned extension direction (i.e., the horizontal line direction from left to right or from right to left as shown in Figure 1A), where the angle θ can be an angle value other than 0 degrees, 90 degrees, 180 degrees, and 270 degrees. Because the calibration test pattern 300 has a hypotenuse 330 forming an angle θ with the aforementioned extension direction, this makes the calibration test piece 50 more suitable for use in the parameter value setting process before the testing operation. Furthermore, as shown in Figure 1C, the calibration test pattern 300 also has a first side 310 and a second side 320, where the first side 310 is parallel to the aforementioned extension direction, and the second side 320 is perpendicular to the aforementioned extension direction. Also, taking Figures 1A and 1C as examples, the calibration test pattern 300 is triangular. In addition, in some other embodiments, the calibration test pattern 300 can also be a geometric shape of various polygons such as rhombuses, pentagons, or hexagons.

[0026] Since the calibration test piece 50 has a metal substrate 100 and metal corrugated fins 200 that are substantially the same as the finished product of the heat exchanger to be tested, and a calibration test pattern 300 is formed between the metal substrate 100 and the metal corrugated fins 200, the calibration test piece 50 will produce areas that pass the test and areas that fail the test after eddy current testing. Therefore, the testing personnel can use the calibration test piece 50 to conduct eddy current testing and then determine whether the parameter values ​​of the testing equipment have been set based on the test results of each test. When the calibration test pattern 300 in the calibration test piece 50 can be clearly identified in the eddy current test results, it means that the parameter values ​​of the testing equipment have been adjusted. Subsequently, the adjusted testing equipment can further perform eddy current testing on the finished product of the heat exchanger to be tested, so as to detect whether the welds are in a normal welding state without damaging the welds of the finished product of the heat exchanger. Conversely, when the eddy current test results for the calibration test piece 50 cannot clearly identify the calibration test pattern 300 in the calibration test piece 50, the tester can adjust the parameter values ​​of the testing equipment based on the test results until the calibration test pattern 300 in the calibration test piece 50 can be clearly identified. In other words, the calibration test piece 50 described in this application can be used in the eddy current testing procedure for regenerators, especially in the parameter value setting stage of the eddy current testing procedure. More specifically, the calibration test piece 50 can first be scanned by the probe of the testing equipment (e.g., an eddy current array probe); subsequently, the testing equipment can display the results of this scan (e.g., a waveform); subsequently, the parameter settings of the testing equipment (e.g., the voltage magnitude display color range of the eddy current signal, the impedance plane diagram display range, phase angle, etc., but not limited to these) can be adjusted according to the results of this scan until the scanning results can clearly identify the calibration test pattern 300 in the calibration test piece 50; finally, the finished product of the heat exchanger to be tested can be subjected to eddy current testing through the adjusted testing equipment so as to detect whether the weld is in a normal welding state without damaging the weld of the finished heat exchanger.

[0027] Therefore, after knowing the defect shape in the calibration test piece 50 (i.e., the calibration test pattern 300), the inspector can continuously adjust parameters such as the voltage magnitude display color range, impedance plane diagram display range, and phase angle of the eddy current signal obtained by scanning. Since the eddy current signal is not absolute, and the voltage value will be different at different phase angles, the inspector needs to adjust it by trial and error until a suitable phase angle and voltage value range of the defect signal are found. At this time, the calibration test pattern 300 in the calibration test piece 50 can be clearly identified by the inspector, and the inspector can then use the adjusted parameters to scan and test the finished heat exchanger to be tested.

[0028] Please refer to Figure 2A, which is a waveform diagram illustrating the detection signal of a calibration test piece for eddy current detection according to one embodiment of this application. The specific configuration of the calibration test piece is shown in Figures 1A to 1C, and the metal substrate of the calibration test piece is made of nickel alloy 800.

[0029] As shown in Figure 2A, when the eddy current test results for the calibration test piece can clearly identify the calibration test pattern in the calibration test piece, it indicates that the parameter settings of the testing equipment have been adjusted. The adjusted testing equipment can further perform eddy current testing on the finished product of the heat exchanger to be tested, so as to detect whether the weld is in a normal welding state without damaging the weld of the finished heat exchanger.

[0030] Please refer to Figure 2B, which is a waveform diagram illustrating the detection signal of a test object in one embodiment of this application. The test object is a heat exchanger, and the metal substrate of the heat exchanger is made of nickel alloy 800.

[0031] As shown in Figure 2B, since the parameter values ​​of the testing equipment have been adjusted through the aforementioned calibration test piece, the adjusted testing equipment can detect the defects of the reheat exchanger, namely, the part where the weld between the metal substrate and the metal corrugated fins of the reheat exchanger is in an abnormal welding state; subsequently, the display results of Figure 2B can be marked on the actual reheat exchanger.

[0032] Please refer to Figure 3A, which is a waveform diagram illustrating the detection signal of a calibration test piece for eddy current detection according to another embodiment of this application. The specific configuration of the calibration test piece is shown in Figures 1A to 1C, and the metal substrate of the calibration test piece is made of nickel alloy 625.

[0033] As shown in Figure 3A, when the eddy current test results for the calibration test piece can clearly identify the calibration test pattern in the calibration test piece, it indicates that the parameter settings of the testing equipment have been adjusted. The adjusted testing equipment can further perform eddy current testing on the finished product of the heat exchanger to be tested, so as to detect whether the weld is in a normal welding state without damaging the weld of the finished heat exchanger.

[0034] Please refer to Figure 3B, which is a waveform diagram illustrating the detection signal of a test object in another embodiment of this application. The test object is a heat exchanger, and the metal substrate of the heat exchanger is made of nickel alloy 625.

[0035] As shown in Figure 3B, since the parameter values ​​of the testing equipment have been adjusted through the aforementioned calibration test piece, the adjusted testing equipment can detect the defects of the reheat exchanger, namely, the part where the weld between the metal substrate and the metal corrugated fins of the reheat exchanger is in an abnormal welding state; subsequently, the display results of Figure 3B can be marked on the actual reheat exchanger.

[0036] The calibration test piece described in this application can not only effectively improve the efficiency of parameter setting adjustment of the testing equipment, but also effectively improve the testing speed and accuracy of eddy current testing of the finished heat exchanger under test.

[0037] Furthermore, using the calibration test piece described in this application, the Probability of Detection (POD), which represents the probability of a defect being detected, can reach 100% (calculated after testing 8 sets of test pieces), while the False Call Probability (FCP), which represents the probability of a non-defect being detected as a defect, averages 2.82% (calculated after testing 8 sets of test pieces). In other words, the calibration test piece described in this application can achieve a 99% confidence level according to the ASME Section V standard.

[0038] This application has been further described through the above embodiments and accompanying drawings. However, those skilled in the art to which this application pertains can still make many modifications and variations without departing from the scope and spirit set forth in the claims of this application. Therefore, the scope of protection of this application should still be determined by the claims of the patent applications and should not be limited by the content disclosed in the specification.

[0039] 50: Calibration test piece 100:Metal substrate 200: Metal wave fins 210: Metallic peak 220: Metal trough 300: Calibration Test Graph 310: First side 320: Second side 330: Hypotenuse θ: included angle

Claims

1. A calibration test piece for eddy current detection, comprising: a metal substrate; a metal corrugated fin soldered to the metal substrate, wherein the metal corrugated fin includes a plurality of metal crests and a plurality of metal troughs, and the plurality of metal crests and the plurality of metal troughs extend parallel to each other along an extension direction parallel to the metal substrate; and a calibration test pattern formed between the metal corrugated fin and the metal substrate, wherein in a region of the calibration test pattern, the metal corrugated fin and the metal substrate are in an abnormal soldering state; wherein... The calibration test pattern has a slanted side, and the slanted side forms an angle with the direction of extension.

2. The calibration test piece as described in claim 1, wherein, The calibration test pattern also has a first side and a second side, the first side being parallel to the extension direction and the second side being perpendicular to the extension direction.

3. The calibration test piece as described in claim 1, wherein, The calibration test pattern is a triangle.

4. The calibration test piece as described in claim 1, wherein, The metal substrate is a metal plate or a metal bent plate.

5. The calibration test piece as described in claim 1, wherein, The calibration test piece was used in the eddy current detection procedure of a regenerator.

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