A method of detecting a welding defect

Abstract

The application discloses a kind of welding defect detection methods, it is related to steel structure bridge detection technical field, comprising the following steps: S1: same material, plate thickness, groove form, assembly angle and welding process parameters are used to the same component to be detected, welding preparation contrast test plate;S2: selected probe, according to the selected probe calculation probe moving area size, cut into multiple samples;S3: using electric pulse drilling method, process long horizontal hole;S4: using ultrasonic testing equipment and probe, scanning, collecting and saving defect, non-defect reflection waveform diagram, form contrast chart;S5: record the defect depth value and horizontal distance value displayed by ultrasonic testing equipment, form the deviation data table of defect positioning;S6: in field detection, and according to the deviation data table, the position of instrument display is position corrected;The application solves the technical problems that U rib and top plate full penetration fillet weld and non-standard T full penetration fillet weld welding defects cannot be accurately distinguished in the prior art.

Description

Technical Field

[0001] This invention relates to the field of steel structure bridge inspection technology, and in particular to a method for detecting welding defects. Background Technology

[0002] In the manufacture of steel bridges, the U-ribs of the bridge deck top plate unit are usually connected to the top plate by full penetration fillet welds. The typical U-rib plate thickness gradually decreases from 16mm at the rib head to 12mm through the curved transition, forming a variable cross-section transition structure. Due to the closed structure of the U-rib, ultrasonic testing can only be carried out from one side (outer side) during on-site inspection. However, the single sound path alone cannot cover the entire area of ​​the U-rib welded joint, so it is necessary to combine the single and double sound paths for joint scanning. However, the ultrasonic beam of the double sound path needs to pass through the curved transition area of ​​the U-rib, which leads to the following technical problems: (1) Dynamic change of actual reflection angle: After the ultrasonic beam passes through the curved transition area, the actual reflection angle changes continuously with the curved contour, which deviates significantly from the theoretical refraction angle built into the instrument. This results in a large deviation between the defect depth and horizontal position displayed by the instrument and the actual position of the defect. (2) Difficulty in waveform identification: The beam distortion caused by the curved transition makes the defect reflection waveform highly similar to the geometric structure reflection waveform (shape wave) in the actual defect-free state, which easily leads to misjudgment or omission of defects.

[0003] On the other hand, for non-standard T-type full penetration fillet welds commonly found in bridge main beams or arch ribs, the web and cover plate are not standard 90° right-angle T-type joints, but large-angle corner joints with a certain inclination angle. The following difficulties exist in the inspection of such welds: (1) Confusion between shape wave and defect wave: The structural reflection waveform generated by the inclined joint geometry is easily confused with the reflection waveform of the real defect, interfering with the interpretation of the inspectors. (2) Difficulty in locating defects at the lower end: When inspecting from the small angle side, the actual position of the defect located at the lower end of the weld cannot be directly measured with conventional tools such as rulers, resulting in a large defect location error. Summary of the Invention

[0004] The purpose of this invention is to provide a welding defect detection method that solves the technical problem that welding defects in U-rib and top plate full penetration fillet welds and non-standard T-type full penetration fillet welds cannot be accurately identified in the prior art.

[0005] This application discloses a method for detecting welding defects, including the following steps: S1: Using the same material, plate thickness, bevel type, assembly angle and welding process parameters as the actual component to be tested, a comparison test plate was prepared by welding. S2: Select a probe, calculate the probe movement area size based on the selected probe, cut the comparison test plate into multiple samples according to the size, and finish them to the required size; S3: Using an electrical pulse drilling method, long horizontal holes are machined at preset positions in the welding area of ​​each of the specimens as artificial defects. Artificial defects are machined in a part of the area of ​​each specimen, and no defects are machined in another part of the area. S4: Using an ultrasonic testing device and the probe from step S2, scan the areas with and without artificial defects of each sample, collect and save defect reflection waveforms and non-defect reflection waveforms to form a comparison diagram; S5: Record the defect depth value and horizontal distance value displayed by the ultrasonic testing equipment, compare them with the actual defect depth and actual horizontal distance of the artificial defect, calculate the depth deviation value and horizontal deviation value, and form a deviation data table for defect location. S6: During on-site testing, the actual detected waveform is compared with the comparison chart to obtain the defect type, and the position displayed on the instrument is corrected according to the deviation data table to obtain the true location of the defect.

[0006] This application obtains waveform diagrams and specific numerical detection deviations by testing the samples, which facilitates the determination of the true location of defects based on the deviation data table during subsequent on-site testing.

[0007] Based on the above technical solution, the present application can be further improved as follows: Furthermore, the welding joint types of the comparative test plate in step S1 include: U-rib full penetration fillet weld joints and non-standard T-type full penetration fillet weld joints. The beneficial effect of using this step is that it is easier to apply to actual scenarios through multiple welding joint types.

[0008] Further, in step S2, the probe includes: a first probe and a second probe, wherein the first probe has a frequency of 2.5MHz, a crystal size of 8mm×12mm, and a refraction angle of 70°; and the second probe has a frequency of 2.5MHz, a crystal size of 13mm×13mm, and a K value of 2.0. The method of selecting the probe in step S2 is as follows: when it is necessary to prepare a U-ribbed sample with a thickness transition range of 12mm-16mm, the first probe is selected. When it is necessary to prepare non-standard T-type full penetration fillet weld specimens with a plate thickness ≥40mm, a second probe is selected. The advantage of this step is that different probes can be used for different specimens to complete subsequent testing.

[0009] Furthermore, the diameter of the elongated transverse hole in step S3 is specifically as follows: For U-ribbed specimens with a plate thickness of 12mm-16mm, long transverse holes with a diameter of 1mm and a length of 40mm are selected. For non-standard T-type full penetration fillet weld specimens with a plate thickness ≥ 40mm, a long horizontal hole with a diameter of 3mm and a length of 40mm is selected. The beneficial effect of this step is to simulate artificial defects through a specific long horizontal hole.

[0010] Furthermore, the processing location of the artificial defects in step S3 includes one or more of the following: the location of the non-fusion defect between the outer weld corner and the top plate, the location of the non-fusion defect between the outer weld corner and the bevel, the location of the non-penetration defect at the root of the weld, the location of the non-fusion defect between the inner weld corner and the top plate, the location of the fusion defect in the heat-affected zone, the location of the non-fusion defect on the upper bevel cover plate side, and the location of the non-fusion defect on the lower bevel side. The beneficial effect of this step is that simulation values ​​under different conditions can be obtained by processing various artificial defects at different locations.

[0011] Furthermore, in step S4, for U-rib type specimens, primary and secondary waves are used to scan and sample the outside of the weld, and single-sided detection is performed during sampling; For non-standard T-type full penetration fillet weld specimens, the outer side of the weld is scanned using a primary wave and / or a secondary wave. During sampling, double-sided testing is performed on both the web and cover plate sides.

[0012] Further, the position correction in step S6 specifically involves adding or subtracting the depth deviation value under the corresponding conditions from the defect depth value displayed in real time by the instrument to obtain the corrected true defect depth. Add or subtract the horizontal deviation value under the corresponding condition from the deviation data table to obtain the corrected true horizontal position of the defect.

[0013] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. This application creates comparative samples with and without artificial defects under identical welding conditions, collects waveform diagrams for each sample, and establishes a comparative diagram of typical defects. This allows on-site inspection personnel to visually distinguish between defective and defect-free shape waves by comparing the waveform diagrams, thereby reducing the false positive and false negative rates.

[0014] 2. This application uses the results to make measurements and compares them with the actual locations to obtain a deviation data table, which effectively compensates for the calculation errors during actual on-site measurements and makes corrections accordingly to obtain accurate defect locations.

[0015] 3. This application is applicable not only to U-rib full penetration fillet welds, but also to large-angle non-standard T-type full penetration fillet welds with inclined angles in structures such as bridge main beams and arch ribs, and has good applicability. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of a welding defect detection method according to a specific embodiment 1 of the present invention; Figure 2 This is a comparative diagram of a welding defect detection method according to a specific embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of sample 2 in a welding defect detection method according to a specific embodiment 1 of the present invention; Figure 4 This is a comparative diagram of a welding defect detection method according to a specific embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the A-side inspection of a sample 1 in a welding defect detection method according to a specific embodiment 2 of the present invention.

[0018] Figure 6 This is a schematic diagram of the B-side inspection of a sample 1 in a welding defect detection method according to a specific embodiment 2 of the present invention. Detailed Implementation

[0019] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0020] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0021] To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0022] Example 1: like Figure 1-3 As shown, this embodiment of the application is for the inspection of the full penetration fillet weld of the U-rib in the top plate unit. The thickness of the U-rib is 16mm, which is gradually reduced to 12mm after the curved transition. The U-rib can only be subjected to single-sided ultrasonic testing from the outside (defined as side A). The specific steps of the inspection are as follows: S1: Welding comparison test plate: The comparison test plate is prepared by welding using the same material, plate thickness, bevel type, assembly angle and welding process parameters as the actual component to be tested; the plate thickness is 16mm transitioning to 12mm, and the length, width and height of the test plate are reserved with sufficient allowance according to the dimensions required for subsequent processing; during welding, the welding joint of the comparison test plate is a U-rib full penetration fillet weld joint; S2: Select a probe, calculate the probe movement area size according to the selected probe, cut the comparison test plate into multiple samples according to the size, and finish them to the required size; the frequency of the probe is 2.5MHz, the probe crystal size is 8mm×12mm, the refraction angle is 70°, and the final size is preferably 150mm×80mm×100mm. S3: Using an electrical pulse drilling method, long horizontal holes are machined as artificial defects (drilling from the side of the weld) at a preset position in the welding area of ​​each of the specimens (the preset position here refers to a typical position where defects are likely to occur during weld welding). A portion of the area of ​​each specimen is machined with artificial defects, while another portion is not machined with defects. The diameter of the long horizontal hole is 1 mm and the length is 40 mm. S4: Using an ultrasonic testing device and the probe from step S2, scan the areas with and without artificial defects of each sample, collect and save defect reflection waveforms and non-defect reflection waveforms to form a comparison diagram; S5: Record the defect depth value and horizontal distance value displayed by the ultrasonic testing equipment, compare them with the actual defect depth and actual horizontal distance of the artificial defect, calculate the depth deviation value and horizontal deviation value, and form a deviation data table for defect location. S6: During on-site testing, the actual detected waveform is compared with the comparison chart to obtain the defect type, and the position displayed on the instrument is corrected according to the deviation data table to obtain the true location of the defect.

[0023] In step S2, five samples are preferred, and the artificial defects in step S3 are as follows:

[0024] In step S3, each sample is designed with artificial defects processed in one area and no defects processed in another area. This allows for different test results to be obtained in the same sample, facilitating intuitive comparison later.

[0025] In step S4: For U-rib type specimens, primary and secondary waves are used for scanning and sampling on the outside of the weld. Sampling is performed on one side, specifically on side A. For specimens 1 and 2 (with shallower defects, 2mm from the upper surface), secondary waves are used; for specimens 3, 4, and 5 (with deeper defects), primary waves are used. The probe is moved back, forth, left, and right to find the position of the maximum echo of the defect reflection wave. The waveform diagrams with and without defects are recorded and saved, as shown in the attached diagram. The deviation data table for step S5 is shown in the table below:

[0026] Regarding depth deviation, a positive result is when the instrument-measured depth is deeper than the actual depth, and a negative result is when the instrument-measured depth is shallower than the actual position. Regarding horizontal deviation, a positive result is when the instrument measurement shows that the horizontal position of the defect from the probe is shorter than the actual horizontal distance from the defect to the probe, and a negative result is when the instrument measurement shows that the horizontal position of the defect from the probe is shorter than the actual horizontal distance from the defect to the probe.

[0027] Regarding step S6, the specific details are as follows: When performing ultrasonic testing on U-rib full penetration fillet welds of the same batch and specifications on-site, the testing personnel will compare the real-time acquired waveforms with the comparison diagrams: if the waveform characteristics are similar to a certain defect waveform diagram, it is determined that a defect of the corresponding type exists; if the waveform characteristics are similar to a defect-free waveform diagram, it is determined that a defect of the same type exists; if the waveform characteristics are similar to a defect-free waveform diagram, it is determined that a defect of the same type exists. Figure 1 If the reflection is consistent with the observed waveform, it is determined to be a geometric structure wave, thus eliminating the defect. At the same time, the depth and horizontal position displayed by the instrument are corrected according to the deviation values ​​of the corresponding defect type and detection conditions in the deviation data table. For example, for the defect type corresponding to sample 2 (outer weld corner and U-rib bevel not fused), if the depth displayed by the instrument is 32mm, the actual defect should be +2mm (32mm-16mm*2+2mm), that is, the actual depth is about 2mm; the horizontal position should be extended 3mm away from the probe.

[0028] Example 2: like Figure 4-6 As shown, this embodiment targets non-standard T-type full penetration fillet weld joints of main beams or arch ribs, with a wall plate thickness of 40mm and a large-angle inclined joint between the web and cover plate that is not at a 90° right angle. Inspection can be performed from both the web side (side A) and the cover plate side (side B). The specific steps are as follows: S1: Welding Comparison Test Plate: A comparison test plate is prepared by welding using the same material, plate thickness, bevel type, assembly angle and welding process parameters as the actual component to be tested; the plate thickness is 40mm, and the length, width and height of the test plate are reserved with sufficient allowance according to the dimensions required for subsequent processing; during welding, the welding joint type of this comparison test plate includes non-standard T-type full penetration fillet weld joints; S2: Select a probe, calculate the probe movement area size according to the selected probe, cut the comparison test plate into multiple samples according to the size, and finish them to the required size; the frequency of the probe is 2.5MHz, the probe chip size is 13mm×13mm, the K value is 2.0, and the final size is preferably 200mm×80mm×100mm, and the number of samples is 3. S3: Using an electrical pulse drilling method, long horizontal holes are machined at preset positions in the welding area of ​​each of the specimens as artificial defects (drilling from the side of the weld). Artificial defects are machined in a part of the area of ​​each specimen, and no defects are machined in another part of the area. The diameter of the long horizontal hole is 3mm and the length is 40mm. Specifically, it is in accordance with the requirements of GB / T 11345-2023. S4: Using an ultrasonic testing device and the probe from step S2, scan the areas with and without artificial defects of each sample, move the probe back and forth and left and right to find the position of the maximum echo of the defect reflection wave, collect and save the defect reflection waveform and the non-defect reflection waveform to form a comparison diagram. S5: Record the defect depth value and horizontal distance value displayed by the ultrasonic testing equipment, compare them with the actual defect depth and actual horizontal distance of the artificial defect, calculate the depth deviation value and horizontal deviation value, and form a deviation data table for defect location. S6: During on-site testing, the actual detected waveform is compared with the comparison chart to obtain the defect type, and the position displayed on the instrument is corrected according to the deviation data table to obtain the true location of the defect.

[0029] In step S2, three samples are preferred, and the artificial defects in step S3 are as follows:

[0030] In step S3, each sample is designed with artificial defects processed in one area and no defects processed in another area. This allows for different test results to be obtained in the same sample, facilitating intuitive comparison later.

[0031] In step S4, a pulse-echo ultrasonic detector with a 2.5P 13×13 K2 probe is used to scan each test block on side A and side B respectively. Specifically, the outer side of the weld is scanned and sampled using a primary wave and / or a secondary wave to obtain defective waveform diagrams and defect-free shape waveform diagrams, as shown in the attached figure. The deviation data table for step S5 is shown in the table below:

[0032] Regarding step S6, the specific details are as follows: When performing ultrasonic testing on non-standard T-type full penetration fillet welds of the same batch and specification on-site, the testing personnel will compare the real-time acquired waveforms with the comparison diagrams: if the waveform characteristics are similar to a certain defect waveform diagram, it is determined that a defect of the corresponding type exists; if the waveform characteristics are similar to a defect-free waveform diagram, it is determined that a defect of the same type exists; if the waveform characteristics are similar to a defect-free waveform... Figure 1 If the reflection is consistent with the observed waveform, it is determined to be a geometric structure wave, thus eliminating the defect. Meanwhile, based on the deviation values ​​of the corresponding defect type and detection conditions in the deviation data table, the depth and horizontal position displayed by the instrument are corrected; for example, for the defect type corresponding to sample 1 (simulating the lack of fusion on the upper bevel cover side), if the depth displayed by the instrument is 60mm (secondary wave detection, the converted depth is 2*40-60=20mm), the actual defect should be -10mm, that is, the actual depth is about 10mm; the horizontal position is based on actual measurement.

[0033] Description of the electrical pulse drilling method in Embodiments 1 and 2 of this application: In this invention, the machining of artificial defects adopts the electrical pulse drilling method instead of the conventional mechanical drill bit drilling method, and the hole is drilled from the side. Electrical pulse machining: the metal material is removed by pulse spark discharge between the electrode and the workpiece, which has the following significant advantages: (1) it can machine deep holes with extremely small diameters (such as Ф1mm×40mm), achieving hole diameters that are difficult to achieve with conventional mechanical drill bits; (2) it has high machining accuracy and controllable hole diameter tolerance; (3) it has good hole wall perpendicularity, and the hole axis will not be offset due to drill bit skew during deep hole machining; (4) it effectively avoids the risk of small diameter drill bits breaking during deep hole machining; (5) it has good surface quality, which is conducive to obtaining stable and consistent ultrasonic reflection signals.

[0034] Numerous specific details are set forth in this specification. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0035] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for detecting welding defects, characterized in that, Includes the following steps: S1: Using the same material, plate thickness, bevel type, assembly angle and welding process parameters as the actual component to be tested, a comparison test plate was prepared by welding. S2: Select a probe, calculate the probe movement area size based on the selected probe, cut the comparison test plate into multiple samples according to the size, and finish them to the required size; S3: Using an electrical pulse drilling method, long horizontal holes are machined at preset positions in the welding area of ​​each of the specimens as artificial defects. Artificial defects are machined in a part of the area of ​​each specimen, and no defects are machined in another part of the area. S4: Using an ultrasonic testing device and the probe from step S2, scan the areas with and without artificial defects of each sample, collect and save defect reflection waveforms and non-defect reflection waveforms to form a comparison diagram; S5: Record the defect depth value and horizontal distance value displayed by the ultrasonic testing equipment, compare them with the actual defect depth and actual horizontal distance of the artificial defect, calculate the depth deviation value and horizontal deviation value, and form a deviation data table for defect location. S6: During on-site testing, the actual detected waveform is compared with the comparison chart to obtain the defect type, and the position displayed on the instrument is corrected according to the deviation data table to obtain the true location of the defect.

2. The welding defect detection method according to claim 1, characterized in that, The welding joint types of the comparative test plates in step S1 include: U-rib full penetration fillet weld joints and non-standard T-type full penetration fillet weld joints.

3. The welding defect detection method according to claim 1, characterized in that, The probe in step S2 includes: a first probe and a second probe. The first probe has a frequency of 2.5MHz, a crystal size of 8mm×12mm, and a refraction angle of 70°. The second probe has a frequency of 2.5MHz, a crystal size of 13mm×13mm, and a K value of 2.

0. The method of selecting the probe in step S2 is as follows: when it is necessary to prepare a U-ribbed sample with a thickness transition range of 12mm-16mm, the first probe is selected. When it is necessary to prepare non-standard T-type full penetration fillet weld specimens with a plate thickness ≥ 40mm, the second probe should be selected.

4. The welding defect detection method according to claim 1, characterized in that, The diameter of the elongated transverse hole in step S3 is as follows: For U-ribbed specimens with a plate thickness of 12mm-16mm, long transverse holes with a diameter of 1mm and a length of 40mm are selected. For non-standard T-type full penetration fillet weld specimens with a plate thickness ≥ 40mm, a long horizontal hole with a diameter of 3mm and a length of 40mm is selected.

5. The welding defect detection method according to claim 1, characterized in that, The processing location of the artificial defects in step S3 includes one or more of the following: the location of the non-fusion defect between the outer weld corner and the top plate, the location of the non-fusion defect between the outer weld corner and the bevel, the location of the non-penetration defect at the root of the weld, the location of the non-fusion defect between the inner weld corner and the top plate, the location of the fusion defect in the heat-affected zone, the location of the non-fusion defect on the upper bevel cover plate side, and the location of the non-fusion defect on the lower bevel side.

6. The welding defect detection method according to claim 1, characterized in that, In step S4, for U-rib type specimens, primary and secondary waves are used to scan and sample the outside of the weld, and single-sided detection is performed during sampling. For non-standard T-type full penetration fillet weld specimens, the outer side of the weld is scanned using a primary wave and / or a secondary wave. During sampling, double-sided testing is performed on both the web and cover plate sides.

7. The welding defect detection method according to claim 1, characterized in that, The position correction in step S6 specifically involves adding or subtracting the depth deviation value under the corresponding conditions from the defect depth value displayed in real time by the instrument to obtain the corrected true defect depth. Add or subtract the horizontal deviation value under the corresponding condition from the deviation data table to obtain the corrected true horizontal position of the defect.

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