A test method for DR digital imaging detection of pipe fittings

Abstract

The application discloses a kind of test methods for DR digital imaging detection of pipe nondestructive testing, which includes the following steps: step 1, test specimen preparation; Step 2, tee pipe welding and pipe conventional nondestructive testing; Step 3, test opening operation; Step 4, test plugging operation; Step 5, DR digital imaging detection; Step 6, experimental summary. The application is provided with a series of structures, for the slow defect inspection after pressure pipeline modification, major repair welding cannot solve the problem on site in time, the DR digital imaging detection technology after pressure pipeline pipe welding is proposed, which can quickly diagnose the welding quality evaluation after welding, revise the welding process, and develop the DR imaging detection process of the pipe welding joint with pressure plugging. The system has strong flexibility and portability, is very suitable for in-service pipeline radiographic testing, and does not need to remove the insulation layer for the pipeline with insulation layer.

Description

Technical Field

[0001] This invention relates to the field of testing technology for DR imaging inspection, specifically to a testing method for DR digital imaging inspection of pipe fittings for non-destructive testing. Background Technology

[0002] DR digital X-ray inspection technology utilizes the penetrating and attenuating characteristics of X-rays to obtain digital images that can be displayed and recorded through a digital detector. During the inspection, after X-ray photons penetrate an object, the attenuated X-ray photons are received by the digital detector, converted into visible light by a scintillator screen, and then the visible light information is converted into electrical signals by subsequent circuits. After being processed by a computer, the signals are displayed in the form of digital images.

[0003] In the petrochemical industry, some pipelines operate at high temperatures for extended periods, leading to deterioration of their structural properties. During use, defects such as thinning and cracking can occur, causing pipeline leaks or even explosions. To ensure safe, stable, long-term, full-capacity, and high-quality operation within the inspection cycle, it is urgent to achieve online detection of pipeline defects and hidden dangers. Conventional detection methods are affected by the insulation layer and the surface temperature after the insulation layer is removed, and they cannot be implemented when there is liquid medium inside the pipeline. Summary of the Invention

[0004] The purpose of this invention is to provide a test method for non-destructive testing of pipe fittings using DR digital imaging, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a test method for non-destructive testing of pipe fittings using DR digital imaging, the test method comprising the following steps:

[0006] Step 1, Test specimen preparation: Cut Φ325 seamless steel pipes of appropriate length to ensure convenient transportation for later testing. Supports are provided at the bottom of opposite ends of the test pipe. The test pipe is welded using J507 manual arc welding.

[0007] Step 2, T-fitting welding and routine non-destructive testing of fittings: According to the relevant regulations on pressurized sealing of steel pipelines, the method of welding by two welders at the same time is selected. The non-destructive testing of the tee includes non-destructive testing of the longitudinal straight weld and the circumferential fillet weld.

[0008] Step 3, Test Hole Drilling Operation: Drill holes in the test pipe using a hole drilling device;

[0009] Step 4, Test sealing operation: Install the sealing mechanism inside the pipeline;

[0010] Step 5, DR digital imaging inspection: Non-destructive DR digital imaging inspection of the test pipe material is carried out using DR digital X-ray inspection equipment;

[0011] Step 6, Experiment Summary: Real-time evaluation of the resolution, sensitivity, contrast, grayscale value, and normalized signal-to-noise ratio of the obtained image spectrum to determine whether it meets the relevant standard requirements, and finally obtain a qualified image; evaluate the qualified image, mark and measure defects, and generate a report.

[0012] Preferably, the support consists of a base steel plate and a support frame. Two base steel plates, each 840mm long and 400mm wide, are placed below the test pipe. Two support frames are welded onto the base steel plates to ensure that the bottom of the test pipe is 500mm from the ground. Several 100*100mm reinforcing ribs are provided on the base steel plate, the support frame, and the pipe to improve the stability of the test.

[0013] Preferably, the welding height of the tee fitting is calculated to be 9.8 mm based on the relationship between the wall thickness of the test steel pipe and the thickness of the protective pipe sealing the tee; the number of welding layers for the circumferential fillet weld is 3.

[0014] Preferably, the specific steps of the test hole drilling operation are as follows:

[0015] (1) Before drilling the pipe fitting, check whether the drilling tool is eccentric in the position of the drilling connector. If so, remove the tool, first use an instrument to measure whether the drilling connector is centered, then measure the center position of the tool, and then tighten the tool.

[0016] (2) Install the clamp valve;

[0017] (3) When drilling, stop the drilling machine after it has cut to the predetermined size, and then manually operate the drilling machine to advance the drilling cutter by 5mm-10mm. Only after confirming that the hole has been completely drilled can the cutter be lifted.

[0018] (4) If the tool gets stuck during the drilling process, it is because the hydraulic station is set too low or the displacement is too low. At this time, just stop the machine and readjust the hydraulic station setting data. When the tool gets stuck during normal cutting, first stop the hydraulic station, change the drill gear to neutral, manually turn the drill gearbox large wheel counterclockwise with the crank handle, and then engage the feed gear to continue cutting.

[0019] (5) After the hole is opened, remove the knife, close the clamp valve, release the pressure, then remove the medium in the hole opening connector and disassemble the hole opening machine.

[0020] Preferably, the specific steps of the test sealing operation are as follows:

[0021] (1) Check the condition of the sealing head before installing the sealing machine, and identify the orientation of the sealing head when hoisting the sealing machine;

[0022] (2) After the sealing machine is installed, nitrogen purging and pressure testing must be carried out;

[0023] (3) When sealing, carefully observe the saddle block cut off during the opening, and determine the degree of compression of the sealing head cup based on the scaling and corrosion of the inner wall of the pipe;

[0024] (4) The pipeline is sealed with a disc.

[0025] Preferably, the specific steps of the DR digital imaging detection are as follows:

[0026] (1) Based on the specifications of the specimen and relevant standards, prepare the exposure curve and select the corresponding exposure parameters;

[0027] (2) Set up the DR detection system and connect the relevant equipment;

[0028] (3) Detector flat panel calibration;

[0029] (4) Set the appropriate exposure parameters and perform X-ray detection;

[0030] (5) DR image analysis: After adjusting the exposure parameters, an image with qualified resolution, sensitivity, contrast, gray value and normalized signal-to-noise ratio can be obtained.

[0031] Preferably, the method for manufacturing slag inclusion defects before welding is as follows:

[0032] (1) At the 12 o'clock position of the circumferential fillet weld, before root welding, place a small amount of sand or welding slag particles on the surface of the pipe and mark them with a marker, numbered as JZ-12-XX.

[0033] (2) The length of the sealing tee is 550mm. At the middle position of the sealing plate, after the root weld is completed, a small amount of sand or slag particles are added to the weld and numbered with a marker pen. The number is JZ-225-XX.

[0034] Preferably, the non-destructive testing of the longitudinal straight weld is as follows: a first magnetic particle test is performed after the root weld is completed, a second magnetic particle test is performed after the filler weld is completed to 50%, an ultrasonic + wet magnetic particle test is performed after the cover weld is completed and the weld is kept warm, and a delayed crack test is performed 24 hours after the welding is completed, wherein the delayed crack test is performed using an ultrasonic + magnetic particle test.

[0035] Non-destructive testing of the circumferential fillet weld: First magnetic particle testing is performed after the root weld is completed; second magnetic particle testing is performed after the filler weld is 50% complete; wet magnetic particle testing is performed after the cover weld is completed and the weld is kept warm; delayed crack detection is performed 24 hours after the welding is completed, and magnetic particle testing is used for delayed crack detection here.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] This non-destructive testing method for pipe fittings utilizes DR digital imaging to quickly and efficiently solve on-site problems. Compared with traditional methods, it provides verifiable and reliable data. The equipment is simple to operate, portable, easy to control and operate, requires no consumables, and poses no threat to environmental protection. It significantly improves the safety factor of equipment operation, thereby increasing economic and social benefits. Operating equipment can be inspected at any time, enabling timely tracking. Based on software, analysis and equipment evaluation are possible. Ultimately, it achieves: 1. Visualization of defects after welding during pressure pipeline modification and major repairs; 2. Traceability of equipment installation to operational status; 3. Evaluation of equipment installation and operation cycles.

[0038] The proposed DR digital imaging inspection technology for pressure pipeline fittings after welding, addressing the slow inspection of defects and the inability to promptly resolve on-site issues during pressure pipeline renovation and major repairs, can quickly diagnose post-weld quality assessments, revise welding processes, and develop DR imaging inspection procedures for welded joints of pressurized sealing fittings. This system is highly flexible and portable, making it ideal for in-service pipeline radiographic inspection, and it eliminates the need to remove insulation layers from pipelines with insulation. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the test pipe of the present invention;

[0040] Figure 2 This is a schematic diagram of the welding direction of the longitudinal straight weld seam of the tee in this invention;

[0041] Figure 3 This is a schematic diagram of the welding direction of the circumferential fillet weld for sealing the tee in this invention.

[0042] Figure 4 The present invention adjusts the exposure parameters to obtain an image with acceptable resolution, sensitivity, contrast, grayscale value, and normalized signal-to-noise ratio.

[0043] Figure 5 This invention provides a clearer and easier-to-determine image obtained through post-processing of the original image.

[0044] Figure 6 This invention provides an image with a resolution of D8 achieved by the dual-wire image quality meter.

[0045] Figure 7 This invention provides an image with a single-filament image quality meter that achieves a sensitivity of W11, detects a minimum grayscale value of 15000 for the effective area, and has a normalized signal-to-noise ratio of 135. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example

[0049] like Figures 1 to 3 As shown in this embodiment, the test method for non-destructive testing of pipe fittings using DR digital imaging includes the following steps:

[0050] Step 1, Test specimen preparation: Cut Φ325 seamless steel pipes of appropriate length to ensure convenient transportation for later testing. Supports are provided at the bottom of opposite ends of the test pipe. The test pipe is welded using J507 manual arc welding.

[0051] Step 2, T-fitting welding and routine non-destructive testing of fittings: According to the relevant regulations on pressurized sealing of steel pipelines, the method of welding by two welders at the same time is selected. The non-destructive testing of the tee includes non-destructive testing of the longitudinal straight weld and the circumferential fillet weld.

[0052] Step 3, Test Hole Drilling Operation: Drill holes in the test pipe using a hole drilling device;

[0053] Step 4, Test sealing operation: Install the sealing mechanism inside the pipeline;

[0054] Step 5, DR digital imaging inspection: Non-destructive DR digital imaging inspection of the test pipe material is carried out using DR digital X-ray inspection equipment;

[0055] Step 6, Experiment Summary: Real-time evaluation of the resolution, sensitivity, contrast, grayscale value, and normalized signal-to-noise ratio of the obtained image spectrum to determine whether it meets the relevant standard requirements, and finally obtain a qualified image; evaluate the qualified image, mark and measure defects, and generate a report.

[0056] Specifically, the support consists of a base steel plate and a support frame. Two base steel plates, each 840mm long and 400mm wide, are placed below the test pipe. Two support frames are welded onto the base steel plates to ensure that the bottom of the test pipe is 500mm from the ground. Several 100*100mm reinforcing ribs are provided on the base steel plate, the support frame, and the pipe to improve the stability of the test.

[0057] Furthermore, based on the relationship between the wall thickness of the test steel pipe and the thickness of the protective pipe sealing the tee, the weld height of the circumferential fillet weld of the tee was calculated to be 9.8 mm; the number of weld layers of the circumferential fillet weld was 3.

[0058] Furthermore, the specific steps of the experimental drilling operation are as follows:

[0059] (1) Before drilling the pipe fitting, check whether the drilling tool is eccentric in the position of the drilling connector. If so, remove the tool, first use an instrument to measure whether the drilling connector is centered, then measure the center position of the tool, and then tighten the tool.

[0060] (2) Install the clamp valve;

[0061] (3) When drilling, stop the drilling machine after it has cut to the predetermined size, and then manually operate the drilling machine to advance the drilling cutter by 5mm-10mm. Only after confirming that the hole has been completely drilled can the cutter be lifted.

[0062] (4) If the tool gets stuck during the drilling process, it is because the hydraulic station is set too low or the displacement is too low. At this time, just stop the machine and readjust the hydraulic station setting data. When the tool gets stuck during normal cutting, first stop the hydraulic station, change the drill gear to neutral, manually turn the drill gearbox large wheel counterclockwise with the crank handle, and then engage the feed gear to continue cutting.

[0063] (5) After the hole is opened, remove the knife, close the clamp valve, release the pressure, then remove the medium in the hole opening connector and disassemble the hole opening machine.

[0064] Furthermore, the specific steps of the test sealing operation are as follows:

[0065] (1) Check the condition of the sealing head before installing the sealing machine, and identify the orientation of the sealing head when hoisting the sealing machine;

[0066] (2) After the sealing machine is installed, nitrogen purging and pressure testing must be carried out;

[0067] (3) When sealing, carefully observe the saddle block cut off during the opening, and determine the degree of compression of the sealing head cup based on the scaling and corrosion of the inner wall of the pipe;

[0068] (4) The pipeline is sealed with a disc.

[0069] Furthermore, the specific steps of the DR digital imaging detection are as follows:

[0070] (1) Based on the specifications of the specimen and relevant standards, prepare the exposure curve and select the corresponding exposure parameters;

[0071] (2) Set up the DR detection system and connect the relevant equipment;

[0072] (3) Detector flat panel calibration;

[0073] (4) Set the appropriate exposure parameters and perform X-ray detection;

[0074] (5) DR image analysis: After adjusting the exposure parameters, an image with qualified resolution, sensitivity, contrast, gray value and normalized signal-to-noise ratio can be obtained.

[0075] Furthermore, the method for manufacturing slag inclusion defects before welding is as follows:

[0076] (1) At the 12 o'clock position of the circumferential fillet weld, before root welding, place a small amount of sand or welding slag particles on the surface of the pipe and mark them with a marker, numbered as JZ-12-XX.

[0077] (2) The length of the sealing tee is 550mm. At the middle position of the sealing plate, after the root weld is completed, a small amount of sand or slag particles are added to the weld and numbered with a marker pen. The number is JZ-225-XX.

[0078] Furthermore, the non-destructive testing of the longitudinal straight weld seam is as follows: a first magnetic particle test is performed after the root weld is completed, a second magnetic particle test is performed after the filler weld is completed to 50%, an ultrasonic + wet magnetic particle test is performed after the cover weld is completed and the surface is kept warm, and a delayed crack test is performed 24 hours after the welding is completed, where the delayed crack test uses an ultrasonic + magnetic particle test.

[0079] Non-destructive testing of the circumferential fillet weld: First magnetic particle testing is performed after the root weld is completed; second magnetic particle testing is performed after the filler weld is 50% complete; wet magnetic particle testing is performed after the cover weld is completed and the weld is kept warm; delayed crack detection is performed 24 hours after the welding is completed, and magnetic particle testing is used for delayed crack detection here.

[0080] By adjusting the exposure parameters, an image with acceptable resolution, sensitivity, contrast, grayscale value, and normalized signal-to-noise ratio can be obtained. Figure 4 All of the above indicators are in Figure 1 Measurements showed that the dual-wire image quality meter achieved an image resolution of D8 (…). Figure 6 The single-filament image quality meter has a sensitivity of W11, with a minimum grayscale value of 15000 for the effective detection area (within 20%~80% of the full scale grayscale value), and a normalized signal-to-noise ratio of 135. Figure 7 Post-processing of the original image can yield a clearer, more easily identifiable image. Figure 5 This effectively improves the ability of inspectors to identify defects.

[0081] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test method for non-destructive testing of pipe fittings using DR digital imaging, characterized in that: The experimental method includes the following steps: Step 1, Test specimen preparation: Cut Φ325 seamless steel pipes of appropriate length to ensure convenient transportation for later testing. Supports are provided at the bottom of opposite ends of the test pipe. The test pipe is welded using J507 manual arc welding. Step 2, T-fitting welding and routine non-destructive testing of fittings: According to the relevant regulations on pressurized sealing of steel pipelines, the method of welding by two welders at the same time is selected. The non-destructive testing of the tee includes non-destructive testing of the longitudinal straight weld and the circumferential fillet weld. Step 3, Test Hole Drilling Operation: Drill holes in the test pipe using a hole drilling device; Step 4, Test sealing operation: Install the sealing mechanism inside the pipeline; Step 5, DR digital imaging inspection: Non-destructive DR digital imaging inspection of the test pipe material is carried out using DR digital X-ray inspection equipment; Step 6, Experiment Summary: Real-time evaluation of the resolution, sensitivity, contrast, grayscale value, and normalized signal-to-noise ratio of the obtained image quality indicators to determine whether they meet the relevant standard requirements, and finally obtain a qualified image; evaluate the qualified image, mark and measure defects, and generate a report; Manufacturing of slag inclusion defects before welding; methods for manufacturing slag inclusion defects: At the 12 o'clock position of the circumferential fillet weld, before root welding, place a small amount of sand or welding slag particles on the surface of the pipe and mark them with a marker, numbered JZ-12-XX. The sealing tee is 550mm long. After the root weld is completed, a small amount of sand or slag particles are added to the weld and marked with a marker, numbered JZ-225-XX. Non-destructive testing of the longitudinal straight weld: First magnetic particle testing is performed after the root weld is completed; second magnetic particle testing is performed after the filler weld is completed to 50%; ultrasonic + wet magnetic particle testing is performed after the cover weld is completed and the weld is kept warm; delayed crack detection is performed 24 hours after the welding is completed, and ultrasonic + magnetic particle testing is used for delayed crack detection here. Non-destructive testing of the circumferential fillet weld: First magnetic particle testing is performed after the root weld is completed; second magnetic particle testing is performed after the filler weld is 50% complete; wet magnetic particle testing is performed after the cover weld is completed and the weld is kept warm; delayed crack detection is performed 24 hours after the welding is completed, and magnetic particle testing is used for delayed crack detection here.

2. The test method for non-destructive testing of pipe fittings using DR digital imaging according to claim 1, characterized in that: The support consists of a base steel plate and a support frame. Two base steel plates, each 840mm long and 400mm wide, are placed below the test pipe. Two support frames are welded onto the base steel plates to ensure that the bottom of the test pipe is 500mm from the ground. Several 100*100mm reinforcing ribs are provided on the base steel plate, support frame, and pipe to improve the stability of the test.

3. The test method for non-destructive testing of pipe fittings using DR digital imaging according to claim 1, characterized in that: Based on the relationship between the wall thickness of the test steel pipe and the thickness of the protective pipe sealing the tee, the weld height of the circumferential fillet weld of the tee was calculated to be 9.8 mm; the number of weld layers for the circumferential fillet weld was 3.

4. The test method for non-destructive testing of pipe fittings using DR digital imaging according to claim 1, characterized in that: The specific steps of the experimental hole-opening operation are as follows: (1) Before drilling the pipe fitting, check whether the drilling tool is eccentric in the position of the drilling connector. If so, remove the tool, first use an instrument to measure whether the drilling connector is centered, then measure the center position of the tool, and then tighten the tool. (2) Install the clamp valve; (3) When drilling, stop the drilling machine after it has cut to the predetermined size, and then manually operate the drilling machine to advance the drilling cutter by 5mm-10mm. Only after confirming that the hole has been completely drilled can the cutter be lifted. (4) If the tool gets stuck during the drilling process, it is because the hydraulic station is set too low or the displacement is too low. At this time, just stop the machine and readjust the hydraulic station setting data. When the tool gets stuck during normal cutting, first stop the hydraulic station, change the drill gear to neutral, manually turn the drill gearbox large wheel counterclockwise with the crank handle, and then engage the feed gear to continue cutting. (5) After the hole is opened, remove the knife, close the clamp valve, release the pressure, then remove the medium in the hole opening connector and disassemble the hole opening machine.

5. The test method for non-destructive testing of pipe fittings using DR digital imaging according to claim 1, characterized in that: The specific steps of the experimental sealing operation are as follows: (1) Check the condition of the sealing head before installing the sealing machine, and identify the orientation of the sealing head when hoisting the sealing machine; After the sealing machine is installed, nitrogen purging and pressure testing must be performed. When sealing, carefully observe the saddle block cut off during the opening, and determine the degree of compression of the sealing head cup based on the scale and corrosion on the inner wall of the pipe. (4) The pipeline is sealed with a disc.

6. The test method for non-destructive testing of pipe fittings using DR digital imaging according to claim 1, characterized in that: The specific steps of the DR digital imaging detection are as follows: (1) Based on the specifications of the specimen and relevant standards, prepare the exposure curve and select the corresponding exposure parameters; (2) Set up the DR detection system and connect the relevant equipment; (3) Detector flat panel calibration; (4) Set the appropriate exposure parameters and perform X-ray detection; (5) DR image analysis: After adjusting the exposure parameters, an image with qualified resolution, sensitivity, contrast, gray value and normalized signal-to-noise ratio can be obtained.

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