Spiral steel pipe detection method

Abstract

The invention provides a spiral steel pipe detection method, and belongs to the field of steel pipe detection. Comprising the following steps that S100, welding data are detected in real time in the spiral steel pipe welding process; s200, the inner diameter, the outer diameter and the length of the welded spiral steel pipe are detected; s300, after the spiral steel pipe is welded, the forming size, surface defects and tensile strength of the surface of a weld joint are detected; s400, the sealing performance of the welded spiral steel pipe is detected; step S500, detecting the thickness, adhesive force and surface defects of the anticorrosive coating after the anticorrosive coating of the spiral steel pipe is coated; s600, the impact resistance of the spiral steel pipe is detected; s700, the service life of the spiral steel pipe is detected; and S800, completing the detection. The objective of the invention is to solve the problem that potential internal defects cannot be timely found in existing spiral steel pipe detection. The technical effect that potential internal defects of the spiral steel pipe can be found in time is achieved.

Description

Technical Field

[0001] This invention relates to the field of steel pipe testing technology, and in particular to a method for testing spiral steel pipes. Background Technology

[0002] Spiral steel pipes are the main pipe material in fields such as long-distance oil and gas pipelines, municipal water supply and drainage networks, and industrial fluid transportation systems. Their quality determines the long-term operational safety, stability, and service life of the transportation system.

[0003] However, current testing methods for spiral welded steel pipes lack a systematic and integrated testing capability covering all critical stages from welding to life assessment. Existing testing methods focus only on static inspections after welding, neglecting dynamic monitoring of real-time data during the welding process. This makes it impossible to detect potential internal defects caused by fluctuations in the welding process in a timely manner. Although some testing methods cover sealing or anti-corrosion coating testing, they do not synergistically correlate the thickness and adhesion of the anti-corrosion coating, its impact resistance, and its actual service life assessment. This makes it difficult to predict the corrosion risk caused by coating failure during long-term use or the structural stability under extreme operating conditions.

[0004] In summary, existing inspection methods for spiral welded steel pipes have significant blind spots in controlling the overall quality, making it easy for products with hidden defects to enter the market. Over long-term operation, these hidden defects may gradually surface, leading to safety accidents such as pipeline leaks and structural fractures. This not only causes economic costs such as loss of the transported medium and equipment maintenance, but may also pose a serious threat to the surrounding environment and public safety. Summary of the Invention

[0005] This invention provides a method for testing spiral steel pipes to solve the above-mentioned problems in the prior art.

[0006] This invention provides a method for testing spiral steel pipes, comprising the following steps: Step S100: Welding process inspection, real-time monitoring of welding data during the spiral steel pipe welding process; Step S200: Dimensional inspection, inspecting the inner diameter, outer diameter, and length of the spiral steel pipe after welding; Step S300: Weld inspection. After the spiral steel pipe is welded, the forming dimensions, surface defects and tensile strength of the weld surface are inspected. Step S400: Sealing test, testing the sealing performance of the spiral steel pipe after welding; Step S500: Anti-corrosion coating inspection. After the anti-corrosion coating of the spiral steel pipe is applied, the thickness, adhesion and surface defects of the anti-corrosion coating are inspected. Step S600: Impact resistance test, to test the impact resistance performance of the spiral steel pipe; Step S700: Life test, test the service life of the spiral steel pipe; Step S800: Detection complete.

[0007] In addition, the spiral steel pipe testing method according to the present invention may also have the following additional technical features: In some embodiments of the present invention, step S100, the detection of the spiral steel pipe welding process includes the following steps: Step S110: Inspect raw materials and welding materials before welding; Step S120: Inspect the welding equipment before welding; Step S130: Before welding, check whether the preheating temperature of the base material meets the standard and whether the interpass temperature is kept within the specified range during multi-pass welding; Step S140: The welding voltage, current, and welding speed are monitored in real time during the welding process; Step S150: Real-time detection of the size and shape of the molten pool and surface defects of the weld during the welding process.

[0008] In some embodiments of the present invention, step S200, the dimensional detection, which detects the inner diameter, outer diameter, and length of the spiral steel pipe after welding, includes the following steps: Step S210: Use an angle grinder or sandpaper to remove weld slag and burrs from both ends of the steel pipe to avoid protrusions affecting the measurement fit. Use a level to calibrate the placement of the spiral steel pipe. Step S220: Use a laser diameter gauge to detect the inner and outer diameters of the spiral steel pipe after welding; Step S230: Use a laser rangefinder to measure the length of the spiral steel pipe after welding.

[0009] In some embodiments of the present invention, step S300, weld inspection, and the inspection of the forming dimensions of the weld surface after welding of the spiral steel pipe include the following steps: Step S310: Use a laser profilometer to obtain two-dimensional cross-sectional data of the weld seam of the spiral steel pipe, and dynamically detect the height and width of the inner wall weld seam and the outer wall weld seam of the spiral steel pipe. Step S320: Use a laser collimator to check the straightness of the spiral steel pipe.

[0010] In some embodiments of the present invention, step S300, weld inspection, and the inspection of weld surface defects after welding of the spiral steel pipe include the following steps: Step S330: The operator moves from one end of the spiral steel pipe to the other end and visually observes whether there are weld beads, surface depressions, or unfilled grooves on the surface of the weld seam on the outer wall of the spiral steel pipe. Step S340: Use a magnifying glass to check whether the root of the weld on the outer wall of the spiral steel pipe is fully welded, whether there is undercut at the edge of the weld on the outer wall, and whether there are cracks at the lap joint of the weld on the outer wall. Step S350: Use an endoscope to inspect the weld seam on the inner wall of the spiral steel pipe for weld beads, surface depressions, unfilled grooves, and cracks.

[0011] In some embodiments of the present invention, step S400, the sealing performance test, which tests the sealing performance of the spiral steel pipe after welding, includes the following steps: Step S410: Install plugs at both ends of the spiral steel pipe to ensure that the spiral steel pipe is completely sealed. Install safety valves, water inlet valves and air vents on the plugs. Step S420: Use the hydrostatic test method to detect the welds and leak points of the spiral steel pipe; Step S430: Use the air tightness test method to test the air tightness of the spiral steel pipe.

[0012] In some embodiments of the present invention, step S500, the detection of the anti-corrosion coating, and the detection of the thickness, adhesion, and surface defects of the anti-corrosion coating after the spiral steel pipe anti-corrosion coating is applied, includes the following steps: Step S510: Observe whether the surface of the anti-corrosion coating is uniform and free from defects such as bubbles, cracks, and peeling; Step S520: Measure the coating thickness using an ultrasonic thickness gauge; Step S530: Quantitatively measure the bonding strength between the anti-corrosion coating and the spiral steel pipe using an adhesion tester; Step S540: Use an electrical discharge machine to scan the surface of the anti-corrosion coating to detect defects on the surface of the anti-corrosion coating.

[0013] In some embodiments of the present invention, step S500, the anti-corrosion coating detection further includes the following steps: Step S550: Conduct a chemical corrosion resistance test on the anti-corrosion coating; Step S560: Salt spray test to detect the salt spray corrosion resistance of the anti-corrosion coating; Step S570: Test the anti-aging ability of the anti-corrosion coating by alternating temperature and humidity changes.

[0014] In some embodiments of the present invention, step S600, the impact resistance test, includes the following steps: Step S610: Process the spiral steel pipe sample into a standard V-notch specimen; Step S620: Set the ambient temperature; Step S630: Using an impact testing machine, impact the specimen with a pendulum to detect the energy absorbed by the spiral steel pipe during fracture.

[0015] In some embodiments of the present invention, step S700, the service life detection, includes the following steps: Step S710: Test the corrosion resistance and durability of the anti-corrosion coating; Step S720: Detect the mechanical degradation properties of the anti-corrosion coating; Step S730: Test the material aging performance of the spiral steel pipe.

[0016] In summary, this application includes the following beneficial technical effects: This spiral welded pipe inspection method, through real-time detection during the welding process, can dynamically capture data fluctuations during welding, promptly identify potential internal defects caused by abnormal welding processes, and avoid the lag of static inspection; by controlling the dimensional accuracy and weld quality of the spiral welded pipe, comprehensive inspection is conducted from external parameters such as inner and outer diameters to weld forming dimensions, defects, and tensile strength, ensuring the structural reliability of the spiral welded pipe; by inspecting the sealing performance of the spiral welded pipe, the risk of leakage during transportation can be effectively reduced; by conducting multi-dimensional inspections of the thickness, adhesion, and surface defects of the anti-corrosion coating, the potential for corrosion during long-term use can be reduced; by coordinating the impact resistance and lifespan testing of the spiral welded pipe, both the structural stability under extreme working conditions and the service life of the spiral welded pipe are verified. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. Figure 1 A flowchart illustrating a method for inspecting spiral steel pipes according to some embodiments of the present invention is shown. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0019] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “” used herein may also indicate the inclusion of the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated, unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0020] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0021] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may also be rotated 90 degrees or in other orientations, and the spatial relative descriptors used in the text will be interpreted accordingly.

[0022] like Figure 1 As shown, according to an embodiment of the first aspect of the present invention, a method for testing spiral steel pipes is proposed, comprising the following steps: Step S100: Welding process inspection, real-time monitoring of welding data during the spiral steel pipe welding process; Step S200: Dimensional inspection, inspecting the inner diameter, outer diameter, and length of the spiral steel pipe after welding; Step S300: Weld inspection. After the spiral steel pipe is welded, the forming dimensions, surface defects and tensile strength of the weld surface are inspected. Step S400: Sealing test, testing the sealing performance of the spiral steel pipe after welding; Step S500: Anti-corrosion coating inspection. After the anti-corrosion coating of the spiral steel pipe is applied, the thickness, adhesion and surface defects of the anti-corrosion coating are inspected. Step S600: Impact resistance test, to test the impact resistance performance of the spiral steel pipe; Step S700: Life test, test the service life of the spiral steel pipe; Step S800: Detection complete.

[0023] The technical effects achieved by the above embodiments are as follows: This spiral steel pipe inspection method can dynamically capture data fluctuations during the welding process through real-time detection, promptly detect potential internal defects caused by abnormal welding processes, and avoid the lag of static detection; by controlling the dimensional accuracy and weld quality of the spiral steel pipe, comprehensive inspection is carried out from external parameters such as inner and outer diameters to weld forming dimensions, defects, and tensile strength, ensuring the structural reliability of the spiral steel pipe; by inspecting the sealing performance of the spiral steel pipe, the risk of leakage during the transportation process can be effectively reduced; by conducting multi-dimensional inspections of the thickness, adhesion, and surface defects of the anti-corrosion coating, the potential for corrosion during long-term use can be reduced; by coordinating the impact resistance test and life test of the spiral steel pipe, the structural stability under extreme working conditions is verified, and the service life of the spiral steel pipe is guaranteed. In summary, this spiral steel pipe testing method provides comprehensive testing from welding to life assessment, eliminating blind spots in quality control, significantly reducing the probability of hidden defects, decreasing the occurrence of safety accidents such as pipeline leaks and breaks, lowering equipment maintenance costs, and ensuring the safety of the surrounding environment and public.

[0024] Optional, such as Figure 1 As shown, the inspection of the spiral steel pipe welding process in step S100 includes the following steps: Step S110: Inspect raw materials and welding materials before welding; Step S120: Inspect the welding equipment before welding; Step S130: Before welding, check whether the preheating temperature of the base material meets the standard and whether the interpass temperature is kept within the specified range during multi-pass welding; Step S140: The welding voltage, current, and welding speed are monitored in real time during the welding process; Step S150: Real-time detection of the size and shape of the molten pool and surface defects of the weld during the welding process.

[0025] In the above optional embodiments, it should be noted that step S110, the inspection of raw materials and welding materials before welding, includes: inspecting the thickness, chemical composition, mechanical properties of the spiral steel pipe base material, and whether the type and specifications of the welding filler material, namely the welding wire and welding rod, match the base material and whether there are any problems such as dampness or corrosion.

[0026] The specific testing method is as follows: First, check the quality certificates of the spiral steel pipe base material and welding materials to confirm that the material and specifications are consistent with the design documents; second, sample the spiral steel pipe base material for testing, and perform tensile and impact tests, and sample the welding materials for chemical composition analysis to ensure that the performance meets the standards.

[0027] Step S120, Pre-welding inspection of welding equipment includes: Use a multimeter or oscilloscope to check the current and voltage fluctuations of the welding machine under no-load and load conditions; after setting the wire feeding speed, use a stopwatch to time the actual wire feeding length and a ruler to measure the error; pressurize the welding cooling device and observe whether the pressure gauge is stable, while checking whether the pipeline is leaking; confirm that the equipment and instruments are within the calibration validity period and that there are no expired or uncalibrated cases.

[0028] Step S130: Before welding, check whether the preheating temperature of the base material meets the standard and whether the interpass temperature is kept within the specified range during multi-pass welding; Use an infrared thermometer to measure the temperature at multiple points within a range of 50mm to 100mm on both sides of the bevel of the spiral steel pipe to confirm that the preheating temperature meets the process requirements. When welding multiple passes, after each pass is completed and before the next pass begins, use an infrared thermometer again to measure the interpass temperature to ensure that it is not lower than the preheating temperature and not higher than 300℃.

[0029] Step S140: The method for real-time detection of welding voltage, current and welding speed during the welding process is as follows: read the current and voltage values ​​in real time using the digital display instrument built into the welding machine, and record them once every 5 to 10 minutes; mark the starting point on the pipe body with a marker, and use a stopwatch to measure the welding distance per unit time, calculate the actual welding speed, and ensure that it is consistent with the requirements; if the parameter fluctuation is found to exceed the specified error, stop the machine immediately and adjust the equipment.

[0030] Step S150, the method for real-time detection of the size and shape of the molten pool and surface defects of the weld during the welding process is as follows: Welders visually inspect the molten pool in real time to ensure it is uniform and free from violent fluctuations. They also use flashlights to inspect the surface of the welded joints. If problems such as porosity, undercut depth exceeding the design value, or incomplete weld height being less than the design value are found on the surface of the spiral steel pipe weld, the machine is immediately stopped to clean the defects and then re-weld.

[0031] In addition, after welding is completed, the quality of the weld is inspected. The weld reinforcement and width are measured with a weld gauge, and then the weld surface is inspected section by section with a magnifying glass. If suspected defects are found, the weld defects are further confirmed by penetrant testing.

[0032] The advantages of the above optional embodiments are: by inspecting the entire welding process, the welding effect can be effectively guaranteed, the probability of hidden defects appearing during the welding process of spiral steel pipes can be reduced, and the yield of spiral steel pipes can be indirectly increased.

[0033] Optional, such as Figure 1 As shown, step S200, the dimensional inspection, which involves inspecting the inner diameter, outer diameter, and length of the spiral steel pipe after welding, includes the following steps: Step S210: Use an angle grinder or sandpaper to remove weld slag and burrs from both ends of the steel pipe to avoid protrusions affecting the measurement fit. Use a level to calibrate the placement of the spiral steel pipe. Step S220: Use a laser diameter gauge to detect the inner and outer diameters of the spiral steel pipe after welding; Step S230: Use a laser rangefinder to measure the length of the spiral steel pipe after welding.

[0034] In the above optional embodiments, it should be noted that step S220, the method of using a laser diameter gauge to detect the inner and outer diameters of the spiral steel pipe after welding, is as follows: First, the inner diameter of the spiral steel pipe is measured. Five basic sections are selected: the end sections at both ends of the spiral steel pipe, one section in the middle of the spiral steel pipe, and two sections at 1 / 4 and 3 / 4 of the length. For each section, four positions around the circumference are selected: 0°, 90°, 180°, and 270°, avoiding the weld seam. Then, an ultrasonic diameter gauge is used to measure the inner diameter of each section of the spiral steel pipe at each position. The average value is taken to obtain the inner diameter of the spiral steel pipe. Then, the outer diameter of the spiral steel pipe is measured using the same method.

[0035] Then, an ultrasonic thickness gauge is used to measure the wall thickness of each section and each direction of the spiral steel pipe. The wall thickness is then calculated by using the inner diameter as equal to the outer diameter minus 2 to ensure accurate measurement.

[0036] Step S230, the method for using a laser rangefinder to detect the length of the welded spiral steel pipe is as follows: At one end of the spiral steel pipe, use a vernier caliper to find the position of the maximum outer diameter and mark it as the starting point; at the other end, use a plumb bob to hang a vertical line and find the endpoint coaxial with the starting point and mark it as the ending point, ensuring that the reference points are aligned; use a laser rangefinder to align with the starting point and the ending point, and take three consecutive measurements to obtain the length of the spiral steel pipe by averaging the values.

[0037] Optional, such as Figure 1As shown, step S300, weld inspection, includes the following steps for inspecting the weld surface dimensions after welding the spiral steel pipe: Step S310: Use a laser profilometer to obtain two-dimensional cross-sectional data of the weld seam of the spiral steel pipe, and dynamically detect the height and width of the inner wall weld seam and the outer wall weld seam of the spiral steel pipe. Step S320: Use a laser collimator to check the straightness of the spiral steel pipe.

[0038] In the above optional embodiments, it should be noted that the method of using a laser collimator to detect the straightness of the spiral steel pipe in step S320 is to use a laser collimator to measure the distance of each position of the steel pipe from the laser beam, thereby determining the straightness of the spiral steel pipe.

[0039] The advantages of the above optional embodiments are as follows: by detecting the inner diameter, outer diameter and length of the spiral steel pipe, it can be ensured that the size, straightness, height and width of the spiral steel pipe are within the set size range, thereby ensuring that the spiral steel pipe meets the size requirements when it leaves the factory, and thus indirectly increasing the yield of finished products.

[0040] Optional, such as Figure 1 As shown, step S300, weld inspection, includes the following steps for detecting surface defects in the weld after welding of the spiral steel pipe: Step S330: The operator moves from one end of the spiral steel pipe to the other end and visually observes whether there are weld beads, surface depressions, or unfilled grooves on the surface of the weld seam on the outer wall of the spiral steel pipe. Step S340: Use a magnifying glass to check whether the root of the weld on the outer wall of the spiral steel pipe is fully welded, whether there is undercut at the edge of the weld on the outer wall, and whether there are cracks at the lap joint of the weld on the outer wall. Step S350: Use an endoscope to inspect the weld seam on the inner wall of the spiral steel pipe for weld beads, surface depressions, unfilled grooves, and cracks.

[0041] In the above optional embodiments, it should be noted that, In steps 330 and 340, the angle for observing weld defects is determined by using a flashlight to illuminate the weld, with the flashlight beam forming an angle of 30° to 45° with the weld surface, using the contrast of light and shadow to highlight the defects.

[0042] Step S350 involves using an endoscope to inspect the weld seam on the inner wall of the spiral steel pipe for weld beads, surface depressions, unfilled grooves, and cracks. Detecting surface defects in the weld seam also includes the following steps: Evenly spray the color penetrant onto the weld seam surface using a spray can, ensuring no areas are missed; maintain the penetration time for 10 to 30 minutes, preventing the penetrant from drying out; gently wipe the weld seam with a clean cloth dampened with the matching cleaning agent, following the direction perpendicular to the weld seam texture; ensure no obvious color residue remains; if residue remains, gently wipe with a cloth dampened with a small amount of cleaning agent, avoiding over-cleaning; after the weld seam surface is completely dry, evenly spray the developer onto the weld seam surface using a spray can, and then observe the changes in the developing film: the color penetrant within the defect will seep out, forming red spots or lines on the developing film, indicating a defect. When the developing film is observed with a magnifying glass, the red lines indicate cracks, and the dots indicate pores.

[0043] In addition, the tensile strength of the weld seam of the spiral steel pipe needs to be tested. Tensile specimens are cut from the weld seam area of ​​the spiral steel pipe, and the original dimensions of the specimen, such as width, thickness and gauge length, are measured and recorded using vernier calipers. Then, the spiral steel pipe specimen is mounted on the tensile testing machine fixture, ensuring that the axis of the spiral steel pipe specimen is consistent with the direction of tensile force. The tensile testing machine is started to test and record data until the specimen breaks. Parameters such as maximum load, fracture location, and elongation are recorded. Then, the elongation of the spiral steel pipe specimen after fracture is calculated to confirm whether the plastic deformation capacity meets the requirements. Finally, the fracture location is analyzed to confirm whether the spiral steel pipe fracture is caused by welding defects or insufficient strength.

[0044] The advantages of the above optional embodiments are: by detecting defects on the weld surface, the weld quality can be effectively improved and the yield rate can be increased.

[0045] Optional, such as Figure 1 As shown, step S400, the sealing performance test, includes the following steps: Step S410: Install plugs at both ends of the spiral steel pipe to ensure that the spiral steel pipe is completely sealed. Install safety valves, water inlet valves and air vents on the plugs. Step S420: Use the hydrostatic test method to detect the welds and leak points of the spiral steel pipe; Step S430: Use the air tightness test method to test the air tightness of the spiral steel pipe.

[0046] In the above optional embodiments, it should be noted that in step S420, the method of using the water pressure test to detect the weld and leakage point of the spiral steel pipe is as follows: at this time, the plug installed on the spiral steel pipe is a blind sealing plate. First, close the vent valve and safety valve, open the "water inlet valve" on the blind flange at one end of the spiral steel pipe, start the pressure test pump, and slowly inject water into the spiral steel pipe. When no air bubbles are continuously discharged from the vent valve on the blind flange at the other end of the spiral steel pipe, close the vent valve and continue injecting water until the spiral steel pipe is full. During the water injection process, observe that there is no air vortex at the water inlet valve. Then, close the water inlet valve, pause the pressure test pump, and let it stand for 5 minutes to allow the air in the spiral steel pipe to rise fully. If there are air bubbles at the vent valve, open the vent valve again to release the air, and repeat until there are no air bubbles.

[0047] Then, start the pressure testing pump and slowly increase the pressure at a rate of ≤0.2MPa / min. When the pressure gauge reading on the pressure testing pump reaches 50% of the test pressure, stop increasing the pressure and maintain the pressure for 10 minutes. During the pressure maintenance period, wipe the weld and spiral steel pipe body with a dry cloth to observe whether there is any water seepage or water droplets. At the same time, check whether there is any leakage at the sealing points at both ends of the spiral steel pipe. If there is leakage at the sealing points, the pressure needs to be released and the sealing points need to be resealed. If there is no leakage, continue to increase the pressure to 80% of the test pressure, hold the pressure for 5 minutes, and check the weld and seal again to confirm that there is no leakage. Then continue to increase the pressure to the test pressure, which is 1.5 to 2 times the rated working pressure of the spiral steel pipe. Hold the pressure for more than 30 minutes. During the pressure holding period, record the pressure value every 2 minutes and observe whether the pressure drops. At the same time, shine a flashlight on the weld to check for any minor water seepage. If there is any minor water seepage, it will form a wet mark on the weld surface, and the location needs to be marked.

[0048] After the pressure holding period is completed, open the pressure relief valve at a rate of ≤0.3MPa / min and close the pressure relief valve when the pressure drops to 0.2MPa. Open the water inlet valve and the air outlet valve, remove the blind flange at one end, and let the water in the spiral steel pipe drain naturally. After draining, use compressed air to blow the inner wall of the spiral steel pipe to remove residual moisture.

[0049] Step S430: The method for testing the airtightness of the spiral steel pipe using the airtightness test is as follows: The plug here is a sealing gasket. Close all valves, start the air compressor, and inject compressed air at a pressure of 0.1 MPa into the spiral steel pipe. Apply soap solution to the plug of the spiral steel pipe and observe whether there are air bubbles. If so, depressurize and reseal to ensure that there is no leakage at the plug.

[0050] Then, start the air compressor and slowly increase the pressure at a rate of ≤0.05MPa / min to 50% of the test pressure. Hold the pressure for 5 minutes and check whether the pressure gauge reading of the air compressor is stable. If no abnormalities are found, continue to increase the pressure to the test pressure, which is 1.1-1.2 times the working pressure. Turn off the air compressor and record the initial pressure and time. Maintain the pressure for at least 60 minutes, recording the pressure every 5 minutes during this period. Calculate the pressure drop. If the pressure drop is ≤5% of the test pressure, it is preliminarily determined that there is no leakage. Use a brush to apply soap solution evenly to the weld surface and observe whether bubbles are generated. If one to two small bubbles appear continuously per second, it is considered a "minor leak"; If more than 5 bubbles per second are observed, it is considered a serious leak, and the leak location must be marked and repaired.

[0051] After the pressure holding is completed, slowly open the vent valve at a pressure relief rate of ≤0.02MPa / min to reduce the pressure inside the spiral steel pipe to atmospheric pressure; Remove the plug, blow compressed air through the inner wall of the spiral steel pipe, and clean the soap residue from the weld surface at the same time.

[0052] The beneficial effects of the above optional embodiments are as follows: by combining the hydrostatic test method with the airtightness test method, the sealing performance of the spiral steel pipe after welding can be fully verified, thereby increasing the reliability and sealing performance of the spiral steel pipe.

[0053] Optional, such as Figure 1 As shown, in step S500, the anti-corrosion coating inspection, after the anti-corrosion coating of the spiral steel pipe is applied, includes the following steps to inspect the thickness, adhesion, and surface defects of the anti-corrosion coating: Step S510: Observe whether the surface of the anti-corrosion coating is uniform and free from defects such as bubbles, cracks, and peeling; Step S520: Measure the coating thickness using an ultrasonic thickness gauge; Step S530: Quantitatively measure the bonding strength between the anti-corrosion coating and the spiral steel pipe using an adhesion tester; Step S540: Use an electrical discharge machine to scan the surface of the anti-corrosion coating to detect defects on the surface of the anti-corrosion coating.

[0054] The beneficial effects of the above optional embodiments are as follows: by observing the surface uniformity and visible defects of the rapid anti-corrosion coating during the initial screening; by using ultrasonic thickness measurement to accurately detect the compliance of the anti-corrosion coating thickness; by using adhesion testing to ensure that the anti-corrosion coating is firmly bonded to the spiral steel pipe; and by using electric spark scanning to capture hidden defects and comprehensively investigate potential hazards, the probability of corrosion during the use of the spiral steel pipe is reduced, and the long-term safety of the spiral steel pipe is ensured.

[0055] Optional, such as Figure 1 As shown, step S500, the anti-corrosion coating inspection also includes the following steps: Step S550: Conduct a chemical corrosion resistance test on the anti-corrosion coating; Step S560: Salt spray test to detect the salt spray corrosion resistance of the anti-corrosion coating; Step S570: Test the anti-aging ability of the anti-corrosion coating by alternating temperature and humidity changes.

[0056] In the above optional embodiments, it should be noted that the chemical corrosion resistance test method for the anti-corrosion coating of spiral steel pipe is as follows: First, a complete pipe section with a length of 300mm to 500mm is cut from the spiral steel pipe to be tested as a sample. Both ends of the pipe section need to be ground flat with an angle grinder to remove burrs. Then, use a camera to photograph the initial appearance of the pipe section's "outer wall non-weld area, weld area, and inner wall," and record the coating color or gloss, etc. Pour the prepared acidic medium into a container, place a temperature control device inside the container, and wait for the medium temperature to stabilize to the test temperature. Suspend the pipe section sample in the container with a nylon rope, ensuring that the sample is completely submerged and that the pipe section does not contact the container wall, bottom, or other samples. Cover the container and remove the pipe section sample every 48 hours. Quickly rinse the surface with deionized water to remove any residual medium, wipe it clean with acetone, and let it air dry. Check whether the weld coating is blistering or peeling, whether the coating edge at the pipe end is lifting, whether the substrate is corroded, and whether the inner wall coating is swollen or discolored. Observe minor defects with a magnifying glass and record changes with a camera. Detect changes in coating thickness and adhesion. If there is no obvious damage, put the sample back into the medium for further immersion. If the area of ​​coating peeling is greater than 5% or the substrate is exposed and corroded, stop the test for that sample and record the total immersion time.

[0057] After the test, the sample was removed, and the data after immersion were measured according to the test items in the initial state. The performance changes were then calculated. Thickness change rate = (thickness after immersion - initial thickness) / initial thickness × 100% (negative deviation ≤ 5% is acceptable, avoid coating dissolution; positive deviation ≤ 10% is acceptable, avoid excessive swelling). Adhesion change: After immersion, the adhesion is not less than 80% of the initial value; Mass change rate = (mass after immersion - initial mass) / initial mass × 100% (an increase in mass may be due to the penetration of the medium, and a decrease may be due to the dissolution of the coating. Generally, a change rate ≤ ±2% is acceptable).

[0058] Then, a dynamic immersion test was conducted on the sample tube section. The prepared corrosive medium was injected into the water tank of the dynamic immersion system, the temperature control device was activated, and the medium temperature was stabilized to the test temperature. The circulation pump was started, the flow meter was adjusted to the set flow rate, and the corrosive medium was allowed to circulate in the system for 30 minutes to ensure stable flow rate and no leakage. Then, the two ends of the pipe section sample are sealed and connected to the pipeline used in the experiment to ensure that the medium flows through the inside of the pipe section while the outer wall of the pipe section is also immersed in the medium; the start time of dynamic immersion is recorded and the test is continuously cyclical; the flow rate, temperature and medium concentration are recorded every 24 hours; after the test, the pipe section sample is disassembled, and the inner wall coating of the pipe section sample is checked for scratches, peeling or exposure of the substrate due to erosion. The adhesion and thickness change of the inner wall coating of the pipe section sample are tested. If the inner wall coating is damaged by erosion over a large area, it is judged as unqualified.

[0059] Then, wipe the spiral weld area of ​​the pipe section with acetone to remove oil and ensure the surface is dry. Use a pipette to take 0.5 mL of acidic solution as the test medium and drop it onto the surface of the weld coating to form a droplet with a diameter of about 8 mm. Cover the droplet with a glass slide. Record the start time of the drop and observe the changes in the coating below the droplet every 15 minutes. If the anti-corrosion coating turns white, wrinkles, or bubbles, or the droplet color turns yellowish-brown, record the time when the first damage occurs, which is the drop resistance time. After the test, rinse the drop area with deionized water, wipe it dry, and observe whether there is any exposed substrate. A drop resistance time of ≥2h is considered qualified.

[0060] Finally, take a small sample of the anti-corrosion coating on the surface of the spiral steel pipe and use a scanning electron microscope to observe whether there are media penetration channels inside the coating. If the penetration depth is ≤ 1 / 3 of the coating thickness, it is qualified.

[0061] Step S560, Salt spray test: The method for testing the salt spray corrosion resistance of the anti-corrosion coating adopts the existing salt spray test method, and the specific method will not be discussed in detail.

[0062] Optional, such as Figure 1 As shown, step S600, the impact resistance test, includes the following steps to test the impact resistance performance of the spiral steel pipe: Step S610: Process the spiral steel pipe sample into a standard V-notch specimen; Step S620: Set the ambient temperature; Step S630: Using an impact testing machine, impact the specimen with a pendulum to detect the energy absorbed by the spiral steel pipe during fracture.

[0063] In the above optional embodiments, it should be noted that the ambient temperature is the temperature required for the spiral steel pipe testing, and the specific temperature can be set according to actual needs.

[0064] The beneficial effects of the above optional embodiments are as follows: by testing the impact resistance of the spiral steel pipe, the impact resistance of the spiral steel pipe can be effectively guaranteed, thereby indirectly increasing the reliability of the spiral steel pipe in use.

[0065] Optional, such as Figure 1 As shown, step S700, the life test, includes the following steps to test the service life of the spiral steel pipe: Step S710: Test the corrosion resistance and durability of the anti-corrosion coating; Step S720: Detect the mechanical degradation properties of the anti-corrosion coating; Step S730: Test the material aging performance of the spiral steel pipe.

[0066] In the above optional embodiments, it should be noted that the method for detecting the corrosion resistance and durability of the anti-corrosion coating in step S710 is to use a salt spray test, immersion test or electrochemical accelerated corrosion method to detect the durability of the anti-corrosion coating.

[0067] In step S720, the method for detecting the mechanical degradation properties of the anti-corrosion coating is to conduct cyclic load fatigue tests, stress corrosion cracking tests, long-term static load creep tests, and simulate the effects of geological activities such as earthquakes and settlement to detect the mechanical degradation properties of the spiral steel pipe.

[0068] Step S730: The method for testing the material aging performance of spiral steel pipe is as follows: simulate ultraviolet light, damp heat, temperature cycling, etc., accelerate aging, and then test the strength, plasticity, coating gloss loss and adhesion of spiral steel pipe to evaluate the degree of aging of spiral steel pipe.

[0069] The beneficial effect of the above optional embodiments is that by detecting the service life of the spiral steel pipe, the service life of the spiral steel pipe is ultimately guaranteed.

[0070] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for testing spiral steel pipes, characterized in that, Includes the following steps: Step S100: Welding process inspection, real-time monitoring of welding data during the spiral steel pipe welding process; Step S200: Dimensional inspection, inspecting the inner diameter, outer diameter, and length of the spiral steel pipe after welding; Step S300: Weld inspection. After the spiral steel pipe is welded, the forming dimensions, surface defects and tensile strength of the weld surface are inspected. Step S400: Sealing test, testing the sealing performance of the spiral steel pipe after welding; Step S500: Anti-corrosion coating inspection. After the anti-corrosion coating of the spiral steel pipe is applied, the thickness, adhesion and surface defects of the anti-corrosion coating are inspected. Step S600: Impact resistance test, to test the impact resistance performance of the spiral steel pipe; Step S700: Life test, test the service life of the spiral steel pipe; Step S800: Detection complete.

2. The method for testing spiral steel pipes according to claim 1, characterized in that, The detection of the spiral steel pipe welding process in step S100 includes the following steps: Step S110: Inspect raw materials and welding materials before welding; Step S120: Inspect the welding equipment before welding; Step S130: Before welding, check whether the preheating temperature of the base material meets the standard and whether the interpass temperature is kept within the specified range during multi-pass welding; Step S140: The welding voltage, current, and welding speed are monitored in real time during the welding process; Step S150: Real-time detection of the size and shape of the molten pool and surface defects of the weld during the welding process.

3. The method for testing spiral steel pipes according to claim 1, characterized in that, In step S200, the dimensional inspection, which involves inspecting the inner diameter, outer diameter, and length of the spiral steel pipe after welding, includes the following steps: Step S210: Use an angle grinder or sandpaper to remove weld slag and burrs from both ends of the steel pipe to avoid protrusions affecting the measurement fit. Use a level to calibrate the placement of the spiral steel pipe. Step S220: Use a laser diameter gauge to detect the inner and outer diameters of the spiral steel pipe after welding; Step S230: Use a laser rangefinder to measure the length of the spiral steel pipe after welding.

4. The method for testing spiral steel pipes according to claim 1, characterized in that, In step S300, weld inspection, specifically the inspection of the weld surface dimensions after the spiral steel pipe is welded, includes the following steps: Step S310: Use a laser profilometer to obtain two-dimensional cross-sectional data of the weld seam of the spiral steel pipe, and dynamically detect the height and width of the inner wall weld seam and the outer wall weld seam of the spiral steel pipe. Step S320: Use a laser collimator to check the straightness of the spiral steel pipe.

5. The method for testing spiral steel pipes according to claim 4, characterized in that, In step S300, weld inspection, the inspection of weld surface defects after welding of spiral steel pipes includes the following steps: Step S330: The operator moves from one end of the spiral steel pipe to the other end and visually observes whether there are weld beads, surface depressions, or unfilled grooves on the surface of the weld seam on the outer wall of the spiral steel pipe. Step S340: Use a magnifying glass to check whether the root of the weld on the outer wall of the spiral steel pipe is fully welded, whether there is undercut at the edge of the weld on the outer wall, and whether there are cracks at the lap joint of the weld on the outer wall. Step S350: Use an endoscope to inspect the weld seam on the inner wall of the spiral steel pipe for weld beads, surface depressions, unfilled grooves, and cracks.

6. The method for testing spiral steel pipes according to claim 1, characterized in that, In step S400, the sealing performance test, which tests the sealing performance of the spiral steel pipe after welding, includes the following steps: Step S410: Install plugs at both ends of the spiral steel pipe to ensure that the spiral steel pipe is completely sealed. Install safety valves, water inlet valves and air vents on the plugs. Step S420: Use the hydrostatic test method to detect the welds and leak points of the spiral steel pipe; Step S430: Use the air tightness test method to test the air tightness of the spiral steel pipe.

7. The method for testing spiral steel pipes according to claim 1, characterized in that, In step S500, the anti-corrosion coating inspection, after the anti-corrosion coating of the spiral steel pipe is applied, includes the following steps: Step S510: Observe whether the surface of the anti-corrosion coating is uniform and free from defects such as bubbles, cracks, and peeling; Step S520: Measure the coating thickness using an ultrasonic thickness gauge; Step S530: Quantitatively measure the bonding strength between the anti-corrosion coating and the spiral steel pipe using an adhesion tester; Step S540: Use an electrical discharge machine to scan the surface of the anti-corrosion coating to detect defects on the surface of the anti-corrosion coating.

8. The method for testing spiral steel pipes according to claim 7, characterized in that, In step S500, the anti-corrosion coating detection also includes the following steps: Step S550: Conduct a chemical corrosion resistance test on the anti-corrosion coating; Step S560: Salt spray test to detect the salt spray corrosion resistance of the anti-corrosion coating; Step S570: Test the anti-aging ability of the anti-corrosion coating by alternating temperature and humidity changes.

9. The method for testing spiral steel pipes according to claim 1, characterized in that, In step S600, the impact resistance test, which tests the impact resistance performance of the spiral steel pipe, includes the following steps: Step S610: Process the spiral steel pipe sample into a standard V-notch specimen; Step S620: Set the ambient temperature; Step S630: Using an impact testing machine, impact the specimen with a pendulum to detect the energy absorbed by the spiral steel pipe during fracture.

10. The method for testing spiral steel pipes according to claim 1, characterized in that, In step S700, the service life test for the spiral steel pipe includes the following steps: Step S710: Test the corrosion resistance and durability of the anti-corrosion coating; Step S720: Detect the mechanical degradation properties of the anti-corrosion coating; Step S730: Test the material aging performance of the spiral steel pipe.

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