A method and apparatus for identifying defects in a welded joint of a small-diameter pipe with a variable thickness girth weld

Abstract

This invention discloses a method and equipment for defect identification in welded joints of small-diameter pipes with unequal thickness welded bushings. The method involves measuring the material and structural dimensions of the welded joint and cleaning its surface. Graphical auxiliary lines are created, and a defect judgment line exceeding the standard is added. A target standard reflector is selected, and the parameters of the phased array ultrasonic testing instrument are set based on the target standard reflector. The focusing and deflection of the phased array ultrasonic beam are adjusted by calculating the delay time of each array element. The phased array ultrasonic probe is connected to the phased array ultrasonic testing instrument, and the probe is moved so that the fan-shaped scanning area covers both ends of the defect judgment line exceeding the standard. A full scan is performed along the circumference of the welded joint, and the safety of the welded joint is assessed based on whether the highest point of the defect exceeds the defect judgment line exceeding the standard. Therefore, based on phased array ultrasonic testing technology, non-destructive testing of the weld is performed from the external surface using ultrasonic transverse waves in a single pass, making defect identification more scientific.

Description

Technical Field

[0001] This application relates to the field of nondestructive testing, and more specifically, to a method and equipment for identifying defects in welded joints of small-diameter pipes with unequal thickness of welded bushings. Background Technology

[0002] Welded joints of small-diameter pipes with unequal thickness and welded bushings are widely used in high-temperature heating surface tubes of some boilers. The welded joint is the weakest part of the heating surface tube and is directly related to the reliability of boiler safe operation. Therefore, the safety condition inspection of welded joints during boiler service is a necessary means to ensure the safe operation of boiler.

[0003] This type of welded joint consists of base materials of different thicknesses on both sides and a welded bushing. Because the bushing is tightly fitted to the base materials on both sides, an unfused zone exists at the joint between the bushing and the base material. The inherent lack of fusion at this bevel causes stress concentration, leading to crack initiation and further propagation during operation, ultimately causing pipe failure. Currently, radiographic testing is generally used to detect internal defects in the weld. However, due to its low sensitivity to crack-like defects, radiographic testing is generally ineffective in detecting existing cracks. Traditional A-mode pulsed ultrasonic testing identifies internal defects in the workpiece by the reflection location of defects and structures. However, due to the complexity of the structure, it is difficult to distinguish between structural reflections and crack waves, resulting in a low detection rate. Phased array ultrasonic testing can achieve a wide-angle scanning range and has the advantage of intuitive defect display. It has good detection effects on irregularly shaped structural components such as welds of small-diameter pipes. However, due to the interference of the inherent lack of fusion between the welded bushing and the base material, it cannot effectively detect microcracks in the weld.

[0004] Therefore, providing a method for identifying defects in welded joints of small-diameter pipes with unequal thickness welded bushings, in order to accurately identify defects in welded joints of small-diameter pipes with unequal thickness welded bushings and ensure production safety, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention provides a method for identifying defects in welded joints of small-diameter pipes with unequal thickness welded bushings, to solve the problem in the prior art that defects in welded joints of small-diameter pipes with unequal thickness welded bushings cannot be effectively detected. The method is as follows:

[0006] Measure the material and structural dimensions of the welded joint, and clean the surface dirt of the welded joint;

[0007] Create graphic auxiliary lines and add defect judgment lines that exceed the standard;

[0008] Select a target standard reflector, set the parameters of the phased array ultrasonic detector based on the target standard reflector, and adjust the focusing and deflection of the phased array ultrasonic beam by calculating the delay time of each array element so that the target detection area can achieve the target imaging effect.

[0009] Connect the phased array ultrasonic probe to the phased array ultrasonic detector, and move the probe so that the fan-shaped scanning area can cover the two ends of the defect judgment line.

[0010] A full scan is performed along the weld joint, and the safety of the weld joint is assessed based on whether the highest point of the defect exceeds the defect judgment line.

[0011] In some embodiments of this application, the material and structural dimensions of the welded joint are measured, specifically as follows:

[0012] The materials of the base material, weld and welding liner on both sides of the small-diameter pipe are measured, as well as the transverse wave velocity, thickness and outer surface radius of curvature of the base material on both sides. The thickness of the base material on the right side is greater than that on the left side.

[0013] In some embodiments of this application, graphic auxiliary lines are created and defect judgment lines exceeding the standard are added, specifically as follows:

[0014] Based on the thickness of the base material on both sides of the weld, the width of the upper surface of the weld, the root width, and the design drawings, the graphic auxiliary lines are made on the weld cross-section. The graphic auxiliary lines include the weld fusion line, the width and height of the upper surface of the weld, the width of the weld root, and the defect judgment line. Specifically, the defect judgment line is the line connecting the intersection of the weld and the base material on both sides.

[0015] In some embodiments of this application, the target standard reflector is specifically a Φ1mm horizontal through hole with a standard length of not less than 20mm and not less than the probe width, and the target standard reflector is made of No. 20 high-quality carbon structural steel with a sound velocity range of 5930m / s to 5950m / s.

[0016] In some embodiments of this application, the parameters of the phased array ultrasonic detector are set based on the target standard reflector, and the focusing and deflection of the phased array ultrasonic beam are adjusted by calculating the delay time of each array element, so that the target detection area achieves the target imaging effect, specifically:

[0017] Set the transverse wave velocity, focusing depth, deflection angle, scanning mode, and array element parameters of the phased array ultrasonic detector;

[0018] Adjust the parameters of the phased array ultrasonic detector so that the amplitude of the reflected echo from the Φ 1mm transverse through-hole reaches 80% of the full screen at different depths and angles.

[0019] When the transverse wave velocity of the base material is greater than 5800m and less than 6000m / s, the amplitude of the reflected echo from the Φ1mm transverse through-hole at different depths and angles reaches 80% of the full screen gain, and then an additional 2-4dB is added.

[0020] In some embodiments of this application, the focusing depth is specifically F = (0.9~1.1)T1, where F is the focusing depth and T1 is the thickness of the base material on the thinner side of the welded joint; the scanning mode includes A-type scanning and sector scanning, and B-type scanning is included during automatic scanning; the array element parameters are specifically that the number of array elements excited at one time is 16.

[0021] In some embodiments of this application, a phased array ultrasonic probe is connected to a phased array ultrasonic detector, and the probe is moved so that the fan-shaped scanning area can cover both ends of the defect judgment line. Specifically:

[0022] Place the probes on both sides of the weld seam and perform single-sided double-sided scanning.

[0023] Move the probe position so that the acoustic beam in the primary wave fan-shaped scanning area can simultaneously scan the fusion positions of the bushing and the base material on both sides;

[0024] The screen displays the structural reflected waves at the junction of the bushing and the parent material on both sides with the bushing.

[0025] In some embodiments of this application, the safety assessment of the welded joint is performed based on whether the position of the highest point of the defect exceeds the defect judgment line. Specifically:

[0026] Place the probe on either side of the probe placement surface so that the primary wave fan-shaped scanning area simultaneously displays the structural reflected wave. If, at this time, the upper endpoint of the initial defect wave at the thick side fusion line is not above the line connecting the two structural reflected waves, it is determined to be an excessive defect.

[0027] Place the probe on either side of the probe placement surface so that the primary wave fan-shaped scanning area simultaneously displays the structural reflected wave. If, at this time, the upper endpoint of the initial defect wave at the thin side fusion line is higher than the reflected wave at the junction of the thin side base material and the bushing, it is determined to be an excessive defect.

[0028] In some embodiments of this application, the reflected waves of the two structures specifically include the reflected waves of the thin-side base material, the bushing and the weld joint, or the reflected waves of the thick-side base material, the bushing and the weld joint.

[0029] Accordingly, the present invention also proposes a defect identification device for welded joints of small-diameter pipes with unequal thickness of welded bushings, the device comprising:

[0030] The measurement module is used to measure the material and structural dimensions of the welded joint and to clean the surface dirt of the welded joint;

[0031] The creation module is used to create graphic auxiliary lines and add defect judgment lines that exceed the standard;

[0032] The selection module is used to select a target standard reflector, set the parameters of the phased array ultrasonic detector based on the target standard reflector, and adjust the focusing and deflection of the phased array ultrasonic beam by calculating the delay time of each array element so that the target detection area achieves the target imaging effect.

[0033] The connection module is used to connect the phased array ultrasonic probe to the phased array ultrasonic detector, and to make the fan-shaped scanning area cover the two ends of the defect judgment line by moving the probe.

[0034] The assessment module is used to scan the entire circumference of the welded joint and assess its safety based on whether the highest point of the defect exceeds the defect threshold.

[0035] By applying the above technical solutions, the material and structural dimensions of the welded joint are measured, and the surface dirt of the welded joint is cleaned; graphic auxiliary lines are created and defect judgment lines are added; a target standard reflector is selected, and the parameters of the phased array ultrasonic detector are set based on the target standard reflector. The focusing and deflection of the phased array ultrasonic beam are adjusted by calculating the delay time of each array element to achieve the target imaging effect in the target detection area; the phased array ultrasonic probe is connected to the phased array ultrasonic detector, and the probe is moved so that the fan-shaped scanning area can cover the two ends of the defect judgment lines; a full scan is performed along the circumference of the welded joint, according to... The safety assessment of the welded joint is conducted by determining whether the highest point of the defect exceeds the defect judgment line. Based on phased array ultrasonic testing technology, non-destructive testing of the weld is performed on the outer surface of the weld using ultrasonic shear waves in a single pass. Factors affecting the testing effect, such as focusing depth, angle selection, number of crystals, crystal frequency, and weld backing ring, are considered during the testing. Fan-shaped scanning and imaging are used to overcome the problem of unintuitive defect display and easy misjudgment when traditional ultrasonic testing is used on welded joints with unequal thickness backing rings. At the same time, this discrimination method uses the line connecting the two points of the inner wall weld and the base material as the basis for determining whether the defect exceeds the standard, making the defect discrimination more scientific. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A flowchart illustrating a method for identifying defects in welded joints of small-diameter pipes with unequal thickness of welded bushings, as proposed in an embodiment of the present invention, is shown.

[0038] Figure 2 A schematic diagram of the graphic auxiliary lines proposed in an embodiment of the present invention is shown;

[0039] Figure 3 This diagram illustrates a defect-free probe during thin-side substrate inspection according to an embodiment of the present invention.

[0040] Figure 4 This diagram illustrates a scenario where the probe, in another embodiment of the present invention, detects no defects exceeding the standard when inspecting a thin-sided base material.

[0041] Figure 5 The diagram shows a structural schematic of a defect identification device for small-diameter pipe welded joints with unequal thickness welded bushings, as proposed in an embodiment of the present invention. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] like Figure 1 As shown, the method includes the following steps:

[0044] Step S101: Measure the material and structural dimensions of the welded joint, and clean the surface dirt of the welded joint.

[0045] In this procedure, the materials of the base material, weld, and welding liner on both sides of the small-diameter pipe are measured. The transverse wave velocity, thickness, and outer surface curvature radius of the base material on both sides are also measured. The outer surface of the small-diameter pipe should be clean and free of contaminants. Oxide scale and other substances that affect the test results should be removed.

[0046] In order to measure the material and structural dimensions of the welded joint, in some embodiments of this application, the material and structural dimensions of the welded joint are measured, specifically as follows:

[0047] The materials of the base material, weld and welding liner on both sides of the small-diameter pipe are measured, as well as the transverse wave velocity, thickness and outer surface radius of curvature of the base material on both sides. The thickness of the base material on the right side is greater than that on the left side.

[0048] Specifically, such as Figure 2 As shown, the thickness of the base material on both sides of the small-diameter pipe is different, with one side being thicker than the other. Figure 2 The thickness on the right side is greater than the thickness on the left side.

[0049] Step S102: Create graphic auxiliary lines and add defect judgment lines that exceed the standard.

[0050] In this embodiment, a cross-sectional view of the weld is created based on the thickness of the base material on both sides of the weld, the width of the upper surface of the weld, the root width, and the design drawings, in order to assist in the judgment of the location of defects.

[0051] To accurately create graphic auxiliary lines, in some embodiments of this application, graphic auxiliary lines are created and excess defect judgment lines are added, specifically as follows:

[0052] Based on the thickness of the base material on both sides of the weld, the width of the upper surface of the weld, the root width, and the design drawings, the graphic auxiliary lines are made on the weld cross-section. The graphic auxiliary lines include the weld fusion line, the width and height of the upper surface of the weld, the width of the weld root, and the defect judgment line. Specifically, the defect judgment line is the line connecting the intersection of the weld and the base material on both sides.

[0053] In this embodiment, a cross-sectional view of the weld is created based on the thickness of the base metal on both sides of the weld, the width of the upper surface of the weld, the root width, and design drawings, to assist in the determination of defect locations. This auxiliary line includes the weld fusion line, the width and height of the upper surface of the weld, the root width of the weld, and the defect judgment line between the weld and the excessive defects. Specifically, the defect judgment line is the line connecting the intersection of the weld and the base metal on both sides. Figure 2 The line connecting points a and b in the middle.

[0054] Step S103: Select a target standard reflector, set the parameters of the phased array ultrasonic detector based on the target standard reflector, and adjust the focusing and deflection of the phased array ultrasonic beam by calculating the delay time of each array element so that the target detection area achieves the target imaging effect.

[0055] In this embodiment, a Φ1mm transverse through-hole with a standard length of not less than 20mm and not less than the probe width is used as the standard reflector. The standard reflector is made of No. 20 high-quality carbon structural steel, and the sound velocity range is 5930m / s~5950m / s. Other requirements should comply with the relevant provisions of standard JB / T8428. At the same time, the focusing and deflection of the phased array ultrasonic beam are realized by calculating the delay time of each array element, and the detection parameters are further adjusted to obtain the best imaging effect of the target detection area.

[0056] In order to select a target standard reflector, in some embodiments of this application, the target standard reflector is specifically a Φ 1mm horizontal through hole with a standard length of not less than 20mm and not less than the width of the probe, and the target standard reflector is made of No. 20 high-quality carbon structural steel with a sound velocity range of 5930m / s to 5950m / s.

[0057] In order to set the parameters of the phased array ultrasonic testing instrument, in some embodiments of this application, the parameters of the phased array ultrasonic testing instrument are set based on the target standard reflector, and the focusing and deflection of the phased array ultrasonic beam are adjusted by calculating the delay time of each array element, so that the target detection area achieves the target imaging effect, specifically as follows:

[0058] Set the transverse wave velocity, focusing depth, deflection angle, scanning mode, and array element parameters of the phased array ultrasonic detector;

[0059] Adjust the parameters of the phased array ultrasonic detector so that the amplitude of the reflected echo from the Φ 1mm transverse through-hole reaches 80% of the full screen at different depths and angles.

[0060] When the transverse wave velocity of the base material is greater than 5800m and less than 6000m / s, the amplitude of the reflected echo from the Φ1mm transverse through-hole at different depths and angles reaches 80% of the full screen gain, and then an additional 2-4dB is added.

[0061] In this embodiment, the shear wave velocity, focusing depth, deflection angle, scanning mode, and array element parameters of the phased array ultrasonic detector are set so that the amplitude of the reflected echo from the Φ1mm transverse through-hole reaches 80% of the full screen at different depths and angles. When the shear wave velocity of the test substrate is 5800 m < CS < 6000 m / s, an additional 2-4 dB is added on top of the above-mentioned gain that makes the amplitude of the reflected echo from the Φ1mm transverse through-hole reach 80% of the full screen at different depths and angles.

[0062] In order to achieve the parameter setting of the phased array ultrasonic testing instrument, in some embodiments of this application, the focusing depth is specifically F = (0.9~1.1)T1, where F is the focusing depth and T1 is the thickness of the base material on the thinner side of the welded joint; the scanning mode includes A-type scanning and sector scanning, and B-type scanning is included during automatic scanning; the array element parameters are specifically that the number of array elements excited at one time is 16.

[0063] Step S104: Connect the phased array ultrasonic probe to the phased array ultrasonic detector, and move the probe so that the fan-shaped scanning area can cover the two ends of the defect judgment line.

[0064] In this embodiment, the phased array ultrasonic probe (including wedge) is connected to the phased array ultrasonic detector. Coupling agent is applied to the outer surface of the weld joint to be inspected. The phased array probe is placed on the outer surfaces of both sides of the weld. By moving the probe, the fan-shaped scanning area can cover the two ends of the defect judgment line and can be clearly displayed. The fan-shaped scanning area is the area scanned by the shear wave primary wave.

[0065] To ensure the normal operation of the probe, in some embodiments of this application, the phased array ultrasonic probe is connected to a phased array ultrasonic detector, and the probe is moved so that the fan-shaped scanning area can cover the two ends of the defect judgment line. Specifically:

[0066] Place the probes on both sides of the weld seam and perform single-sided double-sided scanning.

[0067] Move the probe position so that the acoustic beam in the primary wave fan-shaped scanning area can simultaneously scan the fusion positions of the bushing and the base material on both sides;

[0068] The screen displays the structural reflected waves at the junction of the bushing and the parent material on both sides with the bushing.

[0069] Step S105: Scan the entire circumference of the welded joint and assess the safety of the welded joint based on whether the highest point of the defect exceeds the defect judgment line.

[0070] Specifically, a full scan is performed along the weld joint. The safety of the weld joint is assessed based on whether the highest point of the defect exceeds the defect judgment line. If the upper end of the defect is higher than the defect judgment line, it is considered a defect that exceeds the standard and is unqualified. If the upper end of the defect is lower than the defect judgment line, it can be recorded and judged as qualified.

[0071] To conduct a safety assessment of welded joints, in some embodiments of this application, the safety assessment is performed based on whether the highest point of the defect exceeds the defect threshold. Specifically:

[0072] Place the probe on either side of the probe placement surface so that the primary wave fan-shaped scanning area simultaneously displays the structural reflected wave. If, at this time, the upper endpoint of the initial defect wave at the thick side fusion line is not above the line connecting the two structural reflected waves, it is determined to be an excessive defect.

[0073] Place the probe on either side of the probe placement surface so that the primary wave fan-shaped scanning area simultaneously displays the structural reflected wave. If, at this time, the upper endpoint of the initial defect wave at the thin side fusion line is higher than the reflected wave at the junction of the thin side base material and the bushing, it is determined to be an excessive defect.

[0074] In order to conduct a safety assessment of the welded joint, in some embodiments of this application, the reflected waves of the two structures specifically include the reflected waves of the thin-side base material, the bushing and the weld joint, or the reflected waves of the thick-side base material, the bushing and the weld joint.

[0075] By applying the above technical solutions, the material and structural dimensions of the welded joint are measured, and the surface dirt of the welded joint is cleaned; graphic auxiliary lines are created and defect judgment lines are added; a target standard reflector is selected, and the parameters of the phased array ultrasonic detector are set based on the target standard reflector. The focusing and deflection of the phased array ultrasonic beam are adjusted by calculating the delay time of each array element to achieve the target imaging effect in the target detection area; the phased array ultrasonic probe is connected to the phased array ultrasonic detector, and the probe is moved so that the fan-shaped scanning area can cover the two ends of the defect judgment lines; a full scan is performed along the circumference of the welded joint, according to... The safety assessment of the welded joint is conducted by determining whether the highest point of the defect exceeds the defect judgment line. Based on phased array ultrasonic testing technology, non-destructive testing of the weld is performed on the outer surface of the weld using ultrasonic shear waves in a single pass. Factors affecting the testing effect, such as focusing depth, angle selection, number of crystals, crystal frequency, and weld backing ring, are considered during the testing. Fan-shaped scanning and imaging are used to overcome the problem of unintuitive defect display and easy misjudgment when traditional ultrasonic testing is used on welded joints with unequal thickness backing rings. At the same time, this discrimination method uses the line connecting the two points of the inner wall weld and the base material as the basis for determining whether the defect exceeds the standard, making the defect discrimination more scientific.

[0076] To further explain the technology of this solution, we will now describe it in conjunction with a specific application scenario.

[0077] (1) Visually inspect the quality of the outer surface of the welded joint 1 to be tested, and remove any dirt that may affect the phased array ultrasonic testing. Select a probe 3 with a suitable frequency and number of crystals, and connect it to the phased array ultrasonic testing instrument according to the equipment requirements.

[0078] (2) Check and measure the thickness of the base material on both sides of the weld joint 1, the width of the upper surface of the weld, the width of the lower surface, etc.

[0079] (3) Add auxiliary graphic diagrams to the instrument according to step (2).

[0080] (4) Based on the wall thickness T, set the focusing depth F according to the formula F = (0.9~1.1)T.

[0081] (5) The scanning modes are sector scanning and A-type scanning. The sector scanning angle is set to 35-75°.

[0082] (6) Adjust the instrument parameters so that the amplitude of the reflected echo from the Φ1mm horizontal through hole at different depths and angles reaches 80% of the full screen.

[0083] (7) By moving the probe 2, the fan-shaped scanning area can cover both ends of the defect judgment line 4 and be clearly displayed.

[0084] (9) Coat the outer surface of the weld joint to be inspected with an ultrasonic coupling agent, place the phased array ultrasonic probe 2 on the outer surface of the tube, and perform a circumferential scan of the entire weld joint.

[0085] (10) During the full-cycle scan, find the maximum reflected wave and the best imaging effect for a certain reflection, such as... Figure 4 As shown, the safety of the welded joint is judged based on the amplitude and position of the reflected signal in the welded joint.

[0086] To further explain the technology of this solution, another specific embodiment is provided for illustration, such as... Figure 2 and Figure 3 As shown.

[0087] Step 1: Inspect the outer surface condition of welded joint 2. The surface condition is good, and there is no oil, rust, or other substances that may affect ultrasonic testing.

[0088] Step 2: Consult the drawings and actually measure the thickness of the base material on both sides of the weld joint 1, the width of the upper surface of the weld, the width of the lower surface, etc.

[0089] Step 3: Based on the measurement results in Step 2, draw an auxiliary graphical diagram, such as... Figure 2 As shown.

[0090] Step 4: Select a 16-chip, 5MHz phased array probe and connect it to the phased array ultrasonic testing instrument.

[0091] Step 5: Step 4: On a Φ1mm horizontal through-hole test block made of 20G material, adjust the instrument so that the amplitude of the reflected wave from the Φ1mm horizontal through-hole at different depths and angles reaches 80% of the full screen, and use this to make the DAC curve.

[0092] Step 6: Select a scanning angle of 35-75°, and move probe 2 to make the fan-shaped scanning area cover both ends of the defect judgment line 4 and be clearly displayed.

[0093] Step 7: Based on the DAC in Step 5, use a gain of 4dB as the scan sensitivity.

[0094] Step 8: Coat the outer surface of the tube with a coupling agent, place the phased array ultrasonic probe, scan around the weld joint, and record the test results.

[0095] Step 9: Test results as follows Figure 3 As shown, no defective reflected waves were found, which is acceptable.

[0096] To further explain the technology of this solution, another specific embodiment is provided for illustration, such as... Figure 2 and Figure 4 As shown.

[0097] Step 1: Inspect the outer surface condition of welded joint 2. The surface condition is good, and there is no oil, rust, or other substances that may affect ultrasonic testing.

[0098] Step 2: Consult the drawings and actually measure the thickness of the base material on both sides of the weld joint 1, the width of the upper surface of the weld, the width of the lower surface, etc.

[0099] Step 3: Based on the measurement results in Step 2, draw an auxiliary graphical diagram, such as... Figure 1 As shown.

[0100] Step 4: Select a 16-chip, 5MHz phased array probe and connect it to the phased array ultrasonic testing instrument.

[0101] Step 5: Step 4: On a Φ1mm horizontal through-hole test block made of 20G material, adjust the instrument so that the amplitude of the reflected wave from the Φ1mm horizontal through-hole at different depths and angles reaches 80% of the full screen, and use this to make the DAC curve.

[0102] Step 6: Select a scanning angle of 35-75°, and move probe 2 to make the fan-shaped scanning area cover both ends of the defect judgment line 4 and be clearly displayed.

[0103] Step 7: Based on the DAC in Step 5, use a gain of 4dB as the scan sensitivity.

[0104] Step 8: Coat the outer surface of the tube with a coupling agent, place the phased array ultrasonic probe, scan around the weld joint, and record the test results.

[0105] Step 9: Test results as follows Figure 4 As shown, a defect reflection wave 5 was found below the defect judgment line, and its highest point was located below the defect judgment line 4. Therefore, it was judged to be qualified.

[0106] This application also proposes a defect identification device for welded joints of small-diameter pipes with unequal thickness of welded bushings, such as... Figure 5 As shown, the device includes:

[0107] The measurement module 10 is used to measure the material and structural dimensions of the welded joint and to clean the surface dirt of the welded joint.

[0108] Module 20 is used to create graphic auxiliary lines and add defect judgment lines that exceed the standard;

[0109] The selection module 30 is used to select a target standard reflector, set the parameters of the phased array ultrasonic detector based on the target standard reflector, and adjust the focusing and deflection of the phased array ultrasonic beam by calculating the delay time of each array element so that the target detection area achieves the target imaging effect.

[0110] The connection module 40 is used to connect the phased array ultrasonic probe to the phased array ultrasonic detector, and to move the probe so that the fan-shaped scanning area can cover the two ends of the defect judgment line.

[0111] The assessment module 50 is used to scan the entire circumference of the welded joint and assess the safety of the welded joint based on whether the highest point of the defect exceeds the defect judgment line.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for judging defects of a welded joint of a small-diameter pipe with a variable thickness, which is a welded gasket ring, characterized by, The method includes: Measure the material and structural dimensions of the welded joint, and clean the surface dirt of the welded joint; Based on the thickness of the base metal on both sides of the weld, the width of the upper surface of the weld, the root width, and the design drawings, graphic auxiliary lines are made on the weld cross-section. The graphic auxiliary lines include the weld fusion line, the width and height of the upper surface of the weld, the width of the weld root, and the defect judgment line. The defect judgment line is specifically the line connecting the intersection of the weld and the base metal on both sides. Select a target standard reflector and set the shear wave velocity, focusing depth, deflection angle, scanning mode, and array element parameters of the phased array ultrasonic testing instrument. Adjust the parameters of the phased array ultrasonic testing instrument so that the amplitude of the reflected echo from the Φ1mm transverse through-hole reaches 80% of the full screen at different depths and angles. When the shear wave velocity of the base material is greater than 5800 m / s but less than 6000 m / s, increase the gain by 2-4 dB on top of achieving 80% full screen gain for the reflected echo from the Φ1mm transverse through-hole at different depths and angles. The focusing depth is specifically... Where F is the focusing depth and T1 is the thickness of the base material on the thinner side of the welded joint being detected; the scanning mode includes A-type scanning and sector scanning, and B-type scanning is included during automatic scanning; the array element parameters specifically refer to the number of array elements excited at one time being 16; Connect the phased array ultrasonic probe to the phased array ultrasonic detector, and move the probe so that the fan-shaped scanning area can cover the two ends of the defect judgment line. A full circumference scan is performed along the weld joint. The safety of the weld joint is assessed based on whether the highest point of the defect exceeds the defect threshold. Specifically, the probe is placed on either side of the probe placement surface, and the primary wave fan-shaped scan area simultaneously displays structural reflection waves. If, at this time, the upper endpoint of the initial defect wave at the thick side fusion line is not above the line connecting the two structural reflection waves, it is determined to be an defect exceeding the standard. The probe is placed on either side of the probe placement surface, and the primary wave fan-shaped scan area simultaneously displays structural reflection waves. If, at this time, the upper endpoint of the initial defect wave at the thin side fusion line is higher than the reflection wave at the junction of the thin side base material and the bushing, it is determined to be a defect exceeding the standard. The two structural reflection waves specifically include the reflection waves from the junction of the thin side base material, the bushing, and the weld, or the reflection waves from the junction of the thick side base material, the bushing, and the weld.

2. The method as described in claim 1, characterized in that, The material and structural dimensions of the welded joint are measured, specifically: The materials of the base material, weld and welding liner on both sides of the small-diameter pipe are measured, as well as the transverse wave velocity, thickness and outer surface radius of curvature of the base material on both sides. The thickness of the base material on the right side is greater than that on the left side.

3. The method as described in claim 1, characterized in that, The target standard reflector is specifically a Φ1mm horizontal through hole with a standard length of not less than 20mm and not less than the width of the probe, and the target standard reflector is made of No. 20 high-quality carbon structural steel with a sound velocity range of 5930m / s~5950m / s.

4. The method as described in claim 1, characterized in that, Connect the phased array ultrasonic probe to the phased array ultrasonic detector, and move the probe so that the fan-shaped scanning area can cover both ends of the defect judgment line. Specifically: Place the probes on both sides of the weld seam and perform single-sided double-sided scanning. Move the probe position so that the acoustic beam in the primary wave fan-shaped scanning area can simultaneously scan the fusion positions of the bushing and the base material on both sides; The screen displays the structural reflected waves at the junction of the bushing and the parent material on both sides with the bushing.

5. A defect identification device for welded joints of small-diameter pipes with unequal thickness of welded bushings, characterized in that, The device includes: The measurement module is used to measure the material and structural dimensions of the welded joint and to clean the surface dirt of the welded joint; The module is used to create graphic auxiliary lines for the weld cross-section based on the thickness of the base material on both sides of the weld, the width of the upper surface of the weld, the root width, and the design drawings. The graphic auxiliary lines include the weld fusion line, the width and height of the upper surface of the weld, the width of the root of the weld, and the defect judgment line. The defect judgment line is specifically the line connecting the intersection of the weld and the base material on both sides. The selection module is used to select the target standard reflector and set the shear wave velocity, focusing depth, deflection angle, scanning mode, and array element parameters of the phased array ultrasonic testing instrument. The parameters of the phased array ultrasonic testing instrument are adjusted so that the amplitude of the reflected echo from the Φ1mm transverse through-hole reaches 80% of the full screen at different depths and angles. When the shear wave velocity of the base material is greater than 5800 m / s but less than 6000 m / s, an additional 2-4 dB is added to the gain beyond the 80% full screen gain achieved by the reflected echo from the Φ1mm transverse through-hole at different depths and angles. The focusing depth is specifically... Where F is the focusing depth and T1 is the thickness of the base material on the thinner side of the welded joint being detected; the scanning mode includes A-type scanning and sector scanning, and B-type scanning is included during automatic scanning; the array element parameters specifically refer to the number of array elements excited at one time being 16; The connection module is used to connect the phased array ultrasonic probe to the phased array ultrasonic detector, and to make the fan-shaped scanning area cover the two ends of the defect judgment line by moving the probe. The assessment module is used to scan the entire circumference of the weld joint and assess its safety based on whether the highest point of the defect exceeds the defect threshold. Specifically, the probe is placed on either side of the probe placement surface, and the primary wave fan-shaped scanning area simultaneously displays structural reflection waves. If, at this time, the upper endpoint of the initial defect wave at the thick side fusion line is not above the line connecting the two structural reflection waves, it is determined to be an defect exceeding the standard. The probe is also placed on either side of the probe placement surface, and the primary wave fan-shaped scanning area simultaneously displays structural reflection waves. If, at this time, the upper endpoint of the initial defect wave at the thin side fusion line is higher than the reflection wave at the junction of the thin side base material and the bushing, it is determined to be a defect exceeding the standard. The two structural reflection waves specifically include the reflection waves from the junction of the thin side base material, the bushing, and the weld, or the reflection waves from the junction of the thick side base material, the bushing, and the weld.

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