Vortex through-type flaw detection method for phi 40mm-45mm aluminum alloy cold-drawn thin-walled tube

Abstract

The invention relates to a vortex penetration type flaw detection method for an aluminum alloy cold-drawn thin-walled tube with the diameter phi of 40-45 mm, in particular to a vortex penetration type flaw detection method for an aluminum alloy cold-drawn thin-walled tube with the diameter phi of 40-45 mm. According to the method, aiming at an aluminum alloy cold-drawn thin-walled tube of 40-45mm, a defective part is compared by using a through hole of a sample tube, and if the display amplitude of the defect of the detected tube is less than or equal to the lowest display amplitude in three da holes or no alarm display signal exists, the detected tube is qualified; if the display amplitude of the defect of the detected pipe is greater than the display value of the da hole, the detection is unqualified or the defect part is unqualified, so that the stability of detection parameters and the accuracy of detection results are ensured. The precise and efficient eddy current detection method is summarized, and nondestructive flaw detection of the thin-walled tube with the diameter being 40-45 mm in engineering application is achieved. The method is used in the field of eddy current thin-walled tube flaw detection.

Description

Technical Field

[0001] The invention relates to an eddy current penetration flaw detection method for a Φ40mm-45mm aluminum alloy cold-drawn thin-wall tube. Background Art

[0002] Aluminum and aluminum alloy cold-drawn thin-walled pipes are light alloy pressure-resistant materials, mainly used as medium and high pressure conduits, structural pipes, and tie rods in the fields of aviation, aerospace, and ocean. Nondestructive testing must be carried out before use, and delivery can only be made after passing the test. The demand for its use is huge, with more than 100,000 pipes used each year and even more produced. Eddy current testing, as one of the methods of nondestructive testing, has the characteristics of fast detection speed, no need for coupling agent, no need for contact, and high degree of automation of the detection equipment. It can detect the outer surface, near surface, and inner surface of the pipe. It has advantages that cannot be matched by naked eye detection.

[0003] In order to ensure the quality of thin-walled tubes and avoid quality disputes, which would cause serious economic losses and reputation impact. Eddy current testing method specifically for thin-walled tubes. Summary of the invention

[0004] The present invention is to provide a special Through-type eddy current flaw detection method for aluminum alloy thin-walled tubes.

[0005] The present invention provides an eddy current penetration flaw detection method for a Φ40mm-45mm aluminum alloy cold-drawn thin-walled tube, which is carried out in the following steps:

[0006] 1. Drill 8 artificial defect through holes with a verticality of ≤2° along the axial direction of the comparison sample tube; 3 da holes and 5 db holes, respectively. Drill 1 artificial defect through hole db at 100mm from both ends of the selected tube. The diameters of the artificial defect through holes at both ends are the same, which are used to test the blind areas at the head and tail ends; drill 3 da holes and 3 db holes on the tube wall ≥500mm away from the end of the tube to obtain a comparison through hole sample tube;

[0007] 2. Adjust the signal-to-noise ratio: When setting the test parameters of the eddy current flaw detector with the comparison through-hole sample tube, make the display amplitude of the da hole provide the best signal-to-noise ratio, where the display amplitude of any noise signal is ≤ 50% of the lowest display amplitude in the da hole, and finally make the display amplitude of any da hole compared with the average display amplitude of the three da holes, and its deviation is within ±20%, and the display amplitude of any db hole is compared with the average display amplitude of the three db holes, and its deviation is within ±10%;

[0008] 3. Detection sensitivity setting: Make sure that the three da holes have clearly identifiable amplitudes, and the db hole displays an amplitude ≥ 60%;

[0009] 4. Adjust the detection speed: Use the db holes near the two ends of the comparison through-hole sample tube to adjust the detection speed so that the head and tail end signals and the db hole amplitude can be clearly distinguished;

[0010] 5. Defect assessment: If the displayed amplitude of the defect of the inspected pipe is ≤ the lowest displayed amplitude among the 3 da holes or there is no alarm display signal, it is qualified; if the displayed amplitude of the defect of the inspected pipe is greater than the displayed value of the da hole, it is unqualified or the location of the defect is unqualified.

[0011] Beneficial effects of the present invention:

[0012] The present invention adopts a Thin-walled tube products are used as the test objects, and the eddy current testing technology is used to study Thin-walled tube inner and outer wall defect detection methods and devices. Through field debugging, standard samples are made, the influence of detection parameters on sample tube defects is analyzed, and field tracking tests are carried out. A set of accurate and efficient eddy current detection methods are summarized to achieve engineering applications. Nondestructive testing of thin-walled tube defects has established a method for The eddy current testing method for thin-walled tubes is determined by the current research. Technical parameters for natural flaw detection of thin-walled tubes and the accuracy and reliability of their detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of a through-hole comparison sample tube;

[0014] Figure 2 This is the interface diagram of the sensitivity adjustment of the Φ42mm sample tube;

[0015] Figure 3 This is the interface diagram of the sensitivity adjustment of the Φ45mm sample tube;

[0016] Figure 4 This is the interface diagram of the sensitivity adjustment of the Φ50mm sample tube;

[0017] Figure 5 This is the defect diagram of the Φ42mm sample tube;

[0018] Figure 6 This is the defect diagram detected on the Φ45mm sample tube. DETAILED DESCRIPTION

[0019] Specific implementation method 1: This implementation method is an eddy current penetration flaw detection method for Φ40mm-45mm aluminum alloy cold-drawn thin-walled tubes, characterized in that the method is carried out in the following steps:

[0020] 1. Drill 8 artificial defect through holes with a verticality of ≤2° along the axial direction of the comparison sample tube; 3 da holes and 5 db holes, respectively. Drill 1 artificial defect through hole db at 100mm from the two ends of the selected tube, recorded as the end db hole. The two end db holes have the same diameter and are used to test the blind area of ​​the head and tail ends; drill 3 da holes and 3 db holes on the tube wall ≥500mm away from the end of the tube to obtain a comparison through hole sample tube;

[0021] 2. Adjust the signal-to-noise ratio: When setting the detection parameters of the eddy current flaw detector with the comparison through-hole sample tube, make the da hole display amplitude provide the best signal-to-noise ratio; the best signal-to-noise ratio is determined as follows: the noise signal display amplitude is compared with the display amplitude of the three da holes, and the noise signal is ≤ 50% of the lowest display amplitude among the three da holes; and the display amplitude of any da hole is compared with the average display amplitude of the three da holes, and its deviation is within ±20%, and the display amplitude of any db hole is compared with the average display amplitude of the three db holes, and its deviation is within ±10%;

[0022] 3. Detection sensitivity setting: Make sure that the three da holes have clearly distinguished amplitudes and the db hole displays an amplitude ≥ 60%;

[0023] 4. Adjust the detection speed: Use the db holes near the two ends of the comparison through-hole sample tube to adjust the detection speed so that the head and tail end signals and the db hole amplitude can be clearly distinguished;

[0024] 5. Defect assessment: If the displayed amplitude of the defect of the inspected pipe is ≤ the lowest displayed amplitude among the 3 da holes or there is no alarm display signal, it is qualified; if the displayed amplitude of the defect of the inspected pipe is greater than the displayed value of the da hole, it is unqualified or the location of the defect is unqualified.

[0025] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that the thickness of the comparison sample tube is 0.5-1.8 mm and the outer diameter is 40-45 mm. The rest is the same as the specific implementation method 1.

[0026] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the diameter of each artificial defect through hole is the same. Other aspects are the same as specific implementation method 1 or 2.

[0027] Specific implementation method 4: This implementation method is different from the specific implementation methods 1 to 3 in that the longitudinal spacing between adjacent artificial defect through holes is 150 mm ± 10 mm. The rest is the same as the specific implementation methods 1 to 3.

[0028] Specific implementation method 5: This implementation method is different from specific implementation methods 1 to 4 in that the holes are distributed at an interval of 120°±5° in the circumferential direction. The rest is the same as specific implementation methods 1 to 4.

[0029] Specific implementation method 6: This implementation method is different from specific implementation methods 1 to 5 in that if the display amplitude of the inspected pipe defect is greater than the minimum display amplitude of the db hole, an alarm signal is displayed. The rest is the same as specific implementation methods 1 to 5.

[0030] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.

[0031] Embodiment 1: This embodiment is a special The eddy current flaw detection method for aluminum alloy thin-walled tubes is carried out in the following steps:

[0032] 1. Equipment:

[0033] (1) Equipment: ECT10A eddy current flaw detector; the equipment should have a serial number, be calibrated once a year, and be tested periodically;

[0034] (2) Probe: Eddy current probe and guide path of corresponding size; the probe should have a serial number and a certificate before use, and the probe certificate and test records should be kept for future reference;

[0035] (3) Sample tube: Through-hole sample tube; 8 artificial defect through-holes with a verticality of ≤2° are drilled along the axial direction of the comparison sample tube; they are 3 da holes and 5 db holes, among which 1 artificial defect through-hole db is drilled at 100mm from the two ends of the selected pipe, recorded as the end db hole, and the two end db holes have the same diameter and are used to test the blind area of ​​the head and tail ends; 3 da holes and 3 db holes are drilled on the pipe wall ≥500mm away from the end of the pipe, respectively, to obtain a comparison through-hole sample tube;

[0036] Table 1 Eddy current flaw detection test parameter record table for through hole comparison sample tube

[0037]

[0038]

[0039] 2. Benchmark sensitivity debugging

[0040] When setting the detection parameters with the comparison sample tube, the display amplitude of the da hole must provide the best signal-to-noise ratio. The display amplitude of any noise signal should not be greater than 50% of the lowest display amplitude in the da hole. Finally, the deviation of the display amplitude of any da hole compared with the average display amplitude of the three da holes should be within ±20%, and the deviation of the display amplitude of any db hole compared with the average display amplitude of the three db holes should be within ±10%.

[0041] The detection sensitivity is set so that the three da holes have clearly identifiable amplitudes and the db hole displays an amplitude ≥ 60%;

[0042] Use the db holes near the two ends of the comparison sample tube to adjust the detection speed so that the head and tail end signals and the db holes can be clearly distinguished. The detection speed should be adjusted so that the db holes in the blind areas of the test head and tail ends are effectively displayed in the form of sound, light, marking, etc., and the head and tail end signals are effectively cut off. The interface diagram of the sensitivity adjustment of the Φ42mm sample tube is as follows Figure 2 As shown in the figure, the interface diagram of the sensitivity adjustment of the Φ45mm sample tube is as follows Figure 3 As shown in the figure, the interface diagram of the sensitivity adjustment of the Φ50mm sample tube is as follows Figure 4 shown.

[0043] 3. Operation:

[0044] (1) Before each operation, the instrument should be turned on and preheated. The preheating time is determined according to the performance of the instrument.

[0045] (2) The test parameters should be set before testing. After the instrument is preheated and stabilized, sample tubes with the same alloy, state and specification should be selected for benchmark adjustment according to the parameters of each batch of tubes;

[0046] (3) Basic parameter adjustment: Place the intact part of the comparison sample tube into the probe and set the probe zero potential compensation. Then use the comparison sample tube to adjust the detection speed, filter frequency, gain or attenuation, phase and other parameters to achieve the best signal-to-noise ratio.

[0047] (4) Concentricity adjustment: Adjust the guide device, probe holder and other mechanical devices of the machine series so that the pipe to be inspected is concentric with the probe and can pass through the probe smoothly without scratching the pipe to be inspected;

[0048] (5) Alarm level: when all three through holes of the sample tube are effective, the alarm level is indicated by sound, light, marking, etc. and the test is repeated three times.

[0049] 4. Defect Assessment

[0050] If the displayed amplitude of the defect of the inspected pipe is ≤ the lowest displayed amplitude among the three da holes or there is no alarm display signal, it is qualified; if the displayed amplitude of the defect of the inspected pipe is greater than the displayed value of the da hole, it is unqualified or the location of the defect is unqualified. By adjusting the sample pipe and conducting actual on-site inspection, the defect pictures detected are as follows Figure 5 and Figure 6 As shown by Figure 5 and Figure 6 It can be seen that eddy current penetration testing has a better detection effect on surface and near-surface point defects.

Claims

1. A method for eddy current penetration flaw detection of Φ40mm-45mm aluminum alloy cold-drawn thin-walled tubes, characterized in that The method proceeds as follows:

1. Drill 8 artificial defect through holes with a verticality of ≤2° along the axial direction of the comparison sample tube; 3 da holes and 5 db holes, respectively. Drill 1 artificial defect through hole db at 100mm from the two ends of the selected tube, recorded as the end db hole. The two end db holes have the same diameter and are used to test the blind area of ​​the head and tail ends; drill 3 da holes and 3 db holes on the tube wall ≥500mm away from the end of the tube to obtain a comparison through hole sample tube; 2. Adjust the signal-to-noise ratio: When setting the detection parameters of the eddy current flaw detector with the comparison through-hole sample tube, make the da hole display amplitude provide the best signal-to-noise ratio; the best signal-to-noise ratio is determined as follows: the noise signal display amplitude is compared with the display amplitude of the three da holes, and the noise signal is ≤ 50% of the lowest display amplitude among the three da holes; and the display amplitude of any da hole is compared with the average display amplitude of the three da holes, and its deviation is within ±20%, and the display amplitude of any db hole is compared with the average display amplitude of the three db holes, and its deviation is within ±10%; 3. Detection sensitivity setting: Make sure that the three da holes have clearly distinguished amplitudes and the db hole displays an amplitude ≥ 60%; 4. Adjust the detection speed: Use the db holes near the two ends of the comparison through-hole sample tube to adjust the detection speed so that the head and tail end signals and the db hole amplitude can be clearly distinguished; 5. Defect assessment: If the displayed amplitude of the defect of the inspected pipe is ≤ the lowest displayed amplitude among the 3 da holes or there is no alarm display signal, it is qualified; if the displayed amplitude of the defect of the inspected pipe is greater than the displayed value of the da hole, it is unqualified or the location of the defect is unqualified.

2. The eddy current penetration flaw detection method for Φ40mm-45mm aluminum alloy cold-drawn thin-walled tube according to claim 1 is characterized in that: The thickness of the comparison sample tube is 0.5-1.8 mm and the outer diameter is 40-45 mm.

3. The eddy current penetration flaw detection method for Φ40mm-45mm aluminum alloy cold-drawn thin-walled tube according to claim 1 is characterized in that: The diameter of each artificial defect through hole is the same.

4. The eddy current penetration flaw detection method for Φ40mm-45mm aluminum alloy cold-drawn thin-walled tube according to claim 1 is characterized in that: The longitudinal spacing between adjacent artificial defect holes is 150mm±10mm.

5. The eddy current penetration flaw detection method for Φ40mm-45mm aluminum alloy cold-drawn thin-walled tube according to claim 1 is characterized in that: The holes are distributed circumferentially at an interval of 120°±5°.

6. The eddy current penetration flaw detection method for Φ40mm-45mm aluminum alloy cold-drawn thin-walled tube according to claim 1 is characterized in that: If the displayed amplitude of the defect of the inspected pipe is greater than the minimum displayed amplitude of the db hole, an alarm signal will be displayed.

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