Test tube for verifying corrosion defect detection capability of through-wall pipe

Abstract

The invention belongs to the field of through-wall pipe corrosion, and particularly relates to a test tube for verifying through-wall pipe corrosion defect detection capability, the test tube comprises at least one sample tube, the sample tube is provided with a plurality of hole defects, and the type of each hole defect is independently selected from a cylindrical hole, a hemispherical hole and a semi-ellipsoid hole. The test tube provided by the invention can verify the detection capability of the detection technology and determine the detection capabilities such as the detection distance, the detection precision and the like of the detection technology.

Description

Technical Field

[0001] The invention belongs to the field of through-wall pipe corrosion, and in particular relates to a test pipe for verifying the through-wall pipe corrosion defect detection capability. Background Art

[0002] Through-the-wall pipes are widely used in power plants, chemical plants, water supply, gas supply and other fields. As the service time increases, the pipelines are subject to the combined effects of environmental factors and have the risk of corrosion, thinning and even perforation. Timely and effective monitoring and detection of pipeline corrosion conditions are important for ensuring their operational safety. However, due to the special location, complex structure and inaccessible detection equipment of through-the-wall pipes, the corrosion of the through-the-wall pipe sections cannot be effectively monitored and detected for a long time, which increases the risk of system operation.

[0003] Ultrasonic guided wave testing is an emerging non-destructive testing technology for rapid assessment of pipeline defects. During on-site testing, the results of guided wave testing cannot be compared with actual corrosion defects of in-service through-wall pipes to verify the accuracy of the test.

[0004] Therefore, how to verify the detection capability of detection technology has become an urgent problem to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a test tube for verifying the detection capability of corrosion defects of through-wall pipes, which can verify the detection capability of the detection technology and determine the detection capabilities of the detection technology, such as the detection distance and detection accuracy.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] A test tube for verifying the corrosion defect detection capability of a through-wall pipe, the test tube comprises at least one sample tube, a plurality of hole defects are arranged on the sample tube, and the type of each hole defect is independently selected from cylindrical holes, hemispherical holes and semi-ellipsoidal holes.

[0008] The size specification of the hole defect is: the ratio of the cross-sectional area of ​​the hole defect to the cross-sectional area of ​​the circular ring of the sample tube is independently selected from 0.5%, 1.0%, 1.5% and 2%.

[0009] The material of the sample tube is independently selected from alloy steel, carbon steel, stainless steel and aluminum alloy.

[0010] The surface of the sample tube is provided with a circle of the first material coating or a circle of the second material coating, or is provided with a circle of the first material coating and a circle of the second material coating spaced apart along the axial direction.

[0011] The test tube includes at least two sample tubes, and the diameters of each sample tube are different.

[0012] The test tube includes at least one sample tube, on which at least one type of hole defect is arranged, and there are multiple hole defects of the same type and size; the projections of all the hole defects on the sample tube on a plane perpendicular to the axial direction of the sample tube are arranged at intervals, and on the unfolded plane of the sample tube, the hole defects of the same type and size are arranged at intervals and arranged in a straight line, and the straight line forms an acute angle with the axial direction of the sample tube, and different straight lines formed by hole defects of the same type and different sizes are parallel to each other.

[0013] Along the axial direction of the sample tube, hole defects of the same type and size are distributed at equal intervals.

[0014] The test tube includes at least one sample tube, on which at least one type of hole defect is arranged, and there are multiple hole defects of the same type; on the unfolding plane of the sample tube, the hole defects of the same type are distributed in a cross shape, and two adjacent hole defects are arranged at intervals.

[0015] On the unfolded plane of the sample tube, among the same type of hole defects distributed in a cross shape, among the multiple hole defects distributed along the axial direction of the sample tube, the distance between two adjacent hole defects gradually decreases or increases; among the multiple hole defects distributed along the axial direction perpendicular to the sample tube, the distance between two adjacent hole defects gradually decreases or increases.

[0016] On the unfolded plane of the sample tube, among the same type of hole defects distributed in a cross shape, multiple hole defects distributed along the axial direction of the sample tube are arranged in sequence according to size specifications; multiple hole defects distributed along the axial direction perpendicular to the sample tube are arranged in sequence according to size specifications.

[0017] Among the multiple hole defects distributed along the axial direction of the sample tube, at least two hole defects have the same size and specification; among the multiple hole defects distributed along the axial direction perpendicular to the sample tube, at least two hole defects have the same size and specification.

[0018] The beneficial technical effects of the present invention are:

[0019] The present invention provides a test tube for verifying the corrosion defect detection capability of a through-wall pipe. A plurality of hole defects are arranged on the surface of the test tube. The types of the hole defects are independently selected from cylindrical holes, hemispherical holes and semi-ellipsoidal holes. The test is used to verify the detection capability of the detection technology to be used for actual pipeline inspection, and the detection capabilities such as the detection distance and detection accuracy of the detection technology are determined, thereby providing a higher guarantee for the safe use of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a sample tube with a cylindrical hole provided by the present invention;

[0021] Figure 2A schematic diagram of a sample tube with a hemispherical hole provided by the present invention;

[0022] Figure 3 A schematic diagram of a sample tube with a semi-ellipsoidal hole provided by the present invention;

[0023] Figure 4 A schematic diagram of the first distribution form of defect holes provided by the present invention;

[0024] Figure 5 A schematic diagram of the second distribution form of defect holes provided by the present invention;

[0025] Figure 6 This is a schematic diagram of the third distribution form of defect holes provided by the present invention.

[0026] In the figure: 1- sample tube; 2- cylindrical hole; 3- hemispherical hole; 4- semi-ellipsoidal hole. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0028] The present invention provides a test tube for verifying the corrosion defect detection capability of a through-wall pipe, comprising at least one sample tube, on which a plurality of hole defects (at least one type of hole defects, and each type has a plurality of hole defects) are arranged, and the type of each hole defect is independently selected from cylindrical holes, hemispherical holes and semi-ellipsoidal holes.

[0029] The size specification of the hole defect is: the ratio of the cross-sectional area of ​​the hole defect to the cross-sectional area of ​​the circular ring of the sample tube is independently selected from 0.5%, 1.0%, 1.5% and 2%.

[0030] The material of the sample tube is independently selected from alloy steel, carbon steel, stainless steel and aluminum alloy.

[0031] The surface of the sample tube is provided with a circle of the first material coating or a circle of the second material coating, or is provided with a circle of the first material coating and a circle of the second material coating spaced apart along the axial direction.

[0032] In a specific embodiment, the test tube includes at least two sample tubes, and the diameters of each sample tube are different.

[0033] In another specific embodiment, the test tube includes at least one sample tube, on which at least one type of hole defect is arranged, and the ratio of the cross-sectional area of ​​the hole defect to the cross-sectional area of ​​the circular ring of the sample tube is one or more of 0.5%, 1.0%, 1.5% and 2%; there are multiple hole defects of the same type and the same size.

[0034] In another specific embodiment, the projections of all the hole defects on the sample tube on the plane perpendicular to the axial direction of the sample tube are arranged at intervals, and on the unfolded plane of the sample tube, the hole defects of the same type and the same size are arranged at intervals and arranged in a straight line, and the straight line forms an acute angle θ with the axial direction of the sample tube, and the different straight lines formed by the hole defects of the same type and different sizes are parallel to each other. The distribution form of the defect holes on the sample tube is as follows: Figure 4-5 shown.

[0035] In another specific embodiment, hole defects of the same type and size are distributed at equal intervals along the axial direction of the sample tube.

[0036] In another specific embodiment, the test tube includes at least one sample tube, on which two types of hole defects, cylindrical holes and semi-ellipsoidal holes, are provided; the size specifications of the cylindrical holes are 0.5%, 1.0% and 2%; the size specification of the semi-ellipsoidal holes is 0.5%; and the number of each type of hole defects is six.

[0037] In another specific embodiment, the test tube includes at least one sample tube, on which two types of hole defects, hemispherical holes and semi-ellipsoidal holes, are provided; the size specifications of the hemispherical holes are 0.5%, 1.0% and 2%; the size specification of the semi-ellipsoidal holes is 0.5%; and the number of each type of hole defects is six.

[0038] In another specific embodiment, the test tube includes at least one sample tube, on which at least one type of hole defect is arranged, and the ratio of the cross-sectional area of ​​the hole defect to the cross-sectional area of ​​the circular ring of the sample tube is one or more of 0.5%, 1.0%, 1.5% and 2%; there are multiple hole defects of the same type.

[0039] In another specific embodiment, on the development plane of the sample tube, hole defects of the same type are distributed in a cross shape, and two adjacent hole defects are arranged at intervals.

[0040] In another specific embodiment, on the development plane of the sample tube, among the same type of hole defects distributed in a cross shape, among the multiple hole defects distributed along the axial direction of the sample tube, the distance between two adjacent hole defects gradually decreases or increases; among the multiple hole defects distributed along the axial direction perpendicular to the sample tube, the distance between two adjacent hole defects gradually decreases or increases. The distribution form of defect holes on the sample tube is as follows: Figure 6 shown.

[0041] In another specific embodiment, on the unfolded plane of the sample tube, among the same type of hole defects distributed in a cross shape, multiple hole defects distributed along the axial direction of the sample tube are arranged in sequence according to size specifications; multiple hole defects distributed along the axial direction perpendicular to the sample tube are arranged in sequence according to size specifications.

[0042] In another specific embodiment, among the multiple hole defects distributed along the axial direction of the sample tube, at least two hole defects have the same size and specification; among the multiple hole defects distributed along the axial direction perpendicular to the sample tube, at least two hole defects have the same size and specification.

[0043] The test tube for verifying the corrosion defect detection capability of a through-wall pipe provided by the present invention is used to verify the corrosion defect detection capability of the through-wall pipe, which specifically includes the following steps:

[0044] Step 1: Place the sample tube in a fixed position to prevent it from moving or deflecting;

[0045] Step 2: Set the corresponding ultrasonic guided wave parameters according to the sample tube type and test purpose;

[0046] Step 3: Paste the magnetostrictive tape;

[0047] Step 4: Conduct ultrasonic guided wave testing;

[0048] Step 5: Record relevant data;

[0049] Step 6: Compare the data results of the guided wave detection with the actual data of the corresponding sample tube to verify the guided wave detection capability.

[0050] According to the above verification steps, the sample tubes in the following embodiments were used for detection:

[0051] Example 1: Sample tube 20G-A

[0052] Sample tube specifications: material 20G carbon steel, diameter 159mm, wall thickness 10mm, length 4000mm;

[0053] Detection technology: mid-range guided wave (magnetostrictive principle);

[0054] Wave type: horizontal shear transverse wave;

[0055] Frequency: 128KHz;

[0056] Test purpose: Test different hole defect types / size specifications and detection distance.

[0057] The test results are shown in Table 1.

[0058] Example 2: Sample tube 20G-B

[0059] Sample tube specifications: material 20G carbon steel, diameter 159mm, wall thickness 10mm, length 4000mm;

[0060] Detection technology: mid-range guided wave (magnetostrictive principle);

[0061] Wave type: horizontal shear transverse wave;

[0062] Frequency: 128KHz;

[0063] Test purpose: Test different hole defect types / size specifications and detection distance.

[0064] The test results are shown in Table 1.

[0065] Example 3: Sample tube 20G-C

[0066] Sample tube specifications: material 20G carbon steel, diameter 159mm, wall thickness 10mm, length 4000mm;

[0067] Detection technology: mid-range guided wave (magnetostrictive principle);

[0068] Wave type: horizontal shear transverse wave;

[0069] Frequency: 128KHz;

[0070] Test purpose: To test the arrangement and resolution of different hole defect types.

[0071] The test results are shown in Table 1. When the axial defects are about 100 mm apart, the signal peaks of each hole defect are separated, and the axial position of the hole defect can be distinguished; the circumferential hole defect signal peaks overlap, and the circumferential position of the hole defect cannot be distinguished.

[0072] Example 4: Sample tube P265GH-B

[0073] Sample tube specifications: material P265GH alloy steel, diameter 159mm, wall thickness 10mm, length 4000mm;

[0074] Detection technology: mid-range guided wave (magnetostrictive principle);

[0075] Wave type: horizontal shear transverse wave;

[0076] Frequency: 128KHz;

[0077] Test purpose: Different hole defect types / size specifications, detection distance test.

[0078] The test results are shown in Table 1.

[0079] Example 5: Sample tube 304-B

[0080] Sample tube specifications: material 304 stainless steel, diameter 159mm, wall thickness 10mm, length 4000mm.

[0081] Detection technology: mid-range guided wave (magnetostrictive principle);

[0082] Wave type: horizontal shear transverse wave;

[0083] Frequency: 128KHz;

[0084] Test purpose: Different hole defect types / size specifications, detection distance test, changes after pipe water injection, changes in different coatings.

[0085] The test results are shown in Table 1. Different coatings and water injection have no effect on the test results.

[0086] Example 6: Sample tube 10CrMoAl-E

[0087] Sample tube specifications: material 10CrMoAl alloy steel, diameter 114mm, wall thickness 9mm, length 4000mm;

[0088] Detection technology: low-frequency guided wave (magnetostrictive principle);

[0089] Wave type: torsion wave;

[0090] Frequency: 128KHz;

[0091] Test purpose: Detection of holes with the same size and specifications at 6 different locations.

[0092] The test results of bare pipes and empty pipes are shown in Table 2.

[0093] Example 7: Sample Tube 5083-B

[0094] Sample tube specifications: material 5083 aluminum alloy, diameter 160mm, wall thickness 10mm, length 4000mm;

[0095] Detection technology: low-frequency guided wave (magnetostrictive principle);

[0096] Wave type: torsion wave;

[0097] Frequency: 128KHz;

[0098] Test purpose: Detection of holes with the same size and specifications at 6 different locations.

[0099] The test results of bare pipes and empty pipes are shown in Table 2.

[0100] Table 1 Mid-range guided wave detection results

[0101]

[0102]

[0103] Table 2 Low frequency guided wave detection results

[0104]

[0105] From the results in Table 1-2 above, we can see that:

[0106] (1) Magnetostrictive mid-range guided waves (SH waves) can detect 0.5% and 1% hole defects at about 2.5m on 20G and P265GH pipes with an outer diameter of 159mm and a wall thickness of 10mm, and some can be detected at 3m; 2.0% cylindrical hole and hemispherical hole defects can be detected at 3m. The overall measurement accuracy is high on 20G carbon steel and P265GH alloy steel.

[0107] (2) Magnetostrictive mid-range guided wave (SH wave) on 304 pipes with an outer diameter of 159 mm and a wall thickness of 10 mm, 0.5% and 1% defects can be detected at about 1 m, some can be detected at 2 m, and 2.0% defects can be detected at 3 m. The measurement accuracy of 0.5% and 1.0% defects on 304 stainless steel is not as good as that of 20G carbon steel and P265GH alloy steel.

[0108] (3) The material of 5083 pipeline is special, and the high-frequency wave signal attenuation is large. Therefore, it is not suitable for high-frequency SH wave detection, but can be detected by low-frequency guided wave (LRUT). The outer diameter of 10CrMoAl alloy steel pipeline is small, less than 150mm, and is not suitable for SH wave detection. It can also be detected by low-frequency guided wave. When measuring with low-frequency guided wave, there is a signal peak at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m respectively. The axial hole defect signal peaks are separated, so the axial positions of the hole defects can be distinguished at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m respectively. The circumferential hole defect signal peaks are superimposed at one place, so the circumferential position of the hole defect cannot be distinguished.

[0109] (4) For coatings with a thickness of about 200 μm, if there are no bubbles on the surface that affect the coupling between the magnetic hoop and the pipe surface, then the SH wave measurement defect will have no effect. On the contrary, if bubbles are generated in the coating that affect the coupling, the measurement accuracy will be greatly affected.

[0110] (5) Water flowing through the pipeline has no effect on SH wave measurement, and the signal peak change can be ignored.

[0111] The present invention is described in detail above with reference to the accompanying drawings and embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The contents not described in detail in the present invention can adopt the existing technology.

Claims

1. A test tube for verifying the corrosion defect detection capability of a through-wall pipe, characterized in that: The test tube comprises at least one sample tube, on which a plurality of hole defects are arranged, and the type of each hole defect is independently selected from cylindrical holes, hemispherical holes and semi-ellipsoidal holes.

2. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 1, characterized in that: The size specification of the hole defect is: the ratio of the cross-sectional area of ​​the hole defect to the cross-sectional area of ​​the circular ring of the sample tube is independently selected from 0.5%, 1.0%, 1.5% and 2%.

3. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 1, characterized in that: The material of the sample tube is independently selected from alloy steel, carbon steel, stainless steel and aluminum alloy.

4. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 1, characterized in that: The surface of the sample tube is provided with a circle of the first material coating or a circle of the second material coating, or is provided with a circle of the first material coating and a circle of the second material coating spaced apart along the axial direction.

5. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 1, characterized in that: The test tube includes at least two sample tubes, and the diameters of each sample tube are different.

6. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 2, characterized in that: The test tube includes at least one sample tube, on which at least one type of hole defect is arranged, and there are multiple hole defects of the same type and size; the projections of all the hole defects on the sample tube on a plane perpendicular to the axial direction of the sample tube are arranged at intervals, and on the unfolded plane of the sample tube, the hole defects of the same type and size are arranged at intervals and arranged in a straight line, and the straight line forms an acute angle with the axial direction of the sample tube, and different straight lines formed by hole defects of the same type and different sizes are parallel to each other.

7. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 6, characterized in that: Along the axial direction of the sample tube, hole defects of the same type and size are distributed at equal intervals.

8. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 2, characterized in that: The test tube includes at least one sample tube, on which at least one type of hole defect is arranged, and there are multiple hole defects of the same type; on the unfolding plane of the sample tube, the hole defects of the same type are distributed in a cross shape, and two adjacent hole defects are arranged at intervals.

9. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 8, characterized in that: On the unfolded plane of the sample tube, among the same type of hole defects distributed in a cross shape, among the multiple hole defects distributed along the axial direction of the sample tube, the distance between two adjacent hole defects gradually decreases or increases; among the multiple hole defects distributed along the axial direction perpendicular to the sample tube, the distance between two adjacent hole defects gradually decreases or increases.

10. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 8, characterized in that: On the unfolded plane of the sample tube, among the same type of hole defects distributed in a cross shape, multiple hole defects distributed along the axial direction of the sample tube are arranged in sequence according to size specifications; multiple hole defects distributed along the axial direction perpendicular to the sample tube are arranged in sequence according to size specifications.

11. A test tube for verifying the corrosion defect detection capability of a through-wall pipe according to claim 10, characterized in that: Among the multiple hole defects distributed along the axial direction of the sample tube, at least two hole defects have the same size and specification; among the multiple hole defects distributed along the axial direction perpendicular to the sample tube, at least two hole defects have the same size and specification.

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