Comparison test block for determining blind areas of scanning surface by time-of-flight diffraction ultrasonic testing

Abstract

The comparison test block used for determining the blind area of ​​the scanning surface by the time-of-flight diffraction ultrasonic detection includes a rectangular comparison test block, wherein the interior of the comparison test block is processed by an electric spark CNC wire cutting machine to have an artificial defect consistent with the scanning direction, and the artificial defect has an angle with the upper surface of the comparison test block. When the comparison test block of the present invention is detected by the time-of-flight diffraction ultrasonic detection technology, the comparison test block can be used to verify the blind area of ​​the scanning surface under the current detection parameters, and the supplementary inspection method is determined according to the value of the blind area of ​​the scanning surface, so as to achieve 100% detection of the inspected workpiece.

Description

Technical Field

[0001] The invention belongs to the field of detection, and in particular relates to a comparison test block used for determining a blind area of ​​a scanning surface by using a time-of-flight diffraction ultrasonic detection method. Background Art

[0002] At present, the time-of-flight diffraction ultrasonic testing technology has been widely used in industrial testing and is an advanced testing technology. This technology also has limitations - the blind area of ​​the scanning surface is large. Even if the TOFD technology is optimized, the blind area of ​​the scanning surface is inevitable. Only by accurately understanding the size of the blind area before applying the TOFD technology can we ensure that the inspected product is effectively tested and avoid missed inspections. In addition to calculating the blind area of ​​the scanning surface before testing, corresponding comparison test blocks must be used for verification.

[0003] The reflectors of the blind area comparison test blocks in the NB / T47013.10-2015 standard are horizontal holes of different depths. Currently, there is no effective method to determine the accurate value of the blind area of ​​the scanning surface. Most of them are obtained by comparison method.

[0004] When using the blind area height comparison test block for the scanning surface required by NB / T47013.10-2015 and other standards, except for the blind area of ​​the specified height, the blind area of ​​the scanning surface at other depths can only be roughly determined, and the blind area corresponding to the scanning surface under specific technical testing conditions cannot be accurately determined. The blind hole of the test block must be processed in one go, because each drilling will leave a tiny groove on the hole wall. It is necessary to process a high-precision blind hole test block that meets the requirements, the processing cost is high, and multiple maps are required to verify the blind area range under the current parameters. Summary of the invention

[0005] The invention provides a comparison test block for determining a blind area of ​​a scanning surface by using a diffraction time-of-flight ultrasonic detection method, so as to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A comparison test block used for determining a blind area of ​​a scanning surface by using a diffraction time-of-flight ultrasonic detection comprises a rectangular comparison test block, wherein an artificial defect consistent with a scanning direction is machined inside the comparison test block by an electric spark CNC wire cutting machine, and the artificial defect forms an angle with an upper surface of the comparison test block.

[0008] The angle ranges from 2° to 8°.

[0009] The cross-sectional shape of the artificial defect along the radial direction is rhombus, rectangle or circle.

[0010] The minimum height of the artificial defect from the upper surface of the comparison test block is 0 mm.

[0011] The maximum height of the artificial defect from the upper surface of the comparison test block is not less than 15 mm.

[0012] In the scanning direction, the starting end of the artificial defect is not less than 50 mm from the starting end of the comparison test block.

[0013] The upper surface of the comparison test block is marked with length marks along the scanning direction from the starting position of the artificial defect.

[0014] The height of the artificial defect is 2 mm.

[0015] Beneficial effects of the present invention:

[0016] (1) When the comparison test block of the present invention is used for testing by using the diffraction time-of-flight ultrasonic testing technology, the comparison test block can be used to verify the blind area of ​​the scanning surface under the current testing parameters, and the supplementary inspection method can be determined according to the value of the blind area of ​​the scanning surface to achieve 100% inspection of the inspected workpiece.

[0017] (2) The blind spot test block of the scanning surface of the comparative test block of the present invention uses trigonometric relationship to calculate the height from the artificial defect at that position to the test block surface and the size of the vertical height of the artificial defect, which can verify the true and accurate data of the blind spot of the scanning surface and can verify the size of the actual blind spot under any detection conditions.

[0018] (3) The test block is simple to manufacture and has low cost, strong operability and repeatability, and has a wide coverage range of the blind area of ​​the scanning surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a front view of the comparison test block for determining the blind area of ​​the scanning surface by the ultrasonic detection of the time-of-flight diffraction method according to the present invention;

[0020] Figure 2 yes Figure 1 AA cross-sectional view of the comparison test block shown in;

[0021] Figure 3 yes Figure 1 BB section view of the comparison test block shown in;

[0022] Figure 4 yes Figure 1 The comparison block shown in the figure is scanned by TOFD technology;

[0023] Figure 5 This is a comparison of the blind area of ​​the scanning surface with a PCS of 60mm (the image on the left is the test block map);

[0024] Figure 6 This is a comparison chart of the blind area of ​​the scanning surface with a PCS of 92mm (the image on the left is the test block map).

[0025] Among them, 1-artificial defect; 2-starting end of artificial defect; 3-cutting section; X1-starting end of artificial defect distance comparison test block; h1-minimum height of artificial defect from scanning surface; h2-maximum height of artificial defect from scanning surface. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same technical meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form, and it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention and should not be understood as limitations on the present invention.

[0030] The present invention provides a comparison test block for determining the blind area of ​​the scanning surface by using the diffraction time difference method ultrasonic detection. The scanning surface is generally the upper surface of the test block. The material of the comparison test block is made of a material having acoustic properties close to or similar to those of the workpiece to be inspected. The material used for the comparison test block needs to be strictly tested by methods such as MT, UT, and PA. The area through which the sound beam of the test block passes must not have a flat-bottom hole equivalent defect greater than or equal to φ2. The comparison test block is a rectangular parallelepiped structure. The ground of the rectangular parallelepiped structure has a linear opening. The linear opening is a wire cutting groove. The scanning direction is generally along the length direction of the rectangular parallelepiped structure.

[0031] The interior of the comparison test block is processed by an electric spark CNC wire cutting machine to have an artificial defect consistent with the scanning direction. The wire cutting groove is cut during the processing of the electric spark CNC wire cutting machine. The artificial defect has an angle with the upper surface of the comparison test block. The shape of the artificial defect is not limited. For example, the artificial defect can be a rhombus, a rectangle and a circle. The rhombus can be a rhombus with upper and lower tips of 60 degrees. The rectangle can be a rectangle with a height and width of 2:1.

[0032] The height of the artificial defect is usually set to 2 mm, that is, the defect height of the artificial defect processed is usually 2 mm.

[0033] There is an angle between the artificial defect and the upper surface of the comparison test block, and the angle can be set as needed, for example, can be set to 2°~8.

[0034] like Figures 1 to 3 Shown is an implementation mode of the present invention.

[0035] In this embodiment, the artificial defect should be located in the middle of the width direction of the test block, the width of the comparison test block should meet the use requirements (generally, the width of the comparison test block can be selected to be 200mm), and the artificial defect 1 should be at a certain distance X1 from the left section of the test block at the starting end 0 of the upper surface of the comparison test block, and the distance X1 is generally set to be greater than 50mm. The test block should be marked with scales at the 0 position (i.e.) along the length direction.

[0036] like Figure 2 As shown, the shape of the artificial defect 1 is preferably an artificial defect that is conducive to generating a diffraction signal. The shape of the artificial defect 1 includes but is not limited to a rhombus with upper and lower tips at 60° or a rectangle or circle with a height of 2:1. The angle between the artificial defect 1 and the upper surface of the test block should be known during processing, and then the height value h of the upper tip of the artificial defect 1 from the upper surface of the comparison test block under the corresponding scale can be calculated using the trigonometric function relationship. In order to ensure the measurement of the blind area of ​​the scanning surface under different technical parameters, the minimum height h1 of the artificial defect 1 is 0mm, the maximum height h2 of the artificial defect 1 is greater than or equal to 15mm, and the thickness of the comparison test block is required to be greater than or equal to 20mm.

[0037] like Figure 3 As shown, there is a wire cutting groove of the EDM CNC wire cutting machine below the artificial defect 1 of the comparative test. The thin wire diameter of the EDM CNC wire cutting machine does not affect the evaluation of the blind area of ​​the scanning surface of the test block. During processing, the parallelism error between the artificial defect 1 and the left and right sides is required to be no more than ±0.1°, and no matter what the shape of the artificial defect 1 is, the height error of the artificial defect 1 is required to be no more than ±0.1mm.

[0038] from Figure 4 It can be seen that the artificial defect can be clearly displayed on the scanning map. Although there is an opening on the bottom surface, it does not affect the determination of the blind area of ​​the scanning surface.

[0039] The spectrum collected using the above-mentioned comparison test block is as follows Figure 4 As shown, Figure 4 The artificial defect wave height measurement shown should be consistent with the actual artificial defect height processed. If it is inconsistent, the combined performance of the TOFD detection equipment needs to be verified. Figure 4The blind area height value at the horizontal distance shown should be consistent with the height value h of the tip of the artificial defect 1 from the upper surface under the horizontal scale at the corresponding position. If they are inconsistent, the performance of the encoder of the TOFD detection equipment needs to be verified. In this way, the combined performance of the TOFD equipment, encoder, and probe used on site can be verified to be accurate.

[0040] In the present invention, the comparison test block should be made of a base material with the same or similar acoustic properties as the workpiece, and the verticality and parallelism of the comparison test block should not exceed 0.05 mm. Figure 1 The surface roughness Ra≤1.6μm, and the roughness Ra≤3.2μm of the other surfaces. Other requirements for processing the comparative test blocks shall comply with the provisions of JB / T913 and JB / T10063.

[0041] The inventors used the test blocks to verify the 26mm and 40mm thick on-site butt welds, respectively. They used OmniScan MX2 testing equipment, equipped with a 10MHz φ6mm probe pair, a wedge angle of 60°, and a non-parallel scanning method. The through wave width Tp was 1.5 cycles (0.15μs), and the longitudinal wave speed c was 5.95mm / μs. The theoretical blind area value d was calculated according to formula (1). The blind area value d1 and the actual on-site weld blind area d2 were verified using the comparison test block, and the above three data were compared (see Table 1). The experimental comparison proves that the above comparison test block is effective in practical applications.

[0042]

[0043] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0044] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A comparison test block used for determining the blind area of ​​the scanning surface by using the time-of-flight diffraction ultrasonic detection method, characterized in that: A rectangular comparison test block is included, wherein an artificial defect consistent with the scanning direction is machined inside the comparison test block by an electric spark CNC wire cutting machine, and the artificial defect forms an angle with the upper surface of the comparison test block; The angle ranges from 2° to 8°; The minimum height of the artificial defect from the upper surface of the comparison test block is 0 mm; The maximum height of the artificial defect from the upper surface of the comparison test block is not less than 15 mm; The height of the artificial defect is 2 mm; The comparison test block is a rectangular structure, and the ground of the rectangular structure has a linear opening, and the linear opening is a wire-cut groove.

2. The comparison test block for determining the blind area of ​​the scanning surface by time-of-flight diffraction ultrasonic testing according to claim 1 is characterized in that: The cross-sectional shape of the artificial defect along the radial direction is rhombus, rectangle or circle.

3. The comparison test block for determining the blind area of ​​the scanning surface by time-of-flight diffraction ultrasonic testing according to claim 1 is characterized in that: In the scanning direction, the starting end of the artificial defect is not less than 50 mm from the starting end of the comparison test block.

4. The comparison test block for determining the blind area of ​​the scanning surface by time-of-flight diffraction ultrasonic testing according to claim 1 is characterized in that: The upper surface of the comparison test block is marked with length marks along the scanning direction from the starting position of the artificial defect.

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