Ultrasonic flaw detection scanning frame and flaw detection method

Abstract

The invention provides an ultrasonic flaw detection scanning frame and a flaw detection method, and belongs to the technical field of nondestructive detection device.The ultrasonic flaw detection scanning frame comprises a flat plate, a vertically-through containing hole is formed in the middle of the flat plate, the specification of the containing hole is matched with the size of a standard test block, and at least one magnetic block is fixed to the upper surface of the flat plate; the lower surface of the magnetic block is coplanar with the upper surface of the flat plate; under the view angle of the top view, part of the area of the magnetic block is within the range of the placing hole, the magnetic block and the standard test block can generate magnetic attraction force, and the magnetic attraction force is smaller than the gravity of the standard test block. According to the scanning frame, the situation that the height of the scanning frame is adjusted through threaded adjusting feet to adapt to test blocks with different heights is avoided, and the test blocks are physically limited through the lower surfaces of the magnetic blocks.

Description

Technical Field

[0001] This invention belongs to the field of non-destructive testing equipment technology, specifically relating to an ultrasonic flaw detection scanning frame and flaw detection method. Background Technology

[0002] Before conducting non-destructive testing on the equipment on-site, standard test blocks containing known defects must first be calibrated using non-destructive testing in a laboratory environment. Only after confirming that the defects in the test blocks can be accurately identified can the testing system be applied to on-site testing operations.

[0003] The core function of an ultrasonic scanning frame is to control the relative height between the ultrasonic probe and the defect on the test block. During use, it is essential to ensure that the upper surface of the scanning frame remains coplanar with the upper surface of the test block. Because the thickness of the equipment being tested varies on-site, test blocks of different heights are required for calibration. Therefore, existing ultrasonic scanning frames are designed with an adjustable height to accommodate the coplanar requirements of test blocks of different heights.

[0004] like Figure 1 As shown, existing scanning frames on the market have a through hole in the middle, the size of which matches the standard test block, allowing the scanning frame to fit snugly onto the test block. Simultaneously, the four corners of the lower end of the scanning frame are equipped with threaded adjusting feet. Rotating these feet changes the overall height of the scanning frame, ensuring it is coplanar with the upper surface of the test block. However, this adjustment method has significant drawbacks: the adjustment process requires repeated rotation of the four adjusting feet, resulting in poor operational convenience. Summary of the Invention

[0005] This invention proposes an ultrasonic flaw detection scanning frame and a flaw detection method, which can be conveniently used in conjunction with test blocks of different heights.

[0006] To achieve the above objectives, the present invention proposes the following technical content: An ultrasonic flaw detection scanning frame includes a plate with a vertically penetrating placement hole in the middle of the plate. The size of the placement hole matches the size of a standard test block. At least one magnetic block is fixed on the upper surface of the plate, and the lower surface of the magnetic block is coplanar with the upper surface of the plate. In a top view, a portion of the area of ​​the magnetic block is within the placement hole. The magnetic block and the standard test block can generate a magnetic attraction force, and the magnetic attraction force is less than the weight of the standard test block.

[0007] Furthermore, a damping buffer is installed at each of the four corners of the lower surface of the plate; when the magnetic block is not attracted to the standard test block, the damping buffer is not compressed; when the magnetic block is attracted to the standard test block, the damping buffer is in a compressed state.

[0008] Further, the opposite sides of the flat plate are respectively provided with disengagement plates without magnetic permeability under the perspective of top view.

[0009] Further, the magnetic blocks are arranged in four, respectively located at the four corners of the rectangular placement hole, and under the perspective of top view, more than 1 / 2 area of a single magnetic block is within the range of the placement hole.

[0010] Further, the upper surface of the flat plate is provided with a convex strip, and the lower surface of the convex strip is provided with a magnetic adsorption strip capable of being adsorbed to the upper surface of the flat plate.

[0011] Further, the surface of the flat plate is provided with anti-skid lines.

[0012] Further, an ultrasonic flaw detection method comprises the following steps: S1: according to the thickness of the equipment to be detected on site, a standardized defect test block with a height completely matched is selected; the parameters of the selected test block are input into an ultrasonic simulation software to simulate and calculate the optimal front-end distance K corresponding to the height of the test block, and the value is recorded; S2: the scanning frame is sleeved through the placement hole in the middle of the flat plate and is vertically sleeved on the matched test block from below to ensure that the lower surface of the magnetic block on the scanning frame is adsorbed to the upper surface of the test block; S3: the convex strip is adsorbed to the upper surface of the flat plate, the position of the convex strip is adjusted, and the error between the actual front-end distance and the simulated value K in S1 is controlled within a set range; S4: the walking device carrying the phased array is started to walk on the upper surface of the flat plate, and the front-end distance is kept unchanged during the walking process; after the phased array emits ultrasonic waves, the ultrasonic reflection signals of each detection point of the test block are received by the receiving unit of the phased array and are transmitted to the controller thereof, and based on a multi-source image fusion algorithm, a complete defect visualization image is generated; S5: the imaging signal-to-noise ratio of the image is evaluated, and based on a set signal-to-noise ratio threshold D, if the signal-to-noise ratio of the image is greater than or equal to D, the front-end distance is applied to the on-site flaw detection; if it is less than D, S1-S4 are repeated, a new front-end distance is generated by using computer simulation, a new image of the defect is obtained, and after the imaging signal-to-noise ratio of the image is greater than or equal to D, the corresponding front-end distance is applied to the on-site.

[0013] By using the above technical content, the following beneficial effects can be achieved: 1. The scheme only needs to disengage the magnetic blocks of the flat plate from the standard test block, and then re-adsorb the magnetic blocks to another standard test block with a different height, and the lower surfaces of the magnetic block pairs are used to limit the standard test block, thereby achieving the purposes of convenient disengagement and convenient combination.

[0014] 2. A damping buffer is adopted. When the magnetic block is attracted to the standard test block, the damping buffer is compressed, which slows down the impact speed between the magnetic block and the standard test block and helps to protect the magnetic block. Attached Figure Description

[0015] Figure 1 This is a schematic diagram showing the positional relationship between the pilot block and the scanning frame in the prior art, viewed from the front. Figure 2 This is a schematic diagram of the positional relationship between the magnetic block and the plate in Embodiment 1 from a top-down perspective; Figure 3 This is a schematic diagram showing the positional relationship between the magnetic block and the test block during the test in Example 1, viewed from the front. Figure 4 This is a schematic diagram of the uncompressed state of the damping buffer when the magnetic block and the test block are not in contact, as shown from a frontal view. Figure 5 This is a schematic diagram of the state of the damping buffer after compression when the magnetic block and the test block are in contact, as shown from a frontal view. Figure 6 This is a schematic diagram of the positional relationship between the flat plate and the anti-detachment plate in Example 3 from a top-down view; Figure 7 This is a diagram showing the positional relationship of each component during the experiment in Example 4 from a frontal view.

[0016] 1. Flat plate; 2. Placement hole; 3. Test block; 4. Magnetic block; 5. Damping buffer; 6. Release plate; 7. Anti-slip texture; 8. Raised edge strip. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: As Figure 2 As shown, an ultrasonic flaw detection scanning frame includes a plate 1. The plate 1 is placed horizontally, with a vertically penetrating placement hole 2 in its center; in the top view, the dimensions of the placement hole 2 match those of a standard test block 3 (with an error of approximately 1 mm), and its specific dimensions are 400 mm × 400 mm. The thickness of the plate 1 is set to 20 mm.

[0019] Four magnetic blocks 4 (such as neodymium magnets) are fixed on the upper surface of the flat plate 1 by adhesive. The shape of the magnetic block 4 is rectangular, and the lower surface of the magnetic block 4 is coplanar with the upper surface of the flat plate 1. The design of four magnetic blocks is to ensure the firm adsorption of the magnetic block 4 and the test block 3 during detection. In the perspective view, the four magnetic blocks are symmetrically arranged at the four corners of the placement hole 2, and more than 1 / 2 of the area of a single magnetic block is within the range of the placement hole 2, ensuring that there is a large enough adsorption contact surface between the magnetic block 4 and the test block 3.

[0020] The adsorption force parameter of the magnetic block 4 is 5-8N per single block, and the total adsorption force of the four magnetic blocks is much smaller than the weight of the test block 3 (the weight of the test block 3 is greater than 50N). This design can avoid the magnetic force of the magnetic block 4 lifting the test block 3 when the flat plate 1 is fitted through the placement hole 2 to set the test block 3. The magnetic performance of the magnetic block 4 meets the following requirements: the lower surface can realize stable adsorption with the upper surface of the test block 3 made of iron-nickel material through magnetic force, and the state of the adsorption of the magnetic block 4 and the test block 3 is shown in Figure 3 .

[0021] The cooperation process of the present scanning frame with different test blocks 3 is as follows: when replacing test blocks 3 of different height specifications, the operator only needs to vertically lift the scanning frame upward - because the weight of the test block is greater than the total adsorption force of the four magnetic blocks, no additional force needs to be applied to the test block 3, and the magnetic block and the test block 3 automatically separate; when matching test blocks 3 of new height specifications, the person only needs to re-set the placement hole 2 of the flat plate 1 from below on the test block 3 until the magnetic block 4 and the upper surface of the test block 3 complete adsorption, that is, the assembly of the scanning frame and the test block is completed, and the subsequent scanning work is waited.

[0022] Example 2: see Figure 4 and Figure 5 , an ultrasonic flaw detection scanning frame, which is further improved based on example 1. In this embodiment, four damping buffers 5 (also known as gas spring dampers) are installed at the four corners of the lower surface of the flat plate 1. After installation, the piston rod of the damping buffer 5 faces downward, and the piston rod axis is perpendicular to the lower surface of the flat plate 1.

[0023] The extension stroke of the damping buffer 5 is set to 0-50mm, which is suitable for the assembly of test blocks with a height of 80-100mm and the scanning frame. When the placement hole 2 of the scanning frame is set on the test block 3, the upper surface of the test block 3 is lower than the upper surface of the flat plate 1 (such as Figure 4 state), at this time the piston rod of the damping buffer 5 is in an uncompressed state.

[0024] The operator presses the flat plate 1 downward, and under the combined action of human force and magnetic block adsorption force, the piston rod of the damping buffer gradually shortens, and finally the lower surface of the magnetic block 4 and the upper surface of the test block 3 are adsorbed. During this process, the damping effect of the damping buffer can make the magnetic block 4 and the test block 3 contact slowly, avoiding the magnetic block 4 from being broken due to too fast contact speed; after adsorption is completed, because the spring restoring force of the damping buffer is smaller than the magnetic block adsorption force, the magnetic block and the test block can always maintain a stable adsorption state. When the test block is separated from the flat plate, the operator only needs to lift the flat plate 1 upward, so that the test block and the magnetic block are separated.

[0025] Example 3: see Figure 6 An ultrasonic flaw detection scanning frame is further improved on the basis of example 2. In this example, the plan view shape of the flat plate 1 is set as a rectangle, and the two wide sides are parallel to the X direction, and the two long sides are parallel to the Y direction; the flat plate 1 is provided with a rectangular separation plate 6 at each end along the Y direction.

[0026] The installation and positioning requirements of the separation plate 6 are that the side along the X direction is completely coincided with the corresponding side of the flat plate 1, and the length along the Y direction is shorter than the length of the flat plate 1 along the Y direction; the upper and lower surfaces of the separation plate 6 are coplanar with the upper and lower surfaces of the flat plate 1, and are fixedly connected with the flat plate 1 by means of gluing.

[0027] In this example, the walking device carrying the ultrasonic phased array moves on the upper surface of the scanning frame along the Y direction to detect defects of the test block 3. When the magnetic attraction wheels of the walking device roll on the surface of the flat plate 1, the upper surface of the test block 3 made of iron-nickel material is kept in magnetic adsorption force, ensuring the stability of the walking. Since the separation plate 6 is made of plastic material (without magnetic conductivity), when all the magnetic attraction wheels of the walking device are completely displaced to the upper surface of the separation plate 6, the magnetic adsorption force between the magnetic attraction wheels and the separation plate disappears, facilitating the separation of the walking device from the scanning frame.

[0028] In order to avoid the magnetic attraction wheels of the walking device from slipping (affecting the accuracy of defect scanning data) when walking on the surface of the flat plate 1, the upper surface of the flat plate 1 is provided with a net-like ditch type anti-skid pattern, and the height difference between the highest point of the anti-skid pattern and the surface of the flat plate 1 is 0.2-0.4mm.

[0029] Example 4: as Figure 7 shown, an ultrasonic flaw detection scanning frame is further improved on the basis of example 3. In this example, the scanning frame is additionally provided with a convex edge strip, which is a long strip structure with a rectangular end face, and its core function is to assist the walking device to keep a stable front end distance during scanning. The definition of the front end distance is that the horizontal distance between the detection center of the ultrasonic phased array probe and the center line of the rectangular strip defect on the test block along the X direction, which directly affects the accuracy of defect positioning, so the stable control needs to be realized through the accurate positioning of the convex edge strip.

[0030] To realize the stable control of the front-end distance, the following design and operation mode is adopted for the convex strip: the lower surface of the convex strip is integrated with a magnetic adsorption strip, which can be directly adsorbed and fixed on the upper surface of the flat plate (the adsorption principle is consistent with that of the magnetic block in embodiment 1, and the fixation is reliable and convenient to adjust). During operation, the worker marks two points (P1 and P2) along the Y direction by using a measuring tool, the distance between P1 and P2 and the center line of the defect is the same, and the edge of the convex strip along the Y direction passes through the two points P1 and P2, so that the accurate placement direction of the convex strip can be quickly determined; finally, the wheels of the walking device are placed in close contact with the side surface of the convex strip along the X direction, and then the front-end distance is calibrated by using a ruler, the position of the convex strip along the X direction is re-measured and adjusted according to the calibration result, and the adjustment is repeated until the front-end distance is basically consistent with the result of computer simulation (error ≤0.5 cm), finally, the walking device is started and moves forward along the Y direction, and through the physical limiting action of the convex strip, it can be ensured that the front-end distance remains unchanged during the entire scanning process.

[0031] Embodiment 5: an ultrasonic flaw detection method, specifically comprising the following steps: S1: according to the thickness of the equipment to be detected on site, a standardized defect test block with a height specification completely matched is selected. Since the thickness of the equipment on site is a standardized size, the standardized test block has a preset corresponding height specification, so that the accurate matching of "equipment thickness-test block height" can be directly realized. The selected test block parameters are imported into the ultrasonic simulation software, the optimal front-end distance K corresponding to the height test block is simulated and calculated, and the value is recorded.

[0032] S2: the scanning frame is sleeved in the placement hole passing through the middle part of the flat plate, and is vertically sleeved on the matched test block from below, so that the lower surface of the magnetic block on the scanning frame is adsorbed to the upper surface of the test block; S3: two points are marked along the Y direction by using a measuring tool, the placement direction of the convex strip is determined by the line connecting the two points, the convex strip with a lower surface with a magnetic adsorption strip is adsorbed to the upper surface of the flat plate, so that the placement direction of the convex strip is parallel to the advancing direction of the walking device, the magnetic attraction wheel of the walking device is tightly placed along the side surface of the convex strip along the X direction, the actual front-end distance is measured by using a precision ruler, the position of the convex strip along the X direction is adjusted, and after the error between the actual front-end distance and the simulated value K in S1 is controlled within a set range, the position of the convex strip is no longer adjusted; S4: the walking device carrying the ultrasonic phased array is started, and moves along the Y direction, the encoder of the walking device records the real-time advancing distance of the walking device and transmits it to the controller thereof, the ultrasonic wave reflection signals of each detection point of the test block are received by the ultrasonic phased array and transmitted to the controller thereof, and based on a multi-source image fusion algorithm, a complete defect visualization image is generated; S5: evaluate the imaging signal-to-noise ratio of the image, based on a set signal-to-noise ratio threshold D, if the image signal-to-noise ratio is greater than or equal to D, the front-end distance is applied to the field detection; if less than D, repeat S1-S4, generate a new front-end distance by using computer simulation again, obtain the image of the defect again, until the imaging signal-to-noise ratio of the image is greater than or equal to D, then the corresponding front-end distance is applied to the field.

[0033] The above is the ideal embodiment of the present application, and the above description can be changed and modified without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined by the scope of the claims.

Claims

1. An ultrasonic flaw detection scanning frame, comprising a flat plate, wherein a vertically penetrating placement hole is provided in the middle of the flat plate, the specifications of the placement hole matching the size of a standard test block, characterized in that, At least one magnetic block is fixed on the upper surface of the plate, and the lower surface of the magnetic block is coplanar with the upper surface of the plate. From the top view, part of the area of ​​the magnetic block is within the range of the placement hole. The magnetic block and the standard test block can generate magnetic attraction, and the magnetic attraction is less than the weight of the standard test block.

2. The ultrasonic flaw detection scanning frame according to claim 1, characterized in that, A damping buffer is installed at each of the four corners of the lower surface of the plate; when the magnetic block is not attracted to the standard test block, the damping buffer is not compressed; when the magnetic block is attracted to the standard test block, the damping buffer is in a compressed state.

3. The ultrasonic flaw detection scanning frame according to claim 1, characterized in that, From a top-down view, release plates are installed on opposite sides of the flat plate, and the release plates have no magnetic properties.

4. The ultrasonic flaw detection scanning frame according to claim 1, characterized in that, Four magnetic blocks are provided, located at the four corners of the rectangular placement hole. From a top view, more than half of the area of ​​a single magnetic block is within the placement hole.

5. The ultrasonic flaw detection scanning frame according to claim 1, characterized in that, The upper surface of the plate is provided with a raised edge strip, and the lower surface of the raised edge strip has a magnetic adsorption strip that can be adsorbed onto the upper surface of the plate. The raised edge strip is a long strip structure with a rectangular end face. After the raised edge strip is placed, the distance between the side of the raised edge strip away from the standard test block and the center line of the defect of the standard test block is equal.

6. The ultrasonic flaw detection scanning frame according to claim 1, characterized in that, The surface of the flat plate is covered with anti-slip texture.

7. An ultrasonic flaw detection method, based on the ultrasonic flaw detection scanning frame according to claim 5, characterized in that, Includes the following steps: S1: Select a standardized defect test block with a height that perfectly matches the thickness of the equipment to be tested on site; import the parameters of the selected test block into the ultrasonic simulation software, simulate and calculate the optimal front end distance K corresponding to the height of the test block, and record the value. S2: Place the scanning frame through the placement hole in the middle of the plate and vertically place it on the matching test block from below, ensuring that the lower surface of the magnetic block on the scanning frame is attracted to the upper surface of the test block. S3: Attach the convex edge to the upper surface of the plate, adjust the position of the convex edge, and ensure that the error between the actual front end distance and the simulated value K in S1 is controlled within the set range. S4: Start the walking device carrying the phased array to walk on the upper surface of the plate, keeping the front end distance unchanged during the walking process; after the phased array emits ultrasonic waves, the ultrasonic wave reflection signals at each detection point of the test block are received by the phased array receiving unit and transmitted to its controller. Based on the multi-source image fusion algorithm, a complete defect visualization image is generated. S5: Evaluate the imaging signal-to-noise ratio of the image. Based on the set signal-to-noise ratio threshold D, if the image signal-to-noise ratio is greater than or equal to D, the front-end distance is applied to the field flaw detection. If it is less than D, repeat S1-S4 to regenerate a new front-end distance using computer simulation and obtain the defect image again until the imaging signal-to-noise ratio of the evaluated image is greater than or equal to D, and then apply the corresponding front-end distance to the field.

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