Ultrasonic detection method for surfacing layer of water cooling wall

Abstract

The invention discloses a water-cooled wall surfacing layer ultrasonic detection method, which comprises the following steps: grinding and polishing treatment, tool installation and coupling agent smearing, dynamic scanning detection, signal acquisition and observation, and defect determination and recording. The flexible tool is combined with an adaptive curved surface, full-area coverage of defects of 0.1 mm or above is achieved, the detection rate of micro cracks reaches 99%, the problem of missing detection in a traditional method is solved, the surface roughness is controlled through graded grinding, it is ensured that the flexible tool is attached to a surfacing layer, and design such as automatic supplementary coating of a coupling agent is matched. The problems of poor coupling, signal interference and the like in curved surface surfacing layer detection are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of overlay detection, in particular to a water-cooled wall overlay ultrasonic detection method. BACKGROUND

[0002] The water-cooled wall overlay is the core protective structure of high-temperature and high-pressure equipment (such as boilers and pressure vessels), and its quality directly determines the corrosion resistance and high-temperature resistance of the equipment. Once there are defects such as cracks and incomplete fusion, it may cause leakage or even explosion, so it is necessary to detect the overlay.

[0003] The existing ultrasonic detection relies on complex software operation and requires high skills of the staff. Moreover, since the overlay is mostly a curved surface structure, the coupling effect is poor due to unstable fitting of the rigid tooling, and the defect detection rate is less than 90%. Manual application of the coupling agent is prone to uneven thickness, and the loss of the coupling agent during dynamic scanning further affects the signal quality. The mechanical transmission device has poor adaptability and is difficult to move stably along a complex trajectory, resulting in low detection efficiency and poor consistency of the results. SUMMARY

[0004] The present application provides a water-cooled wall overlay ultrasonic detection method to solve the technical problems raised in the background.

[0005] To solve the above technical problems, the technical solution adopted by the present application is as follows: a water-cooled wall overlay ultrasonic detection method, characterized by comprising the following steps, Step 1: polishing treatment: the staff uses a handheld polisher with an elastic grinding head to polish the surface of the overlay by sequentially replacing sandpaper of different mesh sizes. The grinding head is kept perpendicular to the surface during polishing, and a certain pressure is controlled. The portable roughness instrument is used to measure at random multiple points every certain period of polishing until the roughness reaches the preset standard. Then, the surface debris is removed with a high-pressure air gun; Step 2: installation of tooling and application of coupling agent: select a flexible tooling that is adaptive to the curved surface of the overlay. The flexible tooling is a sheet-shaped structure made of high-elasticity silicone rubber composite material (Shore hardness 50-60), with arrayed probe mounting grooves distributed on the surface. Then, embed the 16-channel phased array probe into the mounting grooves of the tooling. Install the tooling on the mechanical transmission mechanism and make the flexible tooling fit the overlay. Then, evenly apply the 5% carboxymethyl cellulose solution coupling agent on the surface of the overlay with a thickness of 0.1-0.3 mm using a scraper; Step 3: dynamic scanning detection, connect the 16-channel phased array probe with the ultrasonic detector, start the mechanical transmission mechanism, and then make the mechanical transmission mechanism move the probe to complete the comprehensive scanning of the overlay. Ensure that the flexible tooling fits the overlay during movement. The coupling agent thickness sensor monitors in real time during the scanning process, and the automatic coupling agent replenishing device is started to replenish the coupling agent when the thickness is below a certain value. Step four: signal acquisition and observation, the ultrasonic detector receives the electrical signal returned by the probe, after amplification and filtering by the internal circuit, the real-time waveform graph is generated on the display screen, the staff records the waveform characteristics every 5 minutes, and marks the abnormal signals whose amplitude exceeds 50% of the baseline; Step five: defect judgment and record, the staff compares the abnormal signal waveform with the standard defect atlas (crack is sawtooth high amplitude wave, unmelting is interface continuous reflection wave, and porosity is narrow pulse low amplitude wave), combined with the position coordinates of the signal, the defect type and size are judged, the results are manually entered into the detection record table, and are marked on the corresponding position of the surfacing layer diagram; Step six: after the detection is completed, the surface coupling agent is removed with an alcohol-dipped cloth, and the roughness instrument is measured again at points 2-4 to confirm that the surface has not been damaged due to detection, and then the detection record table and the diagram are archived together.

[0006] Preferably, the grinding head of the handheld sander in step one is made of polyurethane material, with a diameter of 50-80mm, and the rotating speed increases with the grit number of the sandpaper: the rotating speed of low grit number sandpaper is 1000-2000r / min, the rotating speed of medium grit number sandpaper is 1500-2500r / min, and the rotating speed of high grit number sandpaper is 2500-3500r / min.

[0007] Preferably, the air pressure of the high-pressure air gun in step one is adjusted to 0.2-0.6MPa, the distance between the air nozzle and the surface is kept at 5-20cm, and the air nozzle is uniformly swept along the transverse direction to ensure that the debris removal rate is ≥90%.

[0008] Preferably, the mechanical transmission mechanism in step three includes two servo motors, which are responsible for the motion drive of X-axis (transverse) and Y-axis (vertical) respectively, and both X-axis and Y-axis adopt ball screw transmission, which converts the rotary motion of the servo motor into linear motion through the cooperation of the ball screw and the nut, and then drives the probe displacement.

[0009] Preferably, the automatic recoating device in step three includes a liquid storage tank, a micro pump body, an atomizing nozzle, and a linkage control module, the volume of the liquid storage tank is 0.5-2L, the output pressure of the micro pump body is 0.1-0.3MPa, the atomizing nozzle is mechanically linked with the probe group, the spraying range covers the probe detection area, and the linkage control module receives the coupling agent thickness sensor signal, when the thickness is detected to be lower than the preset value, the pump body is triggered to work, and the recoating amount is adjusted in real time according to the sensor feedback.

[0010] Preferably, the amplification multiple of the ultrasonic detector in step four can be adjusted within the range of 100-1000 times, the filter frequency is set to 2-10MHz, and the waveform refresh frequency of the display screen is ≥30Hz.

[0011] Preferably, the standard defect atlas in step five is pre-recorded by a Φ0.3-2.5mm artificial defect test block, stored in the built-in memory of the detector, and the workers can compare different defect type atlases by rotating the knob.

[0012] Compared with the prior art, the present application has the following advantages: the present application combines phased array multi-angle scanning and multi-modal signal acquisition, adapts to curved surfaces with flexible tooling, realizes full-area coverage of defects larger than 0.1mm, and has a micro crack detection rate of 99%, solving the problem of missed detection in traditional methods. By controlling the surface roughness through grading polishing, the present application ensures the adhesion of the flexible tooling and the surfacing layer, and cooperates with automatic coating of couplant and other designs to effectively solve the problems of poor coupling and signal interference in surfacing layer detection of curved surfaces. The flexible tooling and the mechanical transmission device adapt to surfacing layers with different curvatures, and the scanning track is fully covered. The detection process uses manual comparison of standard atlases and manual recording, and the results have strong traceability. The present application cooperates with a mechanical structure-based equipment design, is easy to maintain, and reduces the cost by more than 30%, thereby improving the reliability, practicality and economy of surfacing layer detection. DETAILED DESCRIPTION

[0013] In order to make the technical means, creative features, purposes and effects of the present application easy to understand and understand, the present application is further described below in combination with specific embodiments.

[0014] Embodiment 1: Step one: use a 60mm diameter polyurethane polishing head handheld polisher, and use 120 mesh (rotating speed 1500r / min) and 240 mesh (rotating speed 2000r / min) sandpaper in sequence, with a pressure control of 0.2MPa, and measure 5 points every 30 seconds with a roughness instrument until Ra≤6.3μm, and then use a 0.4MPa high-pressure air gun to remove debris; Step two: select a flexible tooling with a Shore hardness of 55, embed a 16-channel phased array probe, and then install it on a mechanical transmission mechanism, and manually apply a 0.2mm thick carboxymethyl cellulose solution couplant; Step three: start the mechanical transmission mechanism, set the X / Y axis step distance to 0.5mm, and set the servo motor power to 1kW. During the scanning process, set the couplant thickness sensor threshold value to 0.1mm, and when the value is lower than the threshold value, start the automatic coating device (liquid tank 5L, pump body flow rate 0.5mL / s); Step four: set the ultrasonic detector magnification to 500 times, set the filter frequency to 5MHz, record the waveform every 5 minutes, and mark the signals with an amplitude exceeding the reference line by 50%; Step five: compare the standard atlas, determine that one jagged high-amplitude wave is a crack (size 2x1x0.5mm), and manually record it in the record table; Step six: clean the couplant with an alcohol cloth, re-measure the roughness of 3 points to confirm that there is no damage, and archive the detection record. Example 2: Step one: use a diameter of 50 mm grinding head, 100 mesh (1000 r / min), 320 mesh (2500 r / min) sandpaper polishing, pressure 0.15 MPa, after polishing roughness Ra≤8 μm, use 0.3 MPa high pressure air gun to clean the debris; Step two: select a flexible tooling (adapt to the curvature of the arc) with a Shore hardness of 50, embed the probe and then adhere through the mechanical transmission mechanism, and apply 0.25 mm thick coupling agent; Step three: adjust the X / Y axis step distance of the mechanical transmission mechanism to 0.3 mm, the power of the servo motor is 1.5 kW, because the curved surface needs to be detected more closely, the coupling agent reapplication threshold is set to 0.12 mm, and the angle of the atomizing nozzle is adjusted to 15°; Step four: the magnification of the ultrasonic detector is 800 times, the filter frequency is 8 MHz, and the waveform of the curved surface transition area is monitored; Step five: find the interface where the continuous reflection wave is located, determine it as a non-fusion defect (size 3x2x1 mm), and mark it on the curved surface development diagram; Step six: after cleaning, retest the roughness of 2 points, and archive after confirming no damage.

[0015] Example 3: Step one: use a diameter of 80 mm grinding head, 80 mesh (1000 r / min), 240 mesh (2000 r / min), 400 mesh (3000 r / min) sandpaper progressive polishing, pressure 0.3 MPa, measure roughness every 20 seconds until Ra≤5 μm, use 0.5 MPa high pressure air gun to clean the debris thoroughly; Step two: use a flexible tooling with a Shore hardness of 60, apply 0.3 mm thick coupling agent to ensure sufficient coupling of the high roughness surface; Step three: the step distance of the mechanical transmission mechanism is 0.4 mm, the coupling agent reapplication threshold is 0.09 mm, the pump flow of the automatic reapplication device is adjusted to 0.8 mL / s to ensure the coverage of the coupling agent on the rough surface; Step four: the magnification of the ultrasonic detector is 1000 times, the filter frequency is 3 MHz, and the micro defect signal is captured; Step five: identify 3 narrow pulse low amplitude waves as pores (diameter 0.5-1 mm), and accurately mark the position coordinates; Step six: after cleaning, retest the roughness of 4 points, confirm that the surface is not scratched, and complete the archive.

[0016] The three examples cover the scenarios of flat surface, curved surface, and high roughness surfacing layer respectively, and all achieve accurate defect detection through steps such as graded polishing, flexible tooling adaptation, and automatic reapplication. The defect detection rate is above 98%, which meets the operation process and parameter range defined in the claims. The above examples only express some embodiments of the present application, which are described in a more specific and detailed manner, but should not be understood as a limitation to the scope of the patent of the present application. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for ultrasonic detection of water-cooled wall cladding layer, characterized in that: The steps include: Step 1: Grinding and polishing. The staff uses a handheld grinder with an elastic grinding head to grind the surface of the surfacing layer by replacing sandpaper of different mesh sizes. When grinding, keep the grinding head perpendicular to the surface and control a certain pressure. After each grinding period, use a portable roughness meter to measure at multiple random points until the roughness reaches the preset standard. Then use a high-pressure air gun to remove surface debris. Step 2: Install the fixture and apply coupling agent. Select a suitable flexible fixture based on the curvature of the weld overlay surface. The flexible fixture is a sheet-like structure made of a highly elastic silicone rubber composite material (Shore hardness 50-60) with array probe mounting slots distributed on its surface. The 16-channel phased array probe is then inserted into the fixture's mounting slots. The fixture is then mounted on the mechanical transfer mechanism and aligned with the weld overlay. A 5% carboxymethyl cellulose solution coupling agent is then evenly applied to the weld overlay surface using a scraper, with a thickness of 0.1-0.3mm. Step 3: Dynamic scanning inspection: Connect the 16-channel phased array probe to the ultrasonic detector and activate the mechanical transmission mechanism, which then drives the probe to move to complete a comprehensive scan of the weld overlay layer. During the movement, ensure that the flexible tooling fits the weld overlay layer. During the scanning process, the coupling agent thickness sensor monitors in real time. When the thickness falls below a certain value, the automatic re-coating device activates to replenish the coupling agent. Step 4: Signal acquisition and observation: The ultrasonic detector receives the electrical signal sent back by the probe, amplifies and filters it through the internal circuit, and generates a real-time waveform on the display screen. The staff records the waveform characteristics every 5 minutes, focusing on marking abnormal signals with amplitudes exceeding 50% of the baseline; Step 5: Defect determination and recording. The staff compares the abnormal signal waveform with the standard defect spectrum (cracks are jagged high-amplitude waves, lack of fusion is a continuous reflection wave at the interface, and pores are narrow pulse low-amplitude waves). Combined with the position coordinates of the signal, the staff determines the defect type and size, manually enters the results into the inspection record sheet, and marks them at the corresponding position on the weld overlay layer schematic diagram; Step 6: After the test is completed, use a cloth dipped in alcohol to remove the surface coupling agent, and measure 2-4 points again with the roughness meter to confirm that the surface is not damaged by the test. Then file the test record sheet and schematic diagram together.

2. The ultrasonic detection method for water-cooled wall cladding layer according to claim 1 is characterized in that: The grinding head of the handheld grinder in step 1 is made of polyurethane, with a diameter of 50-80mm. The speed increases with the mesh number of the sandpaper: low mesh number sandpaper corresponds to a speed of 1000-2000r / min, medium mesh number corresponds to 1500-2500r / min, and high mesh number corresponds to 2500-3500r / min.

3. The ultrasonic detection method for water-cooled wall cladding layer according to claim 1, characterized in that: In step 1, the air pressure of the high-pressure air gun is adjusted to 0.2-0.6 MPa, the distance between the air nozzle and the surface is kept at 5-20 cm, and the surface is swept horizontally at a uniform speed.

4. The ultrasonic detection method for water-cooled wall cladding layer according to claim 1, characterized in that: The mechanical transmission mechanism in step three includes two servo motors, which are responsible for driving the motion of the X-axis (horizontal) and Y-axis (vertical), respectively. Both the X-axis and the Y-axis are driven by ball screws. Through the cooperation of the ball screw and the nut, the rotational motion of the servo motor is converted into linear motion, thereby driving the displacement of the probe.

5. The ultrasonic detection method for water-cooled wall cladding layer according to claim 1, characterized in that: The automatic re-coating device in step three includes a liquid storage tank, a micro pump body, an atomizing nozzle and a linkage control module. The volume of the liquid storage tank is 0.5-2L, the output pressure of the micro pump body is 0.1-0.3MPa, the atomizing nozzle is mechanically linked with the probe group, and the spray range covers the probe detection area. The linkage control module receives the coupling agent thickness sensor signal. When the thickness is detected to be lower than the preset value, the pump body is triggered to work, and the re-coating amount is adjusted in real time according to the sensor feedback.

6. The ultrasonic detection method for water-cooled wall cladding layer according to claim 1, characterized in that: In step 4, the magnification of the ultrasonic detector can be adjusted within the range of 100-1000 times, the filter frequency is set to 2-10MHz, and the display waveform refresh frequency is ≥30Hz.

7. The ultrasonic detection method for water-cooled wall cladding layer according to claim 1, characterized in that: The standard defect map in step five is pre-recorded using a Φ0.3-2.5mm artificial defect test block and stored in the detector's built-in memory. The operator can use the knob to switch between different defect type maps for comparison.