Method and device for detecting cracks in the lower base metal of a roof penetration corner weld of a boiler heating surface

Abstract

The application relates to a method for detecting a lower base material crack of a roof-penetrating sleeve corner weld of a boiler heating surface, which comprises the following steps: a creeping wave probe is attached to a heating surface tube base material with a roof-penetrating sleeve, and a creeping wave signal is sent to the heating surface tube base material; wherein the creeping wave probe is located on one side of the heating surface tube base material close to a weld; and according to a creeping wave reflection signal received by the creeping wave probe, the outer wall crack of the heating surface tube base material with the roof-penetrating sleeve is detected. Compared with the prior art, the application can avoid the problems of crack mis-detection and missed detection caused by the excessively complex structure of a welding position, improves the accuracy of the roof-penetrating position heating surface tube crack detection result, is favorable for guaranteeing the normal operation of a power station boiler, and meets the actual application requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of boiler equipment detection, in particular to a method and device for detecting a crack in a parent material under an angle weld of a boiler heating surface penetration sleeve. BACKGROUND

[0002] In a power station boiler, the superheater of the partition screen, the superheater of the rear screen, the high-temperature reheater and the low-temperature reheater are suspended on the corresponding headers, and the penetration sleeve is welded with the ceiling sealing plate at the penetration position to prevent ash leakage and affect the internal airflow distribution of the boiler. The penetration sleeve and the heating surface tube are connected by an angle weld.

[0003] After the power station boiler is operated for a long time, the weld and the coarse grain zone of the heat affected zone are in a high-hardness organization state, and there is an incomplete penetration defect at the weld root. Under the action of the welding stress, the restraint force of the sealing part on the weld and the additional stress in the operation process, cracking occurs at the stress concentration position of the weld. The cracking position is located at the root of the angle weld. If the crack extends from the weld root to the parent material of the heating surface tube, the parent material of the tube will crack, which may cause leakage and shutdown. Therefore, it is necessary to detect the early crack in the parent material of the heating surface.

[0004] However, the crack occurs at the root of the sealing weld between the penetration sleeve and the heating surface tube, and the crack extends from the weld root to the parent material of the heating surface tube. The weld is located in a narrow ceiling space. If the conventional ultrasonic transverse wave is used to detect the crack, only the second reflection wave can be used. However, multiple structural wave reflection signals usually appear near the weld, which may cause missed detection and misjudgment of the defect, and cannot ensure effective detection of the crack in the penetration sleeve weld. SUMMARY

[0005] Therefore, it is necessary to provide a method and device for detecting a crack in a parent material under an angle weld of a boiler heating surface penetration sleeve to ensure effective detection of the crack in the penetration sleeve weld and normal operation of the boiler.

[0006] The embodiment of the present application provides a method for detecting a crack in a parent material under an angle weld of a boiler heating surface penetration sleeve, which comprises the following steps:

[0007] A creeping wave probe is attached to the parent material of the heating surface tube with the penetration sleeve, and a creeping wave signal is sent to the parent material of the heating surface tube. The creeping wave probe is located on one side of the parent material of the heating surface tube close to the weld.

[0008] According to the creeping wave reflection signal received by the creeping wave probe, the crack in the outer wall of the parent material of the heating surface tube with the penetration sleeve is detected.

[0009] Further, the method for detecting the outer wall crack of the superheater tube base metal with the through- ceiling sleeve according to the creeping wave reflection signal received by the creeping wave probe comprises:

[0010] record the receiving time of the creeping wave reflection signal, and calculate the detection time difference between the receiving time and the creeping wave signal emission time;

[0011] determine whether the outer wall of the superheater tube base metal has a crack and the crack position information according to the detection time difference and the reference time difference;

[0012] determine the crack depth information of the outer wall crack of the superheater tube base metal according to the amplitude difference between the amplitude of the creeping wave reflection signal and the reference amplitude.

[0013] Further, before the creeping wave signal is sent to the superheater tube base metal, the method further comprises:

[0014] the creeping wave probe is attached to the contrast test piece for crack detection simulation; wherein the contrast test piece is provided with a plurality of linear cutting grooves for simulating the outer wall crack of the superheater tube base metal;

[0015] determine the gain information of the outer wall crack detection of the superheater tube base metal according to the crack detection result of the contrast test piece; wherein the gain information includes standard signal gain, reference time difference and reference amplitude.

[0016] Further, the method for attaching the creeping wave probe to the contrast test piece for crack detection simulation comprises:

[0017] determine the moving test range of the creeping wave probe on the contrast test piece; wherein the moving test range includes the maximum distance Lmax and the minimum distance l+k1 of the creeping wave probe from the linear cutting groove, and the maximum distance of the linear cutting groove from the side fusion line length Lmax-l-k1 of the linear cutting groove;

[0018] during the movement of the probe, the creeping wave signal is sent to the contrast test piece through the standard signal gain;

[0019] record the receiving time and amplitude of the creeping wave reflection signal, and calculate the detection time difference between the receiving time and the creeping wave signal emission time;

[0020] the amplitude of the creeping wave reflection signal is taken as the reference amplitude, the detection time difference is taken as the reference time difference, and the corresponding defect detection curve is generated.

[0021] Further, the method for determining the moving test range of the creeping wave probe on the contrast test piece comprises:

[0022] Determine the refraction angle of the head wave and the refracted transverse wave, the transverse wave speed and the creeping wave speed in the contrast sample according to the material of the contrast sample;

[0023] According to the front distance l of the cutting groove from the probe front, the refraction angle and the transverse wave speed, determine the second time t2 when the transverse wave is reflected once and the linear cutting groove is scanned, and the first time t1 when the creeping wave propagates to the linear cutting groove is the ratio of the front distance l and the creeping wave speed;

[0024] According to the first time t1 and the second time t2, determine the maximum distance Lmax of the creeping wave probe from the linear cutting groove;

[0025] According to the front distance l and the weld size K1 of the linear cutting groove, determine the minimum distance l+k1 of the creeping wave probe from the linear cutting groove;

[0026] According to the maximum distance Lmax and the minimum distance l+k1 of the creeping wave probe from the linear cutting groove, determine the maximum distance of the linear cutting groove from the side fusion line Lmax-l-k1 of the linear cutting groove.

[0027] Further, the method for attaching the creeping wave probe to the heated surface pipe base material with the top cover sleeve and sending the creeping wave signal to the heated surface pipe base material comprises:

[0028] According to the defect detection curve, send the creeping wave signal to the heated surface pipe base material.

[0029] Another embodiment of the present application provides a boiler heated surface top cover sleeve corner weld lower base material crack detection device, the device comprises:

[0030] The signal sending module is used for attaching the creeping wave probe to the heated surface pipe base material with the top cover sleeve, and sending the creeping wave signal to the heated surface pipe base material; wherein the creeping wave probe is located on the side of the heated surface pipe base material close to the weld;

[0031] The crack detection module is used for detecting the outer wall crack of the heated surface pipe base material with the top cover sleeve according to the creeping wave reflection signal received by the creeping wave probe.

[0032] Further, the crack detection module is specifically used for,

[0033] Record the receiving time of the creeping wave reflection signal, and calculate the detection time difference between the receiving time and the creeping wave signal emission time;

[0034] According to the detection time difference and the reference time difference, determine whether there is a crack in the outer wall of the heated surface pipe base material, and the crack position information;

[0035] According to the amplitude difference between the amplitude of the creeping wave reflection signal and the reference amplitude, the crack depth information of the outer wall crack of the parent material of the heated surface tube is determined.

[0036] Further, the signal sending module is further used for,

[0037] The creeping wave probe is attached to the contrast test piece for crack detection simulation, and the contrast test piece is provided with a plurality of linear cutting grooves for simulating the outer wall crack of the parent material of the heated surface tube.

[0038] According to the crack detection result of the contrast test piece, the gain information of the outer wall crack detection of the parent material of the heated surface tube is determined, and the gain information includes a standard signal gain, a reference time difference and a reference amplitude.

[0039] Further, the creeping wave probe is attached to the contrast test piece for crack detection simulation, and the contrast test piece is provided with a plurality of linear cutting grooves for simulating the outer wall crack of the parent material of the heated surface tube.

[0040] The moving test range of the creeping wave probe on the contrast test piece is determined, and the moving test range includes the maximum distance Lmax and the minimum distance L0+k1 of the creeping wave probe from the linear cutting groove, and the maximum distance of the linear cutting groove from the side fusion line length Lmax-L0-k1 of the linear cutting groove.

[0041] During the movement of the probe, the creeping wave signal is sent to the contrast test piece through the standard signal gain.

[0042] The receiving time and amplitude of the creeping wave reflection signal are recorded, and the detection time difference between the receiving time and the emission time of the creeping wave signal is calculated.

[0043] The amplitude of the creeping wave reflection signal is taken as the reference amplitude, the detection time difference is taken as the reference time difference, and the corresponding defect detection curve is generated.

[0044] Another embodiment of the present application also provides a computer readable storage medium, which comprises a stored computer program; wherein the computer program controls the device where the computer readable storage medium is located to execute the boiler heated surface through the ceiling sleeve corner weld under the parent material crack detection method as described above when running.

[0045] Another embodiment of the present application also provides a terminal device, which comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, and the processor realizes the boiler heated surface through the ceiling sleeve corner weld under the parent material crack detection method as described above when executing the computer program.

[0046] The boiler heating surface penetration sleeve corner weld under the base material crack detection method, the creeping wave probe is attached to the heating surface pipe base material with penetration sleeve, and the creeping wave signal is sent to the heating surface pipe base material; wherein, the creeping wave probe is located on one side of the heating surface pipe base material close to the weld; according to the creeping wave reflection signal received by the creeping wave probe, the outer wall crack of the heating surface pipe base material with penetration sleeve is detected. Compared with the prior art, the present application can ensure that the penetration sleeve weld crack is effectively detected, ensure the normal operation of the boiler, and meet the actual application requirements. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 The structure diagram of the penetration sleeve sealing weld is shown in the figure;

[0048] Figure 2 The schematic diagram of the creeping wave sound field is shown in the figure;

[0049] Figure 3 The flowchart of the boiler heating surface penetration sleeve corner weld under the base material crack detection method provided by the embodiment of the present application is shown in the figure;

[0050] Figure 4 The propagation diagram of the creeping wave probe refraction wave in the comparison test piece is shown in the figure;

[0051] Figure 5 The diagram of the creeping wave probe moving position on the comparison test piece is shown in the figure;

[0052] Figure 6 The diagram of the creeping wave probe moving position on the comparison test piece is shown in the figure;

[0053] Figure 7 The test diagram of the comparison test piece is shown in the figure;

[0054] Figure 8 The crack defect diagram of the penetration sleeve of the low-temperature reheater of the 300MW unit is shown in the figure;

[0055] Figure 9 The structure block diagram of the boiler heating surface penetration sleeve corner weld under the base material crack detection device provided by the embodiment of the present application is shown in the figure;

[0056] Figure 10 The structure diagram of the equipment terminal provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0058] It should be noted that the step number in the text is only for the convenience of the explanation of the specific embodiment, and does not serve as the function of limiting the execution sequence of the steps. The method provided in the embodiment can be executed by the related server, and the server is taken as an example for description in the following.

[0059] Figure 1 The structure diagram of the roof penetrating sleeve sealing weld. The sealing weld root of the sleeve and the heated surface pipe welding is found to have a crack, the crack extends from the weld root position to the base metal of the heated surface pipe, the roof space where the weld is located is narrow, so it is not suitable to use the ray for detection, the weld is an angle weld, the structure is complex, and the conventional ultrasonic transverse wave can only use the second reflection wave for the crack of the heated surface pipe outer wall at the position, multiple structure wave reflection signals can appear near the angle weld of the heated surface pipe outer wall, which is easy to cause defect missed detection and misjudgment, and cannot guarantee the effective detection of the roof penetrating sleeve weld crack. Therefore, a method for effectively detecting the base metal outer wall crack defect needs to be found.

[0060] Based on the above problems, the working principle of the present application is: according to the propagation characteristics of ultrasonic waves, when ultrasonic waves propagate from one medium to another medium interface, reflection and refraction phenomena occur in the second medium, and when oblique incidence occurs, wave type conversion will occur. According to Snell's law:

[0061]

[0062] CL1<CS2<CL2

[0063] In the formula: CL1 is the longitudinal wave speed of ultrasonic waves in the first medium;

[0064] CS2 is the longitudinal wave speed of ultrasonic waves in the second medium;

[0065] CL2 is the transverse wave speed of ultrasonic waves in the second medium;

[0066] αL is the incidence angle of ultrasonic longitudinal waves in the first medium;

[0067] βL is the refraction angle of ultrasonic longitudinal waves in the second medium;

[0068] βS is the refraction angle of ultrasonic transverse waves in the second medium.

[0069] When an ultrasonic longitudinal wave travels from a medium with a lower sound velocity to a medium with a higher sound velocity, the angle of refraction increases with the angle of incidence. When the angle of incidence α = arcsinC1 / C2, in the second medium, the angle of refraction βL of the longitudinal wave is equal to 90°. In this second medium, the longitudinal wave propagates below the surface. The leading edge where the energy is most concentrated after the longitudinal and transverse waves are superimposed is called the creeping wave. The sound velocity of the longitudinal wave in carbon steel and low-alloy steel is 5920 m / s, and in plexiglass it is 2730 m / s (because plexiglass has good sound transmission properties, ultrasonic probe wedges are generally made of plexiglass). The sound beam of the transverse wave in carbon steel and low-alloy steel is 3230 m / s. Figure 2 This is a schematic diagram of the acoustic field structure of creeping waves in the longitudinal direction of carbon steel and low-alloy steel. To generate creeping waves in carbon steel and low-alloy steel components, the longitudinal wave incident angle in the plexiglass wedge is chosen as α = arcsinC1 / C2 = arcsin2730 / 5920 ≈ 27.5°. This will generate creeping waves with a refraction angle of 90°, parallel to the workpiece surface. Simultaneously, according to Snell's law, a transverse wave with a refraction angle of arcsin(sin27.5° / 2730×3230) ≈ 33° will also be generated. This transverse wave will be reflected at the lower surface of the workpiece, generating a primary reflected transverse wave, which can reach the upper surface of the workpiece.

[0070] Depend on Figure 2 It is known that the ultrasonic creeping wave probe generates a sound field with multiple waveforms in the longitudinally excited carbon steel and low alloy steel. In addition to creeping waves, it also generates strong transverse waves and head waves. The transverse waves propagate longitudinally through the workpiece at a refraction angle of approximately 33°, while the transverse waves continuously radiate as the longitudinal waves propagate forward beneath the surface. Ultrasonic creeping waves are compression waves that propagate near the surface of the material. They are highly sensitive to surface and near-surface cracks, and because the longitudinal waves are the main component, creeping waves are less affected by surface scratches, unevenness, depressions, droplets, etc. Since the sealing weld between the roof sleeve and the heating surface tube of a power plant boiler uses a fillet weld structure, creeping wave detection effectively avoids the influence of the sealing weld. If there is a crack defect in the base material of the heating surface tube at this location, the crack defect is generally perpendicular to the surface of the base material. The creeping wave propagates parallel to the surface of the base material, thus the crack in the base material can be effectively detected by the creeping wave. However, during the propagation of the secondary reflected waves of the transverse wave and the head wave, when they encounter the weld foot, weld surface, or defects within the weld joint sealing weld, they are reflected again. The reflected signals are received by the probe, and multiple non-base material crack reflection signals will appear on the oscilloscope screen of the ultrasonic flaw detector, which makes the judgment somewhat difficult.

[0071] The application utilizes the characteristic that the creeping wave propagates below the workpiece surface and parallel to the base metal surface to detect the cracks on the outer wall of the base metal of the heated surface tube with the roof penetrating sleeve, corresponding comparison test pieces are made, the positions of different reflection signals are analyzed, the corresponding detection process is formulated, and the useless ultrasonic reflection signal interference is excluded, so as to achieve the purpose of accurate and reliable detection results.

[0072] As shown in Figure 3 The boiler heated surface roof penetrating sleeve corner weld under base metal crack detection method provided by the embodiment of the application is applied to a power station boiler, and the method comprises steps S11 to S12.

[0073] In step S11, the creeping wave probe is attached to the base metal of the heated surface tube with the roof penetrating sleeve, and a creeping wave signal is sent to the base metal of the heated surface tube; wherein the creeping wave probe is located on the side of the base metal of the heated surface tube close to the weld.

[0074] Specifically, the creeping wave probe is attached and arranged on the surface of the base metal of the heated surface tube and located close to the weld of the base metal of the heated surface tube, the creeping wave probe is attached to the surface of the base metal of the heated surface tube, and a creeping wave signal is output to the base metal of the heated surface tube. Figure 7 The arrowed dashed line from the signal emission point of the creeping wave probe points to the crack, which is the creeping wave signal, so that the creeping wave signal can be transmitted along the surface of the base metal of the heated surface tube to the position where the base metal of the heated surface tube and the weld are attached, thereby realizing the crack detection of the position where the base metal of the heated surface tube and the weld are attached. It can be understood that, in order to ensure good coupling of the creeping wave probe, the curvature diameter of the wedge block in contact with the workpiece is the same as that of the workpiece to be detected.

[0075] Further, the refraction angle of the ultrasonic wave signal output by the creeping wave probe in the base metal of the heated surface tube is equal to 90 degrees, and in actual application, the angle of the longitudinal wave signal output by the wafer inside the creeping wave probe can be set in combination with the longitudinal wave speed in the creeping wave probe and the transverse wave speed and longitudinal wave speed of the base metal of the heated surface tube, so that the ultrasonic wave signal input into the base metal of the heated surface tube can form a creeping wave signal. In this embodiment, details are not listed.

[0076] In step S12, the cracks on the outer wall of the base metal of the heated surface tube with the roof penetrating sleeve are detected according to the creeping wave reflection signal received by the creeping wave probe.

[0077] Specifically, when a crack exists between the abutting position of the tube base material and the weld of the heated surface tube, the depth direction of the crack is generally along the normal direction of the surface of the tube base material, which is approximately perpendicular to the transmission direction of the creeping wave signal. When the creeping wave signal reaches the position of the crack, the creeping wave signal will be reflected by the crack, thereby forming a creeping wave reflection signal. The dashed arrow pointing from the crack to the creeping wave probe is the creeping wave reflection signal. The creeping wave reflection signal can be transmitted in the reverse direction along the path of the creeping wave signal, and then be received by the creeping wave probe. The distance between the creeping wave probe and the crack can be determined based on the time difference between the transmission of the creeping wave signal and the reception of the creeping wave reflection signal.

[0078] In summary, the application utilizes the creeping wave probe to output the creeping wave signal along the surface direction of the tube base material of the heated surface tube, so that the creeping wave signal can detect the crack at the position where the tube base material surface and the weld are welded to each other, ensuring the effectiveness of the crack detection result of the tube base material surface of the heated surface tube, and facilitating the normal operation of the boiler system in the power plant.

[0079] Based on the above embodiment, the method for detecting the outer wall crack of the heated surface tube base material with the roof-penetrating sleeve based on the creeping wave reflection signal received by the creeping wave probe can further include:

[0080] Recording the reception time of the creeping wave reflection signal, and calculating the detection time difference between the reception time and the transmission time of the creeping wave signal;

[0081] Determining whether the outer wall of the heated surface tube base material has a crack and the crack position information based on the detection time difference and the reference time difference;

[0082] Determining the crack depth information of the outer wall crack of the heated surface tube base material based on the amplitude difference between the amplitude of the creeping wave reflection signal and the reference amplitude.

[0083] As described above, the detection time difference between the transmission time of the creeping wave signal and the reception time of the creeping wave reflection signal reflects whether the outer wall of the heated surface tube base material has a crack and the crack position information; and the amplitude of the creeping wave reflection signal reflects the crack depth information of the outer wall crack of the heated surface tube base material. Therefore, the creeping wave probe can be used for simulation testing on a comparison test piece in advance, so as to obtain the correlation between the detection time difference and the crack position, and set the reference time difference and the reference amplitude based on the correlation.

[0084] It should be noted that, when detecting the crack position information in the crack information of the heat surface tube base material, only the crack condition of the region where the heat surface tube base material and the weld are welded to each other needs to be determined. Obviously, if there is a crack in the region, the distance between the crack and the creep wave probe is obviously within a certain distance range. Correspondingly, the time difference between the emission time of the creep wave signal and the reception time of the creep wave reflection signal should also be within a certain time interval. Therefore, a reference time interval corresponding to a reference time difference can be set. The maximum reference time difference of the time interval is the time difference corresponding to the case that the crack exists at the position point farthest from the creep wave probe at the position where the heat surface tube base material and the weld are welded to each other, and the minimum reference time difference of the time interval is the time difference corresponding to the case that the crack exists at the position point closest to the creep wave probe at the position where the heat surface tube base material and the weld are welded to each other.

[0085] In the method, the creep wave probe is attached to the contrast test piece to perform crack detection simulation, and the contrast test piece is provided with a plurality of wire cutting grooves for simulating cracks in the outer wall of the heat surface tube base material. The standard signal gain, the reference time difference, and the reference amplitude of the crack detection of the outer wall of the heat surface tube base material can be determined according to the crack detection results of the contrast test piece.

[0086] Specifically, the method of attaching the creep wave probe to the contrast test piece to perform crack detection simulation includes:

[0087] determining a movement test range of the creep wave probe on the contrast test piece; wherein the movement test range includes a maximum distance Lmax and a minimum distance l+k1 of the creep wave probe from the wire cutting groove, and a maximum distance Lmax-l-k1 of the wire cutting groove from a side fusion line of the wire cutting groove; in the process of movement of the probe, the creep wave signal is sent to the contrast test piece through the standard signal gain; the reception time and the amplitude of the creep wave reflection signal are recorded, and the detection time difference between the reception time and the emission time of the creep wave signal is calculated; the amplitude of the creep wave reflection signal is taken as the reference amplitude, the detection time difference is taken as the reference time difference, and a corresponding defect detection curve is generated. When the creep wave signal is sent to the heat surface tube base material, the creep wave signal can be sent to the heat surface tube base material according to the defect detection curve. It can be understood that, in other embodiments, the reference time difference can also be the mean square value of the detection time difference of multiple measurements, and the reference amplitude can be the mean square value of the amplitude of multiple measurements.

[0088] Further, the method of determining the movement test range of the creep wave probe on the contrast test piece includes:

[0089] According to the material of the contrast sample, the refraction angle, the transverse wave speed and the creeping wave speed of the creeping wave in the contrast sample are determined. According to the front distance l of the cutting groove from the front of the probe, the refraction angle and the transverse wave speed, the second time t2 when the once-reflected wave of the transverse wave scans the linear cutting groove is determined, and the first time t1 when the creeping wave propagates to the linear cutting groove is the ratio of the front distance l and the creeping wave speed; according to the first time t1 and the second time t2, the maximum distance Lmax of the creeping wave probe from the linear cutting groove is determined. According to the front distance l and the weld size K1 of the linear cutting groove, the minimum distance l+k1 of the creeping wave probe from the linear cutting groove is determined; according to the maximum distance Lmax and the minimum distance l+k1 of the creeping wave probe from the linear cutting groove, the maximum distance of the linear cutting groove from the side fusion line Lmax-l-k1 of the linear cutting groove is determined.

[0090] For example, in the actual detection process, cracks generally occur near the fusion line of the sealing weld between the top cover sleeve and the base metal (carbon steel or low alloy steel pipe) of the heated surface pipe, and the creeping wave decays quickly, so the front of the creeping wave probe cannot be too far away from the sealing weld during detection. When adjusting the instrument, use the A side 2mm linear cutting groove, which is 1mm (i.e. the edge of the linear cutting groove), 10mm, 20mm, and 30mm away from the fusion line.

[0091] According to the conditions for generating a creeping wave, the incident angle in the organic glass wedge is 27.5°, so the refraction angle of the refracted transverse wave in the contrast sample is about 33°, and the propagation forms of the creeping wave, the transverse wave and the head wave in the contrast sample are as shown in the following table. Figure 4

[0092] The creeping wave propagates parallel to the surface of the contrast sample, and the creeping wave speed is close to the longitudinal wave speed, about 0.9 times the longitudinal wave speed, which is 5920m / s, so the creeping wave speed is 5920*0.9≈5330m / s, the transverse wave speed is 3230m / s, the thickness of the contrast sample is T (unit: mm), the front of the probe is L mm, and the refraction angles of the refracted transverse wave and the head wave in the contrast sample are both about 33°. Assuming that the linear cutting groove a1 with a depth of 2mm and a width of 0.5mm is l (which is the minimum length of the distance from the probe front l at which the once-reflected wave of the refracted transverse wave can scan the linear cutting groove), when the once-reflected wave of the refracted transverse wave generated by the creeping wave probe scans the linear cutting groove, the distance from the probe incident point to the linear cutting groove is L0, L0=L1+l, as shown in the following table. Figure 5

[0093] ​​The time when the first reflected wave of the transverse wave just scans the wire cutting groove is: t2=L0 / (sin33°×3230)=2T / (cos33°×3230). At this time, the time when the creeping wave propagates to the wire cutting groove is: t1=L0 / 5330=2T×tg33° / 5330, where L0=L1+l.

[0094] Since the refracted shear wave generated by the climbing wave probe arrives at the wire cut groove earlier than the head wave, the time ratio of the first reflected wave of the refracted shear wave to the first reflected wave of the climbing wave to arrive at the wire cut groove is: t2 / t1==[2T / (cos33°×3230)] / (2T tg33° / 5330)≈3; Similarly, the time t2'=6T / (cos33°×3230) when the third reflected wave of the refracted shear wave generated by the climbing wave probe just scans the 2mm deep wire cut groove is at which time the time t1'=6T×tg33° / 5330 when the climbing wave arrives at the wire cut groove is at which time the time t2' / t1'≈3 and t1' / t1=3. Since t2 / t1≈3, the signal of the first reflected wave of the head wave generated by the probe at this time just scans the 2mm wire cut groove and will coincide with the climbing wave signal. This position is the maximum distance from the 2mm wire cut groove that the climbing wave probe can be free from interference from refracted transverse waves and head wave reflected signals, and the climbing wave reflected signal remains independent. Let it be Lmax.

[0095] As shown above, Lmax = 6T × tan33° = 3.9T. When the distance between the incident point of the creeping wave probe and the wire cut groove is less than Lmax, the creeping wave reflection signal of the wire cut groove can be effectively distinguished from the reflection signal of other waveforms of the wire cut groove generated by the probe.

[0096] In actual testing, such as Figure 6 As shown, the distance between the incident point of the climbing wave probe and the probe's leading edge is a certain length, i.e., the probe's leading edge *l*, which can be measured accurately. During the inspection of the heat-receiving surface tube base material under the sealing weld of the ceiling sleeve using climbing wave technology, the maximum distance *Lmax* from the probe's incident point to the wire cutting groove, and the minimum distance (i.e., the distance when the climbing wave probe just touches the weld) are *l+k1*. The maximum distance from the fusion line length on the heat-receiving surface of the sealing weld is *Lmax* - *l* - *k1*. Therefore, to avoid noise interference, a climbing wave probe with a short leading edge should be selected whenever possible.

[0097] Figure 7 This is a schematic diagram of the test of the comparative specimen in an embodiment of the present invention, wherein,

[0098] 1. The base material of the heated surface tube is made of carbon steel or low alloy steel (the specifications are the same as those of the inspected workpiece, and the material is the same as or similar to that of the inspected workpiece).

[0099] 2, 7: simulate the sealing weld of the penetration sleeve and the base metal of the heated surface tube, the size and dimension are the same as the angle weld of the workpiece (steel tube plus penetration sleeve, remove the penetration sleeve after the angle welding is completed);

[0100] 3, 8: a circumferential line cutting groove with a width of 0.5 mm and a depth of 0.5 mm, which is perpendicular to the axis of the steel tube and is 0.5 mm away from the fusion line of the weld;

[0101] 4, 9: a circumferential line cutting groove with a width of 0.5 mm and a depth of 1 mm, which is perpendicular to the axis of the steel tube and is 0.5 mm away from the fusion line of the weld;

[0102] 5, 10: a circumferential line cutting groove with a width of 0.5 mm and a depth of 2 mm, which is perpendicular to the axis of the steel tube and is 0.5 mm away from the fusion line of the weld;

[0103] 6, 11: a circumferential line cutting groove with a width of 0.5 mm and a depth of 5 mm, which is perpendicular to the axis of the steel tube and is 0.5 mm away from the fusion line of the weld;

[0104] 12, 13: a creeping wave probe, in order to ensure good coupling, the curvature diameter of the wedge block in contact with the workpiece is the same as that of the workpiece to be detected.

[0105] Note: one line cutting groove is processed every 90 degrees of rotation, 3-6 and 8-11 are line cutting grooves with different depths.

[0106] In actual application, the front edge l of the creeping wave probe and the size K1 of the penetration sleeve sealing weld can be measured first, Lmax (equal to 3.9T) is calculated according to the thickness of the heated surface tube of the detected part, then the maximum distance of the probe from the sealing weld is obtained by Lmax-l-K1, and the probe is placed on the comparison test piece, aligned with the 2 mm line cutting grooves at the A side and the lowermost end and the B side and the uppermost end, the creeping wave reflection signal is adjusted to 80% of the full screen wave height, a reference coin is made, and the gain is increased by 6 dB as the flaw detection sensitivity, so that the sealing weld of the heated surface with the penetration sleeve can be detected, if the reflection signal exceeds the flaw detection sensitivity, it is considered that a crack has occurred on the outer wall of the heated surface tube, and then the crack is repaired or replaced.

[0107] Because the intensity of the refracted shear wave is much smaller than that of the creeping wave, the once-reflected shear wave needs to be reflected by the inner wall of the heated surface tube, the inner wall of the heated surface tube is a convex interface, so the once-reflected shear wave is scattered on the inner wall, and its intensity is further weakened, therefore, in the actual detection process, if the size of the creeping wave probe front edge l and the size of the penetration sleeve sealing angle weld limit L≤Lmax, the comparison test piece comparison method can be used, for the same defect, the reflection signal of the creeping wave is much stronger than that of the refracted shear wave, combined with the position of the defect signal, the reflection signal can be judged, and the purpose of detecting the crack on the outer wall of the heated surface tube with the penetration sleeve can be achieved.

[0108] Figure 8It is a crack defect found in the process of detecting the low-temperature reheater penetration sleeve of a 300 MW unit by using the above detection method. After polishing, the penetration detection method is used for rechecking to confirm that the low-temperature reheater tube base material outer wall indeed has cracks.

[0109] The above boiler heating surface penetration sleeve fillet weld under base material crack detection method comprises the following steps: a creeping wave probe is attached to the heating surface tube base material with a penetration sleeve, and a creeping wave signal is sent to the heating surface tube base material; wherein the creeping wave probe is located on one side of the heating surface tube base material close to the weld; and the crack on the outer wall of the heating surface tube base material with the penetration sleeve is detected according to the creeping wave reflection signal received by the creeping wave probe. Compared with the prior art, the present application can ensure that the penetration sleeve weld crack is effectively detected, ensure the normal operation of the boiler, and meet the actual application requirements.

[0110] It should be understood that although each step in the above flowchart is displayed in sequence according to the direction of the arrow, these steps are not necessarily executed in the order indicated by the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other orders. Moreover, at least part of the steps in the above flowchart can include multiple sub-steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or sub-steps or stages of other steps.

[0111] Referring to Figure 9 The present application also provides a boiler heating surface penetration sleeve fillet weld under base material crack detection device, which comprises:

[0112] The signal sending module 21 is used for attaching a creeping wave probe to the heating surface tube base material with a penetration sleeve, and sending a creeping wave signal to the heating surface tube base material; wherein the creeping wave probe is located on one side of the heating surface tube base material close to the weld.

[0113] Before sending the creeping wave signal to the heating surface tube base material, the signal sending module 21 is also used for,

[0114] The creeping wave probe is attached to the comparative test piece for crack detection simulation; wherein the comparative test piece is provided with a plurality of wire cutting grooves for simulating the crack on the outer wall of the heating surface tube base material;

[0115] According to the crack detection result of the comparative test piece, the gain information of the heating surface tube base material outer wall crack detection is determined; wherein the gain information includes standard signal gain, reference time difference and reference amplitude.

[0116] The signal sending module is further configured to send the creep wave signal to the contrast test piece according to the standard signal gain, the reference time difference, and the reference amplitude.

[0117] The creep wave probe is attached to the contrast test piece to perform crack detection simulation, and the contrast test piece is provided with a plurality of linear cutting grooves for simulating the outer wall cracks of the parent material of the heated surface tube.

[0118] According to the crack detection results of the contrast test piece, gain information of the outer wall crack detection of the parent material of the heated surface tube is determined, and the gain information includes a standard signal gain, a reference time difference, and a reference amplitude.

[0119] The creep wave probe is attached to the contrast test piece to perform crack detection simulation, and the contrast test piece is provided with a plurality of linear cutting grooves for simulating the outer wall cracks of the parent material of the heated surface tube.

[0120] The moving test range of the creep wave probe on the contrast test piece is determined, and the moving test range includes a maximum distance and a minimum distance of the creep wave probe from the linear cutting groove, and a maximum distance of the linear cutting groove from the side fusion line of the linear cutting groove.

[0121] During the movement of the probe, the creep wave signal is sent to the contrast test piece through the standard signal gain.

[0122] The receiving time and amplitude of the creep wave reflection signal are recorded, and the detection time difference between the receiving time and the emission time of the creep wave signal is calculated.

[0123] The amplitude of the creep wave reflection signal is taken as the reference amplitude, the detection time difference is taken as the reference time difference, and a corresponding defect detection curve is generated.

[0124] The creep wave signal is sent to the parent material of the heated surface tube according to the defect detection curve.

[0125] The crack detection module 22 is configured to detect the outer wall cracks of the parent material of the heated surface tube with the roof penetrating sleeve according to the creep wave reflection signal received by the creep wave probe.

[0126] The crack detection module is specifically configured to,

[0127] The receiving time of the creep wave reflection signal is recorded, and the detection time difference between the receiving time and the emission time of the creep wave signal is calculated.

[0128] According to the detection time difference and the reference time difference, it is determined whether there is a crack in the outer wall of the parent material of the heated surface tube and crack position information.

[0129] According to the amplitude difference between the amplitude of the creep wave reflection signal and the reference amplitude, the crack depth information of the outer wall crack of the parent material of the heated surface tube is determined.

[0130] The boiler heating surface penetrates the ceiling sleeve corner weld under the parent material crack detection device provided by the embodiment of the present application, a creeping wave probe is attached to the heating surface pipe parent material with a ceiling sleeve, and a creeping wave signal is sent to the heating surface pipe parent material; wherein the creeping wave probe is located on one side of the heating surface pipe parent material close to the weld; according to the creeping wave reflection signal received by the creeping wave probe, the outer wall crack of the heating surface pipe parent material with the ceiling sleeve is detected. Compared with the prior art, the present application can ensure that the ceiling sleeve weld crack is effectively detected, ensure the normal operation of the boiler, and meet the actual application requirements.

[0131] The embodiment of the present application also provides a computer readable storage medium, which comprises a stored computer program; wherein the computer program controls a device where the computer readable storage medium is located to execute the boiler heating surface penetrates the ceiling sleeve corner weld under the parent material crack detection method as described above when running.

[0132] The embodiment of the present application also provides a terminal device, as shown in Figure 10 The terminal device comprises a processor 10, a memory 20, and a computer program stored in the memory 20 and configured to be executed by the processor 10, and the processor 10 realizes the boiler heating surface penetrates the ceiling sleeve corner weld under the parent material crack detection method as described above when executing the computer program.

[0133] Preferably, the computer program can be divided into one or more modules / units (such as computer program 1, computer program 2, and the like), which are stored in the memory 20 and executed by the processor 10 to complete the present application. The one or more modules / units can be a series of computer program instruction segments capable of completing a specific function, which are used to describe the execution process of the computer program in the terminal device.

[0134] The processor 10 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 10 can also be any conventional processor. The processor 10 is a control center of the terminal device, and connects various parts of the terminal device through various interfaces and lines.

[0135] The memory 20 mainly includes a program storage area and a data storage area. The program storage area can store an operating system, at least one application required by a function, etc., and the data storage area can store related data, etc. In addition, the memory 20 can be a high-speed random access memory, and can also be a non-volatile memory such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., or the memory 20 can also be other volatile solid-state storage devices.

[0136] It should be noted that the terminal device described above can include, but is not limited to, a processor and a memory, and those skilled in the art can understand that, Figure 10 The structural block diagram is only an example of the terminal device, and does not constitute a limitation on the terminal device, and can include more or fewer components than those shown, or combine certain components, or different components.

[0137] In summary, the boiler heating surface pipe with a top cover sleeve corner weld under the base material crack detection method and device provided by the present application first adheres the creeping wave probe to the heating surface pipe base material with a top cover sleeve, and sends a creeping wave signal to the heating surface pipe base material. Wherein, the creeping wave probe is located on one side of the heating surface pipe base material close to the weld; according to the creeping wave reflection signal received by the creeping wave probe, the outer wall crack of the heating surface pipe base material with a top cover sleeve is detected. Compared with the prior art, the present application can ensure effective detection of the top cover sleeve weld crack, ensure the normal operation of the boiler, and meet the actual application requirements.

[0138] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A method for detecting a lower base material crack of a roof penetration corner weld of a boiler heating surface, characterized by, The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: Before sending the creeping wave signal to the heat surface pipe base material with the roof penetrating sleeve, the method further comprises: The method comprises the following steps: According to the crack detection result of the contrast test piece, the gain information of the heat surface pipe base material outer wall crack detection is determined; wherein the gain information includes standard signal gain, reference time difference and reference amplitude; The method for detecting the outer wall crack of the heat surface pipe base material with the roof penetrating sleeve according to the creeping wave reflection signal received by the creeping wave probe comprises: The receiving time of the creeping wave reflection signal is recorded, and the detection time difference between the receiving time and the creeping wave signal emission time is calculated; According to the detection time difference and the reference time difference, it is determined whether there is a crack on the outer wall of the heat surface pipe base material and the crack position information; According to the amplitude difference between the amplitude of the creeping wave reflection signal and the reference amplitude, the crack depth information of the outer wall crack of the heat surface pipe base material is determined; The method for detecting the crack of the contrast test piece by attaching the creeping wave probe comprises: The moving test range of the creeping wave probe on the contrast test piece is determined; wherein the moving test range includes the maximum distance and the minimum distance from the line cutting groove to the incident point of the creeping wave probe, and the maximum distance from the line cutting groove to the side fusion line of the line cutting groove; During the movement of the creeping wave probe, the creeping wave signal is sent to the contrast test piece through the standard signal gain; The receiving time and amplitude of the creeping wave reflection signal are recorded, and the detection time difference between the receiving time and the creeping wave signal emission time is calculated; The amplitude of the creeping wave reflection signal is taken as the reference amplitude, the detection time difference is taken as the reference time difference, and the corresponding defect detection curve is generated; The method for determining the moving test range of the creeping wave probe on the contrast test piece comprises: According to the material of the contrast test piece, the refraction angle of the refracted transverse wave and head wave of the creeping wave signal in the contrast test piece, the transverse wave speed and the creeping wave speed are determined; According to the distance from the incident point of the creeping wave probe to the line cutting groove, the refraction angle and the transverse wave speed when the first reflection wave of the refracted transverse wave generated by the creeping wave probe just scans the line cutting groove, the second time when the first reflection wave of the transverse wave just scans the line cutting groove is determined, and the first time when the creeping wave propagates to the line cutting groove is the ratio of the distance from the incident point of the creeping wave probe to the line cutting groove to the creeping wave speed when the first reflection wave of the refracted transverse wave generated by the creeping wave probe just scans the line cutting groove; According to the first time and the second time, the maximum distance from the incident point of the creeping wave probe to the line cutting groove is determined; According to the distance between the incident point of the creeping wave probe and the front edge of the creeping wave probe and the size of the weld toe of the line-cutting groove, the minimum distance between the incident point of the creeping wave probe and the line-cutting groove is determined; According to the maximum distance and the minimum distance between the incident point of the creeping wave probe and the line-cutting groove, the maximum distance of the line-cutting groove from the side fusion line of the line-cutting groove is determined.

2. A device for detecting a lower base material crack of a roof penetration corner weld of a boiler heating surface, characterized by, The device comprises: The signal sending module is configured to fit the creeping wave probe to the heated surface pipe base material with the top penetrating sleeve and send a creeping wave signal to the heated surface pipe base material, wherein the creeping wave probe is located on the side of the heated surface pipe base material close to the weld and sends the creeping wave signal to the heated surface pipe base material according to a defect detection curve; The crack detection module is configured to detect the outer wall crack of the heated surface pipe base material with the top penetrating sleeve according to the creeping wave reflection signal received by the creeping wave probe; The signal sending module is further configured to: fit the creeping wave probe to the comparative test piece for crack detection simulation, wherein the comparative test piece is provided with a plurality of line-cutting grooves for simulating the outer wall crack of the heated surface pipe base material; determine the gain information of the outer wall crack detection of the heated surface pipe base material according to the crack detection result of the comparative test piece, wherein the gain information comprises a standard signal gain, a reference time difference and a reference amplitude; The crack detection module is specifically configured to: record the receiving time of the creeping wave reflection signal and calculate the detection time difference between the receiving time and the emission time of the creeping wave signal; determine whether there is a crack in the outer wall of the heated surface pipe base material and crack position information according to the detection time difference and the reference time difference; determine the crack depth information of the outer wall crack of the heated surface pipe base material according to the amplitude difference between the amplitude of the creeping wave reflection signal and the reference amplitude; The method for fitting the creeping wave probe to the comparative test piece for crack detection simulation comprises: determine the moving test range of the creeping wave probe on the comparative test piece, wherein the moving test range comprises the maximum distance and the minimum distance between the incident point of the creeping wave probe and the line-cutting groove, and the maximum distance of the line-cutting groove from the side fusion line of the line-cutting groove; send the creeping wave signal to the comparative test piece through the standard signal gain during the movement of the creeping wave probe; record the receiving time and amplitude of the creeping wave reflection signal and calculate the detection time difference between the receiving time and the emission time of the creeping wave signal; take the amplitude of the creeping wave reflection signal as the reference amplitude, take the detection time difference as the reference time difference, and generate a corresponding defect detection curve; The method for determining the moving test range of the creeping wave probe on the comparative test piece comprises: determine the refraction angle of refracted transverse wave and head wave, the transverse wave speed and the creeping wave speed of the creeping wave signal in the comparative test piece according to the material of the comparative test piece; The second time when the first reflection wave of the refracted transverse wave generated by the creeping wave probe just scans the linear cutting groove is determined according to the distance from the incident point of the creeping wave probe to the linear cutting groove, the refraction angle and the transverse wave speed when the first reflection wave of the refracted transverse wave generated by the creeping wave probe just scans the linear cutting groove, and the first time when the creeping wave propagates to the linear cutting groove is the ratio of the distance from the incident point of the creeping wave probe to the linear cutting groove to the creeping wave speed when the first reflection wave of the refracted transverse wave generated by the creeping wave probe just scans the linear cutting groove; The maximum distance from the incident point of the creeping wave probe to the linear cutting groove is determined according to the first time and the second time; The minimum distance from the incident point of the creeping wave probe to the linear cutting groove is determined according to the distance from the incident point of the creeping wave probe to the front edge of the creeping wave probe and the weld leg size of the linear cutting groove; The side fusion line length of the linear cutting groove is determined according to the maximum distance and the minimum distance from the incident point of the creeping wave probe to the linear cutting groove.

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