Ultra-thick-wall steel pipe ultrasonic flaw detection device

Abstract

The present invention provides an ultrasonic flaw detection device for ultra-thick wall steel pipes, comprising a probe and a swing frame. Among them, the probe is installed on the swing frame, and when the swing frame drops onto the steel pipe, the probe can be in contact with the steel pipe; the probe includes a number of wafers, each wafer is connected with an ultrasonic signal transmission line, and each wafer can emit ultrasonic waves into the steel pipe. The refracted longitudinal waves of the ultrasonic waves emitted by each wafer entering the steel pipe can be tangent to the inner wall of the steel pipe, so as to realize flaw detection of the steel pipe. This device adopts a probe with a two-way layout and a multi-channel combination, and uses the ultrasonic refracted longitudinal wave L to detect the inner wall defects of the steel pipe, realizing the simultaneous detection of the inner and outer wall defects of steel pipes with a wall thickness to outer diameter ratio t / D≥0.26, especially suitable for the case of 0.26≤t / D (wall thickness to outer diameter ratio)≤0.311.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic flaw detection, and particularly relates to an ultrasonic flaw detection device for ultra-thick-walled steel pipes. Background Art

[0002] Existing saddle-type ultrasonic flaw detection equipment all rotates the steel pipe in place and moves the detection trolley parallelly, driving the ultrasonic detection probe unit to move from one end of the steel pipe to the other end to achieve ultrasonic flaw detection of the inner and outer walls of the steel pipe. When performing ultrasonic flaw detection on a steel pipe, in order to ensure that inner wall defects of the steel pipe are not missed, it is necessary to make the refracted shear wave S generated by the incident ultrasonic wave entering the steel pipe tangent to the inner wall of the steel pipe. Existing ultrasonic flaw detection equipment can only detect inner and outer wall defects of steel pipes with a wall thickness to outer diameter ratio of t / D < 0.26.

[0003] When ultrasonic waves are obliquely incident on the steel interface, refraction occurs, generating shear waves and longitudinal waves. When the incident angle is between 1° and 27°, there are both longitudinal waves and shear waves in the steel pipe. When the incident angle is greater than 27°, only shear waves exist in the steel pipe, that is, 27° is the first critical angle of the organic glass-steel interface. When the inclination angle continues to increase and reaches 54°, the shear waves in the steel disappear, and 54° is called the second critical angle. The condition for generating shear waves at the organic glass-steel interface is that the incident angle is between 27° and 54°. For ultra-thick-walled steel pipes with t / D ≥ 0.26, inner wall defects of the steel pipe cannot be detected. Therefore, it is only possible to consider detecting inner wall defects of ultra-thick steel pipes within the first critical angle. Then, within the first critical angle, the detection sensitivity of shear waves is very low, and inner wall defects of the steel pipe cannot be adjusted at all. Only the refracted longitudinal waves can be adjusted to be tangent to the inner wall of the steel pipe, so that the detection effect of inner wall defects is good. However, since there are still shear waves in the steel pipe, and the angle of the shear waves is very small, there is a certain reflection on the inner wall of the steel pipe, which will have a certain impact on the signal-to-noise ratio of the longitudinal waves and affect the detection of inner wall defects of ultra-thick steel pipes.

[0004] Due to the development of steel pipe production technology, the wall thickness to outer diameter ratio t / D ≥ 0.26 of the produced steel pipes is common. When the wall thickness to outer diameter ratio t / D ≥ 0.26 of the steel pipe, the refracted shear wave S of the existing probe cannot detect the inner wall of the steel pipe, resulting in missed detection of inner wall defects of the steel pipe, as Figure 1 shown. The inner diameter of the steel pipe is φ63.5, the outer diameter of the steel pipe is φ165.1, the wall thickness of the steel pipe is 50.8, the wall thickness to outer diameter ratio of the steel pipe is 0.31, the incident angle of the ultrasonic wave is 30°, the ultrasonic wave propagates along the S direction in the steel pipe, and the refracted shear wave S generated by the ultrasonic wave entering the steel pipe is not tangent to the inner wall of the steel pipe. Therefore, inner wall defects of the steel pipe cannot be detected. And the incident angle of the existing equipment is not adjustable, and only probes with different angles can be replaced according to different wall thicknesses and outer diameter ratios.

[0005] In view of the above reasons, an ultrasonic flaw detection device for ultra-thick wall steel pipes is required to simultaneously detect the defects on the inner and outer walls of the steel pipes. Summary of the Invention

[0006] The object of the present invention is to provide an ultrasonic flaw detection device for ultra-thick wall steel pipes. The device adopts a probe with a two-way layout and multi-channel combination, and uses ultrasonic refracted longitudinal wave L to detect the defects on the inner wall of the steel pipe, realizing the simultaneous detection of the defects on the inner and outer walls of steel pipes with a wall thickness to outer diameter ratio t / D≥0.26, and is particularly suitable for the case of 0.26≤t / D (wall thickness to outer diameter ratio)≤0.311.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] An ultrasonic flaw detection device for ultra-thick wall steel pipes includes a probe and a swing frame. Among them, the probe is installed on the swing frame. When the swing frame drops onto the steel pipe, the probe can be in contact with the steel pipe; the probe includes a number of wafers, each wafer is connected with an ultrasonic signal transmission line, and each wafer can emit ultrasonic waves into the steel pipe. The ultrasonic waves refracted into the steel pipe emitted by each wafer can be tangent to the inner wall of the steel pipe, realizing flaw detection of the steel pipe.

[0009] Further, in the above ultrasonic flaw detection device for ultra-thick wall steel pipes, the probe further includes a housing and plexiglass. The housing is a box structure with an open bottom. The housing includes a top plate and four side plates. The four sides of the plexiglass are respectively connected to the bottoms of the four side plates. A number of wafers are pasted on the plexiglass. The front surface of the wafer faces the steel pipe, and a damping block is cast on the back surface of the wafer. The damping block is located inside the housing; during operation, the lower surface of the plexiglass contacts the steel pipe.

[0010] Further, in the above ultrasonic flaw detection device for ultra-thick wall steel pipes, the housing is machined from aluminum metal; preferably, the damping block is made of a mixture of epoxy resin, tungsten powder and curing agent; preferably, the mass percentages of the epoxy resin, the tungsten powder and the curing agent mixed to form the damping block are 65%, 25%, and 10% respectively.

[0011] Further, in the above ultrasonic flaw detection device for ultra-thick-walled steel pipes, two rows of the wafers are arranged along the length direction of the plexiglass, and 4 wafers are evenly arranged in each row. The two rows of wafers are both inclined. The incident angle of ultrasonic waves emitted into the steel pipe by one row of the wafers is 8°, and the incident angle of ultrasonic waves emitted into the steel pipe by the other row of the wafers is 172°. Preferably, two rows of grooves are provided on the upper surface of the plexiglass, and the bottoms of the two rows of grooves are respectively arranged according to the inclination angles of the two rows of wafers, and the two rows of wafers are respectively pasted in the two rows of grooves.

[0012] Further, in the above ultrasonic flaw detection device for ultra-thick-walled steel pipes, tungsten carbide wear-resistant blocks are inlaid on the lower surface of the plexiglass. There are multiple tungsten carbide wear-resistant blocks, and the multiple tungsten carbide wear-resistant blocks are evenly distributed on the outer periphery of the two rows of wafers.

[0013] Further, in the above ultrasonic flaw detection device for ultra-thick-walled steel pipes, the lower surface of the plexiglass is machined according to the outer diameter curved surface of the steel pipe. Preferably, the wall thickness and outer diameter ratio t / D of the ultra-thick-walled steel pipe ≥ 0.26. Preferably, the ratio of the wall thickness to the outer diameter of the ultra-thick-walled steel pipe is 0.26 ≤ t / D ≤ 0.311.

[0014] Further, in the above ultrasonic flaw detection device for ultra-thick-walled steel pipes, a number of water injection holes are provided on the outer shell, and the coupling water flows through the water injection holes to the contact surface between the plexiglass and the steel pipe, and a water film is formed on the contact surface between the plexiglass and the steel pipe to achieve stable coupling of ultrasonic waves with the steel pipe.

[0015] Further, in the above ultrasonic flaw detection device for ultra-thick-walled steel pipes, a through hole is opened in the middle of the swing frame, and the probe can enter the through hole. Preferably, a balance plate is further included, and the balance plate is placed above the swing frame, and the probe is fixed to the balance plate with screws.

[0016] Further, in the above ultrasonic flaw detection device for ultra-thick-walled steel pipes, a number of support columns are further included. A number of first blind holes are opened outside the through hole, and a number of second blind holes are opened on the balance plate. The positions of one first blind hole and one second blind hole correspond to each other. One support column passes through one second blind hole and then enters one first blind hole, and a floating pressure spring is sleeved outside the support column and at a position above the balance plate.

[0017] Furthermore, in the above ultrasonic flaw detection device for ultra-thick wall steel pipes, both ends of the swing frame are respectively connected with a plurality of support plates, and each support plate is provided with a universal tracking ball. When the swing frame drops onto the steel pipe, the bottom end of the universal tracking ball contacts the surface of the steel pipe and can roll on the surface of the steel pipe, achieving good tracking with the steel pipe; preferably, 4 universal tracking balls are provided.

[0018] Analysis shows that the present invention discloses an ultrasonic flaw detection device for ultra-thick wall steel pipes. Using this device, internal and external wall defects of steel pipes with a wall thickness to outer diameter ratio t / D ≥ 0.26 can be simultaneously detected. The device includes a probe and a swing frame. The probe is installed on the swing frame. The probe is composed of 8 wafers and is arranged bidirectionally and in a multi-channel combination (multiple wafer combinations). The 8 wafers are divided into 2 groups. The 4 wafers on the left are arranged at 8°, and the 4 on the right are arranged at 172°, ensuring the bidirectional and bilateral ultrasonic detection of the steel pipe. Tungsten carbide wear-resistant blocks are inlaid on the bottom arc surface of the plexiglass, greatly increasing the service life of the probe. A number of universal tracking balls are installed on the swing frame. By rolling the universal tracking balls on the surface of the steel pipe, the ultrasonic incident angle is ensured to be relatively stable, so that the refraction angle of the refracted longitudinal wave of the ultrasonic wave entering the steel pipe remains unchanged, realizing the simultaneous detection of internal and external wall defects of steel pipes with a wall thickness to outer diameter ratio t / D ≥ 0.26, especially suitable for the case where 0.26 ≤ t / D ≤ 0.311. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The specification drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0020] Figure 1 It is a schematic diagram of the ultrasonic refracted shear wave of a conventional probe in the prior art.

[0021] Figure 2 It is a schematic diagram of the ultrasonic refracted longitudinal wave of the probe in an embodiment of the present invention.

[0022] Figure 3 It is a front view structural schematic diagram of the probe for detecting a steel pipe in an embodiment of the present invention.

[0023] Figure 4 It is a structural schematic diagram of an embodiment of the present invention.

[0024] Figure 5 It is a schematic diagram of the bidirectional and bilateral ultrasonic refracted longitudinal wave of the probe in an embodiment of the present invention.

[0025] Figure 6 It is a structural schematic diagram of the swing frame in an embodiment of the present invention.

[0026] Figure 7 Schematic structural diagram of the assembly of the support plate and the universal tracking ball in an embodiment of the present invention.

[0027] Figure 8 Top view structural schematic diagram of the wafer and the damping block arranged on the plexiglass in an embodiment of the present invention.

[0028] Explanation of reference numerals: 1 steel pipe; 2 probe; 21 wafer; 22 ultrasonic signal transmission line; 23 housing; 24 plexiglass; 25 damping block; 26 tungsten steel wear-resistant block; 27 water injection hole; 3 swing frame; 31 support column; 32 floating pressure spring; 33 balance plate; 34 support plate; 341 horizontal plate; 342 inclined plate; 35 screw; 36 through hole; 37 bolt; 4 universal tracking ball; 5 refracted longitudinal wave. Detailed implementation manners

[0029] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present invention rather than limitation of the present invention. In fact, those skilled in the art will clearly understand that modifications and variations can be made to the present invention without departing from the scope or spirit of the present invention. For example, features shown or described as part of one embodiment can be used in another embodiment to yield yet another embodiment. Therefore, it is desirable that the present invention includes such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0030] In the description of the present invention, the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. The terms "connected", "connected to", and "disposed" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component; it can be a wired connection, a radio connection, or a wireless communication signal connection. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0031] One or more examples of the present invention are shown in the accompanying drawings. The detailed description uses numerical and alphabetical labels to refer to features in the drawings. Similar or like labels in the drawings and the description have been used to refer to similar or like parts of the present invention. As used herein, terms such as "first", "second", and "third" can be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of individual components.

[0032] As Figures 1 to 8As shown, according to an embodiment of the present invention, an ultrasonic flaw detection device for ultra-thick-walled steel pipes is provided. Using this device, the internal and external wall defects of steel pipes 1 with a wall thickness to outer diameter ratio t / D≥0.26 can be detected simultaneously. The device includes a probe 2 and a swing frame 3. Among them, the probe 2 is installed on the swing frame 3. When the swing frame 3 drops onto the steel pipe 1, the probe 2 can be in contact with the steel pipe 1; the probe 2 includes a number of wafers 21, and each wafer 21 is connected to an ultrasonic signal transmission line 22. The ultrasonic signal transmission line 22 is connected to the wafer 21 by welding. Each wafer 21 can emit ultrasonic waves into the steel pipe 1. After the ultrasonic waves enter the steel pipe 1, refracted longitudinal waves 5 are formed, as Figure 5 shown, the refracted longitudinal waves 5 of the ultrasonic waves emitted by each wafer 21 entering the steel pipe 1 can be tangent to the inner wall of the steel pipe 1, realizing the flaw detection of the inner and outer walls of the steel pipe 1 simultaneously. During operation, the swing frame 3 drops onto the steel pipe 1 to make the probe 2 in contact with the steel pipe 1. The steel pipe 1 rotates in place, and the device is moved so that the device moves from one end of the steel pipe 1 to the other end. During the movement of the device, ultrasonic waves are emitted into the steel pipe 1 through the wafers 21, realizing the flaw detection of the inner and outer walls of the steel pipe 1 simultaneously.

[0033] Furthermore, as Figure 3 shown, the probe 2 further includes a housing 23 and plexiglass 24. The housing 23 is a box structure with an open bottom. The housing 23 includes a top plate and four side plates. The four sides of the plexiglass 24 are respectively connected to the bottoms of the four side plates. A number of wafers 21 are pasted on the plexiglass 24. The front side of the wafer 21 faces the steel pipe 1, and a damping block 25 is cast on the back side of the wafer 21. The damping block 25 is located inside the housing 23; during operation, the lower surface of the plexiglass 24 contacts the steel pipe 1. Figure 3 The front view shows 8 wafers, among which 4 wafers (in a row) are inclined at 8° (not shown) so that the incident angle of the ultrasonic waves emitted by the wafers into the steel pipe is 8°, and the other 4 wafers (in a row) are inclined at 172° (not shown) so that the incident angle of the ultrasonic waves emitted by the wafers into the steel pipe is 172°.

[0034] Furthermore, the housing 23 is machined from low-cost metal aluminum; the damping block 25 is made of a mixture of epoxy resin, tungsten powder and curing agent; the mass percentages of the epoxy resin, tungsten powder and curing agent mixed to form the damping block 25 are 65%, 25%, and 10% respectively. Such a setting can make the damping block 25 play a damping role in the vibration of the wafer 21 to make the vibration of the wafer 21 stop as soon as possible, thereby reducing the pulse width of the ultrasonic waves. The damping block 25 can absorb the ultrasonic waves emitted by the wafer 21 to the back side of the wafer 21. The damping block 25 can play a fixing role for the wafer 21.

[0035] Furthermore, as Figure 4 and Figure 8As shown in the figure, there are two rows of wafers 21 arranged along the length direction of the plexiglass 24. There are 4 wafers 21 evenly arranged in each row. The two rows of wafers 21 are both inclined. The incident angle of the ultrasonic wave emitted by one row of wafers 21 into the steel pipe 1 is 8°, and the incident angle of the ultrasonic wave emitted by the other row of wafers 21 into the steel pipe 1 is 172°. The incident point of each wafer 21 emitting ultrasonic waves into the steel pipe 1 is the highest point of the vertical cross-section of the steel pipe 1. Calculate the maximum ratio of the wall thickness to the outer diameter of the steel pipe 1, t / D = 0.311. When the incident angles of the ultrasonic waves are arranged at 8° and 172° respectively, the refracted longitudinal wave 5 entering the steel pipe 1 can be tangent to the inner wall of the steel pipe 1. Therefore, when detecting the steel pipe 1 with the maximum wall thickness (the ratio of the wall thickness to the outer diameter is t / D = 0.311), the ultrasonic wave can detect the defects on the inner wall of the steel pipe 1. During the propagation of the ultrasonic wave, the sound beam is diffused (for example Figure 1 , Figure 2 , Figure 5 only the main sound line of the ultrasonic wave is drawn in the figure), and it has a certain coverage range, making this device particularly suitable for detecting steel pipes with a ratio of wall thickness to outer diameter between 0.26 ≤ t / D ≤ 0.311. Preferably, there are two rows of grooves on the upper surface of the plexiglass 24. The bottoms of the two rows of grooves are set according to the inclination angles of the two rows of wafers 21 respectively. The two rows of wafers 21 are respectively pasted in the two rows of grooves. Such a setting can ensure that the incident angle of the ultrasonic wave does not change. In an embodiment of the present invention, as Figure 8 shown, the probe 2 is composed of 8 wafers 21 and is arranged bidirectionally. The 8 wafers 21 are divided into 2 groups. The 4 wafers 21 on the left are located in the left half of the plexiglass 24 and on one side of the center line of the length direction of the upper surface of the plexiglass 24. The 4 wafers 21 on the right are located in the right half of the plexiglass 24 and on the other side of the center line of the length direction of the upper surface of the plexiglass 24. The 8 wafers 21 are evenly arranged, and the 4 wafers 21 on the left are arranged at 8°. As Figure 5 shown, the refracted longitudinal wave 5 of the ultrasonic wave entering the steel pipe propagates in the right Y direction of the steel pipe 1, and the 4 wafers 21 on the right are arranged at 172°. The refracted longitudinal wave 5 of the ultrasonic wave entering the steel pipe propagates in the left Z direction of the steel pipe 1, ensuring the two-way and bilateral ultrasonic detection of the steel pipe 1. As Figure 2 shown, the inner diameter of the steel pipe 1 is φ63.5, the outer diameter of the steel pipe 1 is φ165.1, the wall thickness of the steel pipe 1 is 50.8, the ratio of the wall thickness to the outer diameter of the steel pipe 1 is 0.31, the incident angle a of the ultrasonic wave of the wafer 21 on the left is 8°, and the refracted longitudinal wave 5 of the ultrasonic wave propagates in the L direction in the steel pipe 1. The refracted longitudinal wave 5 propagating in the L direction is tangent to the inner wall of the steel pipe 1. Therefore, the defects on the inner wall of the steel pipe 1 can be detected.

[0036] Furthermore, as Figure 3As shown in the figure, tungsten steel wear-resistant blocks 26 processed by wire cutting are inlaid on the lower surface of the plexiglass 24 and firmly pasted with metal glue. There are multiple tungsten steel wear-resistant blocks 26, and the multiple tungsten steel wear-resistant blocks 26 are distributed on the outer periphery of two rows of wafers. One tungsten steel wear-resistant block 26 is respectively arranged at both ends of the two rows of wafers 21, and multiple tungsten steel wear-resistant blocks 26 are respectively arranged on both sides of the two rows of wafers 21 and arranged parallel to the length direction of the plexiglass 24. Since tungsten steel is relatively hard, processing the tungsten steel wear-resistant blocks 26 by wire cutting can improve the dimensional accuracy. Since the tungsten steel wear-resistant blocks 26 are inlaid on the bottom arc surface of the plexiglass 24, during the friction process of the relative movement between the probe 2 and the steel pipe 1, the tungsten steel wear-resistant blocks 26 provide protection, greatly increasing the service life of the probe 2.

[0037] Furthermore, the lower surface of the plexiglass 24 is processed according to the outer diameter curved surface of the steel pipe 1. Such a setting can achieve good tracking between the probe 2 and the steel pipe 1.

[0038] Furthermore, as Figure 4 shown in the figure, a number of water injection holes 27 are provided on the outer shell 23. The coupling water flows to the contact surface between the plexiglass 24 and the steel pipe 1 through the water injection holes 27, forming a water film on the contact surface between the plexiglass 24 and the steel pipe 1, realizing stable coupling of ultrasonic waves with the steel pipe 1. In an embodiment of the present invention, there are 4 water injection holes 27, and the coupling water uniformly flows into the detection window (the contact surface between the plexiglass 24 and the steel pipe 1) through the water injection holes 27, forming a water film between the probe 2 and the steel pipe 1 to realize stable coupling of ultrasonic waves with the steel pipe 1. Injecting coupling water between the probe 2 and the steel pipe 1 can isolate air, enable good contact between the probe 2 and the object surface, reduce the friction between the probe 2 and the steel pipe 1, and keep the movement of the probe 2 smooth. Injecting coupling water between the probe 2 and the steel pipe 1 facilitates the entry of ultrasonic waves into the steel pipe 1, fills the tiny gaps between the contact surfaces of the probe 2 and the steel pipe 1, and does not allow the trace air in these gaps to affect the penetration of ultrasonic waves.

[0039] Furthermore, as Figure 6 shown in the figure, a through hole 36 is opened in the middle of the swing frame 3, and the probe 2 can enter the through hole 36. The device further includes a balance plate 33, and the balance plate 33 is placed above the swing frame 3. The top end of the outer shell 23 of the probe 2 is fixed to the balance plate 33 with screws 35. Such a setting can facilitate the assembly of the device.

[0040] Furthermore, as Figure 4As shown in the figure, it further includes several support columns 31. A number of first blind holes are formed around the through holes, and a number of second blind holes are formed on the balance plate 33. The positions of one first blind hole and one second blind hole correspond to each other. A support column 31 passes through a second blind hole and then enters a first blind hole. The several support columns 31 are evenly distributed around the balance plate 33. A floating pressure spring 32 is sleeved outside the support column 31 and above the balance plate 33. Under the condition of ensuring sufficient pressure, if a long spring is selected, there can be one floating pressure spring 32; if a short spring is selected, there can be two floating pressure springs 32. When the swing frame 3 drops onto the steel pipe 1, the probe 2 installed in the swing frame 3 rises under the action of the top force of the steel pipe 1, and under the action of the floating pressure spring 32, the probe 2 is in close contact with the steel pipe 1.

[0041] Further, as Figure 4 shown, several support plates 34 are respectively connected to both ends of the swing frame 3. A universal tracking ball 4 is arranged on each support plate 34. As Figure 7 shown, the support plate 34 is composed of a horizontal plate 341 and an inclined plate 342. One end of the horizontal plate 341 is located above the end of the swing frame 3 and is connected to the swing frame 3 by a bolt 37. The other end of the horizontal plate 341 extends outward from the swing frame 3. The top end of the inclined plate 342 is connected to the other end of the horizontal plate 341. The universal tracking ball 4 is installed on the inclined plate 342. Preferably, the inclined plate 342 is inclined downward, and the inclination angle β of the inclined plate 342 is 15° (the angle β between the axis of the inclined plate 342 and the axis of the horizontal plate 341 is 15°). When the swing frame 3 drops onto the steel pipe 1, the bottom end of the universal tracking ball 4 contacts the surface of the steel pipe 1 and can roll on the surface of the steel pipe 1 to achieve good tracking with the steel pipe 1; preferably, there are 4 universal tracking balls 4. In an embodiment of the present invention, the 4 universal tracking balls 4 are symmetrically arranged relative to the two rows of wafers 21 at both ends of the swing frame 3. The 4 universal tracking balls 4 on the swing frame 3 contact the surface of the steel pipe 1, and the 4 universal tracking balls 4 ride on the steel pipe 1 stably. By rolling the universal tracking balls 4 on the surface of the steel pipe 1, good tracking between the probe 2 and the steel pipe 1 is achieved. Under the action of the universal tracking balls 4 and the floating pressure spring 32, the position does not change when the probe 2 and the steel pipe 1 move relative to each other, ensuring that the ultrasonic incident angle is relatively stable, thereby ensuring that the refraction angle of the refracted longitudinal wave 5 of the ultrasonic wave entering the steel pipe remains unchanged. Since the ultrasonic incident angle is relatively stable, the refracted longitudinal wave 5 generated when the ultrasonic wave enters the interface of the steel pipe 1 is also relatively stable. As Figure 5 shown, the refracted longitudinal waves 5 generated by the 8 wafers 21 arranged bidirectionally propagate in the Y and Z directions respectively, ensuring the ultrasonic detection of the steel pipe 1 bidirectionally and bilaterally.

[0042] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0043] An ultrasonic flaw detection device for ultra-thick-walled steel pipes can simultaneously detect internal and external wall defects of steel pipes 1 with a wall thickness to outer diameter ratio t / D≥0.26. The device includes a probe 2 and a swing frame 3. The probe 2 is installed on the swing frame 3. The probe 2 is composed of 8 wafers 21 and is arranged bidirectionally and in a multi-channel combination (a combination of multiple wafers 21). The 8 wafers 21 are divided into 2 groups. The 4 wafers 21 on the left are arranged at 8°, and the 4 on the right are arranged at 172°, ensuring the bidirectional and bilateral ultrasonic detection of the steel pipe 1. Tungsten carbide wear-resistant blocks 26 are inlaid on the bottom arc surface of the plexiglass 24, greatly increasing the service life of the probe 2. A number of universal tracking balls 4 are installed on the swing frame 3. By rolling the universal tracking balls 4 on the surface of the steel pipe 1, the relative stability of the ultrasonic incident angle is ensured, so that the refraction angle of the refracted longitudinal wave 5 of the ultrasonic wave entering the steel pipe remains unchanged, realizing the simultaneous detection of internal and external wall defects of steel pipes with a wall thickness to outer diameter ratio t / D≥0.26, especially suitable for the case where 0.26≤t / D≤0.311.

[0044] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An ultrasonic flaw detection device for ultra-thick-walled steel pipes, characterized in that, It includes a probe and a swing frame. Among them, the probe is installed on the swing frame. When the swing frame drops onto the steel pipe, the probe can be in contact with the steel pipe; the probe includes a number of wafers. Each wafer is connected with an ultrasonic signal transmission line. Each wafer can emit ultrasonic waves into the steel pipe. The refracted longitudinal waves of the ultrasonic waves emitted by each wafer entering the steel pipe can be tangent to the inner wall of the steel pipe, so as to realize flaw detection of the steel pipe. The probe further includes a housing and plexiglass. The housing is a box structure with an opening at the bottom. The housing includes a top plate and four side plates. The four sides of the plexiglass are respectively connected to the bottoms of the four side plates. A number of wafers are pasted on the plexiglass. The front of the wafer faces the steel pipe, and a damping block is cast on the back of the wafer. The damping block is located inside the housing; During operation, the lower surface of the plexiglass contacts the steel pipe. The wafers are arranged in two rows along the length direction of the plexiglass. Each row is evenly provided with 4 wafers. The two rows of wafers are both inclined. The incident angle of the ultrasonic waves emitted by one row of wafers into the steel pipe is 8°, and the incident angle of the ultrasonic waves emitted by the other row of wafers into the steel pipe is 172°; The incident point of the ultrasonic waves emitted by each wafer into the steel pipe is the highest point of the vertical section of the steel pipe. The ratio of the wall thickness to the outer diameter of the ultra-thick wall steel pipe is 0.26 ≤ t / D ≤ 0.

311. A through hole is opened in the middle of the swing frame, and the probe can enter the through hole. It further includes a balance plate. The balance plate is placed above the swing frame. The probe and the balance plate are fixed with screws. It further includes a number of support columns. A number of first blind holes are opened outside the through hole. A number of second blind holes are opened on the balance plate. The positions of one first blind hole and one second blind hole correspond. A support column passes through one second blind hole and then enters one first blind hole. A floating pressure spring is sleeved outside the support column and above the balance plate. Both ends of the swing frame are respectively connected with a number of support plates. A universal tracking ball is arranged on each support plate. When the swing frame drops onto the steel pipe, the bottom end of the universal tracking ball contacts the surface of the steel pipe and can roll on the surface of the steel pipe to realize good tracking with the steel pipe.

2. The ultrasonic flaw detection device for ultra-thick wall steel pipes according to claim 1, characterized in that the housing is machined from aluminum metal.

3. The ultrasonic flaw detection device for ultra-thick wall steel pipes according to claim 1, characterized in that the damping block is made of a mixture of epoxy resin, tungsten powder and curing agent; the mass percentages of the epoxy resin, the tungsten powder and the curing agent mixed into the damping block are 65%, 25% and 10% respectively.

4. The ultrasonic flaw detection device for ultra-thick wall steel pipes according to claim 1, characterized in that Two rows of grooves are provided on the upper surface of the plexiglass. The bottoms of the two rows of grooves are respectively arranged according to the inclination angles of the two rows of wafers, and the two rows of wafers are respectively pasted in the two rows of grooves.

5. The ultrasonic flaw detection device for ultra-thick wall steel pipes according to claim 1, wherein Tungsten carbide wear-resistant blocks are inlaid on the lower surface of the plexiglass. There are multiple tungsten carbide wear-resistant blocks, and the multiple tungsten carbide wear-resistant blocks are evenly distributed on the outer periphery of the two rows of wafers.

6. The ultrasonic flaw detection device for ultra-thick wall steel pipes according to claim 1, wherein The lower surface of the plexiglass is machined according to the outer diameter curved surface of the steel pipe.

7. The ultrasonic flaw detection device for ultra-thick wall steel pipes according to claim 1, wherein A number of water injection holes are provided on the outer shell. The coupling water flows through the water injection holes to the contact surface between the plexiglass and the steel pipe, and a water film is formed on the contact surface between the plexiglass and the steel pipe to achieve stable coupling of ultrasonic waves with the steel pipe.

8. The ultrasonic flaw detection device for ultra-thick wall steel pipes according to claim 1, wherein There are 4 universal tracking balls.

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