Pipe end blind area-free flaw detection method and device for inner-layer ultra-thin composite pipe

Abstract

The non-pipe-end blind area flaw detection method comprises the following steps that (1) a plurality of jet flow coupling ultrasonic detection units are installed on a jet flow detection coupling water circulation cavity in the circumferential direction, the jet flow detection coupling water circulation cavity is of a cylindrical structure, the central angles between the detection units are the same, and the jet flow coupling ultrasonic detection units are arranged on the jet flow detection coupling water circulation cavity in the circumferential direction; the plurality of grooves are arranged at equal intervals in the axial direction of the cavity; each detection unit is an ultrasonic detection channel; (2) the composite pipe is coupled with a water circulation cavity through jet flow detection, the height of the cavity is adjusted, and the axis of the cavity and the axis of the composite pipe coincide and coincide; (3) starting a water coupling circulating system, driving the composite pipe to sequentially penetrate through the adjacent detection units at a constant speed, and enabling dynamic water jet coupling ultrasonic waves to enter a pipe body of the composite pipe for imaging detection until the composite pipe completely penetrates through the detection units; 4) enabling the position information of each point of the composite pipe to be in one-to-one correspondence with the sound wave signal of the corresponding position point, and storing; and identifying and judging the unqualified composite pipe according to the detection result.

Description

Technical Field

[0001] The invention relates to nondestructive testing technology, and in particular to a method and a device for flaw detection of a composite pipe with an extremely thin inner layer without a blind area at the pipe end. Background Art

[0002] At present, many industries are in urgent need of high-performance and low-cost pipes. In addition to the conventional mechanical properties, pipes are also required to have high temperature resistance, corrosion resistance, erosion resistance, and oxidation resistance. However, it is particularly difficult for a single material to have the above comprehensive properties at the same time. Even expensive high-alloy steels, such as martensitic stainless steel, duplex stainless steel, nickel-based alloys or titanium alloys, have their own shortcomings. With the development of manufacturing technology, facing this situation, bimetallic composite pipes with various manufacturing processes have emerged. Bimetallic composite pipes are composed of two different metal materials, with carbon steel pipes or low-alloy steel pipes as the base pipe, and a layer of corrosion-resistant alloy layer is compounded on its inner and outer surfaces. It is a product manufactured through certain physical deformation or metallurgical bonding. Through special deformation and connection technology, the bimetallic composite pipe closely combines the base and the lining, maximizes the advantages of the two metals, overcomes the performance defects of single metal materials, and reduces the comprehensive use cost of the product at the same time.

[0003] Bimetallic composite pipe is a new type of steel pipe that combines the base steel pipe and the cladding metal by mechanical or metallurgical bonding. The carbon steel base pipe mainly plays the role of pressure bearing and rigid support, while the cladding plays the role of functional corrosion protection, high temperature oxidation resistance, wear resistance, etc. Bimetallic composite pipe retains the advantages of the base pipe and the cladding metal and makes up for the shortcomings. The base pipe can adjust the pipe diameter, wall thickness and steel grade according to the structure and service requirements, and the cladding metal can use different corrosion-resistant metals or alloys according to the service conditions. Bimetallic composite pipe can effectively reduce the cost of the original high-alloy products, and the cost is only 1 / 5 to 1 / 2 of that of pure corrosion-resistant alloy pipes. The analysis and comparison of the comprehensive performance of various pipelines for oil and gas transportation by domestic professional research institutions shows that the comprehensive performance of bimetallic composite pipes ranks among the best.

[0004] At present, my country's steel pipe flaw detection has mature national standards that stipulate corresponding methods for quality inspection, such as GB / T 5777-2008 "Ultrasonic Flaw Detection of Seamless Steel Pipes". This standard stipulates the use of refracted shear wave flaw detection method, which is to make the incident ultrasonic wave enter the steel pipe at a certain angle to the steel pipe surface, so as to achieve the purpose of fully reflecting the longitudinal wave and using the refracted shear wave to enter the steel pipe for inspection.

[0005] However, for new steel pipe products such as bimetallic composite pipes, if the inner metal is expensive, the thickness of the inner metal will be designed and manufactured to a lower cost thickness level that can meet the application scenario, such as Figure 1As shown, in order to reduce costs, the thickness of the functional layer actually used is very thin, less than 1 mm, resulting in the existing conventional technical performance online flaw detection equipment. Since the defect target at the joint surface 30 of the functional layer 20 and the substrate layer 10 of the bimetallic composite pipe 100 is too small, it is either impossible to detect or the signal is completely covered by the bottom wave signal, causing the existing flaw detection technology equipment to be unable to identify the manufacturing defects of the composite steel pipe product with such a thin inner layer. Therefore, with regard to the flaw detection of composite pipes with extremely thin inner layers, the quality inspection targets and dimensional equivalent requirements are very different from the traditional flaw detection requirements. The previous quality inspection methods are no longer applicable, especially when the inner metal layer is extremely thin. The previous steel pipe flaw detection method is no longer applicable to the quality inspection of bimetallic composite pipes.

[0006] In addition, due to the limitation of the flaw detection principle, the existing standards and methods for flaw detection of steel pipes mentioned above all have the problem that both ends of the steel pipe cannot be detected, that is, there is a blind spot at the pipe end. Among various types of equipment for flaw detection of steel pipes, except for the contact type equipment with the steel pipe rotating in situ / the probe moving axially, which has a smaller blind spot at the pipe end of the steel pipe detection, the blind spots of the pipe ends of other flaw detection equipment are all around 200mm, and some even reach more than 300mm. This is because the coupling water cavity used in the rotating probe method has circular holes on both sides of the cavity for the steel pipe to pass through. The use of plugs adapted to different diameters of pipes can maintain good coupling in the water cavity during the flaw detection process. However, when the end of the steel pipe enters the cavity, the coupling water in the cavity leaks out through the circular holes on both sides, resulting in the inability to detect the pipe end.

[0007] However, the product standard for special steel pipes requires full pipe body flaw detection, and no blind spot is allowed. For this reason, steel pipe flaw detection equipment manufacturers have developed special pipe end flaw detection equipment. The pipe end automatic flaw detection equipment mode is usually partial water immersion or contact type. The partial water immersion method rotates the steel pipe in place, and the overflow probe box carries the probe inside and moves along the bottom of the steel pipe. This equipment is suitable for flaw detection of small and medium diameter steel pipes; the contact method rotates the steel pipe in place, and the water film coupling probe moves axially above the steel pipe. This equipment is suitable for flaw detection of large diameter steel pipes.

[0008] Bimetallic composite pipes with extremely thin inner metal layers are new steel pipe products that have emerged under the current situation of manufacturing industry progress. Their quality inspection objectives and dimensional equivalent requirements are very different from traditional flaw detection requirements.

[0009] At present, the flaw detection method for the inner layer of the ultra-thin composite pipe is basically blank, and various non-destructive testing methods have limitations. The existing non-destructive testing methods are as follows:

[0010] 1. The composite pipe body is a bimetal with an extremely thin inner layer. Defects such as pores and poor bonding exist in the inner layer area, making conventional ultrasonic flaw detection methods no longer applicable;

[0011] 2. It is difficult to automatically detect the inner layer of steel pipes by magnetic powder and eddy current;

[0012] 3. It is also difficult for the X-ray method to achieve the sensitivity required by the current problems;

[0013] 4. It is difficult to achieve the required level of flaw detection sensitivity for bimetallic composite pipes by using ultrasonic guided wave method, let alone to achieve online automatic flaw detection;

[0014] There is also the "composite pipe flaw detection device" disclosed in Chinese patent publication number CN210639145U, which is a flaw detection tool for steel pipe products produced by various conventional composite manufacturing processes. It does not involve the technical principle of online imaging detection involved in our patent application, nor does it involve the characteristics of the object to be tested in our patent for extremely thin inner layers with a thickness of less than 1 mm, nor does it involve the problem of blind spots at both ends of the steel pipe online flaw detection pipe that the present invention intends to solve.

[0015] Chinese patent publication number CN206497075U discloses "a composite pipe ultrasonic flaw detection machine tool", which is also a flaw detection tool for composite steel pipe products using the contact water film method, but does not solve the problem of blind spots at both ends of the steel pipe during online flaw detection.

[0016] Chinese patent publication number CN208457441U discloses a "defect detection device for lined stainless steel composite pipes". The device is a stress detection tool in which a tensile strain gauge is connected to an ammeter via a bridge circuit. It also does not solve the problem of blind spots at both ends of the steel pipe during online flaw detection.

[0017] Although there are more than a dozen mature non-destructive testing methods and more than a thousand types of non-destructive testing instruments and equipment, most of the different non-destructive testing methods that can be used for steel pipes have limitations in the detection principle. It can be seen that in order to achieve the composite pipe flaw detection technology without pipe end blind spots, it is not limited to the conventional steel pipe ultrasonic flaw detection method and various detection methods such as eddy current, X-ray, infrared detection, microwave detection, and laser ultrasound. New methods must be designed. Summary of the invention

[0018] The purpose of the present invention is to provide a method and device for detecting blind spots at the ends of bimetallic composite pipes with extremely thin inner layers, so as to realize online detection of blind spots at the ends of bimetallic composite pipes with extremely thin inner layers (<1 mm) at the lowest possible cost.

[0019] To achieve the above object, the technical solution of the present invention is:

[0020] The method for flaw detection of an extremely thin inner layer composite pipe without a blind area at the pipe end comprises the following steps:

[0021] 1) A plurality of jet-coupled ultrasonic detection units are installed circumferentially on the jet detection coupling water circulation cavity, the jet detection coupling water circulation cavity is a cylindrical structure, the central angles of the detection units are the same, forming a fan-shaped distribution, and are arranged at equal intervals along the axial direction of the jet detection coupling water circulation cavity, the axial spacing x between adjacent detection units is between 30 and 60 mm, the radial spacing y is between 5 and 10 mm, or the central angle between adjacent detection units is 5° to 15°; each detection unit is an ultrasonic detection channel; the concentric height of the detection unit is adjustable;

[0022] 2) Pass the composite pipe through the jet detection coupling water circulation cavity, and adjust the height of the jet detection coupling water circulation cavity so that the axis of the cavity and the composite pipe coincide with each other;

[0023] 3) Start the water coupling circulation system, drive the composite pipe to pass through each adjacent detection unit in sequence at a uniform speed, and the dynamic water jet coupled ultrasonic wave enters the composite pipe body for imaging detection until the composite pipe passes through all the detection units, and the detection is completed;

[0024] 4) The position information of each point of the composite pipe obtained by the detection unit and the sound wave signal of the corresponding position point are matched one by one and stored; the composite pipes that are judged unqualified are identified and judged according to the detection results.

[0025] Preferably, the circumference of the composite pipe body is divided into several sectors in the circumferential direction, and corresponding to each sector, a series of jet-coupled ultrasonic detection units that meet the circumferential resolution requirements of flaw detection are arranged to implement detection; and the flaw detection of the entire composite pipe including the pipe end parts in all sectors is completed in an axial reciprocating working mode of the composite pipe.

[0026] The present invention divides the circumference of the composite pipe into multiple sectors and axially reciprocates to detect a single sector. In one sector, a series of jet-coupled ultrasonic detection units that meet the circumferential resolution requirements of flaw detection are arranged to implement detection. For composite pipes of different diameters, all pipes within a certain diameter specification range can be inspected by adjusting the distance between the series of jet-coupled ultrasonic detection units installed on the coupled cylindrical cavity and the steel pipe.

[0027] The present invention does not require the plug used in conventional steel pipe flaw detection, and can maintain good coupling in the water cavity during the flaw detection process through dynamic water jet coupling. After the jet water coupling is completed, it naturally falls into the circulating water circuit, and is recycled to the water tower water tank for reuse. The purposes of this are: first, ultrasonic wave is used in flaw detection, and water must be used to couple the sound wave into the steel pipe body; second, the detection is carried out by adopting the cooperation of the circulating water circuit system and the water tower type static water coupling ultrasonic wave. The coupled water passes through the jet head and is arranged in a larger cavity. There are as many jet heads as there are channels. This overcomes the problem existing in conventional steel pipe flaw detection that when the end enters the cavity, the coupled water in the cavity leaks out through the circular holes on both sides, resulting in the inability to detect the two ends of the composite pipe. Continuous quality detection of the two ends of the composite pipe can be efficiently achieved.

[0028] The method for flaw detection without blind spots at pipe ends of the present invention adopts the cooperation of a circulating water system and a water tower type static water coupled ultrasonic wave for detection. The ultrasonic sound field can adopt a point focusing or a line focusing method. For example, when the point focusing method is adopted, the sound wave is incident on the inside of the composite pipe in a manner that the central axis of the point focusing sound field intersects perpendicularly with the radial central axis of the composite pipe. When the line focusing method is adopted, the sound wave is incident on the inside of the composite pipe in a manner that the symmetrical central plane of the line focusing sound field passes through the radial central axis of the composite pipe and the focal line is kept parallel thereto. The inspected bimetallic composite pipe is located in a reasonable middle position between the sound source and the focus (line), which can ensure that the energy of the ultrasonic wave can be concentrated on the extremely thin inner layer area of ​​the bimetallic composite pipe, which is conducive to the detection of defects.

[0029] The design of the present invention adopts the structure of a jet detection coupled water circulation cavity, which is assembled from a plurality of concentric, height-adjustable, series of jet-coupled ultrasonic detection units to ensure that the composite steel pipe can freely pass through the entire detection unit, and the coupled water path can also flow freely between each monomer detection unit. After the jet water coupling is completed, the coupled water naturally falls into the circulating water path and is recycled into the water tower tank for reuse. The speed of the jet head water flow can determine the most reasonable speed range based on the designed jet head structure. The principle is that the ejected water flow is stable in columnar shape, without bubbles and with minimal turbulence.

[0030] The method for flaw detection of an extremely thin inner bimetallic composite pipe without a pipe end blind zone of the present invention is aimed at continuous mechanical scanning imaging detection of defects unique to an extremely thin inner bimetallic composite pipe from beginning to end.

[0031] As a flaw detection method for the inner layer of extremely thin bimetallic composite pipes without blind spots at the pipe ends, it involves the following aspects:

[0032] A series of jet-coupled ultrasonic detection units with adjustable concentric height are installed on the jet detection coupling water circulation cavity. Each unit is an ultrasonic detection channel. Ultrasonic waves are coupled into the composite pipe body through dynamic water jets to perform imaging detection tasks for composite quality. Ultrasonic waves with a certain frequency and a certain sound field distribution are controlled to be emitted as detection probes, and the defect detection is realized by acting on the extremely thin inner bimetallic composite pipe in a reasonable ultrasonic detection method.

[0033] The detection units are distributed in a fan shape according to the same circumferential projection angle and are arranged at equal intervals in the axial direction.

[0034] The reason why the detection units are arranged at intervals is that the jet head corresponding to each detection point used in the present invention has a certain size. Usually, if a circular shape is adopted, the diameter is between 30 and 60 mm. Therefore, the distance x between adjacent detection points is between 30 and 60 mm.

[0035] The device for flaw detection of an ultra-thin inner layer composite pipe without a blind area at the pipe end of the present invention comprises:

[0036] Pedestal;

[0037] The detection box is arranged at the center of the top surface of the base, and the inlet and outlet are arranged at the centers of the two side surfaces thereof;

[0038] The jet detection coupled water circulation cavity is a cylindrical structure, which can be lifted and lowered in the detection box, and the bottom is provided with water inlet and outlet and corresponding water inlet and outlet pipes; a plurality of jet-coupled ultrasonic detection units are installed along the circumferential direction on the top surface of the jet detection coupled water circulation cavity, and the central angles of the respective detection units are the same, forming a fan-shaped distribution, and the jet detection coupled water circulation cavity is arranged at equal intervals along the axial direction, and a spacing is maintained between adjacent detection units in the axial and radial directions; each detection unit is an ultrasonic detection channel;

[0039] A coupling water circulation water tank is arranged in the base and connected to the water inlet and outlet pipes of the jet detection coupling water circulation cavity through water inlet and outlet pipes;

[0040] Two clamping mechanisms are respectively arranged on the top surface of the base on both sides of the detection box, and the clamping mechanisms include:

[0041] A pair of clamping rollers are arranged up and down and are disposed at the center of the top surface of the base at the inlet / outlet of the detection box;

[0042] A driving mechanism is arranged on the top surface of the base on one side of the detection box;

[0043] The clamper is connected to the driving mechanism and is driven by the driving mechanism to move left and right along the axial direction of the top surface of the base; the clamper and the clamping roller are located on the same axis.

[0044] Preferably, the jet detection coupling water circulation cavity is composed of a number of detection sub-cavities connected in series as one, each detection sub-cavity is provided with a mounting hole for installing a jet coupling ultrasonic detection unit, and a jet coupling ultrasonic detection unit is installed; the mounting holes on each detection sub-cavity are arranged at equal intervals along the axial direction of the jet detection coupling water circulation cavity, and the central angles between each jet coupling ultrasonic detection unit are the same, so that the jet coupling ultrasonic detection units form a fan-shaped distribution; each jet coupling ultrasonic detection unit is an ultrasonic detection channel.

[0045] Preferably, the driving mechanism comprises:

[0046] Two guide rails and an upper slider are arranged in parallel on the top surface of the base;

[0047] A mounting plate, the two ends of the bottom surface of which are connected to the sliders on the two guide rails, and a connecting block is provided in the center of the bottom surface of the mounting plate;

[0048] A ball screw, both ends of which are arranged in parallel between the two guide rails through a bearing seat, and a screw nut on the ball screw is connected to the connecting block;

[0049] A driving motor has an output shaft connected to one end of the ball screw.

[0050] Preferably, the drive motor is a servo motor.

[0051] Preferably, the axial spacing x between adjacent detection units is between 30 and 60 mm, the radial spacing y is between 5 and 10 mm, or the central angle between adjacent detection units is between 5° and 15°.

[0052] At the beginning of the inspection, the bimetallic composite pipe product passes through the feed roller and is fixed by the clamp. The bimetallic composite pipe is transported into the coupling cavity by the clamp. The coupling cavity is equipped with detection units, which are distributed in the annular space position of the composite pipe that meets the detection conditions. The detection unit is started, and the clamp stably clamps and drives the inspected composite pipe to pass through each adjacent detection unit at a uniform speed in turn. The series of water jet detection units emit ultrasonic waves to the inside of the inspected composite pipe according to the set conditions at a certain period. The detection starts from the time when the inspected composite pipe enters the detection unit and ends when the inspected composite pipe passes through the detection unit. The waveform of each detection position is automatically recorded through the control program, and the position information of each point of the inspected composite pipe obtained by the detection unit and the sound wave signal of the corresponding position point are matched one by one and stored. Finally, according to the identification and judgment of the detection results, for the composite pipe products that are judged to be unqualified, an alarm is issued and the spray marking equipment is driven to mark the composite pipe to distinguish qualified products, and finally the test result output report is printed.

[0053] The present invention uses the above detection device to achieve that when composite pipes of different diameters (such as 50-200 mm) pass through the coupling cavity and enter the detection state, they can all be raised and lowered by adjusting the vertical height of the coupling cavity on the base to keep the axis of the jet detection coupling water circulation cavity coincident with the axis of the composite pipe. It is also possible to adjust the series of jet coupling ultrasonic detection units installed on the jet detection coupling water circulation cavity so that the ultrasonic sensors in the units can be adjusted to the best detection conditions at the concentric height, and each jet coupling ultrasonic detection unit can perform flaw detection tasks under the same working conditions.

[0054] Beneficial effects of the present invention:

[0055] The method for flaw detection of an extremely thin inner layer composite pipe without a blind spot at the pipe end described in the present invention can solve the problem existing in conventional composite pipe flaw detection that when the end enters the cavity, the coupled water in the cavity leaks out through the circular holes on both sides, resulting in the inability to detect the two ends of the composite pipe. The method can efficiently realize continuous quality detection of the two ends of the composite pipe, eliminating the technical barrier of quality non-destructive testing between innovative composite pipe products and their market application. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a schematic cross-sectional view of a bimetallic composite tube;

[0057] Figure 2 It is a schematic diagram of the structure of the jet detection coupling water circulation cavity for the flaw detection of the bimetallic composite pipe according to the present invention;

[0058] Figure 3 It is a schematic diagram of cross-sectional projection of the flaw detection of the bimetallic composite pipe according to the present invention;

[0059] Figure 4 It is a schematic diagram of the sector division of the bimetallic composite pipe flaw detection of the present invention;

[0060] Figure 5 It is a structural schematic diagram of the bimetallic composite pipe flaw detection device of the present invention;

[0061] Figure 6 It is a schematic diagram of the structure of the jet detection coupling water circulation cavity in the bimetallic composite pipe flaw detection device of the present invention;

[0062] Figure 7 It is a schematic diagram of the jet detection of the left pipe end of the composite pipe entering the cavity in the method for flaw detection without pipe end blind zone of the present invention;

[0063] Figure 8 It is a schematic diagram of the jet detection of the right end of the composite pipe leaving the cavity in the method for flaw detection without blind spot of pipe end of the present invention. DETAILED DESCRIPTION

[0064] See also Figure 5 The device for the method of detecting the non-blind zone of the inner layer of the ultra-thin composite pipe of the present invention comprises:

[0065] Base 4;

[0066] The detection box 2 is arranged at the center of the top surface of the base 4, and the inlet and outlet are arranged at the center of the two side surfaces thereof;

[0067] A jet detection coupled water circulation cavity 3 is a cylindrical structure, which can be lifted and lowered in the detection box 4, and has a water inlet and outlet and a corresponding water inlet pipe 31 and a water outlet pipe 32 at the bottom; a plurality of jet-coupled ultrasonic detection units 1, 1' are installed along the circumferential direction on the top surface of the jet detection coupled water circulation cavity 3, and the central angles of the respective detection units 1, 1' are the same, forming a fan-shaped distribution, and are arranged at equal intervals along the axial direction of the jet detection coupled water circulation cavity, and a spacing is maintained between adjacent detection units 1, 1' in the axial and radial directions; each detection unit is an ultrasonic detection channel;

[0068] A coupling water circulation water tank 5 is arranged in the base 4 and connected to the water inlet and outlet pipes of the jet detection coupling water circulation cavity 3 through water inlet and outlet pipes;

[0069] The two clamping mechanisms 6, 6' are respectively arranged on the top surface of the base 4 on both sides of the detection box 2, and the clamping mechanism 6 (taking the clamping mechanism 6 as an example, the same below) includes:

[0070] A pair of clamping rollers 61 are arranged up and down and are disposed at the center of the top surface of the base 4 at the entrance / exit of the detection box 2;

[0071] A driving mechanism 62 is arranged on the top surface of the base 4 on one side of the detection box 1;

[0072] The clamper 63 is connected to the driving mechanism 62 and is driven by the driving mechanism 62 to move left and right along the axial direction of the top surface of the base 4; the clamper 63 and the clamping roller 63 are located on the same axis.

[0073] See also Figure 6The jet detection coupling water circulation cavity 3 of the present invention is composed of a plurality of detection sub-cavities 301, 302, ... 30n connected in series as one body, each detection sub-cavity 301, 302 is provided with a mounting hole 3011, 3021, ... 30n1 for mounting a jet coupling ultrasonic detection unit, and a jet coupling ultrasonic detection unit 1, 1' is mounted thereon; the mounting holes on each detection sub-cavity are arranged at equal intervals along the axial direction of the jet detection coupling water circulation cavity, and the central angles between each jet coupling ultrasonic detection unit are the same, so that the jet coupling ultrasonic detection unit forms a fan-shaped distribution; each jet coupling ultrasonic detection unit is an ultrasonic detection channel.

[0074] Preferably, the driving mechanism comprises:

[0075] Two guide rails and an upper slider are arranged in parallel on the top surface of the base;

[0076] A mounting plate, the two ends of the bottom surface of which are connected to the sliders on the two guide rails, and a connecting block is provided in the center of the bottom surface of the mounting plate;

[0077] A ball screw, both ends of which are arranged in parallel between the two guide rails through a bearing seat, and a screw nut on the ball screw is connected to the connecting block;

[0078] A driving motor has an output shaft connected to one end of the ball screw.

[0079] Preferably, the drive motor is a servo motor.

[0080] Preferably, the axial spacing x between adjacent detection units is between 30 and 60 mm, the radial spacing y is between 5 and 10 mm, or the central angle between adjacent detection units is between 5° and 15°.

[0081] See also Figure 2 to Figure 8 The method for flaw detection of an ultra-thin composite pipe without a pipe end blind zone of the inner layer of the present invention comprises the following steps:

[0082] 1) A plurality of jet-coupled ultrasonic detection units 1, 1' are installed circumferentially on the jet detection coupling water circulation cavity, the jet detection coupling water circulation cavity is a cylindrical structure, the central angles of the various jet-coupled ultrasonic detection units 1, 1' are the same, forming a fan-shaped distribution, and are arranged at equal intervals along the axial direction of the jet detection coupling water circulation cavity, the axial spacing x between adjacent jet-coupled ultrasonic detection units 1, 1' is between 30 and 60 mm, the radial spacing y is between 5 and 10 mm, or the central angles of the adjacent jet-coupled ultrasonic detection units 1, 1' are 5° to 15°; each jet-coupled ultrasonic detection unit 1, 1' is an ultrasonic detection channel; the concentric height of the detection unit is adjustable;

[0083] 2) Pass the composite pipe 100 through the jet detection coupling water circulation cavity, and adjust the height of the jet detection coupling water circulation cavity so that the axis of the cavity and the composite pipe coincide with each other;

[0084] 3) Start the water coupling circulation system, drive the composite pipe to pass through each adjacent detection unit in sequence at a uniform speed, and the dynamic water jet coupled ultrasonic wave enters the composite pipe body for imaging detection until the composite pipe passes through all the detection units, and the detection is completed;

[0085] 4) The position information of each point of the composite tube obtained by the jet-coupled ultrasonic detection unit and the acoustic wave signal of the corresponding position point are matched one by one and stored; according to the detection results, identification and judgment are made,

[0086] For composite pipes that are judged unqualified.

[0087] See also Figure 4 The circumference of the composite pipe 100 is divided into a plurality of sectors 101 in the circumferential direction. Corresponding to each sector, a series of jet-coupled ultrasonic detection units 1 and 1' that meet the requirements of circumferential resolution of flaw detection are arranged to implement detection; and the flaw detection of the entire composite pipe including the pipe end parts in all sectors is completed in an axial reciprocating working mode of the composite pipe.

[0088] The present invention divides the circumference of the composite pipe into multiple sectors in the circumferential direction (the more sectors there are, the more reciprocating detection times are required, but the cost of equipment manufacturing is lower), and a series of jet-coupled ultrasonic detection units that meet the circumferential resolution requirements of flaw detection are arranged in one sector to implement detection. The quality flaw detection of the entire composite pipe, including the pipe end parts in all sectors, is completed in the axial reciprocating working mode of the composite pipe. The sector division and the arrangement of each adjacent jet-coupled ultrasonic detection unit in the sector are as follows: Figure 4 shown.

[0089] For composite pipes of different diameters, the distance between the series of jet coupling ultrasonic detection units installed on the cylindrical coupling cavity and the composite pipe can be adjusted to achieve full inspection within a certain pipe diameter specification range. The present invention divides the circumference into multiple sectors and completes a single sector of the composite pipe circumference each time.

[0090] See also Figure 7 , Figure 8 , Figure 7 The figure shows the jet detection of the left pipe end of the composite pipe 100 entering the detection sub-cavity 301 of the jet detection coupling water circulation cavity 3. Figure 8 The figure shows the jet detection of the right end of the composite tube 100 leaving the 30nth detection sub-cavity.

[0091] The left side of the composite pipe 100 enters the coupled water circulation cavity for flaw detection at the beginning, and when the right side of the composite pipe leaves the coupled water circulation cavity, both sides of the pipe ends can perform the same flaw detection as the pipe body. It can be seen that due to the jet coupling method, when the two ends of the composite pipe enter and leave the coupled water circulation cavity in one direction, the jet flaw detection can be carried out as usual, and the detection will not be unable to be carried out because the side of the coupled water circulation cavity is not blocked after the pipe end enters the coupled water circulation cavity.

[0092] Example

[0093] Taking the detection of composite pipes with an outer diameter of 100mm as an example, the mechanical imaging grid spacing of the inner wall of the composite pipe to be detected must be no less than 1mm to avoid missed detection. If the pipe wall thickness is 10mm, the composite layer thickness is 1mm, and the position of the composite layer is on a circle with a diameter of 80mm, the inner diameter of the composite steel pipe is 78mm.

[0094] The detection of a composite pipe is completed by 8 reciprocating movements, that is, one detection is completed in a sector with an angle of 45 degrees in the circumferential direction. The detection of a composite pipe can be completed by reciprocatingly detecting 8 sectors with an angle of 45 degrees on the circumference of the composite pipe.

[0095] The diameter of the detected circle is 80mm, the circumference is about 251.2mm, the length of each sector corresponding to an angle of 45 degrees is 31.4mm, and the design uses 32 channels.

[0096] Using 32 channels, also Figure 2 There are 32 detection points. On the circumference of the composite pipe, the 32 channels are evenly distributed in a 45-degree sector, because the detection is carried out in the direction of the jet in each channel is perpendicular to the axis of the steel pipe, that is, the angle between the directions of two adjacent jet channels is about 1.4°.

[0097] The diameter of the designed circular coupled water circulation cavity is 500 mm, and its circumference is 1.57 m. The length of the 45-degree angle sector of the composite pipe is 196.25 mm. For the 32-channel detection system, the projection spacing between every two adjacent detection channels on the circumference of the composite pipe is 6.13 mm, that is, Figure 2 In this example, y=6.13mm.

[0098] The diameter of the jet head is 40 mm, and the projection distance between each two adjacent detection channels in the axial direction of the composite tube is 40 mm, that is, Figure 2 x=40 mm, and the total length of the 32 channels is less than 1.28 m. The angle between the detection line formed by all detection points and the axis of the composite pipe is calculated as: arctg(6.13 / 40)=8.7°.

[0099] The above is a case of completing the detection of a composite pipe by reciprocatingly detecting 8 45-degree angle sectors of the circumference of the composite pipe. If the equipment manufacturing cost needs to be reduced, or the detection time is sufficient, the number of channels can be halved, that is, 16 channels. If the diameter of the circular coupled water circulation cavity is still 500 mm, its overall length will be less than 614 mm, and so on.

Claims

1. The method for flaw detection of the inner layer extremely thin composite pipe without blind area at the pipe end is characterized by: The steps include: 1) A plurality of jet-coupled ultrasonic detection units are installed circumferentially on the jet detection coupling water circulation cavity, the jet detection coupling water circulation cavity is a cylindrical structure, the central angles of the detection units are the same, forming a fan-shaped distribution, and are arranged at equal intervals along the axial direction of the jet detection coupling water circulation cavity, the axial spacing x between adjacent detection units is between 30 and 60 mm, the radial spacing y is between 5 and 10 mm, or the central angle between adjacent detection units is 5° to 15°; each detection unit is an ultrasonic detection channel; the concentric height of the detection unit is adjustable; 2) Pass the composite pipe through the jet detection coupling water circulation cavity, and adjust the height of the jet detection coupling water circulation cavity so that the axis of the cavity and the composite pipe coincide with each other; 3) Start the water coupling circulation system, drive the composite pipe to pass through each adjacent detection unit in sequence at a uniform speed, and the dynamic water jet coupled ultrasonic wave enters the composite pipe body for imaging detection until the composite pipe passes through all the detection units, and the detection is completed; 4) The position information of each point of the composite pipe obtained by the detection unit and the sound wave signal of the corresponding position point are matched one by one and stored; the composite pipes that are judged unqualified are identified and judged according to the detection results.

2. The method for flaw detection of an ultra-thin inner layer composite pipe without blind spots at the pipe end as claimed in claim 1, characterized in that: The circumference of the composite pipe body is divided into several sectors in the circumferential direction. Corresponding to each sector, a series of jet-coupled ultrasonic detection units that meet the requirements of circumferential resolution of flaw detection are arranged to implement detection; and the flaw detection of the entire composite pipe including the pipe end parts in all sectors is completed in the axial reciprocating working mode of the composite pipe.

3. A device for the method for flaw detection of the inner layer ultra-thin composite pipe without blind area at the pipe end as claimed in claim 1 or 2, characterized in that: include: Pedestal; The detection box is arranged at the center of the top surface of the base, and the inlet and outlet are arranged at the centers of the two side surfaces thereof; A jet detection coupled water circulation cavity is a cylindrical structure, which can be lifted and lowered in the detection box, and has a water inlet and outlet and corresponding water inlet and outlet pipes at the bottom; a plurality of jet-coupled ultrasonic detection units are installed along the circumferential direction on the top surface of the jet detection coupled water circulation cavity, and the central angles of the respective jet-coupled ultrasonic detection units are the same, forming a fan-shaped distribution, and are arranged at equal intervals along the axial direction of the jet detection coupled water circulation cavity, and a spacing is maintained between adjacent jet-coupled ultrasonic detection units in the axial and radial directions; each jet-coupled ultrasonic detection unit is an ultrasonic detection channel; A coupling water circulation water tank is arranged in the base and connected to the water inlet and outlet pipes of the jet detection coupling water circulation cavity through water inlet and outlet pipes; Two clamping mechanisms are respectively arranged on the top surface of the base on both sides of the detection box, and the clamping mechanisms include: A pair of clamping rollers are arranged up and down and are disposed at the center of the top surface of the base at the inlet / outlet of the detection box; A driving mechanism is arranged on the top surface of the base on one side of the detection box; The clamper is connected to the driving mechanism and is driven by the driving mechanism to move left and right along the axial direction of the top surface of the base; the clamper and the clamping roller are located on the same axis.

4. The device for the method for detecting non-blind area of ​​the inner layer ultra-thin composite pipe as claimed in claim 3 is characterized in that: The jet detection coupling water circulation cavity is composed of a number of detection sub-cavities connected in series as one, each detection sub-cavity is provided with a mounting hole for installing a jet coupling ultrasonic detection unit, and a jet coupling ultrasonic detection unit is installed; the mounting holes on each detection sub-cavity are arranged at equal intervals along the axial direction of the jet detection coupling water circulation cavity, and the central angles between each jet coupling ultrasonic detection unit are the same, so that the jet coupling ultrasonic detection units form a fan-shaped distribution; each jet coupling ultrasonic detection unit is an ultrasonic detection channel.

5. The device for flaw detection method of non-blind zone of inner layer ultra-thin composite pipe as claimed in claim 3, characterized in that: The driving mechanism comprises: Two guide rails and an upper slider are arranged in parallel on the top surface of the base; A mounting plate, the two ends of the bottom surface of which are connected to the sliders on the two guide rails, and a connecting block is provided in the center of the bottom surface of the mounting plate; A ball screw, both ends of which are arranged in parallel between the two guide rails through a bearing seat, and a screw nut on the ball screw is connected to the connecting block; A driving motor has an output shaft connected to one end of the ball screw.

6. The device for flaw detection method of non-blind zone of inner layer ultra-thin composite pipe as claimed in claim 4, characterized in that: The driving motor is a servo motor.

7. The device for flaw detection of the inner layer ultra-thin composite pipe without blind area at the pipe end as claimed in claim 3, characterized in that: The axial spacing x between adjacent detection units is between 30 and 60 mm, and the radial spacing y is between 5 and 10 mm, or the central angle between adjacent detection units is between 5° and 15°.

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