X-ray inspection method for all-position welds of large-diameter aerospace tank inner ducts

Abstract

The invention provides a method for X-ray detection of weld seams of all-position welds of conduits in large-diameter aerospace tanks, comprising the following steps: S1, rotating the laser pen with the aid of an angle measuring tool, selecting two directions without interference, and accurately locating two irradiation directions of the weld seams at an interval of 90°; irradiating the film in the two irradiation directions with a ray machine, respectively, and evaluating the welding results after washing the film. The invention solves the problems of the fixed position of the conduits in large-diameter aerospace tanks, the different plane positions of the welds, the interference between the surrounding environment and the ray beam, and the difficulty in controlling the irradiation direction, and effectively overcomes all the shortcomings of the prior art in the application of X-ray detection of weld seams of all-position welds of conduits in large-diameter aerospace tanks.

Description

Technical Field

[0001] The invention belongs to the technical field of X-ray detection, and in particular relates to an X-ray detection method for all-position welds of a conduit in a large-diameter aerospace tank. Background Art

[0002] The booster delivery pipeline is an important gas transmission path on the new generation of large-diameter launch vehicles, and its pipeline performance will directly affect the success or failure of the rocket's flight mission. In order to further improve reliability, the designers optimized the connection method of the booster delivery pipeline in the large-diameter tank to a full-position welding method. During the welding process, due to the fluctuation of welding equipment parameters and other reasons, cracks, lack of fusion, lack of penetration, pores, inclusions and other defects that lead to reduced joint performance will occur inside the weld. Once the rocket carries the above defects to participate in the flight mission, during the flight, due to the action of different external forces, the defects will expand or crack, and then the booster delivery pipeline will fail and cause the flight failure. X-ray detection is currently an effective detection method for internal defects of the catheter weld, but the space inside the tank is limited, and the environmental structure and the radiation beam interfere with each other, which creates many difficulties for the X-ray detection of the full-position welded catheter weld in the tank; in addition, there is only one manhole with a diameter of no more than 500mm on the surface of the tank for personnel, equipment, tooling, etc. to enter and exit the box, which poses new challenges to the design of the detection tooling. Therefore, developing an effective X-ray detection method for the welds of the ducts inside the box is the key to ensuring the normal flight of the rocket.

[0003] When X-ray testing is performed on non-in-box duct welds, two directions with a 90° interval should be selected to complete the transillumination according to the standard requirements. The specific process is as follows: (1) Adjust the plane where the duct weld is located to be parallel or perpendicular to the horizontal plane (the plane where the xy axis is located), such as Figure 3 and Figure 4 As shown in the figure, the 90° intervals are defined as position 1# and position 2#; (2) Stick the film, lead type, and image quality meter at position 1#; (3) Using the ground or the wall of the radiography room as a reference, adjust the position of the X-ray machine according to the following requirements, marked as the 0° position. When the catheter weld is placed as shown in the figure below, Figure 3 As shown in , the X-ray beam is emitted along the X-axis, the ray source and the film are located on both sides of the catheter, the ray source is located on the positive direction of the X-axis, and the film is placed close to the catheter on the negative direction of the X-axis. The distance F between the ray source and the film is controlled within the range of 1000 to 1500 mm. For specific arrangements, see Figure 5 When the conduit weld is placed as Figure 4 As shown in , the X-ray beam is emitted along the X-axis, the ray source and the film are located on both sides of the catheter, the ray source is located on the positive direction of the X-axis, and the film is placed close to the catheter on the negative direction of the X-axis. The distance F between the ray source and the film is controlled within the range of 1000 to 1500 mm. For specific arrangements, see Figure 6(4) Adjust the voltage of the X-ray machine to 85-120kV according to the thickness of the weld to ensure that the radiation can penetrate the weld of the catheter and reach the film, and the exposure is not less than 20mA·min; (5) Turn on the X-ray machine and start transillumination; (6) Turn off the X-ray machine, remove the film in position 1#, and send it to the darkroom for processing. And stick the film on position 2#; (7) With the ground or the wall of the transillumination room as a reference, adjust the position of the X-ray machine according to the following requirements, record it as the 90° position, when the catheter weld is placed as follows Figure 3 As shown in , the X-ray beam is emitted along the Y axis, the ray source and the film are located on both sides of the catheter, the ray source is located on the positive direction side of the Y axis, and the film is placed close to the catheter on the negative direction side of the Y axis. The distance F between the ray source and the film is controlled within the range of 1000 to 1500 mm. For specific arrangements, see Figure 5 When the conduit weld is placed as Figure 4 As shown in , the X-ray beam is emitted along the Z axis, the ray source and the film are located on both sides of the catheter, the ray source is located on the positive direction of the Z axis, and the film is placed close to the catheter on the negative direction of the Z axis. The distance F between the ray source and the film is controlled within the range of 1000 to 1500 mm. For specific arrangements, see Figure 6 (8) Adjust the voltage of the X-ray machine to 85-120 kV according to the thickness of the weld to ensure that the X-ray can penetrate the weld of the catheter and reach the film, and the exposure is not less than 20 mA min; (9) Turn on the X-ray machine and start transillumination; (10) Turn off the X-ray machine, remove the film in position 2, and send it to the darkroom for processing; (11) After the film is washed, evaluate whether there are any defects exceeding the standard in the weld according to the acceptance standards; (12) The inspection is completed.

[0004] The full position welding seam of the duct in the large diameter aerospace tank is due to the duct being fixed to the inner wall of the tank (see Figure 1 and Figure 2 ), and connected to structures such as gas cylinders, the following technical disadvantages exist when using the existing technology for X-ray detection: (1) The full-position weld seams of the ducts in the large-diameter aerospace tanks are fixed on the inner wall of the tanks, and it is impossible to adjust the plane where the welds are located to be parallel or perpendicular to the horizontal plane in the existing technology, so that the radiation exposure direction cannot be quickly determined; (2) The structure inside the large-diameter aerospace tank is complex and there are many parts. In the existing technology, the radiation beam emitted from the radiation source will be blocked by the surrounding environment structure before reaching the film, resulting in some welds that cannot be detected; (3) The large-diameter aerospace tank is a limited space, and it is difficult to ensure that the distance from the radiation source to the film meets the requirements of the existing technology, which leads to increased geometric blurriness of the film, reduced film sensitivity, and incomplete display of detailed images; (4) The full-position weld seams of the ducts in the large-diameter aerospace tanks are fixed in position, the weld angles are different, and there are many interfering structures in the surrounding environment. It is difficult to use the ground or the wall of the exposure room as a reference according to the operation method of the existing technology. If the angle α of the two radiation beam exposure directions cannot meet the standard requirement of 90°, it will cause the following Figure 7 The defect at the position shown is in the detection blind spot, resulting in an increased risk of missed defect detection. (5) The size of the tooling for auxiliary clamping of the catheter in the existing technology is 1500×1000×400mm, while the large-diameter aerospace tank is a limited space with a maximum manhole diameter of less than 500mm, which makes it impossible for the tooling for auxiliary clamping of the catheter in the existing technology to be transported into the tank. In short, the existing detection technology cannot be applied to the X-ray detection of all-position welds of the catheter in the large-diameter aerospace tank, and a new X-ray detection method is urgently needed. Summary of the invention

[0005] In view of this, the present invention aims to propose a method for X-ray detection of all-position welds of ducts inside large-diameter aerospace tanks, so as to solve the problems of fixed position of ducts inside large-diameter tanks, different plane positions of welds, interference between surrounding environment and ray beam, and difficulty in controlling the direction of penetration.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0007] A method for X-ray detection of all-position weld seams of a large-diameter aerospace tank inner conduit comprises the following steps:

[0008] S1. Use the angle measuring tool to rotate the laser pen, select two directions without interference, and accurately locate the two transillumination directions of the weld with an interval of 90°;

[0009] S2, set the 0° and 90° transillumination directions as the 1# film position and the 2# film position respectively;

[0010] S3, place the film tightly against the catheter at the 1# film position;

[0011] S4, transport the X-ray machine support tooling 2 into the tank through the manhole, determine the position of the X-ray source in the 0° penetration direction by using a laser pen, and the X-ray source emits a X-ray beam along the 0° penetration direction to pass through the pipe weld;

[0012] S5. Adjust the process parameters of the X-ray machine according to the thickness of the weld to ensure that the X-ray can penetrate the weld of the catheter and reach the film;

[0013] S6, washing the film at position 1#;

[0014] S7, place the film tightly against the catheter at the 2# film position;

[0015] S8, determining the position of the radiation source in the 90° transillumination direction by means of a laser pen, and emitting a radiation beam from the radiation source along the 90° transillumination direction through the weld of the catheter;

[0016] S9, after repeating step S5, wash the film in position 2#;

[0017] S10. After washing the film, evaluate whether there are any excessive defects in the weld according to the acceptance standards. The inspection is completed.

[0018] Furthermore, in step S5, the specific method for determining the process parameters of the weld thickness adjustment X-ray machine is as follows:

[0019] According to the definition of geometric unsharpness in ray detection, the formula can be obtained as follows:

[0020]

[0021] U g : geometric unsharpness; d: ray source size; T: penetration thickness; F: distance from ray source to film; It can be seen that in the present invention, the distance F from the ray source to the film has been reduced, in order to reduce the geometric unsharpness U g , it is necessary to reduce the size d of the ray source.

[0022] Furthermore, the rotation angle range of the laser pen is 180°.

[0023] Furthermore, the angle measuring tool includes a pointer, a protractor, a support plate and a restraining plate. The restraining plate is detachably installed under the support plate, and the restraining plate is used to fix the support plate on the weld of the catheter to be inspected. The protractor is fixedly installed above the support plate, and a pointer is movably installed on one side of the protractor. The end of the pointer is used to install a laser pen. When the laser pen rotates with the pointer, the illumination direction of the catheter weld can be determined.

[0024] Furthermore, the support plate includes a supporting portion and a connecting portion of an integrated structure, the connecting portion is semicircular, the supporting portion is a rectangular plate, and the connecting portion is located in the middle above the supporting portion, protractors are symmetrically installed at both ends above the supporting portion, and a semicircular ring gap is formed between the protractor and the connecting portion, a slide rail is installed inside the semicircular ring gap, and the slide rail is connected to the pointer through a roller, so that the pointer can move on the slide rail through the roller under the action of external force.

[0025] Furthermore, a protractor is installed above the support plate. The protractor is a semicircular structure. A slide rail is fixedly installed on one side of the protractor. The slide rail is connected to the pointer through a roller, so that the pointer can move on the slide rail through the roller under the action of external force.

[0026] Furthermore, a mounting hole is provided at the center of the bottom of the support plate, and the mounting hole is used to place the catheter.

[0027] Furthermore, the X-ray machine supporting tooling includes a supporting plate and lifting legs. The lifting legs are installed at the bottom of the supporting plate, and a support plate and a hoop are installed on the top. The top of the support plate is used to install the X-ray machine, and the hoop is used to fix the X-ray machine.

[0028] Furthermore, the maximum dimension of the X-ray machine supporting tooling space does not exceed 400 mm.

[0029] Compared with the prior art, the X-ray detection method for all-position welds of large-diameter aerospace tank inner conduits created by the present invention has the following advantages:

[0030] (1) The invention creates a method for X-ray detection of weld seams of all-position welds of conduits in large-diameter aerospace tanks, which solves the problems of fixed position of conduits in large-diameter tanks, different plane positions of welds, interference between the surrounding environment and the beam, and difficulty in controlling the direction of illumination. It effectively overcomes all the shortcomings of the prior art in the application of X-ray detection of weld seams of all-position welds of conduits in large-diameter aerospace tanks.

[0031] (2) The X-ray detection method for all-position welds of the duct in a large-diameter aerospace tank created by the present invention can accurately locate the irradiation direction of the ray beam through the angle measurement tooling, and is not affected by the fact that the duct weld has been fixed on the inner wall of the tank and the different angles of the weld plane. It can also effectively eliminate the interference of the surrounding environment structure and achieve two irradiations with an interval of 90° in the irradiation direction required by the standard.

[0032] (3) The invention creates a method for X-ray inspection of all-position weld seams of conduits in large-diameter aerospace tanks. The designed X-ray machine support tooling can be smoothly transported from the tank manhole into the interior of the tank and can be normally installed inside the tank without being disturbed by gas cylinders.

[0033] (4) The invention creates a method for X-ray detection of weld seams in all positions of ducts in large-diameter aerospace tanks, optimizes the arrangement of transillumination, selects according to the specific position of the duct, and eliminates the influence of the surrounding environment structure on the detection process; optimizes the detection parameters, reduces the detection geometric unsharpness, improves the ability to display detailed images, and improves the detection sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0035] Figure 1 Schematic diagram of the position distribution of the gas cylinder conduit in the box in the background technology of the present invention Figure 1 ;

[0036] Figure 2 Schematic diagram of the position distribution of the gas cylinder conduit in the box in the background technology of the present invention Figure 2 ;

[0037] Figure 3 It is a schematic diagram of the pipe welding plane being parallel to the horizontal plane in the background technology of the present invention;

[0038] Figure 4It is a schematic diagram of the perpendicularity between the pipe welding plane and the horizontal plane in the background technology of the present invention;

[0039] Figure 5 Schematic diagram of the arrangement of X-ray detection of the catheter weld in the background technology of the present invention Figure 1 ;

[0040] Figure 6 Schematic diagram of the arrangement of X-ray detection of the catheter weld in the background technology of the present invention Figure 2 ;

[0041] Figure 7 A schematic diagram of a defect missed detection in the background technology of the present invention;

[0042] Figure 8 This is a front view of the angle measuring tool described in an embodiment of the present invention;

[0043] Fig. 9 This is a front view of the X-ray machine support tooling according to an embodiment of the present invention;

[0044] Fig.10 A side view of a X-ray machine support tooling according to an embodiment of the present invention;

[0045] Fig.11 This is a process flow chart of X-ray detection of all-position weld seams of a conduit in a tank according to an embodiment of the present invention;

[0046] Fig.12 It is a schematic diagram of a method for determining the transillumination direction of a weld seam of a conduit in a box according to an embodiment of the present invention;

[0047] Fig.13 It is a schematic diagram of the transillumination arrangement of the catheter in the box according to an embodiment of the present invention.

[0048] Description of reference numerals:

[0049] 1-angle measuring tool; 11-laser pen; 12-pointer; 13-protractor; 14-roller; 15-slide rail; 16-conduit; 17-support plate; 18-confinement plate; 19-bolt; 2-ray machine support tool; 21-hoop; 22-ray machine; 23-support plate; 24-support bolt; 25-support plate; 26-nut; 27-lifting leg; A-weld; B-gas cylinder installation position; C-gas cylinder main line position; D-film; Arrow: direction of ray beam propagation. DETAILED DESCRIPTION

[0050] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0052] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0053] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0054] Glossary:

[0055] X-ray testing: It is a non-destructive testing method that uses the different X-ray absorption rates of defects such as cracks, incomplete penetration, and lack of fusion and the base material to project internal defects of products such as welds onto film, forming images of different morphologies and different blackness, and then judge the internal quality of the product. It is widely used in aerospace, aviation and other industrial fields.

[0056] Blackness: The common logarithm of the ratio of incident light brightness to transmitted light brightness;

[0057] Transillumination arrangement: the relative positions of the workpiece, film, and radiation source during the X-ray inspection process, the direction of the central beam during the inspection process, and the maximum range that can be transilluminated at one time;

[0058] Geometric unsharpness: The image caused by the size of the ray source always has a certain boundary expansion area.

[0059] Negative: Film after exposure and darkroom processing;

[0060] Sensitivity: The degree to which detail of a particular shape can be detected using the radiographic detection technique used;

[0061] Focal length: the distance from the radiation source to the film;

[0062] Exposure: The amount of light energy received by the film during exposure.

[0063] X-ray inspection method for all-position welds of large-diameter aerospace tank inner ducts, such as Fig.11 As shown, the following steps are included:

[0064] S1. Use the angle measuring tool 1 to rotate the laser pen, select two directions without interference, and accurately locate two transillumination directions of the weld with an interval of 90°; preferably, the rotatable angle range of the laser pen 11 is 180°.

[0065] S2, set the 0° and 90° transillumination directions as the 1# film position and the 2# film position respectively;

[0066] S3. Stick the film, lead type and image quality meter on the 1# film position, with the film close to the catheter;

[0067] S4, transport the X-ray machine support tooling 2 into the tank through the manhole, determine the position of the X-ray source in the 0° penetration direction by using a laser pen, and the X-ray source emits a X-ray beam along the 0° penetration direction to pass through the pipe weld;

[0068] S5. Adjust the process parameters of the X-ray machine according to the thickness of the weld to ensure that the X-ray can penetrate the weld of the catheter and reach the film;

[0069] S6, washing the film at position 1#;

[0070] S7. Stick the film on the 2# film position, and make sure the film is close to the catheter;

[0071] S8, determining the position of the radiation source in the 90° transillumination direction by means of a laser pen, and emitting a radiation beam from the radiation source along the 90° transillumination direction through the weld of the catheter;

[0072] S9, after repeating step S5, wash the film in position 2#;

[0073] S10. After washing the film, evaluate whether there are any excessive defects in the weld according to the acceptance standards. The inspection is completed.

[0074] The present invention innovates and optimizes the design of the inspection tooling, the arrangement of transillumination, and the process parameters to achieve X-ray inspection of all-position weld seams in the duct of a large-diameter aerospace tank. The present application optimizes the arrangement of transillumination, selects it according to the specific position of the duct, and eliminates the influence of the surrounding environment structure on the inspection process.

[0075] like Figure 8As shown, the angle measuring tool 1 includes a pointer 12, a protractor 13, a roller 14, a slide rail 15, a support plate 17, a restraining plate 18, and a bolt 19. The restraining plate 18 can be detachably installed under the support plate 17. The restraining plate 18 is used to fix the support plate 17 on the weld of the catheter 16 to be detected. The protractor 13 is fixedly installed above the support plate 17. The pointer 12 is movably installed on one side of the protractor 13. The end of the pointer 12 is used to install a laser pen 11. When the laser pen 11 rotates with the pointer 12, the illumination direction of the weld of the catheter 16 can be determined.

[0076] The laser pen 11 is fixed on the pointer 12 by a cable tie, which is easy to install and inexpensive.

[0077] In one embodiment, the support plate 17 includes a supporting portion and a connecting portion of an integrated structure, the connecting portion is semicircular, the supporting portion is a rectangular plate, and the connecting portion is located in the middle above the supporting portion, the protractor 13 is symmetrically installed at both ends above the supporting portion, and a semicircular annular gap is formed between the protractor 13 and the connecting portion. A slide rail 15 is installed inside the semicircular annular gap, and the slide rail 15 is connected to the pointer 12 through a roller 14, so that the pointer 12 can move on the slide rail 15 through the roller under the action of an external force.

[0078] Preferably, a mounting hole is provided at the bottom center of the support plate 17, and the mounting hole is used to place the catheter 16. The mounting hole is inserted into both sides of the catheter 16, and then the support plate 17 is fixed to the weld of the catheter 16 to be tested by the restraining plate 18 and the bolt 19.

[0079] In another embodiment, a protractor 13 is installed above the support plate 17. The protractor 13 is a semicircular structure. A slide rail 15 is fixedly installed on one side of the protractor 13. The slide rail 15 is connected to the pointer 12 through the roller 4, so that the pointer 12 can move on the slide rail 15 through the roller 14 under the action of external force.

[0080] Preferably, a roller 14 is installed inside the slide rail 15, and the roller 14 is fixedly connected to the pointer 12; preferably, a roller 14 is installed on both sides of the slide rail 15, and both rollers 14 are fixedly connected to the pointer 12. The protractor 13 is connected to the support plate 17 by rivets.

[0081] The use process of the angle measurement tool 1 is as follows: insert the mounting holes into both sides of the weld of the conduit 16, and then fix the support plate 17 on the weld of the conduit 16 to be tested by the restraining plate 18 and the bolt 19. Utilizing the principle that laser propagates in a straight line, by rotating the laser pen 11 (the staff member holds the laser pen 11 and rotates it, so that the laser pen 11 drives the pointer 12 to rotate along the slide rail 15, that is, rotates along the center of the protractor 13), the interference of the surrounding environment structure is tested, and two directions where there is no interference are selected.

[0082] The present application can accurately locate the radiation beam penetration direction through the angle measurement tooling, and is not affected by the fact that the catheter weld has been fixed on the inner wall of the tank and the weld plane is at different angles, and effectively eliminates interference from the surrounding environment structure, achieving two penetrations with an interval of 90° in the penetration direction required by the standard.

[0083] like Fig. 9 and Fig.10 As shown, the X-ray machine support tool 2 includes a band 21, a support plate 23, a support bolt 24, a support plate 25, a nut 26 and a lifting leg 27. The lifting leg 27 is installed at the bottom of the support plate 25, and the support plate 23 and the band 21 are installed on the top. The top of the support plate 23 is used to install the X-ray machine 22, and the band 21 is used to fix the X-ray machine 22. The X-ray machine support tool 2 can be smoothly transported from the tank manhole into the tank, and is not interfered by the gas cylinder 28, and can be normally installed inside the tank.

[0084] The band 21 is fixed to the support plate 25 by means of support bolts 24 and nuts 26 , and also serves to fix the head of the X-ray machine 22 .

[0085] The X-ray machine 22 is fastened with a band 21 and placed on a support plate 23, and the support plate 23 is connected to the support plate 25 by bonding.

[0086] The lifting legs 27 are welded to the support plate 25. During detection, the supporting tooling of the X-ray machine 22 can be placed above the gas cylinder 28 or at other locations. The lifting legs 27 can be a commonly used lifting rod with a lifting function.

[0087] The maximum size of the tooling space does not exceed 400mm, and the entire structure can be transported into the box through the manhole.

[0088] The specific method for determining the process parameters of the weld thickness adjustment X-ray machine is as follows: the interior of a large-diameter aerospace tank is a limited curved space, and the distance between the X-ray source and the film should be shortened as much as possible to reduce the interference of the surrounding environment structure on the detection. However, according to the definition of geometric unsharpness in X-ray detection (see formula 1), when the distance F between the X-ray source and the film decreases, the geometric unsharpness U g The increase in geometric unsharpness will reduce the film's ability to display detailed images and reduce detection sensitivity. Therefore, in order to reduce the geometric unsharpness U g There are two ways to reduce the geometric unsharpness U. g , it is necessary to reduce the size d of the ray source.

[0089]

[0090] U g : Geometric unsharpness;

[0091] d: size of the radiation source;

[0092] T: penetration thickness;

[0093] F: distance from the radiation source to the film;

[0094] Through experiments, it was found that the X-ray inspection process parameters for all-position welds of the inner duct of a large-diameter aerospace tank are shown in Table 1.

[0095] Table 1 X-ray inspection process parameters

[0096] Serial number Thickness range Radiation source size Voltage Exposure focal length Film blackness 1 3<δ≤4mm 1.0mm 75<V≤95kV 30~45mA·min 300~550mm 2.4～3.0 2 3<δ≤4mm 1.0mm 80<V≤100kV 30~45mA·min 550~800mm 2.4～3.0 3 4<δ≤5mm 1.0mm 85<V≤100kV 30~45mA·min 300~550mm 2.4～3.0 4 4<δ≤5mm 1.0mm 90<V≤105kV 30~45mA·min 550~800mm 2.4～3.0 5 5<δ≤6mm 1.0mm 95<V≤105kV 30~45mA·min 300~550mm 2.4～3.0 6 5<δ≤6mm 1.0mm 100<V≤110kV 30~45mA·min 550~800mm 2.4～3.0

[0097] The detection parameters are optimized, the detection geometric unsharpness is reduced, the detail image display capability is improved, and the detection sensitivity is improved.

[0098] The optimal embodiment of the X-ray detection method for all-position welds of large-diameter aerospace tank inner conduits is:

[0099] S1. Install the angle measuring tool on the weld to be measured. Based on the principle that laser propagates in a straight line, rotate the laser pen to test the interference of the surrounding environment structure. Select two directions where there is no interference. With the help of the angle measuring tool, the two illumination directions of the weld with an interval of 90° can be accurately located (such as Fig.12 ); Preferably, the rotatable angle range of the laser pen 11 is 180°.

[0100] S2, set the 0° and 90° transillumination directions as the 1# film position and the 2# film position respectively;

[0101] S3, stick the film, lead type and image quality meter at the 1# film position;

[0102] S4. Transport the X-ray machine support tooling from the manhole into the tank, use the laser pen to determine the position of the X-ray source in the 0° penetration direction, and the X-ray source emits a beam of radiation along the 0° penetration direction through the pipe weld, with the film close to the pipe; the distance F between the X-ray source and the film is controlled within the range of 300 to 800 mm. The specific arrangement is as follows: Fig.13 , fix the X-ray machine with the X-ray machine supporting fixture;

[0103] S5. Adjust the voltage value of the X-ray machine to 75-110 kV according to the thickness of the weld to ensure that the X-ray can penetrate the weld of the catheter and reach the film. The exposure is not less than 20 mA min.

[0104] S6. Turn on the X-ray machine and start transirradiation;

[0105] S7. Turn off the X-ray machine, remove the film from position 1, and send it to the darkroom for processing. And put the film on position 2;

[0106] S8. Use a laser pen to determine the position of the radiation source in the 90° transillumination direction. The radiation source emits a beam of radiation along the 90° transillumination direction through the catheter weld, and the film is close to the catheter. The distance F between the radiation source and the film is controlled within the range of 300 to 800 mm. The specific arrangement is as follows: Fig.13 , fix the X-ray machine with the X-ray machine supporting fixture;

[0107] S9. Adjust the voltage value of the X-ray machine to 75-110 kV according to the thickness of the weld to ensure that the X-ray can penetrate the weld of the catheter and reach the film. The exposure is not less than 20 mA min.

[0108] S10, turn on the X-ray machine and start transirradiation;

[0109] S11. Turn off the X-ray machine, remove the film in position 2, and send it to the darkroom for processing;

[0110] S12. After washing the film, assess whether there are any excessive defects in the weld according to the acceptance standards;

[0111] S13. Testing completed.

[0112] The present application solves the problems of fixed position of the conduit inside a large-diameter tank, different plane positions of the welds, interference between the surrounding environment and the beam, and difficulty in controlling the direction of penetration, and effectively overcomes all the shortcomings of the prior art in the application of X-ray detection of all-position welds of conduits inside large-diameter aerospace tanks.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. X-ray detection method for all-position welds of large-diameter aerospace tank inner ducts, characterized by: The steps include: S1. Use the angle measuring tool to rotate the laser pen, select two directions without interference, and accurately locate the two transillumination directions of the weld with an interval of 90°; S2, use films to locate the 0° and 90° transillumination directions respectively; S3. Transport the X-ray machine support tooling from the manhole into the tank, determine the positions of the two irradiation directions in turn by using a laser pen, and place a film in each direction; S4. The process parameters of the X-ray machine are adjusted according to the thickness of the weld. The X-ray source emits a beam of radiation that passes through the weld of the catheter in two directions of penetration, respectively, so that the beam reaches both films. S5. After developing the two films, assess whether there are any excessive defects in the weld according to the acceptance standards; The angle measuring tool comprises a pointer, a protractor, a support plate and a restraining plate. The restraining plate can be detachably installed under the support plate. The restraining plate is used to fix the support plate on the weld of the catheter to be tested. The protractor is fixedly installed on the top of the support plate. The pointer is movably installed on one side of the protractor. The end of the pointer is used to install a laser pen. When the laser pen rotates with the pointer, the illumination direction of the catheter weld can be determined. The connection method between the support plate and the protractor in the angle measuring tool is one of the following two:

1. The support plate comprises a supporting part and a connecting part of an integral structure. The connecting part is semicircular. The supporting part is It is a rectangular plate, and the connecting part is located in the middle above the supporting part. Protractors are symmetrically installed at both ends above the supporting part, and a semicircular gap is formed between the protractor and the connecting part. A slide rail is installed inside the semicircular gap, and the slide rail is connected to the pointer through a roller, so that the pointer can move on the slide rail through the roller under the action of external force; second, a protractor is installed above the support plate, and the protractor is a semicircular structure. A slide rail is fixedly installed on one side of the protractor, and the slide rail is connected to the pointer through a roller, so that the pointer can move on the slide rail through the roller under the action of external force.

2. The X-ray detection method for all-position welds of the conduit in a large-diameter aerospace tank according to claim 1 is characterized in that: In step S4, the specific method for determining the process parameters of the weld thickness adjustment X-ray machine is as follows: According to the definition of geometric unsharpness in ray detection, the formula can be obtained as follows: U g : Geometric unsharpness; d: ray source size; T: penetration thickness; F: distance from ray source to film; It can be seen that in the present invention, the distance F from ray source to film has been reduced, in order to reduce the geometric unsharpness U g , it is necessary to reduce the size d of the ray source.

3. The X-ray detection method for all-position welds of large-diameter aerospace tank inner conduits according to claim 1 is characterized in that: The laser pointer can rotate at an angle of 180°.

4. The X-ray detection method for all-position welds of large-diameter aerospace tank inner conduits according to claim 1 is characterized in that: A mounting hole is provided at the center of the bottom of the support plate, and the mounting hole is used to place the catheter.

5. The X-ray detection method for all-position welds of the conduit in a large-diameter aerospace tank according to claim 1 is characterized in that: The X-ray machine support tooling includes a support plate and lifting legs. The lifting legs are installed at the bottom of the support plate, and a support plate and a hoop are installed on the top. The top of the support plate is used to install the X-ray machine, and the hoop is used to fix the X-ray machine.

6. The X-ray detection method for all-position welds of the conduit in a large-diameter aerospace tank according to claim 1 is characterized in that: The maximum size of the X-ray machine support tooling space shall not exceed 400mm.

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