A special tool and method for ultrasonic testing of the back curved blade root of a compressor rotor blade

Abstract

The present invention discloses a special tooling and method for ultrasonic detection of the back curved surface blade root of a compressor moving blade, comprising a main support, a deflector, a probe clamping module, a bottom drive module, and a front sliding module. The deflector is located in the middle of the main support, and is connected to the main support by a guide rail. The bottom drive module and the front sliding module are connected to the main support by a rotating shaft, and the probe clamping module is connected to the deflector by a stud. The present invention can perform fully automated ultrasonic detection of the back curved surface blade root of a compressor moving blade during temporary shutdown of the unit. It has the functions of recording probe position information to generate a C-scan image, keeping the distance between the front end of the probe and the blade root platform constant and the coupling strength of the probe consistent, and can control the rotation of the probe in a three-dimensional plane. It has the ability to detect blade root cracks with different orientation angles, and the detection results are highly accurate and stable.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic nondestructive testing, and in particular is a special tool and method for ultrasonic testing of the back curved surface blade root of a compressor rotor blade. Background Art

[0002] The compressor moving blades are the core components of the compressor that do work on the gas turbine inlet gas. They are composed of two parts: the blade body and the blade root. The blade body is the part where the blade interacts with the airflow, and the blade root is the part where the blade is assembled to the rotor disc slot. Dovetail blade roots are generally used. As a rotating machine, the compressor moving blades are subjected to complex alternating stresses during service, and are prone to crack defects at the back arc surface and inner arc surface variable cross-section position of the dovetail blade root, seriously affecting the safe and stable operation of the unit. Therefore, in order to ensure the safety and reliability of the gas turbine compressor moving blades, it is very necessary to regularly perform non-destructive testing on the compressor moving blade roots. Especially when the moving blades are not disassembled for maintenance, the effective detection of crack defects on the inner arc surface and back arc surface of the blade root has become the focus of current gas turbine operation and maintenance technology researchers.

[0003] Ultrasonic testing has the advantages of not being restricted by the shape and size of components, strong on-site adaptability, simple operation of equipment, no potential harm to the human body, high accuracy of test results, and good repeatability. It is very suitable for in-situ testing of complex structural components without disassembly. However, since the back arc surface of the compressor moving blade is a large curvature variable cross-section structure, the minimum width of the back arc surface blade root platform is only about 2mm, and there is no condition to place a micro phased array ultrasonic linear array longitudinal wave straight probe for vertical downward detection from the platform. A micro phased array ultrasonic linear array oblique probe can be used to couple from the inner arc surface of the moving blade body, and the sound wave propagates obliquely through the blade body to the back arc surface blade root, so as to achieve effective detection of crack defects at the variable cross-section position of the back arc surface blade root. Since the inner arc surface of the blade body is a variable cross-section curved surface structure, manual scanning cannot control the consistency of the scanning path and the uniformity of the coupling force, and it is difficult to ensure the reliability and repeatability of the test results. A foreign company has developed an ultrasonic inspection and scanning tool for the back curved surface of a moving blade root (patent number: US8365584B1). However, the tool has the following limitations when actually used on site: 1. It does not have the tool stroke position display function, and cannot obtain the specific position data of the probe from the air inlet side to the air outlet side of the moving blade in real time, and cannot generate an ultrasonic C-scan image, making it difficult to accurately measure the length of crack defects; 2. The front end of the tool lacks a positioning and sliding device with the blade root platform. Positioning only by the front end of the probe wedge block will result in inaccurate positioning due to rounded sliding and easy damage to the wedge clamping hole; 3. The three legs of the tool that are in contact with the blade body are fixed structures, and rigid friction with the blade is required during scanning. The head of the leg is The low-friction plastic cap will reduce the suction force of the tooling, affecting the coupling force and detection reliability of the probe; 4. It does not have the ability of fully automatic detection, and needs to rely on the joystick for manual push-pull scanning, which consumes a lot of manpower and time; the patent (US7302851B2) has designed a fully automatic detection tooling for ultrasonic detection of the back curved surface of the blade root of the moving blade, but the tooling is a linear lead screw module structure, which has the following limitations: 1. The lead screw is a linear structure, that is, the probe stroke is a straight line, and the inner curved surface of the moving blade is a variable cross-section curved surface structure. The distance from the scanner to the blade body changes with the position, and the elastic force of the spring that presses the probe will change due to the distance, resulting in uneven coupling force of the probe, which seriously affects the consistency and reliability of the echo signal. In addition, the back arc surface blade root platform is an arc-shaped structure. When the probe is scanning, the distance between the probe and the platform needs to be controlled to a constant value. It is difficult for a straight line stroke to meet the above technical requirements; 2. The probe can only move in two plane dimensions and does not have the ability to adjust in a three-dimensional plane. For crack defects with a certain angle orientation, its detection sensitivity is greatly reduced; 3. The tooling needs to be positioned with the help of the back arc surface of the adjacent blade. The tooling is not fixed at the inlet and outlet edges of the blade. During use, the tooling is prone to axial displacement, affecting the detection reliability.At the same time, the tooling is large in size, and it is cumbersome to disassemble and install the tooling for on-site inspection. The patent (US7654143B2) designs an ultrasonic inspection tooling for the back curved blade root of a moving blade. The tooling uses a hinge structure to fix the blade inlet and outlet edges, overcoming the defect that the tooling is prone to axial displacement. However, this structure requires disassembly and assembly of the tooling and rotor turning once for each blade inspection, resulting in low inspection efficiency. At the same time, the tooling is a guide rail structure, and the probe travel is also a straight line, which also has the limitations of Patent 2. In addition, the tooling does not have the function of rotating the probe in a three-dimensional plane. Summary of the invention

[0004] The purpose of the present invention is to provide a special tool and method for ultrasonic detection of the back curved surface of the blade root of a compressor moving blade in response to the limitations of the currently disclosed ultrasonic detection tool for the back curved surface of the blade root of a gas turbine moving blade, such as the inability to fully automatically scan and record position information, the inability to maintain a constant distance between the probe and the blade root platform, the inability to maintain a constant coupling force of the probe, the inability of the probe to rotate in a three-dimensional plane, and the need for a large amount of rotor turning resulting in low detection efficiency. The tool and method are simple and easy to operate, and can perform fully automated ultrasonic detection of the back curved surface of the blade root of a compressor moving blade during temporary shutdown of the unit. The tool and method have the functions of recording probe position information to generate a C-scan image, maintaining a constant distance between the front end of the probe and the blade root platform and consistent probe coupling force, and being able to control the rotation of the probe in a three-dimensional plane. The tool and method have the ability to detect blade root cracks at different orientation angles, thereby greatly improving detection reliability, accuracy and stability.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A special tooling for ultrasonic detection of the back curved blade root of a compressor rotor blade comprises a main frame, a deflector, a probe clamping module, a bottom drive module and a front sliding module; the deflector is located in the middle of the main frame and is connected to the main frame by a guide rail, the bottom drive module and the front sliding module are connected to the main frame by a rotating shaft, and the probe clamping module is connected to the deflector by a stud.

[0007] A further improvement of the present invention is that the main bracket is a herringbone structure, including a main bracket, a circular T-shaped guide rail, a first angle dial, bottom support ribs, front end support ribs and a stud platform; the first angle dial is arranged on the surface of the circular T-shaped guide rail, the three bottom support ribs are distributed in a triangular shape around the main bracket, and the two front end support ribs are located at the front end of the main bracket.

[0008] A further improvement of the present invention is that the steering gear is a disc structure, including a disc, a T-shaped guide groove, a stud hole, a second angle scale and a positioning stud; the T-shaped guide groove and the circumferential T-shaped guide of the main frame are positive and negative mold structures, which are in sliding fit, two stud holes are arranged inside the disc, the second angle scale is set in the first angle scale, and the positioning stud is arranged on the stud platform, which is used to fix the position of the steering body and the main frame;

[0009] The probe clamping module includes an inner-shaped support arm, a U-shaped stud, a spring, a first nut, a second nut, a clamping stud and an ultrasonic probe; the top of the inner-shaped support arm is rotatably connected to the support rod at the bottom end of the U-shaped stud and is fixed by the first nut; the bottom of the inner-shaped support arm is a left and right parallel flange, and the ultrasonic probe is rotatably fixed by two clamping studs; the U-shaped stud is passed through the stud hole of the steering gear, the spring is sleeved in the U-shaped stud, and the second nut is screwed on the top of the U-shaped stud;

[0010] The bottom driving module includes a first magnetic wheel, a motor and a first rotating shaft; the first magnetic wheel is rotatably connected to the bottom supporting rib of the main frame through the first rotating shaft, the motor is fixed to the side of the bottom supporting rib and connected to the first magnetic wheel through the first rotating shaft, and the motor has both driving and position encoding functions;

[0011] The front sliding module comprises a second magnetic wheel and a second rotating shaft, and the second magnetic wheel is connected to the front supporting rib of the main frame through the second rotating shaft.

[0012] A further improvement of the present invention is that the bottom support ribs and the front support ribs of the main bracket are both bayonet structures and can be replaced with bottom support ribs and front support ribs of different heights. The first angle dial is set at 0°~360°, and the unit division is 1°.

[0013] A further improvement of the present invention is that the positioning stud of the steering gear is a hexagonal external thread stud, and the second angle dial is set at 0° to 360°, with a unit division of 0.9°.

[0014] A further improvement of the present invention is that the first nut and the second nut of the probe clamping module are both external knurled cylindrical nuts, and the clamping stud is an internal hexagonal external thread stud.

[0015] A further improvement of the present invention is that the ultrasonic probe is a linear array phased array probe, which is composed of a probe body and a wedge, and the coupling agent conduit is connected to the interface of the wedge.

[0016] A further improvement of the present invention is that the upper interface of the wedge block of the probe clamping module is a double-conical interface.

[0017] A further improvement of the present invention is that the first magnetic wheel of the bottom driving module and the second magnetic wheel of the front sliding module are both strong NdFeB magnets, and the first rotating shaft and the second rotating shaft are both single keyway cylindrical structures.

[0018] A method for ultrasonic detection of the back curved blade root of a compressor rotor blade, based on a special tool for ultrasonic detection of the back curved blade root of a compressor rotor blade, comprising:

[0019] Connect the T-shaped guide groove of the steering gear with the circumferential T-shaped guide of the main bracket, set the angle value, and tighten the positioning studs;

[0020] Insert the spring into the U-shaped stud, insert the U-shaped stud into the stud hole, and tighten the second nut; put the ultrasonic probe into the inner-shaped support arm, and tighten the clamping stud; insert the inner-shaped support arm into the bottom support rod of the U-shaped stud, and tighten the first nut; adsorb the first magnetic wheel to the inner curved blade body of the moving blade, and adsorb the second magnetic wheel to the inner curved blade root platform of the moving blade; connect the coupling agent addition tube to the interface of the ultrasonic probe, connect the ultrasonic probe to the phased array ultrasonic detector, and connect the motor to the stroke control system; start the motor, and the tooling scans along the air intake side to the air outlet side, collects ultrasonic echoes and position information, and generates ultrasonic results A\B\C\D views; rotate the steering gear to another angle and repeat the scan; if it is necessary to stop or retreat the scan in the middle, the motor can be adjusted to start or stop or turn.

[0021] The present invention has at least the following beneficial technical effects:

[0022] The present invention provides a special tool and method for ultrasonic detection of the back curved surface and blade root of a compressor moving blade. The tool and method can be used to perform fully automated ultrasonic detection of the back curved surface and blade root of a compressor moving blade during temporary shutdown of the unit. The tool has the functions of recording probe position information to generate a C-scan image, keeping a constant distance between the front end of the probe and the blade root platform and consistent probe coupling strength, and controlling the probe to rotate in a three-dimensional plane. The tool and method have the ability to detect blade root cracks with different orientation angles. The detection results have high accuracy and good stability, and can greatly improve the portability and reliability of quality status monitoring of the back curved surface and blade root of a compressor moving blade, thereby ensuring safe and stable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a structural schematic diagram of a special tool for ultrasonic detection of the back curved surface blade root of a compressor rotor blade.

[0024] Figure 2 The present invention is a cross-sectional view of a special tool for ultrasonic testing of the back curved surface of a compressor blade root.

[0025] Figure 3 It is a top view of a special tool for ultrasonic detection of the back curved surface and blade root of a compressor rotor blade according to the present invention.

[0026] Description of reference numerals:

[0027] 1. Main frame, 2. Steering gear, 3. Probe clamping module, 4. Bottom driving module, 5. Front sliding module;

[0028] 101. main bracket, 102. circular T-shaped guide rail, 103. first angle dial, 104. bottom support rib, 105. front support rib, 106. stud platform; 201. disc, 202. T-shaped guide rail groove, 203. stud hole, 204. second angle dial, 205. positioning stud; 301. inner-shaped support arm, 302. U-shaped stud, 303. spring, 304. first nut, 305. second nut, 306. clamping stud, 307. ultrasonic probe, 308. interface, 309. support rod, 310. probe body, 311. wedge; 401. first magnetic wheel, 402. motor, 403. first rotating shaft; 501. second magnetic wheel, 502. second rotating shaft. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings.

[0030] Refer to the attached Figure 1 , Attachment Figure 2 and attached Figure 3 The present invention provides a special tool for ultrasonic detection of the back curved blade root of a compressor rotor blade, comprising a main frame 1, a deflector 2, a probe clamping module 3, a bottom driving module 4, and a front sliding module 5. The deflector 2 is located in the middle of the main frame 1 and is connected to the main frame 1 by a guide rail, the bottom driving module 4 and the front sliding module 5 are connected to the main frame 1 by a rotating shaft, and the probe clamping module 3 is connected to the deflector 2 by a stud.

[0031] The main support 1 is a herringbone structure, including a main support 101, a circumferential T-shaped guide rail 102, a first angle dial 103, a bottom support rib 104, a front support rib 105, and a stud platform 106. The first angle dial 103 is arranged on the surface of the circumferential T-shaped guide rail 102, and the scale is processed by electric spark machining. The three bottom support ribs 104 are distributed around the main support 101 in a triangular shape and are parallel oriented. The two front support ribs 105 are located at the front end of the main support 101 and are parallel oriented. The bottom support rib 104 and the front support rib 105 are both U-shaped structures, with an axial hole at the bottom, and the upper part of the main support 1 is hollowed out for the connection line of the ultrasonic probe 307 and the motor 402 and the coupling agent addition tube to pass through. The T-shaped guide rail 102 can ensure the rotation accuracy and stability with the steering gear 2.

[0032] The steering gear 2 is a disc structure, including a disc 201, a T-shaped guide groove 202, a stud hole 203, a second angle dial 204, and a positioning stud 205. The T-shaped guide groove 202 and the circumferential T-shaped guide 102 of the main frame 1 are positive and negative mold structures, which are in sliding fit. Two stud holes 203 are provided inside the disc 201, and the two stud holes 203 are located on the same straight line. The second angle dial 204 is set inside the first angle dial 103, and the positioning stud 205 is set on the stud platform 106. The surface scale of the second angle dial 204 is processed by electric spark machining. The ultrasonic probe 307 can be rotated in the X-axis plane by rotating the steering gear 2. This feature can ensure the effective detection of crack defects with a certain orientation angle at the blade root position. The steering body 2 and the main bracket 1 are kept fixed in position by the positioning studs 205 in the stud platform 106. The rotation angle can be obtained by the difference in readings between the first angle dial 103 and the second angle dial 204.

[0033] The probe clamping module 3 includes an inner-shaped support arm 301, a U-shaped stud 302, a spring 303, a first nut 304, a second nut 305, a clamping stud 306, an ultrasonic probe 307, and an interface 308. The top of the inner-shaped support arm 301 is rotatably connected to the support rod 309 at the bottom end of the U-shaped stud 302, and is fixed by the first nut 304, so that the ultrasonic probe 307 can be rotated on the Y-axis plane. This feature can ensure that the ultrasonic probe 307 is self-adaptive to the curved surface structure of the back of the moving blade, and ensure coupling stability. The bottom of the inner-shaped support arm 301 is a left and right parallel flange, and the ultrasonic probe 307 is rotatably fixed by two clamping studs 306, so that the ultrasonic probe 307 can be rotated on the Z-axis plane. This feature can ensure that the ultrasonic probe 307 is self-adaptive with the change of the longitudinal shape of the moving blade surface, and ensure coupling stability. The U-shaped stud 302 is inserted into the stud hole 203 of the steering gear 2, the spring 303 is sleeved in the U-shaped stud 302, and the second nut 305 is screwed on the top of the U-shaped stud 302. This feature enables the ultrasonic probe 307 to couple with the blade body with a stable and consistent force, ensuring the reliability of the echo.

[0034] The bottom drive module 4 includes a first magnetic wheel 401, a motor 402, and a first rotating shaft 403. The first magnetic wheel 401 is rotatably connected to the bottom support rib 104 of the main support 1 through the first rotating shaft 403. The motor 402 is fixed to the side of the bottom support rib 104 and connected to the first magnetic wheel 401 through the first rotating shaft 403. The motor 402 has both driving and position encoding functions. This feature can realize full automation of ultrasonic detection. The motor 402 is a servo motor and has the function of encoding, which can realize real-time recording of the position information of the ultrasonic probe 307. In addition, the first magnetic wheel 401 is designed to be in line contact with the blade body. In addition, the triangular herringbone structure can achieve seamless fitting with the curved blade body of the moving blade without the need for special structural profiling.

[0035] The front sliding module 5 includes a second magnetic wheel 501 and a second rotating shaft 502. The second magnetic wheel 501 is connected to the front support rib 105 of the main frame 1 through the second rotating shaft 502. This feature can achieve a fixed distance between the ultrasonic probe 307 and the curved inner surface blade root platform, which is conducive to ensuring the consistency of the crack defect echo signal and improving the quantitative accuracy of the defect depth.

[0036] The bottom support rib 104 and the front support rib 105 of the main support 1 are both bayonet structures, and the bottom support rib 104 and the front support rib 105 of different heights can be replaced and installed. The first angle dial 103 is set to 0°~360°, and the unit division is 1°. The design of the front support rib 105 of different heights can be replaced to realize the detection of blade roots of moving blades of different sizes. The design of the bottom support rib 104 of different heights can realize the detection using ultrasonic probes 307 of different specifications and sizes.

[0037] The positioning stud 205 of the steering gear 2 is a hexagonal external thread stud, and the second angle dial 204 is set to 0° to 360°, with a unit division of 0.9°. The angle misalignment and misalignment amplification design of the first angle dial 103 and the second angle dial 204 can achieve a maximum rotation angle measurement accuracy of 0.1°, which can perform high-precision positioning of the rotation position of the ultrasonic probe 307 in the X-axis plane.

[0038] The first nut 304 and the second nut 305 of the probe clamping module 3 are both external knurled cylindrical nuts. The external knurling design can realize the manual quick disassembly and assembly of the nuts at the detection site. The clamping stud 306 is a hexagonal external thread stud. The ultrasonic probe 307 is a linear array phased array probe, which is composed of a probe body 310 and a wedge block 311. The coupling agent conduit is connected to the interface 308 of the wedge block 311, which can ensure the stable addition of coupling agent during the detection and scanning process, and improve the detection reliability.

[0039] The first magnetic wheel 401 of the bottom driving module 4 and the second magnetic wheel 501 of the front sliding module 5 are both strong NdFeB magnets. The enhanced magnetic design can ensure the firm connection between the tooling and the blade during inspection and prevent the tooling from accidentally falling off. The first rotating shaft 403 and the second rotating shaft 502 are both single keyway cylindrical structures.

[0040] The interface 308 on the wedge block 311 of the probe clamping module 3 is a double-conical interface. This design can strengthen the connection between the coupling agent adding tube and the interface to prevent the coupling agent adding tube from loosening during the scanning process.

[0041] Refer to the attached Figure 1 , Attachment Figure 2 and attached Figure 3 In practical application, the method of using the present invention is as follows:

[0042] 1. Connect the T-shaped guide groove 202 of the steering gear 2 with the circumferential T-shaped guide rail 102 of the main frame 1, set the angle value, and tighten the positioning stud 205;

[0043] 2. Insert the spring 303 into the U-shaped stud 302, insert the U-shaped stud 302 into the stud hole 203, and tighten the second nut 305;

[0044] 3. Place the ultrasonic probe 307 into the inner-shaped support arm 301 and tighten the clamping stud 306;

[0045] 4. Insert the inner-shaped support arm 301 into the bottom support rod 309 of the U-shaped stud 302, and tighten the first nut 304;

[0046] 5. Adsorb the first magnetic wheel 401 to the inner curved blade body of the moving blade, and adsorb the second magnetic wheel 501 to the inner curved blade root platform of the moving blade;

[0047] 6. Connect the coupling agent adding tube to the interface 308 of the ultrasonic probe 307, connect the ultrasonic probe 307 to the phased array ultrasonic detector, and connect the motor 402 to the stroke control system;

[0048] 7. Start the motor 402, and the tooling scans from the air inlet side to the air outlet side, collects ultrasonic echo and position information, and generates A\B\C\D views of ultrasonic results;

[0049] 8. Rotate the steering gear 2 to another angle and repeat the scanning. If you need to stop or retract the scanning, you can adjust the motor 402 to start, stop or turn.

[0050] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A special tool for ultrasonic testing of the back curved blade root of a compressor rotor blade, characterized in that: The invention comprises a main frame (1), a steering gear (2), a probe clamping module (3), a bottom driving module (4) and a front sliding module (5); the steering gear (2) is located in the middle of the main frame (1) and is connected to the main frame (1) by a guide rail; the bottom driving module (4) and the front sliding module (5) are connected to the main frame (1) by a rotating shaft; and the probe clamping module (3) and the steering gear (2) are connected by a stud. The main support (1) is a herringbone structure, comprising a main support (101), a circumferential T-shaped guide rail (102), a first angle dial (103), a bottom support rib (104), a front support rib (105) and a stud platform (106); the first angle dial (103) is arranged on the surface of the circumferential T-shaped guide rail (102), three bottom support ribs (104) are distributed in a triangular shape around the main support (101), and two front support ribs (105) are located at the front end of the main support (101); The steering gear (2) is a disc structure, comprising a disc (201), a T-shaped guide groove (202), a stud hole (203), a second angle dial (204) and a positioning stud (205); the T-shaped guide groove (202) and the circumferential T-shaped guide rail (102) of the main frame (1) are positive and negative mold structures, and are in sliding fit; two stud holes (203) are arranged inside the disc (201); the second angle dial (204) is sleeved inside the first angle dial (103); and the positioning stud (205) is arranged on the stud platform (106) for fixing the positions of the steering gear (2) and the main frame (1); The probe clamping module (3) comprises an inner-shaped support arm (301), a U-shaped stud (302), a spring (303), a first nut (304), a second nut (305), a clamping stud (306) and an ultrasonic probe (307); the top of the inner-shaped support arm (301) is rotatably connected to a support rod (309) at the bottom end of the U-shaped stud (302) and is fixed by the first nut (304); the bottom of the inner-shaped support arm (301) is a left and right parallel flange, and the ultrasonic probe (307) is rotatably fixed by two clamping studs (306); the U-shaped stud (302) is inserted into a stud hole (203) of the steering gear (2); the spring (303) is sleeved in the U-shaped stud (302), and the second nut (305) is screwed on the top of the U-shaped stud (302); The bottom driving module (4) comprises a first magnetic wheel (401), a motor (402) and a first rotating shaft (403); the first magnetic wheel (401) is rotatably connected to the bottom supporting rib (104) of the main frame (1) via the first rotating shaft (403); the motor (402) is fixed to the side of the bottom supporting rib (104) and connected to the first magnetic wheel (401) via the first rotating shaft (403); the motor (402) has both driving and position encoding functions; The front sliding module (5) comprises a second magnetic wheel (501) and a second rotating shaft (502), and the second magnetic wheel (501) is connected to the front supporting rib (105) of the main frame (1) via the second rotating shaft (502).

2. The special tooling for ultrasonic testing of the back curved blade root of a compressor rotor blade according to claim 1, characterized in that: The bottom support rib (104) and the front support rib (105) of the main frame (1) are both of a bayonet structure and can be replaced to install the bottom support rib (104) and the front support rib (105) of different heights. The first angle dial (103) is set at 0° to 360°, and the unit division is 1°.

3. The special tooling for ultrasonic testing of the back curved blade root of a compressor rotor blade according to claim 1, characterized in that: The positioning stud (205) of the steering gear (2) is a hexagonal external thread stud, and the second angle dial (204) is set to 0° to 360°, with a unit division of 0.9°.

4. The special tooling for ultrasonic testing of the back curved blade root of a compressor rotor blade according to claim 1, characterized in that: The first nut (304) and the second nut (305) of the probe clamping module (3) are both external knurled cylindrical nuts, and the clamping stud (306) is a hexagonal external thread stud.

5. The special tooling for ultrasonic testing of the back curved blade root of a compressor rotor blade according to claim 1, characterized in that: The ultrasonic probe (307) is a linear array phased array probe, which is composed of a probe body (310) and a wedge block (311), and the coupling agent conduit is connected to the interface (308) of the wedge block (311).

6. The special tooling for ultrasonic testing of the back curved blade root of a compressor rotor blade according to claim 5, characterized in that: The upper interface (308) of the wedge block (311) of the probe clamping module (3) is a double-conical interface.

7. The special tooling for ultrasonic testing of the back curved blade root of a compressor rotor blade according to claim 5, characterized in that: The first magnetic wheel (401) of the bottom driving module (4) and the second magnetic wheel (501) of the front sliding module (5) are both neodymium iron boron strong magnets, and the first rotating shaft (403) and the second rotating shaft (502) are both single keyway cylindrical structures.

8. A method for ultrasonic testing the back curved blade root of a compressor rotor blade, characterized in that: The method is based on a special tool for ultrasonic testing of the back curved blade root of a compressor rotor blade according to any one of claims 5 to 7, comprising: The T-shaped guide groove (202) of the steering gear (2) is matched and connected with the circumferential T-shaped guide rail (102) of the main frame (1), the angle value is set, and the positioning stud (205) is tightened; The spring (303) is inserted into the U-shaped stud (302), the U-shaped stud (302) is inserted into the stud hole (203), and the second nut (305) is tightened; the ultrasonic probe (307) is placed in the inner-shaped support arm (301), and the clamping stud (306) is tightened; the inner-shaped support arm (301) is inserted into the bottom support rod (309) of the U-shaped stud (302), and the first nut (304) is tightened; the first magnetic wheel (401) is adsorbed on the inner curved surface of the moving blade, and the second magnetic wheel (501) is adsorbed on the inner curved surface of the moving blade. The blade root platform of the inner curved surface of the moving blade; connecting the coupling agent adding tube to the interface (308) of the ultrasonic probe (307), connecting the ultrasonic probe (307) to the phased array ultrasonic detector, and connecting the motor (402) to the stroke control system; starting the motor (402), the tooling scans along the air inlet side to the air outlet side, collects ultrasonic echo and position information, and generates ultrasonic result A\B\C\D views; rotating the steering gear (2) to another angle, and repeating the scanning; if it is necessary to stop or retract the scanning in the middle, the motor (402) can be adjusted to start or stop or turn to proceed.

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