A method and device for phased array ultrasonic testing of a middle shaft of a M701F gas turbine rotor

Abstract

This invention discloses a phased array ultrasonic testing method and apparatus for the intermediate shaft of an M701F gas turbine rotor, belonging to the field of non-destructive testing technology. The method includes first cleaning the outer surface of the shaft and installing probe wedges with matching curvature; setting the fan-shaped scanning angle and focusing rule; using a reference test block for TCG and sensitivity calibration; then driving the probe to perform a circumferential scan and simultaneously acquiring scan data with positional information; and finally performing defect identification and quantitative evaluation. The apparatus includes a pre-detection preparation unit, a focusing rule setting unit, a TCG calibration unit, a scanning detection unit, and a data analysis and imaging unit. This invention solves the technical problem of difficulty in detecting and quantitatively evaluating defects in the rounded area inside the intermediate shaft of the rotor, and has the advantages of high detection sensitivity, good reliability, and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, specifically to a phased array ultrasonic testing method and device for the intermediate shaft of an M701F gas turbine rotor. Background Technology

[0002] As a key component connecting the compressor and turbine rotor, the intermediate shaft of the M701F gas turbine rotor is prone to stress concentration in its internal rounded region under high-speed rotation and alternating loads, making it a high-risk area for fatigue crack initiation. Due to the special structure of this part, cracks usually originate from the internal rounded surface and propagate to the outer surface of the intermediate shaft, posing a significant challenge to traditional detection methods.

[0003] Currently, the main methods for inspecting these types of components are conventional ultrasonic testing and magnetic particle testing. Conventional ultrasonic testing has the following limitations: 1) the single beam angle is difficult to adapt to the elimination of interference echoes caused by rounded geometry; 2) the detection rate of minute defects is low; 3) the accuracy of defect location and quantification is insufficient. Magnetic particle testing is only suitable for surface defects and cannot detect cracks in the internal rounded regions.

[0004] Although phased array ultrasonic testing technology has the ability to deflect and focus sound beams, its direct application to this specific area still has the following problems: 1) The geometric position of the echo of the crack and the rounded structure are close, making crack identification difficult; 2) There is a lack of reference test blocks and testing processes; 3) The stability of probe coupling is difficult to guarantee during on-site testing; 4) There is a lack of reliable basis for quantitative assessment of cracks in the rounded area.

[0005] Therefore, there is an urgent need to develop a targeted and reliable dedicated testing method and system to solve the problem of effectively detecting cracks in the rounded area inside the intermediate shaft of the M701F gas turbine rotor. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a phased array ultrasonic testing method and device for the intermediate shaft of an M701F gas turbine rotor. This invention, through optimization of the reference test block, contour scanner, and testing process, achieves effective coverage and accurate detection of the internal rounded region by an ultrasonic beam incident from the outer surface of the shaft, solving the technical problem of difficulty in detecting and quantitatively assessing defects in this area.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor includes the following steps: S1: Preparation before testing Clean the outer surface of the rotor intermediate shaft to be inspected to ensure it is free of dirt and severe corrosion; select and install phased array probe wedges with appropriate curvature according to the outer diameter of the intermediate shaft and the probe coupling area; adjust the flexible contour scanner and firmly install the scanner on the outer surface of the predetermined scanning shaft section of the intermediate shaft; S2: Focusing Rule Settings The focusing method is selected as projection focusing, with the focal point located near the axial position of the rounded area, and the focal depth covering the entire depth range of the rounded area. S3: TCG Calibration TCG calibration was performed using rectangular grooves on a reference test block to eliminate the influence of refraction angle and sound path on the ultrasonic echo amplitude, and the detection sensitivity was determined based on the rectangular grooves. S4: Scanning Detection The phased array probe is fixed on the flexible contour scanner, and the phased array probe is driven to perform uniform scanning along the circumference of the rotor. The encoder records the scanning position of the phased array probe in real time, and the phased array flaw detector synchronously collects and stores the phased array sector scanning signal data with circumferential position information. S5: Data Analysis and Imaging The collected data is analyzed offline. Phased array sector scanning images are used for preliminary identification and characterization of defects. The depth and height of the defects are measured, the corresponding circumferential position is read from the encoder, and the circumferential shape of the defects is measured.

[0008] A further improvement of the present invention is that the rectangular groove is machined at the middle of the rounded arc, the length direction of the groove is parallel to the circumferential direction, and the depth direction is perpendicular to the surface at the location.

[0009] A further improvement of the present invention is that the rectangular groove is a series of grooves of different sizes, with a depth of 0.2mm-3mm and a length of 5mm.

[0010] A further improvement of the present invention is that the probe wedge is a transverse wave wedge, and the lower surface of the wedge is in the form of an AOD or a plane, ensuring that the maximum gap between the lower surface of the wedge and the coupling surface is less than 0.5 mm.

[0011] A further improvement of the present invention is that the frequency range of the phased array probe is 5-10MHz and the number of array elements is not less than 64, so as to ensure sufficient penetration and resolution.

[0012] A further improvement of the present invention is that the axial position of the flexible contour scanner in step S1 is determined according to the position of the phased array probe, and the axial position of the phased array probe is determined by obtaining the optimal refraction angle through experiments on a reference test block.

[0013] A further improvement of the present invention is that the circumferential scanning in step S4 should cover the entire outer circumference of the intermediate shaft without causing axial displacement.

[0014] An M701F type phased array ultrasonic testing device for intermediate shaft of gas turbine rotor, comprising: Preparation unit before inspection: Clean the outer surface of the rotor intermediate shaft to be inspected to ensure that there is no dirt or severe corrosion; select and install phased array probe wedges with appropriate curvature according to the outer diameter of the intermediate shaft and the probe coupling area; adjust the flexible contour scanner and firmly install the scanner on the outer surface of the predetermined scanning shaft section of the intermediate shaft; Focusing rule setting unit: Select projection focusing as the focusing method, with the focal position near the axial position of the rounded area and the focal depth covering the entire depth range of the rounded area; TCG calibration unit: TCG calibration is performed using rectangular grooves on the reference test block to eliminate the influence of refraction angle and sound path on the ultrasonic echo amplitude, and the detection sensitivity is determined based on the rectangular grooves; Scanning and detection unit: The phased array probe is fixed on the flexible contour scanner, and the phased array probe is driven to perform uniform scanning along the circumference of the rotor. The encoder records the scanning position of the phased array probe in real time. The phased array flaw detector synchronously collects and stores the phased array sector scanning signal data with circumferential position information. Data Analysis and Imaging Unit: Performs offline analysis on the collected data, uses phased array sector scanning images for preliminary identification and characterization of defects, measures the depth and height of defects, reads the corresponding circumferential position from the encoder, and measures the circumferential shape of defects.

[0015] A further improvement of the present invention is that, in the TCG calibration unit, the rectangular groove is machined at the middle position of the rounded arc, the length direction of the groove is parallel to the circumferential direction, and the depth direction is perpendicular to the surface at the location.

[0016] A further improvement of the present invention is that, in the TCG calibration unit, the rectangular groove is a series of grooves of different sizes, with a depth of 0.2mm-3mm and a length of 5mm.

[0017] Compared with the prior art, the present invention has at least the following beneficial technical effects: This invention provides a phased array ultrasonic testing method and device for the intermediate shaft of an M701F gas turbine rotor. It employs a large-aperture phased array probe combined with projection focusing technology to form a focal point covering the depth direction in the rounded area. Simultaneously, it extracts echo characteristics distinct from the rounded structure by using the echo from a grooved reference block, thus improving detection sensitivity. A contour scanner enables semi-automatic scanning, allowing for complete circumferential testing with a single setup. The fan-shaped scan covers all hazardous areas of the rounded section in one pass, eliminating the need for multiple probe angle changes as with conventional UTs, significantly improving detection efficiency. The contour scanner design ensures stable coupling between the probe and the curved surface, reducing reliance on operator experience and technique, and improving detection reliability and repeatability. Finally, the contour scanner, combined with a high-precision encoder, enables precise spatial positioning of defects. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor according to the present invention.

[0020] Figure 2 This is a diagram of a phased array ultrasonic testing system for the intermediate shaft of a gas turbine rotor of type M701F, according to the present invention.

[0021] Figure 3 This is a partial schematic diagram and projection focus image of phased array ultrasonic testing of the intermediate shaft of a gas turbine rotor of type M701F according to the present invention.

[0022] Figure 4 This is an overall diagram of the phased array ultrasonic testing of the intermediate shaft of the M701F gas turbine rotor according to the present invention.

[0023] Figure 5 This is a structural block diagram of a phased array ultrasonic testing device for the intermediate shaft of a gas turbine rotor of type M701F according to the present invention. Detailed Implementation

[0024] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0025] In the description of this invention, it should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0028] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0029] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] Example 1 like Figure 1-4 As shown, the present invention provides a phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor, comprising the following steps: S1: Preparation before testing Clean the outer surface of the rotor intermediate shaft to be inspected to ensure it is free of dirt and severe corrosion; select and install phased array probe wedges with appropriate curvature according to the outer diameter of the intermediate shaft and the probe coupling area; adjust the flexible contour scanner and firmly install the scanner on the outer surface of the predetermined scanning shaft section of the intermediate shaft; S2: Focusing Rule Settings The focusing method is selected as projection focusing, with the focal point located near the axial position of the rounded area, and the focal depth covering the entire depth range of the rounded area. S3: TCG Calibration TCG calibration was performed using rectangular grooves on a reference test block to eliminate the influence of refraction angle and sound path on the ultrasonic echo amplitude, and the detection sensitivity was determined based on the rectangular grooves. S4: Scanning Detection The phased array probe is fixed on the flexible contour scanner, and the phased array probe is driven to perform uniform scanning along the circumference of the rotor. The encoder records the scanning position of the phased array probe in real time, and the phased array flaw detector synchronously collects and stores the phased array sector scanning signal data with circumferential position information. S5: Data Analysis and Imaging The collected data is analyzed offline. Phased array sector scanning images are used for preliminary identification and characterization of defects. The depth and height of the defects are measured, the corresponding circumferential position is read from the encoder, and the circumferential shape of the defects is measured.

[0031] In this embodiment, the rectangular groove is machined at the middle of the rounded arc, with the length direction of the groove parallel to the circumferential direction and the depth direction perpendicular to the surface at that location.

[0032] In this embodiment, the rectangular groove is a series of grooves of different sizes, with a depth of 0.2mm-3mm and a length of 5mm.

[0033] In this embodiment, the probe wedge is a transverse wave wedge, and the lower surface of the wedge is in the form of an AOD or a plane, ensuring that the maximum gap between the lower surface of the wedge and the coupling surface is less than 0.5 mm.

[0034] In this embodiment, the phased array probe has a frequency range of 5-10MHz and a number of array elements of no less than 64 to ensure sufficient penetration and resolution.

[0035] In this embodiment, the axial position of the flexible contour scanner in step S1 is determined based on the position of the phased array probe, and the axial position of the phased array probe is determined by obtaining the optimal refraction angle through experiments on a reference test block.

[0036] In this embodiment, the circumferential scanning in step S4 should cover the entire outer circumference of the intermediate shaft without causing axial displacement.

[0037] In this embodiment, the present invention is based on an M701F gas turbine rotor intermediate shaft phased array ultrasonic testing system, which includes a reference test block, a phased array ultrasonic flaw detector, a phased array probe, and a flexible contour scanner.

[0038] The reference test block material, its heat treatment state, and structural dimensions are consistent with the rotor intermediate shaft. Rectangular grooves are made in the internal rounded area using electrical discharge machining to calibrate detection sensitivity and defect quantification. The phased array ultrasonic flaw detector has built-in inspection process files configured for the rotor intermediate shaft material and typical defects. Its sound beam path is specially calculated and set to ensure that the ultrasonic beam incident from the outer surface of the shaft can effectively cover and focus on the internal rounded area.

[0039] The phased array probe is a linear array probe with a replaceable probe wedge. Its bottom surface curvature can be matched according to the surface condition and curvature of the rotor shaft to be tested to ensure optimal acoustic coupling.

[0040] The flexible contour scanner is coupled to a rigid contour frame with a curvature matching the outer surface coupling region of the intermediate shaft of the M701F gas turbine rotor, ensuring that the probe maintains a stable relative position and coupling state with the shaft surface throughout the scanning process. The flexible contour scanner is mechanically connected to a high-precision encoder to accurately record the probe's circumferential position information (linear and angular displacement) on the outer surface of the intermediate shaft, enabling encoded positioning and imaging of the detection data.

[0041] Example 2 A power plant needs to conduct a comprehensive inspection of the intermediate shaft of the M701F gas turbine rotor during maintenance. The intermediate shaft has an outer diameter of 1300mm, an inner diameter of 1100mm, and a rounding radius of 10mm.

[0042] like Figure 1-4 As shown, the present invention provides an M701F gas turbine rotor intermediate shaft phased array ultrasonic testing system, comprising: (1) Reference test block The material and heat treatment state of the reference test block are the same as those of the rotor intermediate shaft. The dimensions of the rectangular groove at the rounded part of the reference test block are: depth 0.5mm±0.05mm, length 5.0mm±0.1mm, and width 0.2mm.

[0043] (2) Phased array ultrasonic flaw detector The phased array ultrasonic flaw detector has a built-in dedicated testing process file. Based on sound ray tracking calculation, it sets the sound beam refraction angle to 35°-70° to ensure that the sound beam effectively covers the rounded area.

[0044] (3) Phased array probe A 64-element linear array probe with a frequency of 7.5MHz is used, meeting the requirements for penetration depth and resolution. The probe wedge coupling surface adopts an AOD curved surface (axial concave surface), and the maximum gap between it and the outer surface of the shaft is controlled within 0.3mm.

[0045] (4) Flexible contour scanner It uses a 7075 aluminum alloy frame and is equipped with a wheel encoder (resolution 0.1°). During testing, the coupling stability was controlled within ±2dB.

[0046] This invention provides a phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor, comprising: S1: Preparation before testing Clean the outer surface of the rotor intermediate shaft to be inspected, remove surface oil stains with a special cleaning agent, and clean and remove areas with severe rust; install a matching AOD phased array probe wedge (curvature radius ≥ 650 mm) according to the outer diameter of the intermediate shaft (1300 mm); adjust the flexible contour scanner and firmly install the scanner on the outer surface of the intermediate shaft at a distance of about 100 mm from the rounded axis.

[0047] S2: Focusing Rule Settings The focusing method is selected as projection focusing, with the projection focusing distance being approximately 100mm from the leading edge of the phased array probe. The focal depth is set between 140mm and 36mm, completely covering the depth range of the rounded area.

[0048] S3: TCG Calibration TCG calibration was performed using rectangular grooves (depth 0.5mm ± 0.05mm, length 5.0mm ± 0.1mm, width 0.2mm) on a reference test block, and the sensitivity of the detection system was determined based on the rectangular grooves.

[0049] S4: Scanning Detection The probe is fixed on the contour scanner, scanning the intermediate axis 0-360° (complete circumference). The encoder resolution is 0.36° (1000 pulses / revolution), and the position synchronization accuracy is ±0.5°. The coupling status is monitored in real time during the scanning process, and the scanning is paused when the bottom wave fluctuation exceeds ±3dB. The phased array flaw detector synchronously acquires and stores phased array sector scan (S-scan) signal data with circumferential position information.

[0050] S5: Data Analysis and Imaging The collected data is analyzed offline. Phased array sector scanning (S-scan) images are used for preliminary identification and characterization of defects. Measurement tools are used to measure the depth and height of the defects. The corresponding circumferential position is read from the encoder, and the circumferential shape of the defects is measured.

[0051] Example 3 A heavy equipment manufacturing plant is conducting pre-shipment quality inspections on a batch of newly machined M701F gas turbine rotor intermediate shafts. The shaft has an outer diameter of 1300mm, a total length of 2000mm, and a rounding radius of 10mm.

[0052] like Figure 1-4 As shown, the present invention provides an M701F gas turbine rotor intermediate shaft phased array ultrasonic testing system, comprising: (1) Reference test block Materials: Materials from the same batch as the product shaft.

[0053] Heat treatment status: Same heat treatment batch as the product shaft.

[0054] Groove specifications: Three rectangular grooves are machined in the rounded area. Groove #1 has a depth of 0.3mm ± 0.02mm and a length of 5.0mm ± 0.05mm; Groove #2 has a depth of 0.5mm ± 0.02mm and a length of 5.0mm ± 0.05mm; Groove #3 has a depth of 1.0mm ± 0.03mm and a length of 5.0mm ± 0.05mm. All grooves have a width of 0.15mm.

[0055] (2) Phased array ultrasonic testing system Main unit: Olympus OmniScan X3.

[0056] Probe: 128-element linear array probe, center frequency 10MHz.

[0057] Wedge: Custom AOD curved surface wedge with a curvature radius ≥ 650mm.

[0058] Encoder: High-precision optical encoder with a resolution of 0.1°.

[0059] Scanner: Scanner with encoder, repeatability ±0.05mm This invention provides a phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor, comprising: S1: Preparation before testing Clean the outer surface of the rotor intermediate shaft to be inspected and remove surface oil stains using a special cleaning agent; install the matching AOD phased array probe wedge (curvature radius = 800mm) according to the outer diameter of the intermediate shaft (1300mm); adjust the flexible contour scanner and firmly install the scanner on the outer surface of the intermediate shaft at a distance of about 100mm from the rounded axis.

[0060] S2: Detection parameter optimization Sound velocity calibration: Measured sound velocity 5890m / s.

[0061] Sensitivity setting: based on 80% full-screen height of 0.3mm groove echo.

[0062] Signal-to-noise ratio requirement: ≥20dB.

[0063] S3: Detection Process Scanning speed: 50mm / s.

[0064] Data acquisition: Full waveform acquisition, sampling rate 200MHz.

[0065] Coupling stability: fluctuation ≤ ±2dB.

[0066] Temperature drift: Automatically compensated, accuracy ±0.5℃.

[0067] Data acquisition and storage: Synchronously acquire and store phased array sector scan (S-scan) signal data with circumferential position information.

[0068] S4: Data Analysis and Defect Identification The collected data is analyzed offline. Phased array sector scanning (S-scan) images are used for preliminary identification and characterization of defects. Measurement tools are used to measure the depth and height of the defects. The corresponding circumferential position is read from the encoder, and the circumferential shape of the defects is measured.

[0069] Example 4 like Figure 5 As shown, the present invention provides an M701F type phased array ultrasonic testing device for the intermediate shaft of a gas turbine rotor, comprising: Preparation unit before inspection: Clean the outer surface of the rotor intermediate shaft to be inspected to ensure that there is no dirt or severe corrosion; select and install phased array probe wedges with appropriate curvature according to the outer diameter of the intermediate shaft and the probe coupling area; adjust the flexible contour scanner and firmly install the scanner on the outer surface of the predetermined scanning shaft section of the intermediate shaft; Focusing rule setting unit: Select projection focusing as the focusing method, with the focal position near the axial position of the rounded area and the focal depth covering the entire depth range of the rounded area; TCG calibration unit: TCG calibration is performed using rectangular grooves on the reference test block to eliminate the influence of refraction angle and sound path on the ultrasonic echo amplitude, and the detection sensitivity is determined based on the rectangular grooves; Scanning and detection unit: The phased array probe is fixed on the flexible contour scanner, and the phased array probe is driven to perform uniform scanning along the circumference of the rotor. The encoder records the scanning position of the phased array probe in real time. The phased array flaw detector synchronously collects and stores the phased array sector scanning signal data with circumferential position information. Data Analysis and Imaging Unit: Performs offline analysis on the collected data, uses phased array sector scanning images for preliminary identification and characterization of defects, measures the depth and height of defects, reads the corresponding circumferential position from the encoder, and measures the circumferential shape of defects.

[0070] In the TCG calibration unit of this embodiment, the rectangular groove is machined at the middle of the rounded arc, the length direction of the groove is parallel to the circumferential direction, and the depth direction is perpendicular to the surface at the location.

[0071] In the TCG calibration unit of this embodiment, the rectangular groove is a series of grooves of different sizes, with a depth of 0.2mm-3mm and a length of 5mm.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A phased array ultrasonic testing method for a M701F gas turbine rotor intermediate shaft, characterized in that, Includes the following steps: S1: Preparation before testing Clean the outer surface of the rotor intermediate shaft to be inspected to ensure it is free of dirt and severe corrosion; select and install phased array probe wedges with appropriate curvature according to the outer diameter of the intermediate shaft and the probe coupling area; adjust the flexible contour scanner and firmly install the scanner on the outer surface of the predetermined scanning shaft section of the intermediate shaft; S2: Focusing Rule Settings The focusing method is selected as projection focusing, with the focal point located near the axial position of the rounded area, and the focal depth covering the entire depth range of the rounded area. S3: TCG Calibration TCG calibration was performed using rectangular grooves on a reference test block to eliminate the influence of refraction angle and sound path on the ultrasonic echo amplitude, and the detection sensitivity was determined based on the rectangular grooves. S4: Scanning Detection The phased array probe is fixed on the flexible contour scanner, and the phased array probe is driven to perform uniform scanning along the circumference of the rotor. The encoder records the scanning position of the phased array probe in real time, and the phased array flaw detector synchronously collects and stores the phased array sector scanning signal data with circumferential position information. S5: Data Analysis and Imaging The collected data is analyzed offline. Phased array sector scanning images are used for preliminary identification and characterization of defects. The depth and height of the defects are measured, the corresponding circumferential position is read from the encoder, and the circumferential shape of the defects is measured.

2. The method for phased array ultrasonic testing of the intermediate shaft of the rotor of the M701F type gas turbine according to claim 1, characterized in that, The rectangular groove is machined at the center of the rounded arc, with the length direction of the groove parallel to the circumferential direction and the depth direction perpendicular to the surface at that location.

3. The phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor according to claim 1, characterized in that, The rectangular grooves are a series of grooves of different sizes, with a depth of 0.2mm-3mm and a length of 5mm.

4. The phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor according to claim 1, characterized in that, The probe wedge is a transverse wave wedge, and the lower surface of the wedge is in the form of an AOD or a plane, ensuring that the maximum gap between the lower surface of the wedge and the coupling surface is less than 0.5 mm.

5. The phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor according to claim 1, characterized in that, The phased array probe has a frequency range of 5-10MHz and no fewer than 64 array elements to ensure sufficient penetration and resolution.

6. The phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor according to claim 1, characterized in that, The axial position of the flexible contour scanner described in step S1 is determined based on the position of the phased array probe, and the axial position of the phased array probe is determined by obtaining the optimal refraction angle through experiments on a reference test block.

7. The phased array ultrasonic testing method for the intermediate shaft of an M701F gas turbine rotor according to claim 1, characterized in that, The circumferential scan described in step S4 should cover the entire outer circumference of the intermediate shaft without causing axial displacement.

8. A phased array ultrasonic testing device for the intermediate shaft of a gas turbine rotor of type M701F, characterized in that, include: Preparation unit before inspection: Clean the outer surface of the rotor intermediate shaft to be inspected to ensure that there is no dirt or severe corrosion; select and install phased array probe wedges with appropriate curvature according to the outer diameter of the intermediate shaft and the probe coupling area; adjust the flexible contour scanner and firmly install the scanner on the outer surface of the predetermined scanning shaft section of the intermediate shaft; Focusing rule setting unit: Select projection focusing as the focusing method, with the focal position near the axial position of the rounded area and the focal depth covering the entire depth range of the rounded area; TCG calibration unit: TCG calibration is performed using rectangular grooves on the reference test block to eliminate the influence of refraction angle and sound path on the ultrasonic echo amplitude, and the detection sensitivity is determined based on the rectangular grooves; Scanning and detection unit: The phased array probe is fixed on the flexible contour scanner, and the phased array probe is driven to perform uniform scanning along the circumference of the rotor. The encoder records the scanning position of the phased array probe in real time. The phased array flaw detector synchronously collects and stores the phased array sector scanning signal data with circumferential position information. Data Analysis and Imaging Unit: Performs offline analysis on the collected data, uses phased array sector scanning images for preliminary identification and characterization of defects, measures the depth and height of defects, reads the corresponding circumferential position from the encoder, and measures the circumferential shape of defects.

9. The M701F gas turbine rotor intermediate shaft phased array ultrasonic testing device according to claim 8, characterized in that, In the TCG calibration unit, the rectangular groove is machined at the middle of the rounded arc, with the length direction of the groove parallel to the circumferential direction and the depth direction perpendicular to the surface at that location.

10. The M701F gas turbine rotor intermediate shaft phased array ultrasonic testing device according to claim 8, characterized in that, In the TCG calibration unit, the rectangular groove is a series of grooves of different sizes, with a depth of 0.2mm-3mm and a length of 5mm.

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