Method for measuring thickness of single crystal hollow working blade

Abstract

The application discloses a kind of single crystal hollow working blade thickness measuring method, comprising the following steps: making longitudinal parallel [001] crystal direction, transverse deviates [100] crystal direction 0 °, 10 °, 20 °, 30 °, 45 ° deviation angle single crystal sample;Using the single crystal sample of deviation angle 0 ° to make reference correction to ultrasonic equipment;The actual thickness of single crystal sample of deviation angle 0 °, 10 °, 20 °, 30 °, 45 ° is used as initial correction coefficient with the ratio of test thickness;The correction coefficient atlas of different deviation angles in 0-45 ° range of single crystal hollow working blade is extrapolated by initial correction coefficient;The secondary orientation of single crystal hollow working blade is tested and the value is recorded, the correction coefficient angle of the point to be measured is calculated by secondary orientation, and the corresponding correction coefficient of the deviation angle of the point to be measured is determined in correction coefficient atlas;The test thickness of the point to be measured is multiplied by correction coefficient, and the test thickness of the point to be measured after correction is obtained.The application solves the problem of large measurement error caused by ultrasonic thickness measurement orientation.

Description

Technical Field

[0001] This invention belongs to the field of quality inspection technology for single-crystal hollow working blades, specifically relating to a method for measuring the thickness of single-crystal hollow working blades. This method is an ultrasonic thickness measurement method for single-crystal hollow working blades based on crystal orientation. Background Technology

[0002] The overall structure of aero-engine single-crystal hollow working blades is divided into the blade body, fin plate, and tenon. Some blades also include a crown. The longitudinal direction of the single-crystal hollow working blade is close to

[001] orientation, and the blade body is twisted and has a relatively thin wall thickness. Single-crystal hollow working blades are one of the most important hot-end components of aero-engines, and their quality directly affects the performance of aero-engines. The wall thickness measurement of single-crystal hollow working blades is an important part of blade quality inspection. Currently, industrial CT inspection, cross-sectional inspection, and ultrasonic inspection are commonly used to measure the wall thickness of single-crystal hollow blades.

[0003] Each method for measuring the wall thickness of blades has its advantages and disadvantages. Industrial CT inspection for measuring the wall thickness of single-crystal hollow working blades offers high accuracy, but suffers from low efficiency, high cost, and significant errors for thicknesses less than 0.5 mm. While sectioning inspection allows for accurate measurement of various locations on the blade, it is destructive, damaging the entire blade and making it unsuitable for 100% inspection. Ultrasonic testing is an important method for measuring polycrystalline materials, offering high efficiency and low cost. However, ultrasonic testing of single-crystal hollow working blades requires a single standard sample for ultrasonic correction. Because single crystals are anisotropic materials, the orientation of different measurement points affects sound propagation speed, leading to significant testing errors, with relative errors exceeding 10%, especially for thicker areas on single-crystal hollow working blades where absolute deviations can be substantial. Therefore, there is a need to develop an ultrasonic thickness measurement method for single-crystal hollow working blades based on crystal orientation, in order to solve the problem of large errors in the current ultrasonic testing technology for measuring the wall thickness of single-crystal hollow working blades. While there are some existing documents on ultrasonic thickness measurement of single-crystal hollow blades, there are no documents specifically on ultrasonic thickness measurement of single-crystal hollow working blades.

[0004] The invention patent with publication number CN102927935A discloses an ultrasonic testing method for the wall thickness of a single-crystal hollow blade. First, a special testing template is made, and testing points are marked on the blade using the template. The test points on each measurement section, located in the same crystal growth direction, are connected by a straight line, which is then extended to the blade tip. Utilizing the principle that the sound velocity of a single-crystal material is approximately the same along its growth direction, a vernier caliper is used to measure the wall thickness at the blade tip along the growth direction of each test point. The sound velocity at the blade tip along the growth direction of each test point is then measured using an instrument, thus obtaining the sound velocity at each test point. Finally, the sound velocity at each test point is input into a thickness gauge to obtain the wall thickness value at each test point. However, this technical solution does not use a sample with longitudinal parallel to the

[001] crystal orientation and lateral deviation of 0° from the

[100] crystal orientation for ultrasonic correction when ultrasonically measuring the blade wall thickness. Compared with traditional industrial CT testing technology, although the detection efficiency and accuracy are improved, the measurement error remains large due to the lack of consideration for ultrasonic correction, failing to meet the needs of practical applications and production.

[0005] The invention patent with publication number CN109238186A discloses an ultrasonic testing method for the wall thickness of a hollow blade made of single-crystal high-temperature alloy, including the following steps: obtaining the elastic constants (C11, C12, C44) and density of the single-crystal high-temperature alloy of the blade to be tested; calculating the theoretical sound velocity of the ultrasonic wave at each wall thickness measurement point; measuring the wall thickness at each measurement point using an ultrasonic thickness gauge at a fixed sound velocity, thereby obtaining the echo time of the corresponding measurement point; and obtaining the wall thickness value of the corresponding measurement point based on the theoretical sound velocity and echo time. This technical solution still does not consider the need for ultrasonic correction when measuring the blade wall thickness using a sample that is longitudinally parallel to the

[001] crystal orientation and laterally deviates from the

[100] crystal orientation by 0°. Even though the detection efficiency and accuracy are improved compared to industrial CT detection technology, the measurement error is still large and cannot meet the needs of practical applications and production. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method for measuring the thickness of a single-crystal hollow working blade, comprising the following steps in sequence:

[0007] Step 1: Select a single crystal test rod that is the same as the hollow working blade of the single crystal to be tested, and make single crystal samples on the test rod with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 0°, 10°, 20°, 30° and 45° respectively.

[0008] Step 2: Use a single crystal sample with longitudinal parallel to the

[001] crystal orientation and lateral deviation of 0° from the

[100] crystal orientation to perform a reference correction on the ultrasonic equipment;

[0009] Step 3: Using the corrected ultrasonic equipment, perform ultrasonic thickness measurement on single crystal samples with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 10°, 20°, 30°, and 45° respectively. Compare the measured thickness obtained by ultrasonic testing with the actual thickness to obtain the ratio of the actual thickness to the measured thickness of the single crystal samples with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 10°, 20°, 30°, and 45°. Use the ratio of the actual thickness to the measured thickness of the single crystal samples with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 0°, 10°, 20°, 30°, and 45° as the initial correction coefficient.

[0010] Step 4: Using the initial correction coefficients for longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°, 10°, 20°, 30°, and 45°, extrapolate the correction coefficient spectrum of different deviation angles within the range of 0-45° for the longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation of the single crystal hollow working blade.

[0011] Step 5: Use an orientation testing device to test the secondary orientation of the single-crystal hollow working blade, record the value of the secondary orientation of the single-crystal hollow working blade, calculate the correction coefficient angle of the test point on the single-crystal hollow working blade through the secondary orientation, and determine the correction coefficient of the deviation angle of the test point in the correction coefficient spectrum of different deviation angles within the range of 0-45° of longitudinal parallel to

[001] crystal direction and transverse deviation from

[100] crystal direction of the single-crystal hollow working blade.

[0012] Step 6: Use an ultrasonic device to perform ultrasonic thickness measurement on the test point on the single-crystal hollow working blade. Multiply the test thickness by the correction coefficient of the deviation angle of the test point to obtain the corrected test thickness of the test point on the single-crystal hollow working blade. The corrected test thickness is infinitely close to the true thickness.

[0013] The Z-axis orientation of the single-crystal hollow working blade of the present invention is close to

[001] , and the crystal orientation of all thickness measurement points on the blade can be obtained in one test. The single-crystal hollow working blade is different from the single-crystal hollow blade. The Z-axis orientation of the single-crystal hollow blade is unknown and can be any orientation, so it is necessary to test the orientation of each thickness measurement point individually.

[0014] This invention selects five deviation angles—0°, 10°, 20°, 30°, and 45°—for longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation as correction coefficients for different deviation angles within the range of 0-45° for extrapolating the longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation of single-crystal hollow turbine blades. Although the principal stress axis of a nickel-based single-crystal hollow turbine blade is perpendicular to the principal stress axis (0-360°), due to the symmetry of crystal orientation, the effective range of secondary orientation deviation from

[100] is 0-45°. Therefore, by using the correction coefficients for the above five deviation angles from

[100] , correction coefficients for different deviation angles within the full range of 0-45° for a principal stress axis with a near

[001] orientation and a secondary orientation deviation from

[100] orientation can be obtained.

[0015] The ultrasonic equipment used in this invention is an ultrasonic thickness gauge, the model of which can be NDT NOVASCOPE5000, NDT NOVASCOPE6000, etc., and the orientation testing equipment used is a Laue method X-ray single crystal orientation instrument, the model of which can be Laue HT.

[0016] Preferably, in step one, five single-crystal samples are prepared for each of the following deviation angles: longitudinally parallel to the

[001] crystal orientation and laterally deviated from the

[100] crystal orientation by 0°, 10°, 20°, 30°, and 45°. The heights of the five single-crystal samples at each deviation angle are 1mm, 2mm, 3mm, 4mm, and 5mm, respectively, and the length and width of the single-crystal samples are not less than 5mm. That is, the present invention prepares a total of 25 single-crystal samples, of which five single-crystal samples are prepared for each of the five typical deviation angles: longitudinally parallel to the

[001] crystal orientation and laterally deviated from the

[100] crystal orientation by 0°, 10°, 20°, 30°, and 45°. The heights of the five single-crystal samples at each deviation angle are 1mm, 2mm, 3mm, 4mm, and 5mm, respectively. The material of the 25 single-crystal samples is the same as the material of the tested single-crystal hollow working blade.

[0017] In any of the above schemes, it is preferred that, in step two, a single crystal sample with a longitudinal parallel to the

[001] crystal orientation and a lateral deviation of 0° from the

[100] crystal orientation is used to perform a reference correction on the ultrasonic equipment, which includes the following steps in sequence:

[0018] Step (1): Use an ultrasonic device to test five single crystal samples with thicknesses of 1 mm, 2 mm, 3 mm, 4 mm and 5 mm, respectively, with longitudinal parallel to the

[001] crystal direction and transverse deviation from the

[100] crystal direction by 0°. The propagation time of the sound wave between the two surfaces in the thickness direction of the five single crystal samples is measured.

[0019] Step (2): Divide the thickness of the five single crystal samples that are longitudinally parallel to the

[001] crystal orientation and laterally deviated from the

[100] crystal orientation by the corresponding propagation time to obtain the propagation speed of the sound wave in the five single crystal samples respectively.

[0020] Step (3): Take the average propagation speed of the sound wave in five single crystal samples that are parallel to the

[001] crystal direction in the longitudinal direction and deviate from the

[100] crystal direction by 0° in the transverse direction. The average propagation speed of the sound wave in the longitudinal direction parallel to the

[001] crystal direction and deviating from the

[100] crystal direction by 0° in the transverse direction is then input into the ultrasonic device to complete the reference correction of the ultrasonic device.

[0021] This invention inputs the average propagation speed of the longitudinal parallel

[001] crystal direction and the lateral deviation from the

[100] crystal direction at a 0° deviation angle into the ultrasonic equipment to complete the benchmark correction of the ultrasonic equipment. The corrected benchmark is used as the benchmark for ultrasonic thickness measurement of all subsequent single crystal samples and single crystal hollow working blades. That is, the average propagation speed of the longitudinal parallel

[001] crystal direction and the lateral deviation from the

[100] crystal direction at a 0° deviation angle is used to test the wall thickness of single crystal samples with other deviation angles.

[0022] In any of the above schemes, the preferred method for obtaining the initial correction coefficient in step three includes the following steps in sequence:

[0023] Step A: Using the modified ultrasonic equipment, ultrasonic thickness measurements were performed on single crystal samples with thicknesses of 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm that were longitudinally parallel to the

[001] crystal orientation and laterally deviated from the

[100] crystal orientation by 10°, 20°, 30°, and 45°, respectively, and the ratio of the actual thickness to the measured thickness of each single crystal sample was obtained.

[0024] Step B: Take the average of the ratios of the actual thickness to the test thickness of the five single crystal samples that are parallel to the

[001] crystal orientation in the longitudinal direction and deviate from the

[100] crystal orientation by 10°, 20°, 30° and 45° in the lateral direction. Finally, take the average of the ratios of the actual thickness to the test thickness of the single crystal samples that are parallel to the

[001] crystal orientation in the longitudinal direction and deviate from the

[100] crystal orientation by 0°, 10°, 20°, 30° and 45° in the lateral direction as the initial correction coefficient.

[0025] In any of the above schemes, it is preferred that, in step B, the average values ​​of the ratio of the actual thickness to the test thickness of the single crystal sample with longitudinal parallel to the

[001] crystal orientation and lateral deviation angles of 0°, 10°, 20°, 30°, and 45° from the

[100] crystal orientation are 1, 1.03, 1.07, 1.10, and 1.14, respectively.

[0026] In this invention, the actual thickness is the thickness cut during the fabrication of the single-crystal sample, and the test thickness is the thickness measured using ultrasonic equipment. In step three, the test thickness of the single-crystal sample is the thickness measured using corrections for longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°. The average value of the ratio of the actual thickness to the test thickness of the single-crystal sample with longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°, 10°, 20°, 30°, and 45° are respectively used as their respective initial correction coefficients. Because the ultrasonic equipment is corrected using a single-crystal sample with longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°, the average value of the ratio of the actual thickness to the test thickness of the single-crystal sample with longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0° is 1, that is, the initial correction coefficient for longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0° is 1.

[0027] In any of the above schemes, it is preferred that, in step four, the correction coefficient spectrum of the single crystal hollow working blade with longitudinal parallel to the

[001] crystal direction and lateral deviation from the

[100] crystal direction within the range of 0-45° is extrapolated, which includes the following steps in sequence: Step a: The deviation angles of the single crystal samples with longitudinal parallel to the

[001] crystal direction and lateral deviation from the

[100] crystal direction of 0°, 10°, 20°, 30°, and 45° are respectively taken as their respective X-axis, and the average value of the ratio of the actual thickness to the test thickness of the single crystal samples with longitudinal parallel to the

[001] crystal direction and lateral deviation from the

[100] crystal direction of 0°, 10°, 20°, 30°, and 45° are respectively taken as their respective Y-axis;

[0028] Step b: By fitting calculation, the correction coefficient spectrum of different deviation angles within the range of 0-45° of longitudinal parallel to

[001] crystal orientation and lateral deviation from

[100] crystal orientation of single crystal hollow working blade is obtained.

[0029] In any of the above schemes, it is preferred that, in step a, the spatial coordinates of the single crystal samples that are longitudinally parallel to the

[001] crystal orientation and laterally deviate from the

[100] crystal orientation by 0°, 10°, 20°, 30°, and 45° are [0°, 1], [10°, 1.03], [20°, 1.07], [30°, 1.10], and [45°, 1.14], respectively.

[0030] In any of the above schemes, it is preferred that, in step five, the formula for calculating the correction coefficient angle is:

[0031] When P > 90°, β = 45° - |α - (P - 90°) - 45°;

[0032] When P≤90°, β=45°-︱︱α-P︱-45°︱;

[0033] In the formula,

[0034] β—Correction coefficient angle, which is the minimum angle between the normal of the test point on the single-crystal hollow working blade and the

[100] crystal direction and

[010] crystal direction, in °;

[0035] α—Secondary orientation angle, which is the angle between the positive X-axis direction of the single-crystal hollow working blade and the

[100] crystal orientation, in °;

[0036] P—The angle between the normal to the point to be measured on the single-crystal hollow working blade and the positive direction of the X-axis, in degrees.

[0037] The normal to the test point on the single-crystal hollow working blade forms an angle with both the

[100] crystal direction and the

[010] crystal direction, and the smallest of these angles is used as the correction coefficient angle β. Angle α is the secondary orientation value of the single-crystal hollow working blade, which can be directly read from the orientation testing equipment, 0°≤α≤90°; angle P can be measured on the cross-section of the test point on the single-crystal hollow working blade, 0°≤P≤180°.

[0038] The thickness measurement method for single-crystal hollow working blades of the present invention solves the problem of large measurement error caused by orientation in ultrasonic thickness measurement. It can measure the wall thickness efficiently and accurately, with low testing cost and meets product quality and safety requirements. More importantly, the ultrasonic testing of the thickness of single-crystal hollow working blades based on orientation has a testing accuracy of over 99%, especially for the thicker parts of the single-crystal hollow working blades, the testing error does not exceed 1.0%. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the main crystal orientations on a single crystal sample according to a preferred embodiment of the thickness measurement method for single crystal hollow working blades of the present invention.

[0040] Figure 2 for Figure 1 The schematic diagrams shown in the embodiment are of single crystal samples with longitudinal parallel to the

[001] crystal orientation and lateral deviation from the

[100] crystal orientation at angles of 0°, 10°, 20°, 30°, and 45°. The thickness h of the single crystal sample can be 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, where: (a) is a single crystal sample with a deviation angle of 0°, (b) is a single crystal sample with a deviation angle of 10°, (c) is a single crystal sample with a deviation angle of 20°, (d) is a single crystal sample with a deviation angle of 30°, and (e) is a single crystal sample with a deviation angle of 45°.

[0041] Figure 3 for Figure 1 The above embodiment shows a schematic diagram of the placement of the single-crystal hollow working blade during the secondary orientation test of the single-crystal hollow working blade.

[0042] Figure 4 for Figure 1 A schematic diagram of the cross-section of the test point on the single-crystal hollow working blade in the embodiment shown;

[0043] Figure 5 for Figure 1 The diagram shows the correction coefficients obtained by extrapolation in the embodiment, for different deviation angles within the range of 0-45° for the longitudinal parallel

[001] crystal orientation and the lateral deviation from the

[100] crystal orientation.

[0044] The diagram shows: 1-Single-crystal hollow working blade, 2-Detector, 3-X-ray tube. Detailed Implementation

[0045] To further understand the invention, the following detailed description of the invention will be provided in conjunction with specific embodiments.

[0046] According to a preferred embodiment of the thickness measurement method for single-crystal hollow working blades of the present invention, the following steps are included in sequence:

[0047] Step 1: Select a single crystal test rod that is the same as the hollow working blade of the single crystal to be tested, and make single crystal samples on the test rod with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 0°, 10°, 20°, 30° and 45° respectively.

[0048] Step 2: Use a single crystal sample with longitudinal parallel to the

[001] crystal orientation and lateral deviation of 0° from the

[100] crystal orientation to perform a reference correction on the ultrasonic equipment;

[0049] Step 3: Using the corrected ultrasonic equipment, perform ultrasonic thickness measurement on single crystal samples with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 10°, 20°, 30°, and 45° respectively. Compare the measured thickness obtained by ultrasonic testing with the actual thickness to obtain the ratio of the actual thickness to the measured thickness of the single crystal samples with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 10°, 20°, 30°, and 45°. Use the ratio of the actual thickness to the measured thickness of the single crystal samples with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation by 0°, 10°, 20°, 30°, and 45° as the initial correction coefficient.

[0050] Step 4: Using the initial correction coefficients for longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°, 10°, 20°, 30°, and 45°, extrapolate the correction coefficient spectrum of different deviation angles within the range of 0-45° for the longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation of the single crystal hollow working blade.

[0051] Step 5: Use an orientation testing device to test the secondary orientation of the single-crystal hollow working blade, record the value of the secondary orientation of the single-crystal hollow working blade, calculate the correction coefficient angle of the test point on the single-crystal hollow working blade through the secondary orientation, and determine the correction coefficient of the deviation angle of the test point in the correction coefficient spectrum of different deviation angles within the range of 0-45° of longitudinal parallel to

[001] crystal direction and transverse deviation from

[100] crystal direction of the single-crystal hollow working blade.

[0052] Step 6: Use an ultrasonic device to perform ultrasonic thickness measurement on the test point on the single-crystal hollow working blade. Multiply the test thickness by the correction coefficient of the deviation angle of the test point to obtain the corrected test thickness of the test point on the single-crystal hollow working blade. The corrected test thickness is infinitely close to the true thickness.

[0053] In this embodiment, the Z-axis orientation of the single-crystal hollow working blade is close to

[001] , and the crystal orientation of all thickness measurement points on the blade can be obtained in one test. The single-crystal hollow working blade is different from the single-crystal hollow blade. The Z-axis orientation of the single-crystal hollow blade is unknown and can be any orientation, so it is necessary to test the orientation of each thickness measurement point individually.

[0054] In this embodiment, five deviation angles—0°, 10°, 20°, 30°, and 45°—are selected as correction coefficients for different deviation angles within the 0-45° range of longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation for extrapolating single-crystal hollow working blades. For nickel-based single-crystal hollow turbine working blades with a principal stress axis close to

[001] orientation, although the angle perpendicular to the principal stress axis is 0-360°, due to the symmetry of crystal orientation, the effective range of secondary orientation deviation from

[100] is 0-45°. Therefore, by using the correction coefficients for the above five deviation angles from

[100] , correction coefficients for different deviation angles within the full range of 0-45° can be obtained when the principal stress axis is close to

[001] orientation and the secondary orientation deviates from

[100] orientation. For example... Figure 1 As shown, the single crystal sample contains the following main crystal orientations:

[001] ,

[012] ,

[011] ,

[112] ,

[122] ,

[111] ,

[123] ,

[010] , and

[100] .

[0055] The ultrasonic equipment used in this embodiment is an ultrasonic thickness gauge, the model of which can be NDTNOVASCOPE5000 or NDT NOVASCOPE6000. The orientation testing equipment used is a Laue method X-ray single crystal orientation instrument, the model of which can be Laue HT.

[0056] In step one, five single crystal samples are prepared with longitudinal parallel

[001] crystal orientation and transverse deviation from

[100] crystal orientation at 0°, 10°, 20°, 30° and 45° deviation angles. The heights of the five single crystal samples at each deviation angle are 1mm, 2mm, 3mm, 4mm and 5mm respectively, and the length and width of the single crystal sample are not less than 5mm.

[0057] like Figure 2 As shown, this is a schematic diagram of single-crystal samples with longitudinal parallel to the

[001] crystal orientation and lateral deviations from the

[100] crystal orientation at angles of 0°, 10°, 20°, 30°, and 45°. The thickness h of the single-crystal samples is 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, where: (a) is a single-crystal sample with a deviation angle of 0°, (b) is a single-crystal sample with a deviation angle of 10°, (c) is a single-crystal sample with a deviation angle of 20°, (d) is a single-crystal sample with a deviation angle of 30°, and (e) is a single-crystal sample with a deviation angle of 45°. That is, a total of 25 single-crystal samples were made in this embodiment, with 5 single-crystal samples made at each of the five typical deviation angles of longitudinal parallel to the

[001] crystal orientation and lateral deviations from the

[100] crystal orientation at 0°, 10°, 20°, 30°, and 45°. The heights of the 5 single-crystal samples at each deviation angle are 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, respectively. The material of the 25 single crystal samples is the same as that of the single crystal hollow working blades being tested.

[0058] In step two, a single crystal sample with a longitudinal parallel to the

[001] crystal orientation and a lateral deviation of 0° from the

[100] crystal orientation is used to perform a reference correction on the ultrasonic equipment. The steps are as follows:

[0059] Step (1): Use an ultrasonic device to test five single crystal samples with thicknesses of 1 mm, 2 mm, 3 mm, 4 mm and 5 mm, respectively, with longitudinal parallel to the

[001] crystal direction and transverse deviation from the

[100] crystal direction by 0°. The propagation time of the sound wave between the two surfaces in the thickness direction of the five single crystal samples is measured.

[0060] Step (2): Divide the thickness of the five single crystal samples that are longitudinally parallel to the

[001] crystal orientation and laterally deviated from the

[100] crystal orientation by the corresponding propagation time to obtain the propagation speed of the sound wave in the five single crystal samples respectively.

[0061] Step (3): Take the average propagation speed of the sound wave in five single crystal samples that are parallel to the

[001] crystal direction in the longitudinal direction and deviate from the

[100] crystal direction by 0° in the transverse direction. The average propagation speed of the sound wave in the longitudinal direction parallel to the

[001] crystal direction and deviating from the

[100] crystal direction by 0° in the transverse direction is then input into the ultrasonic device to complete the reference correction of the ultrasonic device.

[0062] In this embodiment, the average propagation speed of the longitudinal parallel

[001] crystal direction and the lateral deviation from the

[100] crystal direction at a 0° deviation angle is input into the ultrasonic equipment to complete the reference correction of the ultrasonic equipment. The corrected reference is used as the reference for ultrasonic thickness measurement of all subsequent single crystal samples and single crystal hollow working blades. That is, the average propagation speed of the longitudinal parallel

[001] crystal direction and the lateral deviation from the

[100] crystal direction at a 0° deviation angle is used to test the wall thickness of single crystal samples with other deviation angles.

[0063] Step three, the method for obtaining the initial correction coefficient, includes the following steps in sequence:

[0064] Step A: Using the modified ultrasonic equipment, ultrasonic thickness measurements were performed on single crystal samples with thicknesses of 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm that were longitudinally parallel to the

[001] crystal orientation and laterally deviated from the

[100] crystal orientation by 10°, 20°, 30°, and 45°, respectively, and the ratio of the actual thickness to the measured thickness of each single crystal sample was obtained.

[0065] Step B: Take the average of the ratios of the actual thickness to the test thickness of the five single crystal samples that are parallel to the

[001] crystal orientation in the longitudinal direction and deviate from the

[100] crystal orientation by 10°, 20°, 30° and 45° in the lateral direction. Finally, take the average of the ratios of the actual thickness to the test thickness of the single crystal samples that are parallel to the

[001] crystal orientation in the longitudinal direction and deviate from the

[100] crystal orientation by 0°, 10°, 20°, 30° and 45° in the lateral direction as the initial correction coefficient.

[0066] In step B, the average values ​​of the ratio of the actual thickness to the test thickness of the single crystal sample with longitudinal parallel to the

[001] crystal orientation and transverse deviation from the

[100] crystal orientation at 0°, 10°, 20°, 30° and 45° are 1, 1.03, 1.07, 1.10 and 1.14, respectively.

[0067] In this embodiment, the actual thickness is the thickness cut during the fabrication of the single crystal sample, and the test thickness is the thickness measured using ultrasonic equipment. In step three, the test thickness of the single crystal sample is the thickness measured using corrections for longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°. The average value of the ratio of the actual thickness to the test thickness of the single crystal sample with longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°, 10°, 20°, 30°, and 45° deviation angles is used as the initial correction coefficient for each. Because the ultrasonic equipment is corrected using a single crystal sample with longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0°, the average value of the ratio of the actual thickness to the test thickness of the single crystal sample with longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0° is 1, that is, the initial correction coefficient for longitudinal parallel

[001] crystal orientation and lateral deviation from

[100] crystal orientation at 0° is 1.

[0068] In step four, the extrapolation of the correction coefficient spectrum for the longitudinal parallel

[001] crystal orientation and the lateral deviation from the

[100] crystal orientation within the range of 0-45° for the single-crystal hollow working blade includes the following steps in sequence:

[0069] Step a: Take the deviation angles of the single crystal samples that are parallel to the

[001] crystal orientation in the longitudinal direction and deviate from the

[100] crystal orientation by 0°, 10°, 20°, 30° and 45° in the lateral direction as their respective X-axis, and take the average value of the ratio of the actual thickness to the test thickness of the single crystal samples that are parallel to the

[001] crystal orientation in the longitudinal direction and deviate from the

[100] crystal orientation by 0°, 10°, 20°, 30° and 45° in the lateral direction as their respective Y-axis;

[0070] Step b: By fitting calculation, the correction coefficient spectrum of different deviation angles within the range of 0-45° of longitudinal parallel to

[001] crystal orientation and lateral deviation from

[100] crystal orientation of single crystal hollow working blade is obtained.

[0071] In step a, the spatial coordinates of the single crystal samples that are longitudinally parallel to the

[001] crystal orientation and laterally deviated from the

[100] crystal orientation by 0°, 10°, 20°, 30°, and 45° are [0°, 1], [10°, 1.03], [20°, 1.07], [30°, 1.10], and [45°, 1.14], respectively.

[0072] In step five, the formula for calculating the correction coefficient angle is:

[0073] When P > 90°, β = 45° - |α - (P - 90°) - 45°;

[0074] When P≤90°, β=45°-︱︱α-P︱-45°︱;

[0075] In the formula,

[0076] β—Correction coefficient angle, which is the minimum angle between the normal of the test point on the single-crystal hollow working blade and the

[100] crystal direction and

[010] crystal direction, in °;

[0077] α—Secondary orientation angle, which is the angle between the positive X-axis direction of the single-crystal hollow working blade and the

[100] crystal orientation, in °;

[0078] P—The angle between the normal to the point to be measured on the single-crystal hollow working blade and the positive direction of the X-axis, in degrees.

[0079] The normal to the test point on the single-crystal hollow working blade forms an angle with both the

[100] crystal direction and the

[010] crystal direction, and the smallest of these angles is used as the correction coefficient angle β. Angle α is the secondary orientation value of the single-crystal hollow working blade, which can be directly read from the orientation testing equipment, 0°≤α≤90°; angle P can be measured on the cross-section of the test point on the single-crystal hollow working blade, 0°≤P≤180°.

[0080] The formula is verified as follows:

[0081] When α = 0° and p = 0°, the correction coefficient angle β of the point to be measured is 0°;

[0082] When α = 0° and p = 10°, the correction coefficient angle β of the point to be measured is 10°;

[0083] When α = 50° and p = 45°, the correction factor angle β of the point to be measured is 5°;

[0084] When α = 40° and p = 10°, the correction factor angle β of the point to be measured is 30°;

[0085] When α = 60° and p = 10°, the correction coefficient angle β of the point to be measured is 40°;

[0086] When α = 0° and p = 90°, the correction coefficient angle β of the point to be measured is 0°;

[0087] When α = 0° and p = 100°, the correction factor angle β of the point to be measured is 10°;

[0088] When α = 50° and p = 135°, the correction factor angle β of the point to be measured is 5°;

[0089] When α = 40° and p = 100°, the correction coefficient angle β of the point to be measured is 30°;

[0090] When α = 60° and p = 100°, the correction coefficient angle β of the point to be measured is 40°.

[0091] Based on the formula verification data above, the correction coefficient angle β of the test point on the single-crystal hollow working blade is always in the range of 0-45°.

[0092] In this implementation, when using an orientation testing device to test the secondary orientation angle of the point to be tested on a single-crystal hollow working blade, the single-crystal hollow working blade needs to be aligned according to... Figure 3 The arrangement is as shown, where the positive X-axis of the single-crystal hollow working blade 1 is parallel to the plane formed by the X-ray emitted from the X-ray tube 3 and the normal to the detection center, and points towards the detector 2. The Z-axis of the single-crystal hollow working blade 1 is parallel to the bisector of the angle between the X-ray emitted from the X-ray tube 3 and the normal to the detection center, with the angle between the X-ray and the normal to the detection center being between 50° and 90°. The orientation of a single-crystal hollow working blade is tested at only one point, namely a point on the bottom surface of the blade tenon, to obtain the secondary orientation angle α of the blade. The P angle needs to be determined later. Figure 4 The cross-section of the test point on the single-crystal hollow working blade shown is measured, and the correction coefficient angle β of the test point can be calculated using the correction coefficient angle calculation formula in step five.

[0093] like Figure 5 As shown, this is a spectrum of correction coefficients for a single-crystal hollow working blade at different deviation angles within the 0-45° range, obtained by extrapolating the initial correction coefficients for longitudinal parallelism to the

[001] crystal orientation and lateral deviation from the

[100] crystal orientation at 0°, 10°, 20°, 30°, and 45°. After calculating the correction coefficient angle β at a certain test point on the single-crystal hollow working blade, ... Figure 5 Find the correction coefficient corresponding to the deviation angle of the test point in the correction coefficient spectrum of different deviation angles within the range of 0-45° of the single crystal hollow working blade shown. Then multiply the correction coefficient of the test point by the ultrasonic test thickness of the test point to obtain the corrected test thickness of the single crystal hollow working blade at that test point. The corrected test thickness is infinitely close to the true thickness.

[0094] The thickness measurement method for single-crystal hollow working blades in this embodiment solves the problem of large measurement errors caused by orientation in ultrasonic thickness measurement. It can measure wall thickness efficiently and accurately, with low testing cost, and meets product quality and safety requirements. More importantly, it performs ultrasonic testing on the thickness of single-crystal hollow working blades based on orientation, with a testing accuracy of over 99%. Especially for the thicker parts of the single-crystal hollow working blades, the testing error does not exceed 1.0%.

[0095] Special Note: The technical solution of this invention involves numerous parameters, and the synergistic effects between these parameters must be comprehensively considered to achieve the beneficial effects and significant progress of this invention. Furthermore, the value ranges of each parameter in the technical solution were obtained through extensive experimentation. For each parameter and the combinations thereof, the inventors have recorded a large amount of experimental data; however, due to space limitations, the specific experimental data is not disclosed here.

[0096] Those skilled in the art will readily understand that the thickness measurement method for single-crystal hollow working blades of the present invention includes any combination of the inventive content and specific embodiments described in the above specification and the various parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combinations have been described in detail. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring the thickness of a single-crystal hollow working blade, characterized in that, The thickness measurement method includes the following steps in sequence: Step 1: Select a single crystal test rod that is the same as the hollow working blade of the single crystal to be tested, and make single crystal samples on the test rod with longitudinal parallel to the [001] crystal orientation and transverse deviation from the [100] crystal orientation by 0°, 10°, 20°, 30° and 45° respectively. Step 2: Use a single crystal sample with longitudinal parallel to the [001] crystal orientation and lateral deviation of 0° from the [100] crystal orientation to perform a reference correction on the ultrasonic equipment; Step 3: Using the corrected ultrasonic equipment, perform ultrasonic thickness measurement on single crystal samples with longitudinal parallel to the [001] crystal orientation and transverse deviation from the [100] crystal orientation by 10°, 20°, 30°, and 45° respectively. Compare the measured thickness obtained by ultrasonic testing with the actual thickness to obtain the ratio of the actual thickness to the measured thickness of the single crystal samples with longitudinal parallel to the [001] crystal orientation and transverse deviation from the [100] crystal orientation by 10°, 20°, 30°, and 45° respectively. Use the ratio of the actual thickness to the measured thickness of the single crystal samples with longitudinal parallel to the [001] crystal orientation and transverse deviation from the [100] crystal orientation by 0°, 10°, 20°, 30°, and 45° respectively as their respective initial correction coefficients. Step 4: Using the initial correction coefficients for longitudinal parallel [001] crystal orientation and lateral deviation from [100] crystal orientation at 0°, 10°, 20°, 30°, and 45°, extrapolate the correction coefficient spectrum of different deviation angles within the range of 0-45° for the longitudinal parallel [001] crystal orientation and lateral deviation from [100] crystal orientation of the single crystal hollow working blade. Step 5: Use an orientation testing device to test the secondary orientation of the single-crystal hollow working blade, record the value of the secondary orientation of the single-crystal hollow working blade, calculate the correction coefficient angle of the test point on the single-crystal hollow working blade through the secondary orientation, and determine the correction coefficient of the deviation angle of the test point in the correction coefficient spectrum of different deviation angles within the range of 0-45° between the longitudinal parallel to the [001] crystal direction and the lateral deviation from the [100] crystal direction of the single-crystal hollow working blade; the normal of the test point forms an angle with the [100] crystal direction and the [010] crystal direction respectively, and the smallest angle is taken as the correction coefficient angle; Step 6: Use an ultrasonic device to perform ultrasonic thickness measurement on the test point on the single-crystal hollow working blade. Multiply the test thickness by the correction coefficient of the deviation angle of the test point to obtain the corrected test thickness of the test point on the single-crystal hollow working blade. The corrected test thickness is infinitely close to the true thickness.

2. The method for measuring the thickness of a single-crystal hollow working blade according to claim 1, characterized in that, In step one, five single crystal samples are prepared with longitudinal parallel [001] crystal orientation and transverse deviation from [100] crystal orientation at 0°, 10°, 20°, 30° and 45° deviation angles. The heights of the five single crystal samples at each deviation angle are 1mm, 2mm, 3mm, 4mm and 5mm respectively, and the length and width of the single crystal sample are not less than 5mm.

3. The method for measuring the thickness of a single-crystal hollow working blade according to claim 2, characterized in that, In step two, a single crystal sample with a longitudinal parallel to the [001] crystal orientation and a lateral deviation of 0° from the [100] crystal orientation is used to perform a reference correction on the ultrasonic equipment. The steps are as follows: Step (1): Use an ultrasonic device to test five single crystal samples with thicknesses of 1 mm, 2 mm, 3 mm, 4 mm and 5 mm, which are parallel to the [001] crystal direction in the longitudinal direction and deviated from the [100] crystal direction by 0° in the transverse direction. The propagation time of the sound wave between the two surfaces in the thickness direction of the five single crystal samples is measured. Step (2): Divide the thickness of the five single crystal samples that are longitudinally parallel to the [001] crystal orientation and laterally deviated from the [100] crystal orientation by the corresponding propagation time to obtain the propagation speed of the sound wave in the five single crystal samples respectively. Step (3): Take the average propagation speed of the sound wave in five single crystal samples that are parallel to the [001] crystal direction in the longitudinal direction and deviate from the [100] crystal direction by 0° in the transverse direction. The average propagation speed of the sound wave in the longitudinal direction parallel to the [001] crystal direction and deviating from the [100] crystal direction by 0° in the transverse direction is then input into the ultrasonic device to complete the reference correction of the ultrasonic device.

4. The method for measuring the thickness of a single-crystal hollow working blade according to claim 3, characterized in that, Step three, the method for obtaining the initial correction coefficient, includes the following steps in sequence: Step A: Using the modified ultrasonic equipment, ultrasonic thickness measurements were performed on single crystal samples with thicknesses of 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm that were longitudinally parallel to the [001] crystal orientation and laterally deviated from the [100] crystal orientation by 10°, 20°, 30°, and 45°, respectively, and the ratio of the actual thickness to the measured thickness of each single crystal sample was obtained. Step B: Take the average of the ratios of the actual thickness to the test thickness of the five single crystal samples that are parallel to the [001] crystal orientation in the longitudinal direction and deviate from the [100] crystal orientation by 10°, 20°, 30° and 45° in the lateral direction. Finally, take the average of the ratios of the actual thickness to the test thickness of the single crystal samples that are parallel to the [001] crystal orientation in the longitudinal direction and deviate from the [100] crystal orientation by 0°, 10°, 20°, 30° and 45° in the lateral direction as the initial correction coefficient.

5. The method for measuring the thickness of a single-crystal hollow working blade according to claim 4, characterized in that, In step B, the average values ​​of the ratio of the actual thickness to the test thickness of the single crystal sample with longitudinal parallel to the [001] crystal orientation and transverse deviation from the [100] crystal orientation at 0°, 10°, 20°, 30° and 45° are 1, 1.03, 1.07, 1.10 and 1.14, respectively.

6. The method for measuring the thickness of a single-crystal hollow working blade according to claim 5, characterized in that, In step four, the extrapolation of the correction coefficient spectrum for the longitudinal parallel [001] crystal orientation and the lateral deviation from the [100] crystal orientation within the range of 0-45° for the single-crystal hollow working blade includes the following steps in sequence: Step a: Take the deviation angles of the single crystal samples that are parallel to the [001] crystal orientation in the longitudinal direction and deviate from the [100] crystal orientation by 0°, 10°, 20°, 30° and 45° in the lateral direction as their respective X-axis, and take the average value of the ratio of the actual thickness to the test thickness of the single crystal samples that are parallel to the [001] crystal orientation in the longitudinal direction and deviate from the [100] crystal orientation by 0°, 10°, 20°, 30° and 45° in the lateral direction as their respective Y-axis; Step b: By fitting calculation, the correction coefficient spectrum of different deviation angles within the range of 0-45° of longitudinal parallel to [001] crystal orientation and lateral deviation from [100] crystal orientation of single crystal hollow working blade is obtained.

7. The method for measuring the thickness of a single-crystal hollow working blade according to claim 6, characterized in that, In step a, the spatial coordinates of the single crystal samples that are longitudinally parallel to the [001] crystal orientation and laterally deviated from the [100] crystal orientation by 0°, 10°, 20°, 30°, and 45° are [0°, 1], [10°, 1.03], [20°, 1.07], [30°, 1.10], and [45°, 1.14], respectively.

8. The method for measuring the thickness of a single-crystal hollow working blade according to claim 7, characterized in that, In step five, the formula for calculating the correction coefficient angle is: When P > 90°, β = 45° - |α - (P - 90°) | -45°; When P≤90°, β=45°-||α-P|-45°|; In the formula: β--Correction coefficient angle, that is, the angle formed between the normal of the test point on the single-crystal hollow working blade and the [100] crystal direction and the [010] crystal direction respectively, and the smallest of the angles is taken as the correction coefficient angle, with the unit being °; α -- Secondary orientation angle, which is the angle between the positive X-axis direction of the single-crystal hollow working blade and the [100] crystal orientation, in °; P -- The angle between the normal to the point to be measured on the single-crystal hollow working blade and the positive direction of the X-axis, in degrees.

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