A method for detecting surface roughness of a blade coating

Abstract

The present application relates to the technical field of blade detection, and more particularly to a kind of roughness detection method of blade coating surface, comprising the following steps: S1, using standard test piece to calibrate roughness measuring equipment;S2, using calibrated roughness measuring equipment to detect blade coating, specifically as follows: first, according to the technical requirements of blade coating surface roughness, select magnification objective, set filtering parameter, sampling length and theoretical evaluation length;Then, multiple detection is carried out, and the average value of multiple measurement results is taken as the detection value.The roughness detection method of the present application adjusts and determines the measurement parameters of three-dimensional optical profile roughness measuring equipment by calibrating coating test piece, which meets the quantitative detection requirements of surface roughness of different regions of high-pressure turbine blade without affecting the integrity of blade coating surface.

Description

Technical Field

[0001] This invention relates to the field of blade inspection technology, specifically a method for detecting the surface roughness of blade coatings. Background Technology

[0002] Currently, there are two main methods for detecting the surface roughness of high-pressure turbine blade coatings for aero-engines. One method is visual measurement, which compares the surface roughness of the blade coating with a roughness sample to determine whether it meets the requirements. This method is a qualitative measurement, and its results are greatly affected by the skill level of the measurement personnel. The other method is to use a stylus-type surface roughness measuring instrument to measure directly on the blade surface. However, since the stylus material of the stylus-type surface roughness measuring instrument is generally diamond or hard alloy, it will form tiny scratches on the blade surface during measurement, affecting the integrity of the blade surface. At the same time, due to the limitation of the location of the air film vents on the blade, the measurable area in some local locations of the blade cannot reach an evaluation length. Summary of the Invention

[0003] To address the problem of low accuracy in blade surface inspection results in existing technologies, this invention provides a method for detecting the surface roughness of blade coatings.

[0004] This invention is achieved through the following technical solution:

[0005] A method for detecting the surface roughness of a blade coating includes the following steps:

[0006] S1, Calibrate the roughness measuring equipment using a standard test piece;

[0007] S2. The blade coating is inspected using a calibrated roughness measuring device, as follows: First, select the magnification objective lens, set the filter parameters, sampling length, and theoretical evaluation length according to the technical requirements of the blade coating surface roughness; then, perform multiple tests and take the average of the multiple measurement results as the test value.

[0008] Preferably, in S1, the calibration process is as follows:

[0009] S11, Use a stylus-type surface roughness measuring instrument to measure the measurement area of ​​the coating sample and record the measured values;

[0010] S12, the measurement area of ​​the coating sample is compared and measured using a three-dimensional optical profile roughness measuring device. The relevant parameters are adjusted according to the technical requirements of the coating surface roughness until the measurement results of the two are consistent.

[0011] Preferably, the deviation between the measurement results of the three-dimensional optical profile roughness measuring device and the measurement results of the stylus-type surface roughness measuring instrument is less than 0.05 μm.

[0012] Preferably, the standard test piece and the blade are manufactured using the same process.

[0013] Preferably, when the surface roughness of the blade coating is 0.1 to 2 μm, the sampling length is 800 μm, the theoretical evaluation length is 4 mm, and the objective lens magnification is selected as 10X, 20X, 50X, or 100X.

[0014] Preferably, when the surface roughness of the blade coating is 2-4 μm, the sampling length is 2500 μm, the theoretical evaluation length is 12.5 mm, and the objective lens magnification is selected as 10X, 20X, 50X, or 100X.

[0015] Preferably, when the surface roughness of the blade coating is 4-10 μm, the sampling length is 2500 μm, the theoretical evaluation length is 12.5 mm, and the objective lens magnification is selected as 5X, 10X, 20X, 50X, or 100X.

[0016] Preferably, during the S2 detection process, a region consisting of multiple parallel lines is selected as the detection area at the same test site on the blade.

[0017] Preferably, the distance between two adjacent parallel lines is less than 0.2 mm.

[0018] Preferably, when the tested area has a blade film pore and the location of the film pore is smaller than the evaluation length, a unit broken line length L is first selected on the pre-processed three-dimensional micro-profile surface, and the number of broken lines n = Ln / L, where n is determined according to the width of the film pore and Ln is the evaluation length; when the evaluation length Ln of the broken line reaches the theoretical evaluation length, the surface roughness of the tested area is then evaluated.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention discloses a method for detecting the surface roughness of blade coatings. By calibrating the coating specimen, the measurement parameters of a three-dimensional optical profile roughness measuring device are adjusted, meeting the quantitative detection requirements for surface roughness in different areas of high-pressure turbine blades without affecting the integrity of the blade coating surface. Simultaneously, it achieves quantitative measurement of the coating surface roughness in the film pore area of ​​the blade. The surface roughness detection results obtained using this method are accurate and reliable, and the operation is convenient. It is a non-contact quantitative detection method based on the high pressure, high temperature, and high flow rate characteristics of high-pressure turbine blade coatings and the surface roughness detection requirements. Furthermore, the three-dimensional optical profile roughness measuring device uses an optical lens to perform three-dimensional non-contact scanning of the microstructure of the measured surface. Three-dimensional data extraction and two-dimensional and three-dimensional roughness analysis are performed using measurement software, avoiding damage to the coating surface.

[0021] Furthermore, measuring within a region composed of multiple parallel lines can avoid or reduce the problem of large differences in surface roughness measurements caused by factors such as uneven particle size of the coating material. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of a method for detecting the surface roughness of a blade coating according to the present invention.

[0023] Figure 2 This is a schematic diagram of the surface roughness detection area of ​​the blade coating of the present invention.

[0024] Figure 3 This is a schematic diagram showing the selection of parallel lines in the surface roughness detection area of ​​the blade coating of the present invention.

[0025] Figure 4 This is a schematic diagram of the coating detection area at the air film pores of the blade in this invention.

[0026] Figure 5 This is a schematic diagram of the broken-line method for detecting the coating in the air film pore area of ​​the blade according to the present invention.

[0027] Figure 6 This is a schematic diagram of the evaluation of the surface roughness of the blade coating using a three-dimensional optical profile roughness measurement device. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0029] This invention discloses a method for detecting the surface roughness of blade coatings, referring to... Figure 1 This includes the following steps:

[0030] S1. The surface roughness measuring equipment is calibrated using a standard test piece (the standard test piece is manufactured using the same process as the blade). The calibration process is as follows:

[0031] S11, Use a stylus-type surface roughness measuring instrument to measure the measurement area of ​​the coating sample and record the measured values;

[0032] S12, the measurement area of ​​the coating sample is compared and measured using a three-dimensional optical profile roughness measuring device. The relevant parameters are adjusted according to the technical requirements of the coating surface roughness until the measurement results of the two are consistent, that is, the deviation between the measurement results of the three-dimensional optical profile roughness measuring device and the measurement results of the stylus-type surface roughness measuring instrument is less than 0.05μm.

[0033] S2, The blade coating is inspected using a calibrated roughness measuring device, as detailed below:

[0034] First, select the magnification objective lens, set the filter parameters, sampling length, and theoretical evaluation length according to the technical requirements of the surface roughness of the blade coating; then conduct multiple tests and take the average of the multiple measurement results as the test value.

[0035] The selection principles for sampling length, theoretical evaluation length, and objective lens magnification are as follows:

[0036] When the surface roughness of the blade coating is 0.1-2μm, the sampling length is 800μm, the theoretical evaluation length is 4mm, and the objective lens magnification is selected as 10X, 20X, 50X, or 100X.

[0037] When the surface roughness of the blade coating is 2-4 μm, the sampling length is 2500 μm, the theoretical evaluation length is 12.5 mm, and the objective lens magnification is selected as 10X, 20X, 50X, or 100X.

[0038] When the surface roughness of the blade coating is 4-10 μm, the sampling length is 2500 μm, the theoretical evaluation length is 12.5 mm, and the objective lens magnification is selected as 5X, 10X, 20X, 50X, or 100X.

[0039] During the S2 inspection process, to reduce the impact of coating material uniformity on the test results, multiple parallel lines were selected for measurement in the same test area of ​​the blade. The distance between the parallel lines was less than 0.2 mm. Figure 2 , 3 The three parallel lines in the diagram are labeled as selected.

[0040] During the testing process, when the tested area contains film pores on the blade, and the location of the film pores is smaller than the evaluation length, a unit broken line length L is first selected on the three-dimensional microscopic contour surface of the pre-treated blade. The number of folds n = Ln / L, where n is determined according to the width of the film pores, and Ln is the evaluation length. Once the evaluation length Ln of the broken line reaches the theoretical evaluation length, the surface roughness of the tested area is then evaluated, referring to... Figure 4 , 5 .

[0041] During testing, the incident light from the lens is perpendicular to the part being tested.

[0042] Taking a turbine blade as an example, the roughness of its coating surface is measured, and the steps are as follows:

[0043] (1) Prepare coating test pieces. The coating test pieces and the product use the same process parameters. Determine and mark the measurement area on the test pieces.

[0044] (2) Determine the surface roughness measurement value of the coating test piece. Use a stylus-type surface roughness measuring instrument to measure the measurement area of ​​the coating test piece and record the measured value.

[0045] (3) Use a three-dimensional optical profile roughness measuring device to compare and measure the measurement area of ​​the coating specimen. Adjust the relevant parameters according to the technical requirements of the coating surface roughness. For example, if the coating surface roughness Ra≤3.2, the objective lens magnification should be 10X, the coating specimen should be a flat thin sheet, the lens detection distance should be 0.5mm, the filter wavelength should be 800μm, and the theoretical evaluation length should be 4mm.

[0046] (4) Using a properly adjusted three-dimensional optical profile roughness measuring device, perform a three-dimensional scan of relevant parts of the turbine blade coating surface to accurately reflect its surface characteristics and quality. Then, filter the acquired three-dimensional surface (eliminating the influence of profile and waviness) to obtain the original image that meets the surface roughness detection requirements. Select the roughness profile length on the scanned original image, set the corresponding filter length (e.g., 800m, where the default evaluation length is 4mm), and the roughness evaluation image can be displayed. Perform roughness analysis to obtain the Ra value, and refer to... Figure 6 .

[0047] This invention adjusts and determines the measurement parameters of a three-dimensional optical profile roughness measuring device by calibrating the coated specimen, thus meeting the quantitative detection requirements of surface roughness in different areas of high-pressure turbine blades without affecting the integrity of the blade coating surface. It also enables the quantitative measurement of the coating surface roughness in the film pore area of ​​the blade.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A method for detecting the surface roughness of a blade coating, characterized in that, Includes the following steps: S1, Calibrate the roughness measuring equipment using a standard test piece; S2. The blade coating is inspected using a calibrated roughness measuring device, as follows: First, select the magnification objective lens, set the filter parameters, sampling length, and theoretical evaluation length according to the technical requirements of the blade coating surface roughness; then, perform multiple tests and take the average of the multiple measurement results as the test value. During the S2 inspection process, a region consisting of multiple parallel lines is selected as the inspection area at the same test site on the blade. The distance between two adjacent parallel lines is less than 0.2 mm; During the testing process, when the tested area has air film pores on the blade and the location of the air film pores is smaller than the evaluation length, a unit broken line length L is first selected on the pre-processed three-dimensional micro-profile surface. The number of broken lines n = Ln / L, where n is determined according to the width of the air film pores and Ln is the evaluation length. When the evaluation length Ln of the broken line reaches the theoretical evaluation length, the surface roughness of the tested area is then evaluated.

2. The method for detecting the surface roughness of blade coatings according to claim 1, characterized in that, In S1, the calibration process is as follows: S11, Use a stylus-type surface roughness measuring instrument to measure the measurement area of ​​the coating sample and record the measured values; S12, the measurement area of ​​the coating sample is compared and measured using a three-dimensional optical profile roughness measuring device. The relevant parameters are adjusted according to the technical requirements of the coating surface roughness until the measurement results of the two are consistent.

3. The method for detecting the surface roughness of blade coatings according to claim 2, characterized in that, The deviation between the measurement results of the three-dimensional optical profile roughness measuring device and the measurement results of the stylus-type surface roughness measuring instrument is less than 0.05 μm.

4. The method for detecting the surface roughness of blade coatings according to claim 1, characterized in that, The standard test piece and the blade are manufactured using the same process.

5. The method for detecting the surface roughness of blade coatings according to claim 1, characterized in that, In S2, when the surface roughness of the blade coating is 0.1~2μm, the sampling length is 800μm, the theoretical evaluation length is 4mm, and the objective lens magnification is selected as 10X, 20X, 50X, or 100X.

6. The method for detecting the surface roughness of blade coatings according to claim 1, characterized in that, When the surface roughness of the blade coating is 2~4μm, the sampling length is 2500μm, the theoretical evaluation length is 12.5mm, and the objective lens magnification is selected as 10X, 20X, 50X, or 100X.

7. The method for detecting the surface roughness of blade coatings according to claim 1, characterized in that, When the surface roughness of the blade coating is 4~10μm, the sampling length is 2500μm, the theoretical evaluation length is 12.5mm, and the objective lens magnification is selected as 5X, 10X, 20X, 50X, or 100X.

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