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CN-115931488-B - Preparation method of metallographic detection sample of axial section of air film hole of aeroengine

CN115931488BCN 115931488 BCN115931488 BCN 115931488BCN-115931488-B

Abstract

The invention discloses a preparation method of a metallographic detection sample of an axial section of an aeroengine air film hole, which comprises the steps of clamping and fixing a metallographic sample cut from an aeroengine blade through a special clamp, realizing stable positioning of the metallographic sample, ensuring that the axial direction of the air film hole of the metallographic sample can be parallel to an observation surface, inlaying the metallographic sample by adopting a cold inlaying technology, ensuring that inlay liquid is filled into the air film hole, and preventing the metallographic sample from being biased during inlaying.

Inventors

  • CHEN MINGXU
  • XIE SHAN
  • BAI HE
  • LI YONGKUN
  • SUN YIYAO
  • QIN JIANG

Assignees

  • 国营川西机器厂

Dates

Publication Date
20260505
Application Date
20221109

Claims (6)

  1. 1. The preparation method of the metallographic detection sample of the axial section of the air film hole of the aeroengine is characterized by comprising the following steps: firstly, cutting a metallographic specimen with a gas film hole from a blade of an aeroengine; step two, manufacturing a clamp for assisting in positioning a metallographic specimen, wherein symmetrically-distributed positioning holes are formed in the clamp and are formed by fixedly connecting a bottom plate and two side plates, the longitudinal section of the clamp is U-shaped, the positioning holes are arranged on the two side plates of the clamp in a plurality of rows, the metallographic specimen is fixed between the two side plates of the clamp, the metallographic specimen is placed in the clamp, and the metallographic specimen is fixed on the clamp by utilizing a silk thread, so that the axial direction of a gas film hole on the metallographic specimen is parallel to an observation surface; step three, placing the clamp fixed with the metallographic specimen into a vacuum embedding machine for pre-vacuumizing; preparing cold mosaic liquid, wherein the cold mosaic liquid is prepared from cold mosaic resin and a curing agent, the weight ratio of the cold mosaic resin to the curing agent is 1:3, pumping the cold mosaic liquid into a clamp fixed with a metallographic specimen by using a vacuum mosaic machine, and performing cold mosaic, wherein the cold mosaic work lasts for 3-10 min; Step five, taking out the inlaid metallographic specimen after the cold inlaid liquid is solidified; and step six, polishing the metallographic specimen.
  2. 2. The method for preparing the metallographic detection sample for the axial section of the air film hole of the aeroengine, as set forth in claim 1, is characterized in that in the third step, the vacuum mosaic machine is pre-vacuumized until the vacuum degree is less than 0.3bar and then kept for 3-10 min.
  3. 3. The method for preparing the metallographic detection sample of the axial section of the air film hole of the aeroengine, as set forth in claim 1, is characterized in that in the step six, an automatic grinding and polishing machine is adopted to grind and polish the metallographic sample, the rotating speed of a turntable of the automatic grinding and polishing machine is 220-300 r/min, the rotating speed of the metallographic sample is 120-200 r/min, and the steering direction is the same as that of the turntable.
  4. 4. The preparation method of the metallographic detection sample for the axial section of the air film hole of the aeroengine is characterized by firstly adopting 120# abrasive paper to carry out rough grinding when the metallographic detection sample is ground and polished, changing 500# abrasive paper to carry out grinding and polishing when the metallographic detection sample is observed to be ground to the air film hole quickly, changing 1000# abrasive paper to carry out fine polishing for 10-30 s when the metallographic detection sample is ground and polished to the axial center of the air film hole, and finally changing polishing cloth to carry out polishing.
  5. 5. The method for preparing a metallographic examination sample of an axial section of an air film hole of an aeroengine according to claim 4, wherein the polishing cloth is acetate fiber satin woven fabric polishing cloth, and the diamond suspension with a diameter of 3 μm is added in the polishing process.
  6. 6. The method for preparing the metallographic detection sample of the axial section of the air film hole of the aeroengine according to claim 1, wherein the clamp is prepared by adopting a 3D printing technology.

Description

Preparation method of metallographic detection sample of axial section of air film hole of aeroengine Technical Field The invention relates to the technical field of aeroengine production, in particular to a preparation method of a metallographic detection sample of an axial section of an aeroengine air film hole. Background After the blade of the aeroengine is processed, the surface state of the air film hole on the blade is required to be detected, a metallographic specimen of the air film hole along the axial direction is generally prepared for detection by adopting a metallographic method, and a thermal mosaic protection metallographic specimen is adopted for preparing the metallographic specimen. Because the air film holes are distributed on the cambered surface of the blade, the axial direction of the air film holes cannot be accurately determined after the air film Kong Jinxiang sample is cut, and because the sample cut from the aeroengine blade is a thin-wall special-shaped piece, the sample is difficult to clamp stably when the sample is clamped, and the metallographic sample cannot be ensured to be stable to obtain a stable observation surface when observed, the metallographic sample is clamped by a spring ring, and then is put into an embedding machine for thermal embedding. The method has the following defects that 1, the axial direction of the air film hole cannot be accurately judged, the axial direction of the air film hole cannot be determined only by naked eyes, the air film hole of the metallographic sample cannot be guaranteed to be parallel to an observation surface, 2, the metallographic sample is clamped by a spring ring during embedding, the axial direction of the air film hole of the metallographic sample cannot be guaranteed to be parallel to the observation surface, the metallographic sample is pressed during thermal embedding, and the metallographic sample is easy to fall. When the problems occur in the preparation process of the metallographic specimen, the qualified metallographic specimen cannot be prepared and can only be reworked for preparation. Disclosure of Invention The invention aims to solve the technical problem of providing a preparation method of a metallographic detection sample of an axial section of an air film hole of an aeroengine, which can improve the qualification rate of the metallographic detection sample. The technical scheme adopted for solving the technical problems is that the preparation method of the metallographic detection sample for the axial section of the air film hole of the aeroengine comprises the following steps: firstly, cutting a metallographic specimen with a gas film hole from a blade of an aeroengine; Step two, manufacturing a clamp for assisting in positioning the metallographic specimen, wherein symmetrically distributed positioning holes are formed in the clamp, the metallographic specimen is placed in the clamp, and the metallographic specimen is fixed on the clamp by utilizing a silk thread, so that the axial direction of a gas film hole on the metallographic specimen is parallel to an observation surface; step three, placing the clamp fixed with the metallographic specimen into a vacuum embedding machine for pre-vacuumizing; Preparing cold embedding liquid, sucking the cold embedding liquid into a clamp fixed with a metallographic specimen by using a vacuum embedding machine, and cold embedding the clamp fixed with the metallographic specimen; Step five, taking out the inlaid metallographic specimen after the cold inlaid liquid is solidified; and step six, polishing the metallographic specimen. The method comprises the steps of first, carrying out a first step, and carrying out a second step, wherein the first step is to fix the metal sample on the metal sample, and the second step is to fix the metal sample on the metal sample. Further, in the third step, the vacuum embedding machine is pre-vacuumized until the vacuum degree is less than 0.3bar, and then the vacuum embedding machine is kept for 3-10 min. The cold mosaic liquid is prepared from cold mosaic resin and a curing agent in a weight ratio of 1:3, and the cold mosaic work lasts for 3-10 min. Further, in the step six, an automatic grinding and polishing machine is adopted to grind and polish the metallographic sample, the rotating speed of a turntable of the automatic grinding and polishing machine is 220-300 r/min, the rotating speed of the metallographic sample is 120-200 r/min, and the steering direction is the same as that of the turntable. The method comprises the steps of firstly adopting 120# abrasive paper to perform rough grinding when a metallographic sample is ground and polished, changing 500# abrasive paper to perform grinding and polishing when the metallographic sample is observed to be quickly ground to a gas film hole, changing 1000# abrasive paper to perform fine polishing for 10-30 s when the metallographic sample is ground and polished to the axial cente