A method for finishing closed integral bladed disks by combining sandblasting and abrasive flow through inter-blade channels.

Abstract

This invention discloses a combined mirror blasting and abrasive flow finishing method for the inter-blade channel of a closed integral bladed disk, comprising the following steps: 1) dividing the inter-blade channel of the integral bladed disk into a blasting zone and a non-blasting zone; 2) applying a surface protection treatment to the non-blasting zone; 3) processing the blasting zone of the inter-blade channel using a manual blasting process until the surface roughness is reduced to the process value; 4) removing the surface protection treatment from the non-blasting zone; 5) performing a finishing process using an abrasive flow finishing process to refine the entire inter-blade channel until the surface roughness meets the drawing requirements. This invention combines the sandblasting process, which has good localization and high processing efficiency, with the abrasive flow finishing process, which has good processing accessibility and high processing quality. This allows for the leveraging of the strengths of both processes to achieve the goal of high uniformity, high efficiency, and low cost finishing of the inter-blade channel of a closed integral bladed disk.

Description

Technical Field

[0001] This invention belongs to the field of finishing technology, specifically relating to a closed integral bladed disk inter-blade channel sandblasting + abrasive flow combined finishing method. Background Technology

[0002] Closed integral bladed disks are one of the key core components of aero engines and gas turbines. They are generally made of high-temperature resistant and difficult-to-machine materials such as stainless steel, titanium alloy, and nickel-based alloy. The blades are bent and twisted, numerous, and the inter-blade passages are narrow, resulting in poor machinability. In addition, they require high machining accuracy and surface quality, making them recognized both domestically and internationally as difficult-to-machine workpieces.

[0003] Electrical discharge machining (EDM) technology is particularly suitable for precision machining of inter-blade channels in closed integral bladed disks due to its good machinability, high precision, wide applicability to materials, and absence of macroscopic cutting forces. After more than 70 years of development, it has been successfully used to solve the overall manufacturing challenges of various types of closed integral bladed disks both domestically and internationally.

[0004] Although electrical discharge machining (EDM) can guarantee the machining accuracy and surface roughness uniformity of the inter-blade channels in a closed integral bladed disk, achieving the surface roughness (R0) required by the drawings using this technology is challenging. a The efficiency of EDM (electrode discharge machining) is relatively low (around 0.8 μm), and the processing cost is high, making it difficult to meet the needs of mass production. Therefore, EDM still needs to be combined with subsequent finishing processes to balance processing quality, efficiency, and cost. Summary of the Invention

[0005] The technical problem to be solved by this invention is to find a method for finishing the inter-blade channel of a closed integral bladed disk that has good processing uniformity, high processing efficiency, and low processing cost. The technical solution adopted by this invention is as follows:

[0006] A method for finishing a closed integral bladed disk by combining sandblasting and abrasive flow through the inter-blade channel includes the following steps:

[0007] Step 1: Divide the inter-blade passage of the closed integral bladed disk into a sandblasting zone and a non-sandblasting zone;

[0008] Step 2: Apply surface protection treatment to the non-sandblasted areas;

[0009] Step 3: Use manual sandblasting to process the sandblasted area of ​​the inter-blade passage until the surface roughness is reduced to the process value;

[0010] Step 4: Remove the protective coating from non-blasted areas;

[0011] Step 5: Use abrasive finishing process to finish the entire inter-blade passage until the surface roughness meets the requirements of the drawing.

[0012] This invention is based on the following principles:

[0013] Sandblasting offers advantages such as good localization, simple operation, high efficiency, and low cost. However, its accessibility is poor, and it's difficult to achieve grinding textures on the processed surface, making it unsuitable as a final finishing process for inter-blade channels. Abrasive flow finishing offers advantages such as good accessibility, high efficiency, good surface quality, and low cost. However, its uniformity in the inter-blade channels of closed integral bladed disks is poor, specifically, the finishing efficiency at the inner and outer annular surfaces and blade root radius is lower than that at the blade itself, limiting its application in closed integral bladed disks. Therefore, combining sandblasting and abrasive flow finishing can balance processing uniformity, efficiency, and cost.

[0014] To optimize the above technical solution, the specific measures also include:

[0015] The closed integral bladed disk inter-blade channel is obtained by electrical discharge machining before surface finishing, and the average surface roughness is controlled to R. a 1.0μm~R a 2.0μm.

[0016] In step 1 above, the sandblasting area includes the inner annular surface, the outer annular surface, and the blade root R angle; the other inter-blade passage surfaces are non-sandblasting areas.

[0017] The non-sandblasted area protection treatment in step 2 above is achieved by spraying or applying a film. When spraying, cold spraying is preferred, with a coating thickness of not less than 0.1 mm and a hardness of not less than 30 HRC after curing. When applying a film, aluminum foil tape is preferred, with a tape thickness of not less than 0.1 mm.

[0018] In step 3 above, the surface roughness values ​​of the inner and outer annular surfaces after sandblasting should not exceed 0.5 times the average surface roughness before sandblasting, and should not be lower than the requirements of the drawing. Furthermore, the surface roughness value of the blade root radius (R-angle) after sandblasting must meet the requirements of the drawing.

[0019] The abrasive finishing process used in step 5 above employs a viscoelastic solid-liquid two-phase mixture fluid abrasive, preferably silicon carbide fluid abrasive, and the silicon carbide abrasive particle size is no greater than 80 mesh.

[0020] The present invention has the following beneficial effects:

[0021] By combining the advantages of sandblasting in terms of its localization and abrasive finishing in terms of its accessibility and surface quality, it is possible to achieve the goal of high uniformity in the inter-blade channels of a closed integral bladed disk.

[0022] Sandblasting and abrasive finishing share the common advantages of high processing efficiency and low processing cost. Therefore, the combined process can achieve efficient and low-cost finishing of the inter-blade channels of closed integral bladed disks.

[0023] This combined process is applicable not only to closed integral bladed disks but also to open integral bladed disks; it is applicable not only to integral bladed disks manufactured by electrical discharge machining but also to integral bladed disks manufactured by additive manufacturing. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the closed integral bladed disk structure in an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the inter-blade channel area division of a closed integral bladed disk in an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the sandblasting process for the inter-blade channel of the closed integral bladed disk in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the abrasive finishing process of the inter-blade channel of the closed integral bladed disk in an embodiment of the present invention.

[0028] In the figure, 1-outer ring surface, 2-blade root, 3-blade body, 4-inner ring surface, 5-inter-blade channel sandblasting area, 6-spray gun, 7-abrasive finishing fixture. Detailed Implementation

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

[0030] like Figures 1-4 As shown.

[0031] A closed integral bladed disk component consists of blades, an outer ring, and an inner ring. The blades are arranged in a circular pattern on the disk and are surrounded by the outer and inner rings. The inter-blade channel is formed by the outer ring surface 1, the blade root 2, the blade body 3, and the inner ring surface 4. The material of this component is nickel-based alloy GH4169, and the surface roughness value of the inter-blade channel required by the drawing is R. a <0.8μm. The previous process used electrical discharge machining to complete the inter-blade channel, at which point the surface roughness value was R. a 2.0μm. Based on this, it is necessary to use finishing to reduce the surface roughness value of the inter-blade channel to the design value in the drawing.

[0032] According to the sandblasting + abrasive flow combined finishing method proposed in this invention, the following processing steps are designed:

[0033] 1) Division of the inter-blade passage sandblasting area. First, the inter-blade passage is divided into sandblasting areas. The sandblasting area includes the outer ring surface 1, the blade root 2, and the inner ring surface 4, while the non-sandblasting area is the blade body 3.

[0034] 2) Surface protection treatment for non-sandblasted areas. Since the blades of this part are close to the ruled surface shape in the radial direction, aluminum foil tape with a thickness of 0.15mm is selected for surface protection when applying a film.

[0035] 3) Use spray gun 6 to manually sandblast the inter-blade passage sandblasting area 5 until the surface roughness drops to R. a 1.0μm. Sandblasting uses black silicon carbide abrasive grains, first roughing with 80-mesh abrasive and then finishing with 120-mesh abrasive.

[0036] 4) After sandblasting, manually peel off the tape on the blade surface. There may be adhesive residue on the blade surface at this time, which can be completely removed in the subsequent abrasive finishing process, so no treatment is required.

[0037] 5) Using a fixture, the sandblasted workpieces are subjected to bidirectional abrasive finishing. The process parameters are as follows: the abrasive is black silicon carbide, the abrasive mass fraction is 60%, the fluid abrasive viscosity is 8000 Pa·s (measured using a Bollerfeld rotational viscometer at 20℃), and the fluid abrasive density is 1650 kg / m³. 3 The machine tool operates at a pressure of 5.5 MPa with no back pressure. The processing room temperature is 20°C, the fluid abrasive temperature is 22–25°C, and the total fluid abrasive consumption is 8800 kg.

[0038] After abrasive finishing, the surface roughness value of the inter-blade channel was measured as R. a The material removal depth is 0.8–0.6 μm, the total material removal depth is 0.08–0.11 mm, the processing uniformity is good, and it meets the requirements of the drawings.

[0039] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

[0040] The parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. A method for finishing a closed integral bladed disk by combining sandblasting and abrasive flow through the inter-blade channel, characterized in that, Includes the following steps: Step 1: Divide the inter-blade channels of the closed integral bladed disk into a sandblasting zone and a non-sandblasting zone; the sandblasting zone is the inner ring surface, the outer ring surface and the blade root R angle, and the other inter-blade channel surfaces are non-sandblasting zones; Step 2: Apply surface protection treatment to the non-sandblasted areas; Step 3: The inter-blade passage sandblasting area is processed using a manual sandblasting process until its surface roughness is reduced to the process value. The process value is: for the inner and outer ring surfaces, not greater than 0.5 times the average surface roughness before sandblasting, and not lower than the drawing requirements; for the blade root R angle, it meets the drawing requirements. The abrasive used in the manual sandblasting process is silicon carbide abrasive, first using 80-mesh abrasive for roughing, and then using 120-mesh abrasive for finishing. Step 4: Remove the protective coating from non-blasted areas; Step 5: Use abrasive finishing process to finish the entire inter-blade channel until the surface roughness meets the requirements of the drawing.

2. The method for finishing a closed integral bladed disk with inter-blade channel sandblasting and abrasive flow combined finishing according to claim 1, characterized in that, The closed integral bladed disk inter-blade channel is obtained by electrical discharge machining before finishing, and the average surface roughness is controlled to be Ra1.0μm~Ra2.0μm.

3. The method for finishing a closed integral bladed disk with inter-blade channel sandblasting and abrasive flow combined finishing according to claim 1, characterized in that, The surface protection treatment in step 2 is achieved by spraying or applying a film.

4. The method for finishing a closed integral bladed disk with inter-blade channel sandblasting and abrasive flow combined finishing according to claim 3, characterized in that, When the surface protection treatment is achieved by spraying, a cold spraying process is selected, the coating thickness is not less than 0.1 mm, and the hardness of the coating after curing is not less than 30 HRC.

5. The method for finishing a closed integral bladed disk with inter-blade channel sandblasting and abrasive flow combination according to claim 3, characterized in that, When the surface protection treatment is achieved by applying a film, aluminum foil tape should be used, and the tape thickness should not be less than 0.1 mm.

6. The method for finishing a closed integral bladed disk with inter-blade channel sandblasting and abrasive flow combination according to claim 1, characterized in that, The abrasive finishing process in step 5 is a bidirectional abrasive finishing process, and the fluid abrasive used is silicon carbide fluid abrasive with a particle size of no more than 80 mesh.

7. The method for finishing a closed integral bladed disk with inter-blade channel sandblasting and abrasive flow combined finishing according to claim 1, characterized in that, The abrasive finishing process used in step 5 employs a viscoelastic solid-liquid two-phase mixture fluid abrasive.

Images