Graphite runway local chromium plating clamp and method for aero-engine

Abstract

The invention discloses a local chromium plating clamp and method for a graphite runway for an aero-engine. The clamp is mainly composed of a hook, a stainless steel outer mounting ring, a stainless steel outer mounting ring universal part and a stainless steel bolt. The stainless steel outer installation ring is composed of a base body, a lug piece with a hole and a connecting rod, and the stainless steel outer installation ring universal piece is composed of a base body and a lug piece with a hole. A stepped through hole coaxial with the base body is formed in the axial end face of the base body, and the stepped through hole at least comprises a first installation hole, a threaded hole and a second installation hole. The end face of the head portion is provided with a cross groove, the outer diameter of the head portion is equal to the diameter of an inner hole of the graphite runway, and the height of the head portion is equal to the axial height of the graphite runway. The fringe effect in the electroplating process is eliminated, the current efficiency during electroplating is improved, the clamp is convenient and flexible to assemble and disassemble during electroplating, and the clamp is shaped at a time and can be repeatedly used.

Description

Technical Field

[0001] The invention belongs to the technical field of surface treatment in aircraft engine manufacturing, and in particular relates to a local chrome plating fixture for an aircraft engine graphite runway and a chrome plating method. Background Art

[0002] Sealing technology is crucial in aircraft engines to reduce or eliminate fluid leakage at mating surfaces, and graphite sealing technology is widely used. Graphite sealing technology is a contact-type sealing device that achieves a tight seal through contact between a graphite ring and the sealing object. However, graphite sealing technology is primarily used in dry friction environments without lubricants. This results in extensive dry friction on the sealing surface formed between the sealing object and the graphite sealing ring, causing surface wear and significantly shortening the service life of the parts.

[0003] like Figure 1 The figure shows a cross-section of a graphite runway part for an aircraft engine. The W surface needs to be chrome-plated to enhance the wear resistance of the surface of the part. The B surface (inner surface) and the C surface (outer surface) are allowed to be plated, and the D surface is allowed to be partially plated. The electroplating area of this part is small (0.05dm 2 ), long electroplating time (660min~720min), thick electroplated chromium layer (200μm~250μm, the figure shows the thickness before plating H and the thickness after plating H+0.2), high process technology requirements, difficult electroplating process, and no dedicated chrome plating fixture on the work site. During processing, the operator needs to make the electroplating fixture according to the process requirements. However, the current self-made fixtures have the following problems:

[0004] 1. The fixture is simple and rough, and the fit between the fixture and the parts is not tight, which causes problems such as rough edges of the electroplated chrome layer of the parts, frequent chromium seepage on the non-plated surface, and the electroplated chrome layer failing to meet the process requirements.

[0005] 2. The fixture cannot be reused and needs to be remade before each processing, resulting in long production preparation time and low production efficiency.

[0006] Based on the above reasons, it is necessary to design a special local chrome plating fixture for graphite runway parts according to the chrome plating process regulations of engine graphite runway parts, so as to solve the serious edge effect and chromium penetration problems of parts in the chrome plating process of traditional fixtures. Summary of the Invention

[0007] The present invention aims to provide a fixture and method for partial chrome plating of a graphite runway for an aircraft engine, which eliminates the edge effect during the electroplating process, ensures that the edge of the graphite runway after electroplating is smooth, fine, not rough, and free of chromium seepage, improves the current efficiency during electroplating, ensures the electroplating effect, and facilitates and flexibly loads and unloads the fixture during electroplating. At the same time, the fixture can be shaped once and can be reused.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A fixture for partial chrome plating of a graphite runway for an aircraft engine, comprising:

[0010] The substrate is a rotating body made of stainless steel, and the axial end surface of the substrate is provided with a stepped through hole coaxial with the substrate, and the stepped through hole includes at least three parts: a first mounting hole, a threaded hole, and a second mounting hole. The first mounting hole and the second mounting hole are mirror-symmetrical about the threaded hole, and the shape of the inner wall of the first mounting hole and the second mounting hole includes the outer contour feature of the graphite runway. The hole depth of the first mounting hole and the second mounting hole is equal to the axial height of the graphite runway before chrome plating.

[0011] A stainless steel outer mounting ring, which consists of a base, perforated lugs, and a connecting rod. The outer surface of the base is connected to two parallel, spaced-apart lugs. One end of the connecting rod is connected to the outer surface of the base, and the other end is free.

[0012] A universal stainless steel outer mounting ring component, comprising a base and a perforated lug. Three lugs are connected to the outer surface of the base, two of which are paired, parallel, and spaced apart. The thickness of the third lug is less than or equal to the spacing between the two parallel lugs.

[0013] The stainless steel bolt is a flat head bolt, whose axial length is less than or equal to half of the axial length of the base body, a cross groove is opened on the end face of the head of the stainless steel bolt, the outer diameter of the head of the stainless steel bolt is equal to the inner hole diameter of the graphite runway, the height of the head of the stainless steel bolt is equal to the axial height of the graphite runway, and the external thread of the stainless steel bolt matches the threaded hole of the base body.

[0014] Furthermore, the partial chrome plating fixture for the graphite runway for aircraft engines also includes a hook, which is made of copper. One end of the hook is welded to the free end of the connecting rod on the stainless steel outer mounting ring, and the other end is connected to the cathode of the chrome plating tank.

[0015] Furthermore, the partial chrome plating fixture of the graphite runway for aircraft engines also includes a demonstration ring part, the outer contour and size of the demonstration ring part are consistent with the graphite runway, and the demonstration ring part can be detachably installed in the first mounting hole and the second mounting hole.

[0016] As an option:

[0017] The base body is a circular ring body, and its inner ring surface forms a stepped through hole;

[0018] In the universal stainless steel outer mounting ring, three lugs with holes are arranged along the radial line of the base, two of which are arranged in parallel at one end of the radial line, and the third lug is located at the other end of the radial line;

[0019] In the stainless steel outer mounting ring, two parallel and spaced-apart lugs and a connecting rod are respectively located at two ends of a same radial line on the base.

[0020] As an option, the inner wall shapes of the first mounting hole and the second mounting hole include contour features of an outer circumferential surface of a graphite raceway and a non-chrome-plated axial end surface.

[0021] Furthermore, the shapes of the inner walls of the first mounting hole and the second mounting hole include inner walls, chamfers and support platforms.

[0022] As a solution, a plurality of the stainless steel outer mounting ring universal parts are interconnected to form a group, wherein any two stainless steel outer mounting ring universal parts are connected by inserting the third ear piece of one of the stainless steel outer mounting ring universal parts into the gap between two parallel and spaced ear pieces on the other stainless steel outer mounting ring universal part and inserting the countersunk bolts into the holes on the three ear pieces.

[0023] A method for local chrome plating of a graphite runway for an aircraft engine uses a fixture for local chrome plating of a graphite runway for an aircraft engine with a hook, and includes the following steps:

[0024] Step 1: Place a graphite runway into the first mounting hole of the stainless steel outer mounting ring, with the end of the graphite runway to be chrome-plated facing outward;

[0025] Step 2: Screw the stainless steel bolt into the threaded hole of the stainless steel outer mounting ring until the head end face of the stainless steel bolt, the end face to be chrome-plated of the graphite runway and the axial end face of the stainless steel outer mounting ring are flush with each other in the same plane;

[0026] Step 3. Connect the other end of the hook to the cathode of the chrome plating tank.

[0027] As an option, before step 1, the hook is polished to remove the oxide film on the hook surface, and the chromium nodules on the stainless steel outer mounting ring and the stainless steel outer mounting ring universal part are removed.

[0028] When there are two graphite runways, the step between step 2 and step 3 further includes placing another graphite runway into the second mounting hole of the stainless steel outer mounting ring, with the end face of the graphite runway to be chrome-plated facing outward, repeating step 2 and then performing step 3;

[0029] When the number of graphite runways is greater than two and is an even number, use a stainless steel outer mounting ring and one or more stainless steel outer mounting ring universal parts. Every two graphite runways share one stainless steel outer mounting ring or one stainless steel outer mounting ring universal part. First perform steps one and two, then place another graphite runway in the second mounting hole of the stainless steel outer mounting ring, with the end face of the graphite runway to be chrome-plated facing outward, repeat step two, and then connect a stainless steel outer mounting ring universal part to the stainless steel outer mounting ring through an ear piece, or connect multiple stainless steel outer mounting ring universal parts to form a group through the ear piece and then connect them to the stainless steel outer mounting ring, wherein the stainless steel outer mounting ring universal parts and the stainless steel outer mounting ring universal parts and the stainless steel outer mounting ring universal parts are connected by inserting countersunk bolts into the holes on the ear pieces. Then, for each stainless steel outer mounting ring universal part, install a graphite runway in its first mounting hole and screw the stainless steel bolt into the threaded hole. Then place another graphite runway in the second mounting hole and screw the stainless steel bolt into the threaded hole. Finally, perform step three.

[0030] When the number of graphite runways is greater than two and is an odd number, use a stainless steel outer mounting ring and one or more stainless steel outer mounting ring universal parts. Every two graphite runways share one stainless steel outer mounting ring or one stainless steel outer mounting ring universal part. The remaining graphite runway uses a stainless steel outer mounting ring universal part alone. First perform steps one and two, then place another graphite runway in the second mounting hole of the stainless steel outer mounting ring, with the end of the graphite runway to be chrome-plated facing outward, repeat step two, and then connect a stainless steel outer mounting ring universal part to the stainless steel outer mounting ring through the ear piece, or connect multiple stainless steel outer mounting ring universal parts through the ear piece. After the pieces are connected to form a group, they are connected to the stainless steel outer mounting ring, wherein the stainless steel outer mounting ring universal parts and the stainless steel outer mounting ring universal parts, as well as the stainless steel outer mounting ring universal parts and the stainless steel outer mounting ring are connected by inserting countersunk bolts into the holes on the ear pieces. Then, for each stainless steel outer mounting ring universal part, a graphite runway is installed in its first mounting hole and the stainless steel bolt is screwed into the threaded hole. Then, another graphite runway is placed in the second mounting hole and the stainless steel bolt is screwed into the threaded hole. For the stainless steel outer mounting ring universal part with only one graphite runway installed, a demonstration ring part is installed in its second mounting hole, and finally step three is performed.

[0031] The present invention provides a chrome plating fixture and method for a graphite runway of an aircraft engine, which has the following advantages over the prior art:

[0032] (1) The graphite runway parts after plating fully meet the process technology requirements. The stainless steel outer mounting ring or the stainless steel outer mounting ring universal part is screwed and fixed to the graphite runway by stainless steel bolts. After the three are installed, the end face of the graphite runway to be chrome-plated, the head end face of the stainless steel bolt and the axial end face of the stainless steel outer mounting ring or the axial end face of the stainless steel outer mounting ring universal part are in the same plane without any protruding parts. Therefore, the electric lines that are too concentrated on the edge of the graphite runway parts are dispersed by the stainless steel outer mounting ring and the stainless steel bolt, or the stainless steel outer mounting ring universal part and the stainless steel bolt. The stainless steel outer mounting ring and the stainless steel bolt or the stainless steel outer mounting ring universal part and the stainless steel bolt jointly play the role of protecting the cathode, and the edge effect disappears. After electroplating, the edge of the graphite runway is smooth and delicate without being rough, and there is no chromium seepage phenomenon, which fully meets the process technology requirements.

[0033] (2) Avoids the problem of reduced current efficiency and ensures the electroplating effect. The head of the stainless steel bolt is flat (flat), which avoids the problem of the protruding head exceeding the flat part and grabbing (diverting) the electroplating current of the chrome-plated surface caused by the use of stainless steel bolts with protruding heads. The outer surface of the stainless steel bolt head is provided with a cross groove to facilitate installation operation;

[0034] (3) The chrome plating fixture is easy to disassemble and flexible to use. Three lugs are set on the outer surface of the stainless steel outer mounting ring universal part. When in use, according to the processing requirements of the graphite runway, multiple fixtures can be assembled to install and electroplate multiple parts at the same time, or they can be disassembled to plate only one part;

[0035] (4) The chrome-plated fixture is finalized once and can be reused, which reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is an enlarged cross-section of the graphite runway parts;

[0037] Figure 2 The final assembly of the fixture for partial chrome plating of graphite runway for aircraft engines and its cross-section;

[0038] Figure 3 Exploded view of the assembly of a fixture for partial chrome plating of graphite runway for aircraft engines;

[0039] Figure 4 Schematic diagram of the stainless steel substrate and the lugs on its surface;

[0040] Figure 5 This is a schematic diagram of a stainless steel bolt;

[0041] Figure 6 This is the overall assembly drawing of the graphite runway parts and fixtures;

[0042] In the figure: 1. Demonstration ring parts, 2. Hook, 3. Universal stainless steel outer mounting ring parts, 31. Ear, 4. Stainless steel outer mounting ring, 5. Stainless steel bolt, 6. Countersunk bolt, 7. Chamfer, 8. Inner wall, 9. Support platform. DETAILED DESCRIPTION

[0043] The present invention is further described below with reference to specific embodiments. However, it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various modifications, substitutions and changes made according to common technical knowledge and customary means in the field are included in the scope of the present invention.

[0044] like Figures 2 to 6 , which demonstrates the partial chrome plating fixture of the graphite runway for aircraft engines designed by the present invention. The main components of the fixture include: a demonstration ring part 1 (this part has two functions, one is to demonstrate how to install the graphite runway, and the other is to be installed in the vacant part installation position when only one graphite runway is installed in the stainless steel outer mounting ring universal part 3 or the stainless steel outer mounting ring 4, which can better control the current and the thickness of the chrome plating layer. Of course, it can also be not used), a hook 2, a stainless steel outer mounting ring universal part 3 (one or more), a stainless steel outer mounting ring 4 (one), a stainless steel bolt 5 and a countersunk bolt 6.

[0045] The installation and functions of each component are as follows:

[0046] 1) One end of the hook 2 in the fixture is welded to the connecting rod of the stainless steel outer mounting ring 4 (such as Figure 2 (The hook 2 is welded to the connecting rod of the stainless steel outer mounting ring 4.) During the chrome plating process, the hook 2 is used to secure the fixture and connect it to the cathode copper rod of the chrome plating tank. The stainless steel outer mounting ring 4 and the stainless steel outer mounting ring universal member 3 are both used to hold the graphite runway parts. The graphite runway parts are fixed to the stainless steel outer mounting ring 4 and / or the stainless steel outer mounting ring universal member 3 via stainless steel bolts 5. The end faces of the stainless steel outer mounting ring 4, the graphite runway parts (demonstration ring parts 1), and the stainless steel bolts 5 are aligned. The end faces of the stainless steel outer mounting ring universal member 3, the graphite runway parts (demonstration ring parts 1), and the stainless steel bolts 5 are aligned to ensure that only the W side of the graphite runway parts is plated with chrome.

[0047] 2) Figure 4This is a schematic diagram of the stainless steel outer mounting ring universal part 3 and its three lugs 31. The stainless steel outer mounting ring universal part 3 primarily serves to mount the graphite track component and to position it via the stainless steel bolts 5. The stainless steel outer mounting ring 4 serves two functions: one is to connect the hook, and the other, similarly, to mount the graphite track component and position it via the stainless steel bolts 5. Both the stainless steel outer mounting ring universal part 3 and the stainless steel outer mounting ring 4 have chamfers 7, inner walls 8, and support platforms 9 within the through-holes on both axial end faces that match the D-surface dimensions of the graphite track component. These structures align with the graphite track component, thereby positioning it and ensuring that the graphite track component's flat surface (the W-surface that requires chrome plating) is flush with the end faces of the stainless steel outer mounting ring 4 and the stainless steel outer mounting ring universal part 3, facilitating fastening.

[0048] 3) Figure 5 This is a structural diagram of a stainless steel bolt 5. The stainless steel bolt 5 is a flat-head bolt with a cross groove on the flat end face of the head (the portion with a larger outer diameter than the threaded section). Its main function is to secure the demonstration ring part 1 or the graphite runway part. The head thickness of the stainless steel bolt 5 is consistent with the axial thickness of the demonstration ring part 1 or the graphite runway part, and the outer surface is cross-grooved (it is necessary to avoid using screws or bolts with raised heads, as this will block the chrome-plated surface and also disperse some current, resulting in insufficient and uneven chrome plating thickness within the time specified by the process, and even causing the chrome-plated surface of the part to be partially chromium-free due to the blocking effect). The screw of the stainless steel bolt 5 matches the threaded hole diameter and thread of the stainless steel outer mounting ring 4 and the stainless steel outer mounting ring universal part 3. What is important is that when the stainless steel bolt 5 is installed into the stainless steel outer mounting ring 4 and the stainless steel outer mounting ring universal part 3 using a Phillips screwdriver, the head of the stainless steel bolt 5 is in close contact with the inner hole wall of the demonstration circle part 1 or the graphite runway part, and the supporting platform 9 of the stainless steel outer mounting ring 4 or the stainless steel outer mounting ring universal part 3, thereby fastening the parts and ensuring that the end faces of the stainless steel outer mounting ring 4 or the stainless steel outer mounting ring universal part 3, the graphite runway part (demonstration circle part 1) and the stainless steel bolt 5 are flush.

[0049] 4) Considering processing efficiency, the fixture can be used to batch chrome-plated graphite racetrack components by increasing the number of stainless steel outer mounting ring universal parts 3. Each stainless steel outer mounting ring universal part 3 is mounted on two graphite racetrack components. The fixture only contains one stainless steel outer mounting ring 4, but multiple stainless steel outer mounting ring universal parts 3 are permitted. The graphite racetrack components are secured to the stainless steel outer mounting ring 4 and the stainless steel outer mounting ring universal part 3 via stainless steel bolts 5. 6x25mm countersunk bolts 6 are used to connect the stainless steel outer mounting ring 4 to the stainless steel outer mounting ring universal part 3, and the stainless steel outer mounting ring universal parts 3 to each other. Specifically, a single tab 31 of one stainless steel outer mounting ring universal part 3 is inserted into the gap between two parallel tabs 31 on another stainless steel outer mounting ring 4, or between two parallel tabs 31 on another stainless steel outer mounting ring universal part 3. Countersunk bolts 6 are then inserted into the openings of the three tabs 31 to achieve connection.

[0050] The materials used for the various parts of the fixture are shown in Table 1:

[0051] Table 1 Graphite track fixture parts names and materials

[0052]

[0053] When the graphite runway parts are electroplated with chrome using the aircraft engine graphite runway local chrome plating fixture of the present invention, the following steps are followed:

[0054] 1. Grinding fixture: Grind the partially chrome-plated fixture of the graphite runway for aircraft engines to remove the oxide film on the copper hook 2, and remove the chrome nodules on the stainless steel outer mounting ring 4 and the stainless steel outer mounting ring universal part 3;

[0055] 2. Parts clamping:

[0056] 21. Install the graphite track part into the through hole of the stainless steel outer mounting ring 4 with its W side facing outward and its D side facing the stainless steel outer mounting ring 4, and ensure that the D side is in close contact with the inner wall of the through hole of the stainless steel outer mounting ring 4;

[0057] 22. Pass the threaded section (stud) of the stainless steel bolt 5 through the inner hole of the graphite runway part and then insert it into the inner threaded section of the through hole of the stainless steel outer mounting ring 4;

[0058] 23. Use a Phillips screwdriver to tighten the stainless steel bolt 5 until the end face of the stainless steel outer mounting ring 4, the W surface of the graphite runway part, and the end face of the stainless steel bolt 5 head are flush;

[0059] According to the processing quantity requirements of the graphite runway, a stainless steel outer mounting ring 4 is used in combination with multiple stainless steel outer mounting ring universal parts 3. When multiple stainless steel outer mounting ring universal parts 3 are needed, the multiple stainless steel outer mounting ring universal parts 3 are connected in series through the ear pieces 31 on the surface of the stainless steel outer mounting ring universal parts 3, and then assembled with the stainless steel outer mounting ring 4.

[0060] 3. Electroplating: Hang the hook 2 on the electroplating cathode and perform electroplating according to the process requirements;

[0061] 4. Disassemble parts: Use a Phillips screwdriver to loosen the stainless steel bolt 5 and remove the graphite runway parts.

[0062] Any matters not described in detail in the present specification are prior art known to those skilled in the art. Although the above description of the present invention is based on illustrative embodiments to facilitate understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the specific embodiments. As long as various modifications are within the spirit and scope of the present invention as defined and determined by the appended claims, such modifications will be obvious to those skilled in the art, and all inventions and creations utilizing the concepts of the present invention are protected.

Claims

1. A fixture for partial chrome plating of graphite runway for aircraft engines, characterized in that: include: The substrate is a rotating body made of stainless steel, and the axial end surface of the substrate is provided with a stepped through hole coaxial with the substrate, and the stepped through hole includes at least three parts: a first mounting hole, a threaded hole, and a second mounting hole. The first mounting hole and the second mounting hole are mirror-symmetrical about the threaded hole, and the shape of the inner wall of the first mounting hole and the second mounting hole includes the outer contour feature of the graphite runway. The hole depth of the first mounting hole and the second mounting hole is equal to the axial height of the graphite runway before chrome plating. A stainless steel outer mounting ring (4), the stainless steel outer mounting ring (4) consisting of a base, an ear piece (31) with a hole, and a connecting rod, the outer surface of the base being connected to two parallel ear pieces (31) spaced apart, one end of the connecting rod being connected to the outer surface of the base, and the other end being a free end; A stainless steel outer mounting ring universal part (3), the stainless steel outer mounting ring universal part (3) consisting of a base and an ear piece (31) with a hole, the outer surface of the base being connected to three ear pieces (31), wherein two ear pieces (31) are paired and arranged in parallel and spaced apart, and the thickness of the third ear piece (31) is less than or equal to the spacing distance between the two parallel ear pieces (31); The stainless steel bolt (5) is a flat head bolt, the axial length of which is less than or equal to half the axial length of the base body, the head end face of the stainless steel bolt (5) is provided with a cross groove, the outer diameter of the head of the stainless steel bolt (5) is equal to the inner hole diameter of the graphite runway, the height of the head of the stainless steel bolt (5) is equal to the axial height of the graphite runway, and the external thread of the stainless steel bolt (5) matches the threaded hole of the base body.

2. The fixture for partial chrome plating of a graphite runway for an aircraft engine according to claim 1, characterized in that: It also includes a hook (2) made of copper, one end of which is welded to the free end of the connecting rod on the stainless steel outer mounting ring (4), and the other end of which is connected to the cathode of the chrome-plated tank.

3. The fixture for partial chrome plating of a graphite runway for an aircraft engine according to claim 1, characterized in that: It also includes a demonstration circle part (1), the outer contour and size of the demonstration circle part (1) are consistent with those of the graphite runway, and the demonstration circle part (1) can be detachably installed in the first installation hole and the second installation hole.

4. The fixture for partial chrome plating of a graphite runway for an aircraft engine according to claim 1, characterized in that: The base body is a circular ring body, and its inner ring surface forms a stepped through hole; In the stainless steel outer mounting ring universal part (3), three ear pieces (31) with openings are arranged along the radial line of the base body, wherein two ear pieces (31) arranged in parallel are located at one end of the radial line, and the third ear piece (31) is located at the other end of the radial line; In the stainless steel outer mounting ring (4), two parallel and spaced-apart lugs (31) and a connecting rod are respectively located at two ends of the same radial line on the base.

5. The fixture for partial chrome plating of a graphite runway for an aircraft engine according to claim 1, characterized in that: The inner wall shapes of the first mounting hole and the second mounting hole include the contour features of the outer circumferential surface of the graphite raceway and the non-chrome-plated axial end surface.

6. The fixture for partial chrome plating of a graphite runway for an aircraft engine according to claim 5, characterized in that: The inner wall shapes of the first mounting hole and the second mounting hole include an inner wall (8), a chamfer (7) and a supporting platform (9).

7. The fixture for partial chrome plating of a graphite runway for an aircraft engine according to claim 1, characterized in that: A plurality of the stainless steel outer mounting ring universal parts (3) are connected to each other to form a group, wherein any two stainless steel outer mounting ring universal parts (3) are connected by inserting the third lug (31) of one of the stainless steel outer mounting ring universal parts (3) into the gap between two lugs (31) arranged in parallel and spaced apart on the other stainless steel outer mounting ring universal part (3) and inserting the countersunk bolts (6) into the holes on the three lugs (31).

8. A method for local chrome plating of a graphite runway for an aircraft engine, characterized in that: The fixture for partial chrome plating of a graphite runway for an aircraft engine according to claim 2 is used, and includes the following steps: Step 1: Place a graphite runway into the first mounting hole of the stainless steel outer mounting ring (4), with the end of the graphite runway to be chrome-plated facing outward; Step 2: Screw the stainless steel bolt (5) into the threaded hole of the stainless steel outer mounting ring (4) until the head end face of the stainless steel bolt (5), the end face to be chrome-plated of the graphite runway and the axial end face of the stainless steel outer mounting ring (4) are flush in the same plane; Step 3: Connect the other end of the hook (2) to the cathode of the chrome plating tank.

9. The method for partial chrome plating of a graphite runway for an aircraft engine according to claim 8, characterized in that: Before the step 1, the hook (2) is polished to remove the oxide film on the surface of the hook (2), and the chromium nodules on the stainless steel outer mounting ring (4) and the stainless steel outer mounting ring universal part (3) are removed.

10. The method for partial chrome plating of a graphite runway for an aircraft engine according to claim 8, characterized in that: When the number of graphite runways is two, the step between step 2 and step 3 further includes placing another graphite runway into the second mounting hole of the stainless steel outer mounting ring (4), with the end face of the graphite runway to be chrome-plated facing outward, repeating step 2 and then executing step 3; When the number of graphite racetracks is greater than two and is an even number, a stainless steel outer mounting ring (4) and one or more stainless steel outer mounting ring universal parts (3) are used, and every two graphite racetracks share one stainless steel outer mounting ring (4) or one stainless steel outer mounting ring universal part (3). Steps 1 and 2 are first performed, and then another graphite racetrack is placed in the second mounting hole of the stainless steel outer mounting ring (4), with the end face of the graphite racetrack to be chrome-plated facing outward, and step 2 is repeated. Then, a stainless steel outer mounting ring universal part (3) is connected to the stainless steel outer mounting ring (4) through the ear piece (31), or multiple stainless steel outer mounting ring universal parts (3) are connected. ) are connected to form a group through the ear piece (31) and then connected to the stainless steel outer mounting ring (4), wherein the stainless steel outer mounting ring universal parts (3) and the stainless steel outer mounting ring universal parts (3) and the stainless steel outer mounting ring universal parts (3) are connected by inserting the countersunk bolts (6) into the holes on the ear piece (31), and then for each stainless steel outer mounting ring universal part (3), a graphite runway is installed in the first mounting hole and the stainless steel bolt (5) is screwed into the threaded hole, and then another graphite runway is placed in the second mounting hole and the stainless steel bolt (5) is screwed into the threaded hole, and finally step three is performed; When the number of graphite racetracks is greater than two and is an odd number, a stainless steel outer mounting ring (4) and one or more stainless steel outer mounting ring universal parts (3) are used, and every two graphite racetracks share one stainless steel outer mounting ring (4) or one stainless steel outer mounting ring universal part (3), and the remaining graphite racetrack uses a stainless steel outer mounting ring universal part (3) alone. First, perform steps 1 and 2, then place another graphite racetrack in the second mounting hole of the stainless steel outer mounting ring (4), with the end face of the graphite racetrack to be chrome-plated facing outward, repeat step 2, and then connect a stainless steel outer mounting ring universal part (3) to the stainless steel outer mounting ring (4) through the ear piece (31), or connect multiple stainless steel outer mounting ring universal parts (3) through the ear piece (31). After forming a group, they are connected to the stainless steel outer mounting ring (4), wherein the stainless steel outer mounting ring universal parts (3) and the stainless steel outer mounting ring universal parts (3) and the stainless steel outer mounting ring universal parts (3) are connected by inserting the countersunk bolts (6) into the holes on the ear pieces (31). Then, for each stainless steel outer mounting ring universal part (3), a graphite runway is installed in its first mounting hole and the stainless steel bolt (5) is screwed into the threaded hole. Then, another graphite runway is placed in the second mounting hole and the stainless steel bolt (5) is screwed into the threaded hole. For the stainless steel outer mounting ring universal part (3) with only one graphite runway installed, a demonstration ring part (1) is installed in its second mounting hole. Finally, step three is performed.

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