Method for repairing copper-aluminum coating of tenon of rotor blade of high-pressure compressor

Abstract

The invention relates to a method for repairing a copper-aluminum coating of a tenon of a rotor blade of a high-pressure compressor. The method comprises the steps of coating removal and coating recovery. Wherein the coating removal process flow comprises the steps of hanging, chemical coating removal, cold water washing, high-pressure water gun flushing, neutralization, cold water washing, drying and disassembly. The coating recovery technological process comprises the steps of preparation, oil removal, protection, sand blowing, plasma spraying and cleaning. The coating is removed by adopting a chemical method, and the recovery of the coating is completed in an automatic manner. On the premise that a titanium alloy blade base body is not damaged, the coating can be removed and recovered efficiently, meanwhile, the machining difficulty is reduced, and the process cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft engine coating repair, and in particular to a method for repairing copper-aluminum coating on a tenon of a high-pressure compressor rotor blade. Background Art

[0002] The high-pressure compressor rotor blade is a key part of an aircraft engine. The blade is assembled in the tenon groove of the disk shaft through the tenon. In order to reduce the micro-vibration wear of the blade during operation and increase the service life of the blade, a copper-aluminum coating is usually prepared on both sides of the blade tenon and the contact position of the tenon groove (see Figure 1 ). The copper-aluminum coating has good anti-wear and anti-adhesion effects, and can also effectively limit the expansion of fatigue cracks.

[0003] After a service life, aircraft engines need to be repaired as a whole and deformed, damaged, and faulty rotor blades need to be replaced. For blades without faults, they can continue to be used after repair, thereby reducing the cost of engine repairs and shortening the repair cycle. When repairing blades, the coating on the tenon needs to be removed and restored. The coating removal process is complicated, and traditional mechanical methods are prone to damage to the substrate or incomplete removal of residual coatings, and the operation is difficult to control. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for repairing the copper-aluminum coating on the tenon of a high-pressure compressor rotor blade; the specific technical scheme is as follows:

[0005] A method for repairing copper-aluminum coating on the tenon of a high-pressure compressor rotor blade, comprising coating removal and coating restoration;

[0006] The coating removal process is as follows:

[0007] Step 1: Mounting

[0008] Place the parts into the high-temperature alloy frame fixture, place the parts upright with the tenons facing downwards, and avoid collision between the parts;

[0009] Step 2: Chemical coating removal

[0010] Place the parts in the coating removal tank. The tank liquid should submerge the tenon. Set the concentration of the tank liquid and heat the tank liquid. Visually check that the coating is completely removed and then take it out. The time is 35 minutes.

[0011] Step 3: Wash with cold water

[0012] Move the parts to the cold water tank and clean them with running cold water for 2 minutes;

[0013] Step 4: High-pressure water washing

[0014] Use a high-speed water stream mixed with compressed air and tap water to wash the surface of components through a high-pressure spray gun;

[0015] Step 5: Neutralization

[0016] Place the parts in the neutralization tank for 1 minute;

[0017] Step 6: Wash with cold water

[0018] Move the parts to the cold water tank and clean them with running cold water for 2 minutes;

[0019] Step 7: Drying

[0020] Blow dry the parts with clean compressed air;

[0021] Step 8: Disassembly

[0022] After drying, the parts are removed from the fixture and placed on clean kraft paper for inspection;

[0023] The coating restoration process is as follows:

[0024] Step 1: Preparation

[0025] Dry the copper and aluminum powder at 90°C for 1 hour and stir evenly before spraying;

[0026] Step 2: Degreasing

[0027] Use absorbent cotton dipped in acetone to wipe and clean the spraying area and adjacent areas of the parts;

[0028] Step 3: Protection

[0029] Use tooling and pressure-sensitive tape to protect non-spraying areas;

[0030] Step 4: Sand Blowing

[0031] A suction sand blower is used for sand blowing, with a sand blowing pressure of 0.50MPa, a sand blowing distance of 100mm, and a sand blowing angle of 75°;

[0032] Step 5: Plasma spraying

[0033] The coating was prepared using PT-A2000 equipment, the spray gun was F4 type, the argon flow rate was 55NLPM, the hydrogen flow rate was 12NLPM, the current was 700A, and the powder feeding rate was 70g / min;

[0034] Step 14: Clean up

[0035] Remove the part from the fixture and remove the protective material.

[0036] The preferred embodiment of the copper-aluminum coating repair method for the tenon of a high-pressure compressor rotor blade is that in step 2 of the coating removal process, the tank liquid for chemically removing the coating is nitric acid, the concentration of which is 365g / L-465g / L, and the temperature is 25°C-50°C.

[0037] The preferred embodiment of the copper-aluminum coating repair method for the tenon of a high-pressure compressor rotor blade is that during the coating removal process, the coating reacts with the solution to produce a large number of bubbles. When the bubbles stop, the coating is left for another 5 minutes to check whether the coating has been removed completely. Parts from which the coating has not been removed continue to be placed in the tank until the coating is removed completely, and the longest time cannot exceed 5 hours.

[0038] The preferred embodiment of the copper-aluminum coating repair method for the tenon of a high-pressure compressor rotor blade is as follows: in step 2 of the coating removal process, sodium carbonate is used for neutralization at a concentration of 30g / L-50g / L; when removing the coating, nitric acid will form a passivation film on the surface of the titanium alloy, which will not corrode the part matrix. Moreover, since nitric acid is a strong oxidant, it will not produce hydrogen when reacting with metals and will not cause the titanium alloy material to absorb hydrogen. Both copper and aluminum can react with nitric acid to generate corresponding nitrate solutions, thereby achieving a removal effect.

[0039] The preferred embodiment of the copper-aluminum coating repair method for the tenon of a high-pressure compressor rotor blade is that in the coating restoration process, sand blowing and spraying are both performed in an automated manner, the parts are placed in a special tooling, clamped in turn on the turntable of the sand blowing machine and the spraying equipment, the robot clamps the spray gun, the running program is linked with the equipment, and the sand blowing and spraying are completed in sequence.

[0040] The described method for repairing the copper-aluminum coating on the tenon of a high-pressure compressor rotor blade has a preferred embodiment that, in the coating restoration process, the roughness of the substrate after sandblasting is 2.0 μm-3.8 μm, the thickness of the copper-aluminum coating is 0.16 mm-0.22 mm, and the roughness of the coating after spraying is ≤6.3 μm. The control of the coating performance, thickness, and roughness is achieved through atmospheric plasma spraying process technology and process control.

[0041] Compared with the prior art, the present invention has the following beneficial technical effects:

[0042] The coating removal method of the present invention will not damage the TA11 titanium alloy part substrate, will not cause hydrogenation to the substrate, and can completely remove the coating with high removal efficiency. The coating restoration method adopts automated technology, has good coating quality stability, and has a high coating qualification rate.

[0043] The coating repair method of the present invention adopts automation technology, and has good coating quality stability and high pass rate.

[0044] The coating repair method described in the present invention has a simple process, convenient operation, low production cost, high efficiency, is suitable for mass production, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of preparing copper-aluminum coating on blade tenon;

[0046] Figure 2 To detect residual coating by metallographic method;

[0047] Figure 3 The metallographic structure of the restored copper-aluminum coating;

[0048] Figure 4 The corrosion condition was detected by metallographic method.

[0049] In the figure: 1-Copper-aluminum coating. DETAILED DESCRIPTION

[0050] The following is combined with Figure 2-4 The present invention is described in detail, but the protection scope of the present invention is not limited by the accompanying drawings.

[0051] Embodiment 1:

[0052] A method for repairing copper-aluminum coating on the tenon of a high-pressure compressor rotor blade, the specific steps are as follows:

[0053] Step 1: Mounting

[0054] Place the parts into the high-temperature alloy frame fixture, place the parts upright with the tenons facing downwards, and avoid collision between the parts;

[0055] Step 2: Chemical coating removal

[0056] Place the parts in the coating removal tank. The tank liquid should submerge the tenon. The nitric acid concentration in the tank liquid is 400g / L. The tank liquid is heated to 40℃. Visually check that the coating is completely removed and then take it out. The time is 35 minutes.

[0057] Step 3: Wash with cold water

[0058] Move the parts to the cold water tank and clean them with running cold water for 2 minutes;

[0059] Step 4: High-pressure water washing

[0060] Use a high-speed water stream mixed with compressed air and tap water to wash the surface of components through a high-pressure spray gun;

[0061] Step 5: Neutralization

[0062] Place the parts in a neutralization tank with a sodium carbonate concentration of 40 g / L for 1 min.

[0063] Step 6: Wash with cold water

[0064] Move the parts to the cold water tank and clean them with running cold water for 2 minutes;

[0065] Step 7: Drying

[0066] Blow dry the parts with clean compressed air;

[0067] Step 8: Disassembly

[0068] After drying, the parts are removed from the fixture and placed on clean kraft paper for inspection;

[0069] Step 9: Preparation

[0070] Dry the copper and aluminum powders at 90°C for 1 hour and stir them evenly before spraying.

[0071] Step 10: Degreasing

[0072] Use absorbent cotton dipped in acetone to wipe and clean the spraying area and adjacent areas of the parts;

[0073] Step 11: Protection

[0074] Use tooling and pressure-sensitive tape to protect non-spraying areas;

[0075] Step 12: Sand Blowing

[0076] A suction sand blower is used for sand blowing, with a sand blowing pressure of 0.50MPa, a sand blowing distance of 100mm, and a sand blowing angle of 75°;

[0077] Step 13: Plasma spraying

[0078] The coating was prepared using PT-A2000 equipment, the spray gun was F4 type, the argon flow rate was 55NLPM, the hydrogen flow rate was 12NLPM, the current was 700A, and the powder feeding rate was 70g / min;

[0079] Step 14: Clean up

[0080] Remove the part from the fixture and remove the protective material.

[0081] After the coating was removed, the blade tenon was cut and placed under an optical microscope for residual coating detection. The results are shown in Figure 2 .

[0082] The metallographic test results show that the copper-aluminum coating removal method can completely remove the coating on the surface of the parts. The microstructure of the restored copper-aluminum coating is shown in Figure 3 .

[0083] Embodiment 2:

[0084] A method for repairing copper-aluminum coating on the tenon of a high-pressure compressor rotor blade, the specific steps are as follows:

[0085] Step 1: Mounting

[0086] Place the parts into the high-temperature alloy frame fixture, place the parts upright with the tenons facing downwards, and avoid collisions between the parts.

[0087] (2) Chemical decoating: Place the parts in a decoating tank. The tank liquid should submerge the tenon. The nitric acid concentration in the tank liquid is 465g / L. The tank liquid is heated to 50°C for 5 hours.

[0088] (3) Cold water wash: Move the parts to a cold water sink and wash them with running cold water for 2 minutes.

[0089] (4) High-pressure water washing: Use a high-speed water stream (high-pressure spray gun) mixed with compressed air and tap water to wash the surface of the components.

[0090] (5) Neutralization: Place the parts in a neutralization tank with a sodium carbonate concentration of 50 g / L for 1 min.

[0091] (6) Cold water wash: Move the parts to a cold water sink and wash them with running cold water for 2 minutes.

[0092] (7) Drying: Dry the parts with clean compressed air.

[0093] (8) Disassembly: After drying, remove the parts from the fixture and place them on clean kraft paper for inspection.

[0094] (9) Preparation: Dry the copper and aluminum powders at 70°C for 1.5 h and stir them evenly before spraying.

[0095] 10) Degreasing: Use absorbent cotton dipped in acetone to wipe and clean the sprayed area and adjacent areas of the parts.

[0096] (11) Protection: Use tooling and pressure-sensitive tape to protect the non-spraying area.

[0097] (12) Sand blowing: A suction sand blower is used for sand blowing, with a sand blowing air pressure of 0.40 MPa, a sand blowing distance of 150 mm, and a sand blowing angle of 60°.

[0098] (13) Plasma spraying: The coating was prepared using PT-A2000 equipment, the spray gun was F4 type, the argon flow rate was 50 NLPM, the hydrogen flow rate was 11 NLPM, the current was 650 A, and the powder feeding rate was 80 g / min.

[0099] (14) Cleaning: Remove the parts from the fixture and remove the protective materials.

[0100] This example uses the limit parameters of coating removal, cuts the blade tenon after coating removal and examines the corrosion situation under an optical microscope. The results are shown in Figure 4 .

[0101] The metallographic examination results show that no corrosion has been observed. After the blade tenon part was fluorescently inspected with penetrant ZL-37, no defects were found on the surface of the coating and the surface of the base material, indicating that no defects were generated during the coating removal process. Hydrogen increase test was carried out, and the immersion time was selected as 0.5h, 1h, 2h, 3h, and 5h, respectively. The hydrogen increase test results are shown in Table 1.

[0102] Table 1 Hydrogen increment detection results at different times

[0103]

[0104] It can be seen from the data that there is no obvious change in the hydrogen increment before and after decoating, and it does not increase with the extension of decoating time. Therefore, this process does not increase hydrogen to the substrate.

[0105] Matters not covered by the present invention are known technologies.

[0106] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for repairing copper-aluminum coating on tenon of high-pressure compressor rotor blade, characterized in that: Including coating removal and coating restoration; The coating removal process is as follows: Step 1: Mounting Place the parts into the high-temperature alloy frame fixture, place the parts upright with the tenons facing downwards, and avoid collision between the parts; Step 2: Chemical coating removal Place the parts in the coating removal tank. The tank liquid should submerge the tenon. Set the concentration of the tank liquid and heat the tank liquid. Visually check that the coating is completely removed and then take it out. The time is 35 minutes. Step 3: Wash with cold water Move the parts to the cold water tank and clean them with running cold water for 2 minutes; Step 4: High-pressure water washing Use a high-pressure spray gun to wash the surface of components with a high-speed stream of compressed air and tap water; Step 5: Neutralization Place the parts in the neutralization tank for 1 minute; Step 6: Wash with cold water Move the parts to the cold water tank and clean them with running cold water for 2 minutes; Step 7: Drying Blow dry the parts with clean compressed air; Step 8: Disassembly After drying, the parts are removed from the fixture and placed on clean kraft paper for inspection; The coating restoration process is as follows: Step 1: Preparation Dry the copper and aluminum powder at 90°C for 1 hour and stir evenly before spraying; Step 2: Degreasing Use absorbent cotton dipped in acetone to wipe and clean the spraying area and adjacent areas of the parts; Step 3: Protection Use tooling and pressure-sensitive tape to protect non-spraying areas; Step 4: Sand Blowing A suction sand blower is used for sand blowing, with a sand blowing pressure of 0.50MPa, a sand blowing distance of 100mm, and a sand blowing angle of 75°; Step 5: Plasma spraying The coating was prepared using PT-A2000 equipment, the spray gun was F4 type, the argon flow rate was 55NLPM, the hydrogen flow rate was 12NLPM, the current was 700A, and the powder feeding rate was 70g / min; Step 14: Clean up Remove the part from the fixture and remove the protective material.

2. A method for repairing copper-aluminum coating on tenons of high-pressure compressor rotor blades according to claim 1, characterized in that: In step 2 of the coating removal process, the bath solution for chemical coating removal is nitric acid, the concentration of which is 365 g / L-465 g / L, and the temperature is 25° C.-50° C.

3. A method for repairing copper-aluminum coating on tenons of high-pressure compressor rotor blades according to claim 1, characterized in that: During the coating removal process, the coating reacts with the solution to produce a large number of bubbles. When the bubbles stop, leave it for another 5 minutes to check whether the coating has been completely removed. Parts that have not been completely removed should continue to be placed in the tank until the coating is completely removed, which should not exceed 5 hours at most.

4. A method for repairing copper-aluminum coating on tenons of high-pressure compressor rotor blades according to claim 1, characterized in that: In step 2 of the coating removal process, sodium carbonate is used for neutralization at a concentration of 30g / L-50g / L. When removing the coating, nitric acid will form a passivation film on the surface of the titanium alloy, which will not corrode the part substrate. Moreover, since nitric acid is a strong oxidant, it does not produce hydrogen when reacting with metals and will not cause the titanium alloy material to absorb hydrogen. Copper and aluminum can react with nitric acid to generate corresponding nitrate solutions, thereby achieving the removal effect.

5. The method for repairing copper-aluminum coating on tenon of high-pressure compressor rotor blade according to claim 1, characterized in that: In the coating restoration process, sand blowing and spraying are carried out in an automated manner. The parts are placed in special tooling and clamped on the turntable of the sand blowing machine and spraying equipment in sequence. The robot clamps the spray gun, and the running program is linked with the equipment to complete sand blowing and spraying in sequence.

6. A method for repairing copper-aluminum coating on tenons of high-pressure compressor rotor blades according to claim 1, characterized in that: In the coating restoration process, the roughness of the substrate after sand blasting is 2.0μm-3.8μm, the thickness of the copper-aluminum coating is 0.16mm-0.22mm, and the coating roughness after spraying is ≤6.3μm. The control of coating performance, thickness and roughness is achieved through atmospheric plasma spraying process technology and process control.

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