A protection method for special-shaped parts sprayed by supersonic flame

Abstract

The present invention provides a protection method for special-shaped parts sprayed by supersonic flame, specifically: before using supersonic flame spraying technology to spray Co‑Cr‑W wear-resistant coating on the narrow surfaces on both sides of the notch on the outer edge of the special-shaped part, different materials are used to protect other non-spraying areas: first, high-temperature pressure-sensitive tape and unannealed copper skin are used to prime the part protection area, and a layer of unannealed copper skin is wrapped between two layers of high-temperature pressure-sensitive tape; then the annealed copper skin is cut and bent into a required special shape to fit the surfaces on both sides of the spraying area of ​​the part, and the annealed copper skin is fixed on the outer edge of the special-shaped part; then the unannealed copper skin is used to surround the outer ring of the part for one week, and is fixed with a metal or alloy wire hoop; finally, supersonic flame spraying technology is used to spray Co‑Cr‑W wear-resistant coating on the spraying area in the notch on the outer edge of the special-shaped part. This method can solve the problem that the existing technology cannot effectively protect special-shaped parts with complex structures.

Description

Technical Field

[0001] The invention relates to a protection technology for special-shaped parts of aircraft engines with complex and peculiar geometric shapes, and in particular provides a protection method for special-shaped parts sprayed by supersonic flame. Background Art

[0002] Supersonic flame spraying is a technology that continuously explodes and burns the combustion-supporting gas and fuel in the combustion chamber. The generated flame generates high pressure in the combustion chamber and generates a high-speed flame flow through an expansion nozzle connected to the combustion chamber outlet. The spraying material is sent into the high-speed jet to be heated, accelerated and sprayed onto the pre-treated substrate surface to form a coating. Due to its ultra-high flame flow speed and relatively low temperature compared to plasma flame flow, it has obvious advantages in spraying materials such as metal carbides and metal alloys. Therefore, it is widely used in the spraying production of dense coatings such as anti-oxidation and wear-resistant coatings on aircraft engine parts. The narrow surfaces on both sides of the outer edge notch of a certain welded assembly part of an aircraft engine (see Figure 1 (as shown) requires supersonic flame spraying of Co-Cr-W wear-resistant coating. Due to the large size of the parts, the special shape of the spraying position and the complex surface, it is difficult to effectively protect the non-spraying area using conventional protection methods, so it belongs to the spraying of special-shaped parts. There is no introduction to the protection technology of non-spraying areas of special-shaped parts by supersonic flame spraying in public patents and journal articles. The commercially promoted supersonic spraying protection tape also has different degrees of ablation during the spraying process, which cannot meet the supersonic spraying protection requirements of special-shaped parts of aircraft engines.

[0003] Usually, high-temperature pressure-sensitive tape is used to protect special-shaped parts during spraying. However, due to the large impact force of the flame flow during supersonic flame spraying, the conventional high-temperature pressure-sensitive tape often cannot withstand the strong impact and is damaged or detached from the substrate surface. In particular, various types of high-temperature tapes cannot play a due protective role in the non-spraying area of ​​special-shaped parts. For this reason, a variety of metal protection fixtures are designed. However, due to the complex surface of the spraying area, the coating is easily bonded between the parts and the metal fixtures during the spraying process. As a result, the removal of the fixture causes the coating to fall off. Moreover, after the protective fixture has been used for a period of time, the coating deposited on its surface is difficult to remove and forms a shield (such as Figure 2 As shown in the figure), it seriously affects the quality and effect of the supersonic flame spraying of the parts coating. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a protection method for special-shaped parts sprayed by supersonic flame, so as to improve the quality and effect of supersonic flame spraying of coatings on special-shaped parts.

[0005] The technical solution of the present invention is as follows:

[0006] A method for protecting a special-shaped part by supersonic flame spraying, characterized in that before spraying the Co-Cr-W wear-resistant coating on the narrow surfaces on both sides of the notch of the outer edge of the special-shaped part by supersonic flame spraying technology, different materials are used to protect other non-spraying areas, as follows:

[0007] 1) Use high temperature pressure sensitive tape and unannealed copper sheet to prime the parts protection area, and wrap a layer of unannealed copper sheet between two layers of high temperature pressure sensitive tape;

[0008] 2) Cut the annealed copper sheet and bend it to the required special shape on both sides of the spraying area of ​​the part, and fix the annealed copper sheet on the outer edge of the special-shaped part;

[0009] 3) Use unannealed copper to wrap around the outer ring of the part and fix it with metal or alloy wire;

[0010] 4) Use supersonic flame spraying technology to spray Co-Cr-W wear-resistant coating on the spraying area inside the notch on the outer edge of the special-shaped part.

[0011] As the preferred technical solution:

[0012] In step 1), the copper sheet that has not been annealed is only arranged at a position corresponding to the lower part of the notch spraying area on the outer edge of the special-shaped part.

[0013] In step 2), the corresponding annealing process is determined according to the hardness and flexibility of the copper sheet required by the geometric shape of the spraying area. The annealing process is: keeping warm at 700±50°C for 2 hours.

[0014] The copper sheet is H62 brass strip, and the alloy wire is HGH3030 alloy wire.

[0015] The present invention adopts brass and other materials that have poor bonding with supersonic flame spraying coatings, combines the heat treatment annealing system to control the flexibility of the copper skin, and uses conventional high-temperature pressure-sensitive tape to make a homemade protective tooling. The copper skins with different flexibility are used to effectively protect the non-spraying areas of special-shaped parts, while solving the problem that the deposited coating is difficult to remove. The main materials of the protective tooling can be reused, thereby greatly reducing the production cost.

[0016] The method of the present invention is easy to operate, solves the problem of low impact resistance of high-temperature pressure-sensitive tape, saves the high cost of special tooling for supersonic flame spraying, and shortens the production cycle. The method of the present invention can effectively protect the non-spraying area of ​​the parts, and solves the production bottleneck and quality assurance problems of spray protection technology.

[0017] The method described in the present invention has been used in the coating spraying production of special-shaped parts of a certain type of aircraft engine, which has opened up the processing blockage channel of the spraying process and laid a strong foundation for the smooth production of a certain type of series engine. At the same time, the design concept of the present invention can be extended to other special-shaped parts that use supersonic spraying. When the shape of the parts is irregular or the spraying position is complex, the traditional tooling cannot play the due protective role, and this method can be used. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the spraying area of ​​a special-shaped part of an aircraft engine.

[0019] Figure 2 Schematic diagram of surface coating deposition between conventional metal protection tooling and the adjacent substrate of the part (the coating accumulated in this transition zone causes the coating to adhere and fall off after the tooling is removed).

[0020] Figure 3 Schematic diagram of the macroscopic morphology of aluminum foil tape, copper tape, and annealed copper skin.

[0021] Figure 4 Schematic diagram of the macroscopic morphology of various protective materials after supersonic flame spraying (from left to right: aluminum foil tape, copper tape, annealed copper skin).

[0022] Figure 5 Schematic diagram of a layer of unannealed copper wrapped between two layers of protective tape.

[0023] Figure 6 Annealed copper is used to protect non-sprayed special-shaped areas.

[0024] Figure 7 Schematic diagram of the protection status of special-shaped parts sprayed by supersonic flame.

[0025] Figure numerals: 1, protective tape, 2, annealed copper sheet, 3, unannealed copper sheet. DETAILED DESCRIPTION

[0026] Example 1

[0027] A method for protecting a special-shaped part by supersonic flame spraying, such as Figures 5 to 7 As shown, protective tools composed of different materials are required to protect the non-spraying area. The copper sheet is H62 brass strip, and the alloy wire is HGH3030 alloy wire, as follows:

[0028] 1) Use high temperature pressure sensitive tape and unannealed copper sheet to prime the parts protection area, and wrap a layer of unannealed copper sheet between two layers of high temperature pressure sensitive tape;

[0029] 2) Cut the annealed copper sheet and bend it into a required special shape to fit the surfaces on both sides of the spraying area of ​​the part, and fix the annealed copper sheet on the outer edge of the special-shaped part. The copper sheet used in this embodiment is annealed at 700±50℃ for 2 hours;

[0030] 3) Use unannealed copper to wrap around the outer circle of the part and fix it with metal or alloy wire. The copper here can reinforce the annealed copper and protect the other non-spraying positions.

[0031] 4) Use supersonic flame spraying technology to spray Co-Cr-W wear-resistant coating on the spraying area inside the notch on the outer edge of the special-shaped part. Remove the protective material after spraying. There is no coating attached to the non-spraying area on the surface of the special-shaped part, and there is no coating adhesion between the special-shaped part and the protective material.

[0032] Example 2

[0033] The difference from Example 1 is that aluminum foil tape is used instead of the annealed copper sheet, resulting in the aluminum foil tape being damaged by the impact of the spray gun flame during the spraying process, and the surface of the special-shaped part is not effectively protected.

[0034] Example 3

[0035] The difference from Example 1 is that copper tape is used instead of the annealed copper sheet, resulting in the aluminum foil tape being damaged by the impact of the spray gun flame during the spraying process, and the surface of the special-shaped part is not effectively protected.

[0036] Matters not covered by the present invention are known technologies.

[0037] 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 protecting special-shaped parts by supersonic flame spraying, characterized in that: Before the Co-Cr-W wear-resistant coating is sprayed on the narrow surfaces on both sides of the notch on the outer edge of the special-shaped part by using the supersonic flame spraying technology, different materials are used to protect other non-spraying areas, as follows: 1) Use high temperature pressure sensitive tape and unannealed copper sheet to prime the parts protection area, and wrap a layer of unannealed copper sheet between two layers of high temperature pressure sensitive tape; 2) Cut the annealed copper sheet and bend it to the required special shape on both sides of the spraying area of ​​the part, and fix the annealed copper sheet on the outer edge of the special-shaped part; 3) Use unannealed copper to wrap around the outer ring of the part and fix it with alloy wire; 4) The Co-Cr-W wear-resistant coating is sprayed on the spraying area inside the notch on the outer edge of the special-shaped part by using supersonic flame spraying technology; in step 1), the copper sheet that has not been annealed is only arranged at a position corresponding to the lower part of the spraying area of ​​the notch on the outer edge of the special-shaped part; in step 2), the corresponding annealing process is determined according to the hardness and flexibility of the copper sheet required by the geometric shape of the spraying area, and the annealing process is: keeping warm at 700±50℃ for 2 hours; the copper sheet is H62 brass strip.

2. The method for protecting special-shaped parts by supersonic flame spraying according to claim 1, characterized in that: The alloy wire is HGH3030 alloy wire.

Images