High-temperature alloy sealing ring coated with soluble polytetrafluoroethylene on surface and manufacturing process

Abstract

The invention relates to a high-temperature alloy sealing ring coated with soluble polytetrafluoroethylene on the surface and a manufacturing process. The manufacturing process comprises the following steps: (1) cleaning the surface; (2) workpiece hanging; (3) preheating the oven; (4) primary spraying; (5) secondary spraying; (6) spraying for the third time; (7) cooling and piece taking; the high-temperature alloy comprises an iron-nickel-based alloy and an iron-nickel-cobalt-based alloy; the diameter of the stainless steel wire ranges from 0.20 mm to 0.50 mm. The sealing ring is composed of a framework and a protective layer arranged on the surface of the framework. The framework is a high-temperature alloy pipe with a hollow structure, and the protective layer is a soluble polytetrafluoroethylene coating layer; the high-temperature alloy pipe is bent to form an annular structure. The framework of the sealing ring is made of the hollow high-temperature alloy, the surface of the sealing ring is coated with the soluble polytetrafluoroethylene material through the electrostatic spraying technology to form a protective layer, and therefore the corrosion resistance, abrasion resistance and non-stick performance of the sealing ring are greatly improved; the sealing performance is excellent and the reliability is high.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature alloy static sealing elements, in particular to a high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface and a manufacturing process thereof. Background Art

[0002] In recent years, with the rapid development of my country's aerospace industry and the intensification of the energy crisis, it has provided an opportunity for the application of low expansion high temperature alloys in the aerospace field, and also promoted the application and development of low expansion high temperature alloy materials. Such high temperature alloy materials generally include iron-based, nickel-based and cobalt-based alloys, and other elements such as chromium, aluminum, titanium, tungsten, and molybdenum. High temperature alloy materials have the characteristics of low expansion.

[0003] High-temperature alloy materials are used in rotating and stationary parts of aircraft engines, which can meet the strict requirements of component clearance and tolerance control, thereby improving the energy output and fuel efficiency of aircraft engines. At present, low-expansion high-temperature alloys are widely used in gas turbines, steam turbines, rocket engines and their sealing parts. Sealing parts generally include sealing rings, outer rings and thermal insulation rings. With the development of the aerospace industry, higher requirements are also put forward for traditional sealing rings. There have been serious aerospace accidents abroad due to rocket fuel leakage caused by sealing failure.

[0004] The performance of soluble polytetrafluoroethylene (PFA for short) is the best among fluoroplastics. PFA is inert to almost all chemical reagents and solvents, and has little change when in contact with common acids, strong bases, redox agents, halogens or solvents. Its chemical stability, physical and mechanical properties, electrical insulation, lubricity, non-stickiness, aging resistance and thermal stability are all excellent, similar to ordinary polytetrafluoroethylene (PTFE), but its high temperature mechanical strength is about twice that of ordinary polytetrafluoroethylene. PFA has good thermoplasticity, which overcomes the disadvantage of polytetrafluoroethylene being difficult to process. Summary of the invention

[0005] The purpose of the present invention is to provide a low expansion high temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface and a manufacturing process thereof.

[0006] The purpose of the present invention is achieved by adopting the following technical solutions:

[0007] A manufacturing process for a high-temperature alloy sealing ring with a soluble polytetrafluoroethylene coated surface, comprising the following steps:

[0008] (1) Surface cleaning: Use a 300-400 mesh dense soft scouring pad to wipe the surface of the sealing ring to make it shiny. First, clean the sealing ring three times with anhydrous ethanol, then wipe it clean with a dust-free cloth, hang it on a special tooling, and let it dry naturally;

[0009] (2) Workpiece hanger: fix the sealing ring obtained in step (1) on a special stainless steel hanger with two stainless steel wires;

[0010] (3) Preheating the oven: preheat the oven to 180° C., open the door of the oven, and push the rack with the sealing ring obtained in step (2) into the oven via a special flatbed car with tracks;

[0011] (4) Spraying once: Heat the oven to 280°C, open the middle door of the oven, and insert the heat-resistant tip of the spray gun into the oven for the first spraying; then, heat the oven to 380°C and keep it warm for 5 to 10 minutes, and observe through the window on the oven. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes;

[0012] (5) Secondary spraying: Open the middle door of the oven for the second spraying, then heat the oven to 380°C and keep it warm for 5 to 10 minutes. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes.

[0013] (6) Three spraying: Open the middle door of the oven for the third spraying, then heat the oven to 380°C and keep it warm for 5 to 10 minutes. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes.

[0014] (7) Cooling down and removing the parts: Turn off the "heating" function of the oven to complete the sintering of the product, then open the oven door to form a small gap for heat dissipation. When the oven temperature drops below 200°C, use a lifting platform truck to pull the hanger together with the sealing ring out of the oven, and take out the sealing ring for inspection according to the process requirements.

[0015] As a preferred technical solution of the present invention, the high temperature alloy includes an iron-nickel based alloy and an iron-nickel-cobalt based alloy.

[0016] As a preferred technical solution of the present invention, the diameter of the stainless steel wire is 0.20 mm to 0.50 mm.

[0017] As a preferred technical solution of the present invention, the first spraying in step (4) is to first spray the sealing ring clockwise for 3 to 5 circles with a spray gun, and then spray it counterclockwise for 3 to 5 circles, and the spraying time is 5 to 10 seconds.

[0018] As a preferred technical solution of the present invention, the second spraying in step (5) is to first use a spray gun to spray the sealing ring clockwise for 3 to 5 circles and counterclockwise for 3 to 5 circles, and the spraying time is 5 to 10 seconds; the temperature of the oven during the second spraying is 360°C.

[0019] As a preferred technical solution of the present invention, the third spraying in step (6) is to first use a spray gun to spray the sealing ring clockwise for 2 to 3 circles, and then spray it counterclockwise for 2 to 3 circles. The spraying time is 3 to 6 seconds. The temperature of the oven during the third spraying is 360°C.

[0020] As a preferred technical solution of the present invention, the sealing ring is an O-ring formed by bending a high-temperature alloy with a hollow structure.

[0021] A high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface is composed of a skeleton and a protective layer arranged on the surface of the skeleton; the skeleton is a high-temperature alloy tube with a hollow structure, and the protective layer is a soluble polytetrafluoroethylene coating layer; the high-temperature alloy tube is bent to form a ring structure.

[0022] As a preferred technical solution of the present invention, the diameter of the high-temperature alloy tube is 3 mm to 5 mm, and the thickness of the tube wall is 0.4 mm to 0.5 mm; the thickness of the soluble polytetrafluoroethylene coating layer is 0.05 mm to 0.15 mm.

[0023] As a preferred technical solution of the present invention, the sealing ring is a circular ring with a closed structure, and the diameter of the circular ring is 50 mm to 1200 mm.

[0024] Beneficial effects of the present invention: Compared with traditional metal sealing rings, the skeleton of the sealing ring of the present invention is a hollow high-temperature alloy, and the soluble polytetrafluoroethylene material is coated on the surface of the sealing ring by an electrostatic spraying process to form a protective layer, thereby greatly improving the corrosion resistance, wear resistance and non-stick properties of the sealing ring.

[0025] The present invention coats soluble polytetrafluoroethylene on the surface of a hollow high-temperature alloy O-type sealing ring, which can prevent the metal surface of the sealing ring from oxidation and rusting, and has multiple properties such as corrosion resistance, wear resistance, high temperature resistance and non-stickiness, as well as high pressure resistance, medium resistance and air tightness. It is suitable for industries such as petroleum, chemical industry, aviation, aerospace, metallurgy, and weapons industry, and is used in important sealing fields such as high pressure, high vacuum, and high temperature media, with excellent sealing performance and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a main structural schematic diagram of the present invention;

[0027] Figure 2 yes Figure 1 Schematic diagram of the AA partial cross-section structure.

[0028] In the figure: 1. sealing ring, 2. high temperature alloy tube, 3. soluble polytetrafluoroethylene layer, 4. cavity. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0030] like Figure 1 and Figure 2 As shown, the manufacturing process of the high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface includes the following steps:

[0031] (1) Surface cleaning: Use a 300-400 mesh dense soft scouring pad to wipe the surface of the sealing ring to make it shiny. First, clean the sealing ring three times with anhydrous ethanol, then wipe it clean with a dust-free cloth, hang it on a special tooling, and let it dry naturally;

[0032] (2) Workpiece hanger: fix the sealing ring obtained in step (1) on a special stainless steel hanger with two stainless steel wires;

[0033] (3) Preheating the oven: preheat the oven to 180° C., open the door of the oven, and push the rack with the sealing ring obtained in step (2) into the oven via a special flatbed car with tracks;

[0034] (4) Spraying once: Heat the oven to 280°C, open the middle door of the oven, and insert the heat-resistant tip of the spray gun into the oven for the first spraying; then, heat the oven to 380°C and keep it warm for 5 to 10 minutes, and observe through the window on the oven. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes;

[0035] (5) Secondary spraying: Open the middle door of the oven for the second spraying, then heat the oven to 380°C and keep it warm for 5 to 10 minutes. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes.

[0036] (6) Three spraying: Open the middle door of the oven for the third spraying, then heat the oven to 380°C and keep it warm for 5 to 10 minutes. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes.

[0037] (7) Cooling down and removing the parts: Turn off the "heating" function of the oven to complete the sintering of the product, then open the oven door to form a small gap for heat dissipation. When the oven temperature drops below 200°C, use a lifting platform truck to pull the hanger together with the sealing ring out of the oven, and take out the sealing ring for inspection according to the process requirements.

[0038] In this embodiment, the high temperature alloy includes an iron-nickel-based alloy and an iron-nickel-cobalt-based alloy; the diameter of the stainless steel wire is 0.20 mm to 0.50 mm. The first spraying of step (4) is to first spray the sealing ring with a spray gun clockwise for 3 to 5 circles, and then spray it counterclockwise for 3 to 5 circles, and the spraying time is 5 to 10 seconds. The second spraying of step (5) is to first spray the sealing ring with a spray gun clockwise for 3 to 5 circles, and then spray it counterclockwise for 3 to 5 circles, and the spraying time is 5 to 10 seconds; the temperature of the oven during the second spraying is 360°C. The third spraying of step (6) is to first spray the sealing ring with a spray gun clockwise for 2 to 3 circles, and then spray it counterclockwise for 2 to 3 circles, and the spraying time is 3 to 6 seconds, and the temperature of the oven during the third spraying is 360°C. The sealing ring of the present invention is an O-ring formed by bending a high temperature alloy with a hollow structure.

[0039] A high-temperature alloy sealing ring with a soluble polytetrafluoroethylene coated on the surface, the sealing ring 1 is composed of a skeleton and a protective layer arranged on the surface of the skeleton; the skeleton is a high-temperature alloy tube 2 with a hollow structure, and a cavity 4 is arranged inside the high-temperature alloy tube 2; the protective layer is a soluble polytetrafluoroethylene layer 3 coated on the surface of the high-temperature alloy tube 2; the high-temperature alloy tube 2 is bent to form a ring structure.

[0040] In this embodiment, the diameter of the high temperature alloy tube 2 is 3mm to 5mm, the thickness of the tube wall is 0.4mm to 0.5mm, and the thickness of the soluble polytetrafluoroethylene layer 3 is 0.05mm to 0.15mm. The sealing ring 1 in this embodiment is a circular ring with a closed structure, and the diameter of the circular ring is 50mm to 1200mm.

[0041] The present invention adopts soluble polytetrafluoroethylene to coat the surface of the hollow high-temperature alloy O-type sealing ring through an electrostatic spraying process, which can prevent the metal surface of the high-temperature alloy sealing ring from oxidation and rusting, and has multiple properties such as corrosion resistance, wear resistance, high temperature resistance, and non-stickiness.

[0042] The above embodiments are limited to illustrating the concept and technical features of the present invention, and their purpose is to enable those skilled in the art to understand the technical solutions and implementation methods of the present invention, and they cannot limit the protection scope of the present invention. Any equivalent replacement or equivalent change made according to the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A manufacturing process for a high-temperature alloy sealing ring with a soluble polytetrafluoroethylene coating on the surface, characterized in that The process comprises the following steps: (1) Surface cleaning: Use a 300-400 mesh dense soft scouring pad to wipe the surface of the sealing ring to make it shiny. First, clean the sealing ring three times with anhydrous ethanol, then wipe it clean with a dust-free cloth, hang it on a special tooling, and let it dry naturally; (2) Workpiece hanger: fix the sealing ring obtained in step (1) on a special stainless steel hanger with two stainless steel wires; (3) Preheating the oven: preheat the oven to 180° C., open the door of the oven, and push the rack with the sealing ring obtained in step (2) into the oven via a special flatbed car with tracks; (4) Spraying once: Heat the oven to 280°C, open the middle door of the oven, and insert the heat-resistant tip of the spray gun into the oven for the first spraying; then, heat the oven to 380°C and keep it warm for 5 to 10 minutes, and observe through the window on the oven. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes; (5) Secondary spraying: Open the middle door of the oven for the second spraying, then heat the oven to 380°C and keep it warm for 5 to 10 minutes. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes. (6) Three spraying: Open the middle door of the oven for the third spraying, then heat the oven to 380°C and keep it warm for 5 to 10 minutes. When the coating reaches a completely molten transparent state, cool it down to 360°C and keep it warm for 20 minutes. (7) Cooling down and removing the parts: Turn off the "heating" function of the oven to complete the sintering of the product, then open the oven door to form a small gap for heat dissipation. When the oven temperature drops below 200°C, use a lifting platform truck to pull the hanger together with the sealing ring out of the oven, and take out the sealing ring for inspection according to the process requirements.

2. The manufacturing process of the high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 1 is characterized by: The high temperature alloys include iron-nickel based alloys and iron-nickel-cobalt based alloys.

3. The manufacturing process of the high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 1 is characterized by: The diameter of the stainless steel wire is 0.20 mm to 0.50 mm.

4. The manufacturing process of the high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 1 is characterized by: The first spraying of step (4) is to first spray the sealing ring with a spray gun clockwise for 3 to 5 circles, and then spray it counterclockwise for 3 to 5 circles, and the spraying time is 5 to 10 seconds.

5. The manufacturing process of the high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 1 is characterized by: The second spraying of step (5) is to first use a spray gun to spray the sealing ring clockwise for 3 to 5 circles and counterclockwise for 3 to 5 circles, and the spraying time is 5 to 10 seconds; the temperature of the oven during the second spraying is 360°C.

6. The manufacturing process of the high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 1 is characterized by: The third spraying of step (6) is to first use a spray gun to spray the sealing ring clockwise for 2 to 3 circles, and then spray it counterclockwise for 2 to 3 circles. The spraying time is 3 to 6 seconds. The temperature of the oven during the third spraying is 360°C.

7. The manufacturing process of the high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 1 is characterized by: The sealing ring is an O-ring formed by bending a high-temperature alloy with a hollow structure.

8. A high-temperature alloy sealing ring with a surface coated with soluble polytetrafluoroethylene obtained by the process according to any one of claims 1 to 7, characterized in that: The sealing ring is composed of a skeleton and a protective layer arranged on the surface of the skeleton; the skeleton is a high-temperature alloy tube with a hollow structure, and the protective layer is a soluble polytetrafluoroethylene coating layer; the high-temperature alloy tube is bent to form a ring structure.

9. The high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 8 is characterized in that: The diameter of the high-temperature alloy tube is 3 mm to 5 mm, and the thickness of the tube wall is 0.4 mm to 0.5 mm; the thickness of the soluble polytetrafluoroethylene coating layer is 0.05 mm to 0.15 mm.

10. The high-temperature alloy sealing ring with soluble polytetrafluoroethylene coated on the surface according to claim 8, characterized in that: The sealing ring is a circular ring with a closed structure, and the diameter of the circular ring is 50 mm to 1200 mm.

Images