Design standards and specifications for metal sealing rings

Metal seals are essential in industrial applications and are commonly used in aerospace, petrochemical, automotive and nuclear industries. To ensure their performance and reliability, the design must follow strict standards and specifications. The following are the main design standards, specifications and design principles.

1. Basic standards and specifications

1.1 International Standards Organization (ISO)

ISO 6162: Specifies the design requirements for flange connections and seals for hydraulic transmission systems, including metal seals.

ISO 3601: Provides design standards for O-rings and seal grooves for hydraulic and pneumatic transmission systems, which can also be used for metal seals.

ISO 15465: Specifically for metal seals in static seals, covering material selection and design guidance.

1.2 American Society of Mechanical Engineers (ASME)

ASME B16.20: Specifies the design and size requirements for annular, semi-annular and spiral wound metal gaskets for flange connections.

ASME Section VIII: Used for the design and manufacture of pressure vessels, involving the design requirements of metal seals.

1.3 American Petroleum Institute (API)

API 6A: Specifies the design requirements for metal seals used in wellhead equipment and Christmas tree equipment.

API 6D: Involves the design and application of metal seals in pipeline valves.

1.4 European Standards (EN)

EN 12560: Specifies the design and application requirements for mechanical seals and sealing systems.

EN 13555: Involves the design requirements for gaskets in flange connections, including metal seals.

2. Material standards

The material selection of metal seals is crucial, and the commonly used standards are as follows:

ASTM A193: Specifies alloy steel and stainless steel bolt materials for high temperature and high pressure.

ASTM B16: Specifies metal gasket materials, covering copper, aluminum, stainless steel, etc.

ASTM F36: Specifies metal seal materials, especially for applications in high temperature, high pressure and corrosive environments.

3. Industry application standards

Different industries have specific requirements for metal seals. The following are several typical industry application standards:

Aerospace: SAE AS5311 specifies the standards for metal seals for aerospace.

Nuclear industry: ASME NQA-1 specifies the design, manufacturing and testing requirements for metal seals used in the nuclear industry.

Automotive industry: SAE J266 specifies the material and design requirements for metal seals used in automotive exhaust systems.

4. Design principles and specifications

4.1 Dimensions and tolerances

Sealing surface machining accuracy: Ensure that the surface roughness, flatness and finish of the sealing surface reach specific machining accuracy.

Tolerance matching: Strictly control the tolerance matching of the metal seal and its mating parts to ensure that the compression and stress distribution of the seal after installation are uniform.

4.2 Material selection

Temperature resistance: Select appropriate materials according to the working temperature, such as stainless steel or nickel-based alloys for high temperature environments.

Corrosion resistance: Select corrosion-resistant materials according to the chemical properties of the working medium, such as stainless steel or titanium alloys when working in acidic or alkaline media.

4.3 Structural design

Compression and elastic deformation: Ensure that the seal provides sufficient sealing force under compression and elastic deformation.

Anti-extrusion design: In a high-pressure environment, the seal ring can be prevented from being extruded by adding an anti-extrusion ring or selecting a suitable gasket structure.

5. Testing and verification

After the metal seal ring design is completed, a series of tests and verifications need to be carried out to ensure performance and reliability:

Pressure test: Including static and dynamic pressure tests to evaluate pressure resistance.

Temperature test: High and low temperature tests to evaluate temperature resistance.

Fatigue test: Evaluate fatigue resistance through cyclic pressure and thermal cycle tests.

Leak test: Air tightness and liquid tightness tests to evaluate sealing performance.

Chemical compatibility test: Evaluate the corrosion resistance and material compatibility of metal seals in different chemical media.

6. Design tools and software

In the modern design process, tools such as CAD and FEA are often used to improve design quality and efficiency:

CAD system: used for geometric modeling, visualization and simulation, and to check assembly and interference.

FEA analysis: Perform stress analysis, thermal analysis and fatigue analysis to optimize the design.

Conclusion

The design and manufacture of metal seals must strictly follow various standards and specifications. Combining material science, fluid dynamics and modern design tools to ensure high performance and reliability under various extreme conditions. Through reasonable design principles, strict compliance with standards and comprehensive testing and verification, metal seals can provide excellent sealing effects and long-term operation guarantees in a wide range of applications.

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