In Rohrleitungssystemen, Die Flanschverkleidung is a critical feature that determines how two flanges seal together with the help of a gasket. Without proper facing, even the strongest flanges and the best bolts cannot prevent leaks. Two of the most widely recognized standards for flanges are ASME B16.5 Und ASME B16.47. While both cover different flange size ranges, their facing types share common design principles and applications.

This article provides a detailed guide on flange facing for B16.5 and B16.47 flanges, explaining the types of facings, their functions, and the key considerations engineers must evaluate when selecting the right flange connection for industrial projects.

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Overview of B16.5 and B16.47 Flanges

ASME B16.5

• Covers flanges and flanged fittings from NPS ½ to NPS 24

• Pressure ratings: Klasse 150 zur Klasse 2500

• Common in small- to medium-diameter piping systems

ASME B16.47

• Abdeckungen Stahlflansche mit großem Durchmesser aus NPS 26 zum NPS 60

• Two series: Serie A (heavier, for high-pressure applications) Und Serie B (leichter, cost-effective, derived from MSS SP-44)

• Pressure ratings: Klasse 75 zur Klasse 900

Together, these two standards cover nearly the entire range of industrial flanges used in oil and gas, chemische Verarbeitung, Stromerzeugung, Wasseraufbereitung, und Meerestechnik.

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What is Flange Facing?

Der Flanschverkleidung is the finish applied to the surface of the flange that comes into contact with the gasket. Its purpose is to ensure tight sealing, proper load distribution, and gasket retention. Different facing types are specified depending on the application’s pressure, Temperatur, und Flüssigkeitstyp.

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Common Flange Facing Types for B16.5 and B16.47

1. Erhöhtes Gesicht (RF)

• Most widely used facing type

• A small area around the bore is raised above the bolt circle

• Standard roughness ensures gasket grip

• Used in Classes 150 Zu 2500

Anwendungen: Oil refineries, Chemieanlagen, Wasseraufbereitungssysteme

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2. Flaches Gesicht (FF)

• Entire face of the flange is flat

• Usually used with cast iron and fiberglass piping

• Designed for low-pressure, non-critical applications

Anwendungen: Wasserverteilung, Pumpenanschlüsse, Niederdruckleitungen

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3. Ringgelenk (RTJ)

• A machined groove accommodates a metallic ring gasket

• Provides metal-to-metal seal

• Withstands very high pressure and temperature

• Available in Classes 600 und darüber

Anwendungen: Offshore drilling, Petrochemie, high-pressure gas systems

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4. Nut und Feder (T&G)

• One flange has a raised tongue, and the other has a matching groove

• Prevents gasket displacement during installation

• Provides excellent alignment

Anwendungen: Wärmetauscher, chemische Reaktoren, custom piping assemblies

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5. Männlich und weiblich (M&F)

• Ähnlich wie T&G but with flat mating surfaces

• Male flange has a raised portion; female flange has a matching recess

• Ensures accurate gasket positioning

Anwendungen: Specialty piping, Luft- und Raumfahrt, and chemical systems

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Surface Finish Requirements

ASME standards specify the surface roughness of flange facings to ensure proper gasket interaction:

• Lagerfinish: Am häufigsten, concentric or spiral serrated finish (Ra 125–500 µin)

• Glatte Oberfläche: For soft gaskets, provides improved contact area (Ra 63–125 µin)

• Kaltwasser-Finish: Extremely smooth finish for special soft gaskets (Ra ≤ 63 µin)

Key Point: The correct surface finish prevents leakage and extends gasket life.

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Key Considerations for Selecting Flange Facing

1. Betriebsdruck und Temperatur

• Für Hochdruck, hohe Temperatur applications → RTJ is recommended

• Für Niederdruck, ambient conditions → FF or RF may be sufficient

2. Dichtungstyp

• Weiche Dichtungen (Gummi, PTFE): Require smooth finishes

• Metallische Dichtungen (spiralförmig gewickelt, RTJ): Require serrated or grooved facings

3. Piping Material Compatibility

• Cast iron and non-metallic pipes → Use Flat Face

• Steel and alloy pipelines → Use Raised Face or RTJ

4. Maintenance and Accessibility

• RF and FF flanges are easier to assemble and maintain

• RTJ flanges require precise machining and ring gasket handling

5. Cost and Availability

• RF and FF are cost-effective and widely available

• RTJ, T&G, and M&F are more expensive but necessary for critical service

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Applications of B16.5 and B16.47 Flange Facing

Öl- und Gasindustrie

• RTJ flanges for offshore rigs, Unterwasserpipelines, und Raffinerien

• RF flanges for midstream and downstream processing

Chemie und Petrochemie

• RF and T&G flanges in reactors and distillation units

• Corrosion-resistant alloys required for aggressive chemicals

Stromerzeugung

• RTJ flanges for high-pressure steam lines

• RF flanges for cooling water systems

Wasseraufbereitung und -verteilung

• FF flanges for low-pressure water pipelines

• RF flanges for desalination and wastewater plants

Marine und Schiffbau

• Stainless steel RF flanges for seawater cooling

• RTJ flanges for marine exhaust and fuel systems

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Flange Facing and Leak Prevention

The correct flange facing directly influences Leckverhinderung. Poorly selected or incorrectly finished facings lead to gasket failure, Ausfallzeit, and costly repairs. Engineers must evaluate the Dichtungsmaterial, bolt torque, and pressure-temperature rating when specifying flange facings.

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Abschluss

Flange facing is a critical element of ASME B16.5 and B16.47 flanges, ensuring reliable sealing and safe operation in diverse industries. Erhöhtes Gesicht is the most commonly used, Flaches Gesicht is preferred for low-pressure systems, Und Ringgelenk is indispensable for high-pressure, Hochtemperaturanwendungen. Other facings such as Zunge & Rille Und Male & Female are used in specialized systems requiring precision alignment.

For industries seeking reliable, high-quality flange solutions, sasa länglich Angebote ASME B16.5 and B16.47 flanges with precise facings tailored to specific applications. With strict adherence to global standards and advanced manufacturing technology, sasa länglich ensures long-term safety, Leistung, and efficiency in piping systems worldwide.

By carefully considering flange facing types, engineers and buyers can optimize system integrity, reduce leakage risks, and extend the service life of critical piping components.