Pipe flanges are vital components in piping systems, dienen als Verbindungen zwischen Rohren, Ventile, Pumps, und andere Ausrüstung. Sie bieten Stärke, flexibility, und Wartungsfreundlichkeit in industries such as oil and gas, chemische Verarbeitung, Stromerzeugung, Wasseraufbereitung, und Schiffbau. Choosing the right flange is essential to ensure Sicherheit, Zuverlässigkeit, und Wirtschaftlichkeit of the system.

This article explains what to look for in pipe flanges, focusing on key considerations such as materials, Druckstufen, Verkleidungstypen, Standards, und Anwendungen. By understanding these aspects, engineers and procurement professionals can make informed decisions when selecting flanges.

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Was sind Rohrflansche??

A pipe flange is a forged or cast ring that allows the connection of pipes, Beschläge, Ventile, und andere Komponenten. Flanges are joined by bolting and sealing with a gasket, creating a leak-proof joint that can be dismantled when necessary.

Common Types of Pipe Flanges:

• Vorschweißflansch – Strong and suitable for high-pressure systems

• Aufsteckflansch – Easy to install, used in low-to-medium pressure pipelines

• Muffenschweißflansch – Ideal for small-diameter, Hochdrucksysteme

• Gewindeflansch – Used where welding is not possible

• Überlappungsflansch – Allows easy alignment, often used with stub ends

• Blindflansch – Used to close or seal off a pipeline

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Key Factors to Look For in Pipe Flanges

1. Materialauswahl

Material choice directly affects performance, Korrosionsbeständigkeit, und Haltbarkeit.

• Kohlenstoffstahl – Economical, hohe Festigkeit, used in general industry

• Edelstahl – Excellent resistance to corrosion and oxidation

• Legierter Stahl – Withstands high temperatures and pressures

• Nickellegierungen – Superior resistance to aggressive chemicals

• Duplex- und Super-Duplex-Edelstahl – Outstanding strength and chloride corrosion resistance

Tipp: Always ensure flange material matches the pipe material to avoid galvanic corrosion.

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2. Druckstufe

Flanges are classified into Druckklassen, indicating the maximum pressure they can withstand at a specific temperature.

• Klassen: 150, 300, 600, 900, 1500, Und 2500 (per ANSI/ASME B16.5)

• Higher class = higher pressure and temperature capability

Beispiel:

• Klasse 150: Used for low-pressure water pipelines

• Klasse 600 und darüber: Required in refineries and power plants

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3. Flange Facing Types

The flange facing ensures proper gasket seating and leak-proof connections.

• Erhöhtes Gesicht (RF): Am häufigsten, good for general-purpose sealing

• Flaches Gesicht (FF): Used in low-pressure systems or with cast iron equipment

• Ringgelenk (RTJ): Designed for high-pressure, high-temperature conditions

• Männlich und weiblich / Nut und Feder: Prevents gasket displacement and ensures precise alignment

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4. Dichtungskompatibilität

The gasket material must match the flange facing and operating environment.

• Weiche Dichtungen (Gummi, PTFE): Geeignet für Niederdruckanwendungen

• Spiralgewickelte Dichtungen: Widely used in high-pressure and high-temperature systems

• Ring Joint Gaskets: Specifically for RTJ facings in extreme conditions

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5. Standards und Compliance

Pipe flanges must comply with international standards to ensure safety and interchangeability.

• ASME/ANSI B16.5: Pipe flanges up to 24 Zoll

• ASME B16.47: Flansche mit großem Durchmesser

• DIN/EN Standards: Widely used in Europe

• JIS-Standards: Common in Japan and Asia

Tipp: Always confirm client or project requirements before procurement.

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6. Dimensions and Tolerances

• Überprüfen Außendurchmesser (VON), inner diameter (AUSWEIS), Lochkreisdurchmesser (BCD), and thickness.

• Ensure tolerances meet project design codes to prevent misalignment.

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7. Bolt and Torque Requirements

Bolts must be selected based on:

• Material: Corrosion resistance and strength

• Torque Application: Correct torque prevents both under-tightening (Lecks) and over-tightening (gasket damage).

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8. Korrosionsbeständigkeit

Pipelines exposed to seawater, Säuren, or chemicals require flanges with high corrosion resistance.

• Stainless steel and duplex grades are preferred in marine and chemical plants.

• Coatings and linings can be used for carbon steel flanges in corrosive service.

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9. Installation und Wartung

• Inspect flanges before installation for cracks or warping

• Ensure proper alignment during installation

• Use torque sequences for bolts to ensure even pressure distribution

• Schedule regular maintenance checks to prevent leakage and downtime

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Applications of Pipe Flanges

1. Öl- und Gasindustrie

   • Pipelines, Raffinerien, Offshore-Plattformen

   • High-pressure weld neck and RTJ flanges

2. Chemie und Petrochemie

   • Reaktoren, Lagertanks, chemical pipelines

   • Stainless steel and alloy flanges for corrosion resistance

3. Stromerzeugung

   • Kessel, Dampfleitungen, nuclear plants

   • Hochdruck, high-temperature flanges

4. Meerestechnik

   • Ballastsysteme, Entsalzungsanlagen

   • Duplex stainless steel flanges

5. Wasseraufbereitung

   • Distribution pipelines, wastewater systems

   • Large-diameter slip-on and lap joint flanges

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Pipe Flanges vs. Other Connection Methods