Duplex-Stahlflansche sind Rohrleitungskomponenten aus Duplex-Edelstahl, eine Familie rostfreier Stähle, die eine ausgewogene Mischung aus austenitischen und ferritischen Phasen enthält. This dual-phase structure gives duplex steel superior mechanical strength, ausgezeichnete Korrosionsbeständigkeit, and high resistance to stress corrosion cracking.

These flanges are used in a variety of critical applications, including offshore oil rigs, Entsalzungsanlagen, chemische Verarbeitungseinheiten, and marine structures. The combination of strength and corrosion resistance makes duplex steel flanges an ideal choice for demanding environments where conventional stainless steels may fail.

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Chemical Composition and Grades

Duplex stainless steels generally contain:

• Chrom: 21 Zu 25 Prozent

• Nickel: 4.5 Zu 7 Prozent

• Molybdän: bis zu 3.5 Prozent

• Stickstoff: added to enhance pitting resistance

• Low carbon content to minimize carbide precipitation

Common grades used for duplex steel flanges include:

• UNS S31803 / S32205 (auch bekannt als 2205 Duplex)

• UNS S32750 (Super-Duplex)

• UNS S32760

• UNS S32550

Each grade is selected based on the specific mechanical and environmental requirements of the application.

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Advantages of Duplex Steel Flanges

Duplex steel flanges offer a wide range of benefits compared to traditional stainless or carbon steel flanges:

1. Hohe Festigkeit

Duplex steel has nearly twice the yield strength of standard austenitic stainless steel, allowing for thinner sections and reduced weight without compromising strength.

2. Korrosionsbeständigkeit

They provide excellent resistance to general corrosion, Lochfraß, Spaltkorrosion, and especially to chloride-induced stress corrosion cracking.

3. Kosteneffizienz

Despite higher initial material costs, the long service life and reduced maintenance needs make duplex flanges more cost-effective over time.

4. Superior Toughness

The austenitic component enhances toughness even at sub-zero temperatures, making these flanges suitable for arctic or deep-sea conditions.

5. Resistance to Erosion

Duplex alloys resist erosion from fast-flowing seawater or corrosive fluids, making them ideal for high-pressure applications.

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Common Types of Duplex Steel Flanges

sasaflange manufactures a full range of duplex steel flanges according to international standards such as ASME, ASTM, EN, und DIN. Some of the most common types include:

• Vorschweißflansche – Ideal for high-pressure applications

• Aufsteckflansche – Easier installation in low-pressure systems

• Muffenschweißflansche – Excellent for small diameter high-pressure pipes

• Blindflansche – Used to terminate or isolate pipe sections

• Überlappungsflansche – Allow for quick bolt alignment in systems

• Gewindeflansche – Used for non-welded connections

• Öffnungsflansche – Used with flow meters and instrumentation

All flanges produced by sasaflange are available in a variety of face types, wie zum Beispiel ein erhabenes Gesicht (RF), Ringgelenk (RTJ), and flat face (FF).

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Applications of Duplex Steel Flanges

Thanks to their exceptional properties, duplex flanges are widely used in:

1. Öl- und Gasindustrie

Duplex flanges are preferred for offshore platforms, subsea equipment, and transport pipelines due to their strength and resistance to seawater corrosion.

2. Entsalzungsanlagen

The high chloride resistance makes them ideal for saltwater processing and brine management.

3. Chemische und petrochemische Verarbeitung

Duplex steel can handle aggressive media and temperature variations common in reactors and storage tanks.

4. Marineindustrie

Used in shipbuilding, underwater pipelines, and marine structures for their resistance to erosion and corrosion.

5. Stromerzeugung

From nuclear plants to renewable energy systems, duplex flanges are used in high-pressure steam and fluid systems.

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Standards und Zertifizierungen

sasaflange ensures all duplex steel flanges meet or exceed the following international standards:

• ASTM A182 / A240

• ASME B16.5 / B16.47

• EN 1092-1

• NORSOK M-630 / M-650

• ISO 15156 (für sauren Service)

Each flange is also traceable by heat number, ensuring complete transparency and accountability throughout the supply chain.

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Duplex vs Super Duplex Flanges

While both duplex and super duplex flanges offer superior performance, super duplex contains higher levels of chromium and molybdenum, offering better corrosion resistance and mechanical properties. Super duplex flanges are generally used in even more extreme environments such as:

• Deepwater oil drilling

• High salinity applications

• Aggressive chemical environments

sasaflange provides both duplex and super duplex flange solutions tailored to specific industrial needs.

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Welding and Machining Considerations

Welding duplex steel flanges requires expertise and control over heat input to maintain the phase balance. Poor welding can lead to loss of corrosion resistance and mechanical integrity.

Machining duplex steel is more challenging than austenitic stainless steel due to its higher strength. Proper tooling and coolant techniques must be used to ensure precision and tool longevity.

sasaflange works with experienced welders and machinists to ensure all flanges are fabricated to exact specifications without compromising structural integrity.

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Surface Finish and Protection

Abhängig von der Anwendung, sasaflange offers several surface finishes for duplex flanges:

• Pickled and passivated for restoring corrosion resistance

• Machined or polished surfaces for smooth flow and sealing

• Coated surfaces (where needed) for enhanced protection

Special attention is paid to surface cleanliness, especially for industries like food, pharmazeutisch, und Entsalzung.

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Quality Control and Testing

Every duplex steel flange from sasaflange undergoes rigorous quality control, einschließlich:

• Sicht- und Maßkontrolle

• Ultraschallprüfung (UT)

• Dye penetrant testing (PT)

• Hydrostatische Prüfung

• Positive Materialidentifizierung (PMI)

• Inspektionen durch Dritte (as requested)

All test results are documented in Mill Test Certificates (MTCs) and comply with EN 10204 Typ 3.1 oder 3.2.

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Packaging and Delivery

To prevent contamination and damage during shipping, sasaflange packs each duplex steel flange with:

• Plastic caps to protect sealing faces

• Anti-corrosion paper wrapping

• Plywood boxes or crates for export

• Clear labeling with product information and heat numbers

Global delivery is available with full documentation support, including certificates of origin, material test reports, and shipping invoices.

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Letzte Gedanken

Duplex steel flanges are a smart investment for industries demanding high performance, Haltbarkeit, und Korrosionsbeständigkeit. Their ability to perform under pressure in extreme environments makes them one of the most reliable flange materials available today.

Whether you are sourcing for offshore drilling, chemische Verarbeitung, oder Meeressysteme, sasa länglich provides high-quality duplex flange solutions engineered to meet your specifications and exceed expectations.