الشفاه هي مكونات أساسية في أنظمة الأنابيب, تستخدم لتوصيل الأنابيب, الصمامات, مضخات, وغيرها من المعدات. أنها توفر القوة, ختم, والمرونة في الصيانة والتفتيش. من بين أنواع الفلنجات المختلفة, duplex flanges stand out for their unique material composition and excellent performance in demanding environments.

Duplex flanges are made from duplex stainless steels, which combine the advantages of both austenitic and ferritic microstructures. This results in superior strength, مقاومة التآكل, and toughness compared to conventional stainless steels. But not all duplex flanges are the same—the specific materials used for manufacturing play a key role in determining their performance.

This article explores the different materials used for duplex flanges, their applications across industries, and the benefits they deliver.

---

1. Introduction to Duplex Stainless Steel Flanges

Duplex stainless steel flanges are manufactured from alloys that typically contain:

• Around 22–25% chromium

• 4–7% nickel

• 3–5% molybdenum

• Controlled amounts of nitrogen

This unique balance of alloying elements produces a two-phase microstructure (austenite + الفريت), which provides a combination of strength and corrosion resistance unmatched by most standard stainless steels.

---

2. Different Materials Used for Duplex Flanges

Several grades of duplex stainless steels are commonly used for flanges. Each grade is tailored for specific environmental and mechanical conditions.

أ. Standard Duplex (2205 / UNS S32205)

• تعبير: 22% الكروم, 5% النيكل, 3% الموليبدينوم.

• ملكيات: قوة عالية, twice that of 304 و 316 الفولاذ المقاوم للصدأ, with excellent resistance to chloride stress corrosion cracking.

• التطبيقات: خطوط أنابيب النفط والغاز, النباتات الكيميائية, and marine structures.

ب. سوبر دوبلكس (2507 / UNS S32750)

• تعبير: 25% الكروم, 7% النيكل, 4% الموليبدينوم, والنيتروجين.

• ملكيات: Even higher strength and superior resistance to pitting and crevice corrosion compared to standard duplex.

• التطبيقات: المنصات البحرية, خطوط الأنابيب تحت سطح البحر, ومحطات تحلية المياه.

ج. Lean Duplex (UNS S32101 / 2101)

• تعبير: Lower nickel (1–2%) and molybdenum levels but higher manganese and nitrogen.

• ملكيات: أكثر فعالية من حيث التكلفة, مقاومة جيدة للتآكل, and higher strength than 304/316 الفولاذ المقاوم للصدأ.

• التطبيقات: Structural applications, storage tanks, and bridges.

د. Hyper Duplex (UNS S32707 / S33207)

• تعبير: Very high chromium (27–29%), النيكل (6–8%), والموليبدينوم (ما يصل الى 5%).

• ملكيات: Exceptional strength and extreme resistance to aggressive chemical environments.

• التطبيقات: Specialized chemical processing, النباتات الحمضية, and extreme offshore conditions.

---

3. Manufacturing of Duplex Flanges

Duplex flanges are produced using forging, بالقطع, and heat treatment processes to ensure strength and durability. Key types of duplex flanges include:

• لحام الشفاه الرقبة

• Slip-on flanges

• Socket weld flanges

• الشفاه العمياء

• الشفاه المشتركة اللفة

• الشفاه الخيوط

All of these flange types benefit from the superior properties of duplex stainless steels.

---

4. Applications of Duplex Flanges

Duplex flanges are widely used across multiple industries where strength and corrosion resistance are crucial.

صناعة النفط والغاز

• Subsea pipelines and offshore platforms.

• Heat exchangers and pressure vessels.

• High-pressure piping systems.

Chemical and Petrochemical Industry

• Storage tanks, reactors, and piping exposed to acids and chlorides.

• Flue gas desulfurization systems.

الصناعة البحرية

• Shipbuilding components.

• Desalination plants and seawater cooling systems.

Construction and Infrastructure

• Bridges and load-bearing structures.

• مرافق معالجة المياه.

Renewable Energy

• Offshore wind turbine foundations.

• Geothermal energy plants exposed to corrosive brines.

---

5. Benefits of Duplex Flanges

أ. قوة عالية

• Duplex steels have roughly double the yield strength of austenitic stainless steels, allowing the use of thinner and lighter components.

ب. مقاومة فائقة للتآكل

• مقاومة ممتازة للتنقر, تآكل الشق, and chloride stress corrosion cracking.

ج. كفاءة التكلفة

• Reduced material usage due to high strength.

• Lean duplex grades reduce nickel and molybdenum content, lowering overall costs.

د. عمر خدمة ممتد

• High durability reduces maintenance frequency and downtime.

ه. براعة

• Suitable for a wide range of industries from oil and gas to renewable energy and construction.

---

6. Duplex Flanges vs. Conventional Stainless Steel Flanges