Duplex Steel Flanges Manufacturer
Midland Alloys Inc. is a reputable Indian manufacturer and international supplier of duplex steel flanges, known for providing industries all over the world with precisely engineered solutions. Specialized pipe fittings known as duplex steel flanges are made of duplex stainless steel a special alloy that combines equal amount of ferritic and austenitic stainless steel. Excellent mechanical strength and remarkable corrosion resistance are the outcomes of this well balanced structure. Duplex stainless steel, which is typically composed of 22% chromium, 5% nickel and 3% molybdenum with additional nitrogen, provides exceptional performance in demanding conditions. We produce a variety of Duplex S31803 flanges, Duplex S32205 flanges and UNS S32205 pipe flanges that meet international standards and specifications such as ASTM A182 F51 Flange and ASME SA182 Duplex Steel Socket Weld Flanges.
Key Benefits of Duplex Steel Flanges
In demanding industries, using Duplex stainless steel flanges provides a major technical and financial advantage.
- High yield strength lowers the cost and weight of materials.
- Outstanding resistance to stress corrosion cracking, pitting, and crevices
- Superior weldability over ferritic grades making fabrication easier
- Reduced lifecycle cost as a result of enduring dependability and performance
- Useful in a variety of industries including construction and oil and gas
- Under pressure it maintains exceptional ductility and impact toughness.
- Complies with international standards such as EN1092 Duplex Flanges and ANSI B16.5
- Reasonably priced duplex flanges per kilogram with guaranteed quality and traceability
Duplex Steel Flanges Specification

1/2" (15 NB) to 48" (1200NB)

ASTM A182 / A240 & ASME SA182 / SA240

ANSI/ASME B16.5, B 16.47 Series A & B, B16.48, BS4504, BS 10, EN-1092, DIN, etc.

Threaded / Screwed / Forged / Plate

150#, 300#, 600#, 900#, 1500#, 2500#, PN6, PN10, PN16, PN25, PN40, PN64 etc.

Flate Face (FF), Raised Face (RF), Ring Type Joint (RTJ)

Forging, Rolling, Casting

FNPT, NPT, BSPT, MNPT, BSPP
Contact us today to discuss how Duplex Steel Flanges can benefit your application. Whether you need guidance in selecting the right pipes or have specific requirements, our team of experts is here to help you find the optimal solution.
Duplex Steel Flanges Grades We Offer
Difference Between Stainless Steel Flanges and Duplex Steel Flanges
Stainless Steel Flanges, such as SS 304 and SS 316, are single-phase austenitic alloys known for excellent corrosion resistance and workability. In contrast, Duplex Steel Flanges contain a mixed microstructure of austenite and ferrite, offering higher strength and improved resistance to chloride stress corrosion cracking. Duplex flanges perform better in mechanical strength, and are frequently used in harsh chloride-rich or offshore conditions, even though stainless steel offers superior formability and weldability. Both materials meet ASTM A182 standards but differ in application suitability, based on corrosion resistance and mechanical demands.
Plate

Shear

Press

Inspection

Lathe

Drilling

Cleaning

Flange

Inspection

Analytic

Marking

Packing & Shipping
Applications of Duplex Steel Flanges
Because of their strength, weldability and resistance to corrosion duplex stainless steel socket weld flanges are essential in a variety of industries. They are utilized in offshore platforms and subsea pipelines in the oil and gas sector which are exposed to high levels of pressure and chloride. Chemical plants and marine environments rely on duplex flanges to resist aggressive acids and saline waters. Desalination units, pulp and paper mills, and power generation plants use these flanges for reliable flow control. The construction sector integrates Duplex Steel S31803 pipe flange dimensions into structural pipe assemblies and mechanical joints, while pollution control systems use them for efficient waste and gas handling.
Why Choose Midland Alloys Inc. for Duplex Steel Flanges
One of India’s top producers and exporters of premium duplex steel flanges, Midland Alloys Inc. offers performance driven flange solutions that satisfy demanding international standards. We use manufacturing processes certified by ISO 9001:2015 and adhere to ASTM, EN and ANSI B16.5 specifications. We provide complete customization including surface treatments, machined end finishes, cut-to-length sizes and particular pressure ratings. We provide prompt lead times and logistical support to clients in the Gulf, Europe, Africa and Southeast Asia. All flanges go through internal testing, which includes hydro, ultrasonic, and PMI testing. On request, mill certifications and third-party inspections are provided. We promise precision, dependability and a long-term collaboration egardless of whether your project calls for small batch flexibility or bulk order consistency. Every flange is shipped with a Mill Test Certificate (MTC) attesting to its mechanical and chemical composition and it is clearly marked in accordance with ASTM A182 / ASME SA182 standards.
FAQ
Compared to Super Duplex 2507 (UNS S32750) Duplex 2205 (UNS S32205) has less molybdenum and chromium. Because of its increased strength and improved resistance to corrosion Super Duplex is appropriate for harsher environments.
Yes, duplex stainless steel flanges are especially suited for saline and chloride-heavy marine environments due to their excellent pitting and crevice corrosion resistance.
Absolutely. Duplex S31803 flanges are perfect for pressure piping and structural assemblies because they are easy to weld and have a low chance of heat affected zone cracking.
Duplex flanges are covered under ASTM A182, ASME SA182, ANSI B16.5 and EN‑1092 depending on design and dimensional requirements.
Although prices vary by size, grade, and pressure rating, the price per kilogram of duplex flange normally falls between ₹350 and ₹650, contingent on the necessary certifications and specifications.
Yes we provide third-party inspection services from agencies ensuring compliance and customer peace of mind.



