Duplex Steel Flanges

Duplex steel flanges are piping components made from duplex stainless steel, an alloy with a mixed austenitic-ferritic microstructure in roughly equal proportions. These flanges are also known as duplex SS flanges or DSS flanges. These flanges consist of around 22% chromium, 5% nickel, 3% molybdenum, and 0.15% nitrogen. This composition gives the material a minimum tensile strength of 620 MPa and the yield strength of 450 MPa, both higher than standard austenitic grades. The dual-phase structure also provides strong resistance to chloride stress corrosion cracking, pitting, and crevice corrosion. The Duplex Steel Flanges are commonly used in oil and gas, marine, chemical processing, and desalination applications.

Duplex Steel Flange Prices

The Duplex steel flange price is subject to change depending on the grade, size, pressure class, and order quantity. Here are some of the major factors that help to determine the overall cost.

Approximate Price Range

The price of duplex steel flanges is Rs. 500 to Rs. 750 per kg, depending on the common grades (ASTM A182 F51 and F60). The overall cost is determined by larger sizes or higher pressure classes (Class 900 and up).

Factors Affecting Price

There are several factors that determine the price of duplex steel flanges. The grade is significant, as the higher alloy content of S32205 and S32750 contributes to the higher cost of the grades. The price is also influenced by flange size and pressure rating; larger sizes (NPS > 10") and higher pressure classes (Class > 1500) call for higher material consumption and precise manufacturing. The quantity ordered may affect the final price, as larger quantities could lead to lower prices per kilogram, while urgent orders with tight delivery times might result in higher prices, as they would involve expediting the production. Third-party inspections, mill test reports (EN 10204 3.2), and NACE compliance are all elements of certification that add to the cost and are usually required for critical applications. Moreover, the cost of special surface finish and protective coat is usually higher than the cost of the standard finish flanges due to the additional process required.

Duplex Steel Flange Grades

The Duplex steel flanges are available in multiple standard grades. Each grade has its own level of corrosion resistance, strength, and weldability. The best grade to use depends on where it will be used and what pressure it must handle.

• Duplex Steel S31803 Flanges
• Duplex Steel 2205 Flanges
• Duplex Steel S32205 Flanges

Types Of Duplex Steel Flanges

The Duplex stainless steel flanges are manufactured in 8 standard types, each designed to meet specific connection, pressure, and installation requirements across industrial piping systems.

• Weld Neck Flanges (WNRF)
• Slip-On Flanges (SORF)
• Blind Flanges (BLRF)
• Socket Weld Flanges (SWRF)
• Threaded Flanges
• Lap Joint Flanges (LJRF)
• Ring Type Joint Flanges (RTJ)
• Orifice Flanges
• Spectacle Blind Flanges

Duplex Steel Flanges Specifications

The table below covers the complete technical specifications for duplex steel flanges, from material standards and dimensional norms to pressure ratings and corrosion performance.

Duplex Steel Flanges Size Chart

The following size chart lists dimensional data for duplex steel flanges from 1/2" to 24" NPS, referenced to the ANSI/ASME B16.5 Class 150 raised face configuration.

Schedule Chart Of Duplex Steel Flanges

The pressure-temperature rating table below shows allowable working pressures (in psi) for duplex steel flanges from Class 150 to Class 2500 across the full temperature service range.

Key Features Of Duplex Steel Flanges

Duplex steel flanges offer 9 performance advantages that make these the preferred choice for demanding piping applications across multiple industries.

• High Strength
• Corrosion Resistance
• Good Ductility and Toughness
• High Abrasion Resistance
• Low Thermal Expansion
• Good Weldability
• Stress Corrosion Cracking (SCC) Resistance
• Fatigue Strength
• Cost-Effectiveness

Applications Of Duplex Steel Flanges

Duplex steel flanges are specified across 7 major industries where corrosion resistance, mechanical strength, and long service life are non-negotiable.

• Oil and Gas Industry
• Marine Engineering
• Power Generation
• Pulp and Paper Industry
• Desalination Plants
• Construction Industry
• Chemical and Petrochemical Processing

How To Choose The Right Duplex Steel Flange Supplier And Manufacturer?

Selecting the right supplier of duplex steel flanges directly impacts project timeliness, compliance, and long-term operational reliability. Before finalising the purchase decision, evaluate each possible manufacturer based on four important factors.

Choosing the Right Supplier and Manufacturer

Make sure the manufacturer’s flanges meet ASTM A182 / ASME SA182 standards. A verified production plant with integrated forging capabilities significantly reduces lead times and quality concerns.

Technical Considerations

Make sure that the manufacturer of the duplex steel flange can provide the correct grade (F51 or F60), size, and pressure. On ordering, obtain material test certificates according to the EN 10204 3.1/3.2 standard.

Evaluating Supplier Credibility

Look for the ISO 9001, NACE, and PED-certified supplier. Refer to the previous projects in the oil and gas industries or the marine industries, which are significant credibility factors.

Procurement Strategy

For high-volume orders, negotiate a price based on overall weight rather than each piece. Suppliers and manufacturers listed on Piping Mart provide mill test certifications, third-party inspection services, and low duplex steel flange rates for both spot and scheduled deliveries.