Duplex Steel Flanges

Duplex Steel Flanges Supplier in Mumbai, India

Nicorex Alloys is an ISO 9001 and ISO 14001 certified importer, stockist, and supplier of duplex steel flanges in Mumbai, India. We stock Duplex 2205 flanges in grades F51 (UNS S31803) and F60 (UNS S32205) under ASTM A182 / ASME SA182. All shipments carry EN 10204/3.1 mill test certificates.

Duplex stainless steel flanges are a type of forged piping component consisting of a two-phase stainless steel matrix, having equal amounts of ferrite and austenite. The composition of the alloy is 22% chromium, 3% molybdenum, 5-6% nickel, and nitrogen. These flanges have a yield strength approximately twice that of 316L stainless steel, i.e., 450 MPa vs. 220 MPa. These flanges have superior resistance to pitting and cracking. PREN is about 35. They comply with NACE MR0175 / ISO 15156.

We stock a wide range of Duplex Steel Flanges in multiple grades, including:

Duplex Steel Flanges Specifications

The table that can be found below contains all of the information that you need to know about duplex steel flanges.

Specifications	ASTM A182 / ASME SA182
Standards	ANSI/ASME B16.5, B16.47, B16.48, MSS SP-44, EN-1092, DIN 2633/2635
Grades	F51 (UNS S31803, 1.4462), F60 (UNS S32205, 1.4462)
Pressure Classes	150# to 2500#, PN6 to PN64
Size Range	1/2″ to 48″ NB (DN15 to DN1200)
Face Types	RF, FF, RTJ, LJF, Tongue & Groove
Types	Weld Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint, Long Weld Neck, Spectacle Blind, Orifice, RTJ, Reducing

What are Duplex Steel Flanges?

ASTM A182 duplex steel flanges are forged components forming leak-proof joints. It’s a dual-phase structure. With 22% chromium and a boost of nitrogen, these pipes stay rock-solid even when the internal pressure increases. UNS S32205 (F60) is the refined version of S31803 (F51), endorsed in 1996 for better corrosion performance. These flanges are forged at 1100 to 1150°C and solution annealed at 1020 to 1100°C with water quench. Duplex 2205 is typically used up to approximately 315°C due to the risk of sigma phase formation at elevated temperatures. Lower temperature service depends on impact testing requirements as per ASTM A182.

Types of Duplex Stainless Steel Flanges

Duplex steel flanges come in all standard types per ANSI/ASME B16.5 in F51 and F60.

Duplex Steel Weld Neck Flange (WNRF)

Duplex Steel Blind Flange (BLRF)

DSS Slip-On Flange (SORF)

Duplex Socket Weld Flanges

Duplex Steel Threaded Flange

Duplex Steel Orifice Flange

Duplex SS Lap Joint Flange

Duplex 2205 Spectacle Blind Flange

Duplex Steel Ring Type Joint Flange (RTJ)

Duplex Steel Reducing Flange

Duplex Long Weld Neck Flange

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Available Grades of Duplex Steel Flanges

Explore our range of Duplex Steel Flanges, manufactured in various grades to meet your specific industrial requirements.

Industries and Applications of Duplex Steel Flanges

The following are the industrial applications for duplex steel flanges:

Oil and Gas: Pressure vessel flanges, sour gas piping (NACE), and subsea connections.
Chemical and Petrochemical: Reactor vessel and acid handling piping for sulfuric and phosphoric acid service.
Marine and Offshore: Seawater system flanges and fire main connections.
Desalination: RO system piping and brine handling in chloride-rich environments.
Pulp, Paper, and Food Processing: Digestor piping and bleach plant connections.
Pulp, Paper, and Food Processing: Digestor piping and bleach plant connections.
Power Generation: Cooling water and FGD system flanges.

Frequently Asked Questions

What is the maximum service temperature for duplex flanges?

Duplex 2205 flanges have a working temperature range of -50°C to 315°C. However, if the temperature exceeds the above range, the formation of the sigma phase occurs, which makes the steel less tough. It also reduces the corrosion resistance of the steel.

Are duplex steel flanges NACE MR0175 compliant?

Yes. Duplex 2205 flanges in the solution-annealed condition comply with NACE MR0175 / ISO 15156 for sour gas service.

How does duplex 2205 yield strength compare with 316L?

Duplex 2205 has a minimum yield of 450 MPa, about double the 220 MPa of 316L. This allows thinner sections at the same pressure rating, saving 30 to 50% in weight.

What welding filler metals are used for duplex flanges?

For TIG/MIG welding, you need ER2209 filler wire and E2209 electrodes for SMAW. The heat input should be between 0.5 and 2.5 kJ/mm, and the temperature between passes should be below 150°C.