Duplex 2205 (UNS S32205 / S31803 / F60) – The Industry Standard Duplex Stainless Steel

Short Description:

Duplex 2205 (UNS S32205 / S31803 / F60 / W.Nr. 1.4462) is the most widely used duplex stainless steel grade, offering an exceptional combination of high strength and excellent corrosion resistance. Womic Steel supplies Duplex 2205 in multiple product forms including seamless pipe, welded pipe, steel bar, steel plate, steel coil, strip, flanges, fittings, forgings, and valves for chemical processing, marine engineering, oil and gas, desalination, and structural applications worldwide.

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Product Description

Duplex 2205 is the industry standard duplex stainless steel, featuring a balanced ferritic-austenitic microstructure with approximately 50% ferrite and 50% austenite . This dual-phase structure provides approximately twice the yield strength of 316L stainless steel (450 MPa vs 220 MPa) while delivering superior resistance to chloride stress corrosion cracking, pitting, and crevice corrosion . The enhanced chemistry of UNS S32205 provides tighter control on molybdenum and nitrogen, ensuring PREN ≥ 36 for reliable performance in demanding chloride environments .

Key characteristics include:

High strength – approximately twice that of 316L stainless steel

Excellent corrosion resistance – PREN ≥ 36

Superior chloride stress corrosion cracking resistance

Good weldability with proper procedures and filler metals

Cost-effective alternative to nickel alloys

Wide operating temperature range from -50°C to 300°C

Industry standard for chemical tankers and offshore platforms

Chemical Composition

Element	UNS S31803	UNS S32205 (F60)	Role
Chromium (Cr)	21.0 – 23.0	22.0 – 23.0	Oxidation resistance, corrosion resistance
Nickel (Ni)	4.5 – 6.5	4.5 – 6.5	Austenite stabilizer, corrosion resistance
Molybdenum (Mo)	2.5 – 3.5	3.0 – 3.5	Pitting and crevice corrosion resistance
Nitrogen (N)	0.08 – 0.20	0.14 – 0.20	Austenite stabilizer, strengthening
Carbon (C)	≤ 0.030	≤ 0.030	Controlled for weldability
Manganese (Mn)	≤ 2.00	≤ 2.00	Deoxidizer
Silicon (Si)	≤ 1.00	≤ 1.00	Deoxidizer
Phosphorus (P)	≤ 0.030	≤ 0.030	Impurity control
Sulfur (S)	≤ 0.020	≤ 0.020	Impurity control
Iron (Fe)	Balance	Balance	Base element

Room Temperature Properties (Solution Annealed)

Property	Value
Tensile Strength	≥ 620 MPa (90 ksi)
Yield Strength (0.2% Offset)	≥ 450 MPa (65 ksi)
Elongation	≥ 25%
Hardness	≤ 290 HB
Density	7.80 g/cm³
PREN (S32205)	≥ 36
Critical Pitting Temperature (CPT)	≥ 50°C

Impact Properties (Typical)

Temperature	Impact Energy (Longitudinal)
Room Temperature	≥ 100 J
-40°C	≥ 50 J
-50°C	≥ 27 J

Key Advantages of Duplex 2205

Industry Standard Duplex Grade – Duplex 2205 is the most widely used duplex stainless steel grade, recognized globally as the benchmark for duplex performance. Its combination of properties has made it the material of choice for chemical tankers, offshore platforms, and critical process equipment in chloride environments.

High Strength – Duplex 2205 offers approximately twice the yield strength of 316L stainless steel, allowing designers to specify thinner wall sections and reduce overall weight. This strength advantage translates to significant weight savings in structural applications and reduced material costs in pressure vessel design.

Superior Chloride Stress Corrosion Cracking Resistance – The ferritic-austenitic microstructure provides outstanding resistance to chloride stress corrosion cracking (SCC) – a common failure mode for 304 and 316 stainless steels in marine and chemical environments. This makes Duplex 2205 the preferred choice for seawater systems and chloride-containing process streams.

Excellent Pitting and Crevice Corrosion Resistance – With PREN ≥ 36, Duplex 2205 offers excellent resistance to pitting and crevice corrosion in chloride environments. This is significantly better than 316L (PREN ~25) and comparable to many higher-alloyed materials.

Good Weldability – Duplex 2205 can be welded using standard techniques (GTAW, GMAW, SMAW, SAW) with appropriate filler metals (typically ER2209). Proper heat input control and interpass temperature management are essential to maintain the correct ferrite-austenite balance in the weld zone. The alloy is also weldable without preheat for most thicknesses.

Cost-Effective – Duplex 2205 offers an excellent balance of performance and price, providing corrosion resistance approaching that of nickel alloys at a significantly lower cost. This makes it an attractive alternative to 316L in demanding environments and to nickel alloys in moderate chloride service.

Good Fabricability – The alloy can be readily formed, machined, and fabricated using standard techniques. It has good hot and cold workability, though its high strength requires more powerful equipment for forming and shearing.

Available Product Forms from Womic Steel

Seamless Pipe & Seamless Tube

Outside Diameter: 6mm – 350mm (1/4" – 14")

Wall Thickness: 1mm – 40mm (Schedule 5S to XXS)

Length: Up to 12m

Standards: ASTM A790, ASTM A789, ASME SA-790

Applications: Heat exchanger tubes, process piping, seawater systems, chemical tanker cargo piping, oil and gas flowlines

Keywords: Duplex 2205 seamless pipe, UNS S32205 tube, F60 pipe, 1.4462 seamless tube, SAF 2205 pipe

Welded Pipe

Outside Diameter: 50mm – 1200mm (2" – 48")

Wall Thickness: 1.0mm – 25mm

Standards: ASTM A790, ASTM A928, ASME SA-790

Applications: Large-diameter process piping, structural applications, marine platform systems, desalination piping

Keywords: Duplex 2205 welded pipe, F60 ERW pipe, 2205 large diameter pipe

Steel Bar (Round, Square, Flat, Hex)

Diameter: 6mm – 500mm

Surface: Hot rolled, Bright (cold drawn), Ground, Turned, Peeled

Standards: ASTM A276, ASTM A479, ASME SA-479

Applications: Valve stems, fasteners, shafts, pumps, machining stock, fittings, flanges

Keywords: Duplex 2205 round bar, F60 bar stock, S32205 bar, 2205 stainless steel bar

Steel Plate & Sheet

Thickness: 1mm – 100mm

Width: Up to 3000mm

Length: Up to 12000mm

Standards: ASTM A240, ASME SA-240

Applications: Vessel shells, heat exchanger plates, structural components, flange blanks, chemical tanker cargo tank linings

Keywords: Duplex 2205 plate, F60 sheet, S32205 plate, 2205 stainless steel plate

Steel Coil & Strip

Thickness: 0.5mm – 6.0mm

Width: 10mm – 1500mm

Weight: Up to 2,000kg per coil

Standards: ASTM A240

Applications: Formed components, bellows, expansion joints, stampings, thin-walled tubing

Keywords: Duplex 2205 coil, F60 strip, 2205 coil

Flanges & Pipe Fittings

Types: Weld Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint

Sizes: 1/2" – 48" (DN15 – DN1200)

Pressure Rating: Class 150 – Class 2500

Standards: ASTM A182, ASME SA-182, ASME B16.5, ASME B16.47

Fittings: Elbows (90°, 45°), Tees, Reducers, Caps, Stub Ends, Couplings

Keywords: Duplex 2205 flanges, F60 weld neck flange, 2205 pipe fittings

Forgings

Types: Rings, disks, shafts, valve bodies, pump parts, custom geometries

Weight: Up to 5,000kg per piece

Standards: ASTM A182, ASME SA-182

Applications: High-strength structural components, valve bodies, flanges, custom engineered parts

Keywords: Duplex 2205 forging, F60 ring, 2205 forged block

Duplex 2205 Valves

Types: Ball valves, Gate valves, Globe valves, Check valves, Plug valves

Sizes: 1/2" – 24" (DN15 – DN600)

Pressure Rating: Class 150 – Class 2500

Temperature Range: -50°C to +300°C

Design Standards: API 608, API 6D, ASME B16.34

Seating: Stellite hardfaced, RPTFE, PEEK, PCTFE (cryogenic)

Actuation: Manual, Pneumatic, Electric

Applications: Seawater isolation, chemical process control, oil and gas manifolds, desalination plants

Keywords: Duplex 2205 ball valve, F60 gate valve, 2205 stainless steel valve

Duplex 2205 vs 316L Stainless Steel

Property	Duplex 2205 (F60)	316L
PREN	≥ 36	~25
Yield Strength	≥ 450 MPa	≥ 220 MPa
Tensile Strength	≥ 620 MPa	≥ 485 MPa
SCC Resistance	Excellent	Poor in chlorides
Pitting Resistance	Excellent	Moderate
Cost	Higher	Lower
Weight Savings	Up to 50% (thinner walls)	Standard
Seawater Service	Excellent	Limited
Chemical Tankers	Industry standard	Not recommended

Duplex 2205 vs Super Duplex 2507

Property	Duplex 2205 (F60)	Super Duplex 2507 (F53)
PREN	≥ 36	≥ 40
Yield Strength	≥ 450 MPa	≥ 550 MPa
Mo Content	3.0 – 3.5%	4.0 – 5.0%
N Content	0.14 – 0.20%	0.24 – 0.32%
CPT	≥ 50°C	≥ 80°C
Seawater Performance	Excellent	Superior
Cost	Moderate	Higher
Application	General chemical, marine, oil & gas	Extreme seawater, subsea, HPHT

Standards & Specifications

Product Form	ASTM Standard	ASME Standard
Seamless Pipe/Tube	ASTM A790, ASTM A789	ASME SA-790
Welded Pipe	ASTM A790, ASTM A928	ASME SA-790
Bar/Rod	ASTM A276, ASTM A479	ASME SA-479
Plate/Sheet/Strip	ASTM A240	ASME SA-240
Forgings	ASTM A182	ASME SA-182
UNS Designation (Preferred)	S32205 (F60)
UNS Designation (Original)	S31803
W.Nr.	1.4462
EN	1.4462

Applications of Duplex 2205

Chemical Tankers – Duplex 2205 is the industry standard material for chemical carrier cargo tanks, cargo piping, and associated equipment. Its combination of high strength, corrosion resistance, and weldability makes it ideal for transporting corrosive chemicals. Major shipyards including Hudong-Zhonghua and Wuchang Shipbuilding have delivered multiple chemical carriers utilizing Duplex 2205 cargo tank construction.

Offshore Oil and Gas – The alloy is used extensively in offshore platforms, subsea equipment, topside piping, and process modules. Its resistance to seawater corrosion and high strength make it ideal for North Sea and deepwater applications.

Seawater Systems – Duplex 2205 is widely used in seawater piping, firewater systems, ballast systems, and cooling water systems on ships, platforms, and coastal facilities. Its resistance to pitting and crevice corrosion ensures long service life in seawater environments.

Desalination Plants – The alloy is used in seawater intake systems, brine handling equipment, and evaporator tubes in desalination plants. Its resistance to chloride corrosion makes it suitable for high-temperature, high-salinity service.

Chemical Processing – Duplex 2205 is used in heat exchangers, reactors, distillation columns, piping systems, and storage tanks in chemical plants handling corrosive media.

Pulp and Paper – The alloy is used in digesters, bleaching equipment, and chemical recovery systems in pulp and paper mills.

Structural Applications – The high strength of Duplex 2205 makes it suitable for structural applications requiring corrosion resistance, such as offshore platform walkways and supports.

Frequently Asked Questions

Q: What is the difference between UNS S31803 and S32205?

A: UNS S32205 (F60) has tighter compositional controls on molybdenum (3.0-3.5% vs 2.5-3.5%) and nitrogen (0.14-0.20% vs 0.08-0.20%), providing improved corrosion resistance (PREN ≥ 36) and mechanical properties. S32205 is the preferred specification for Duplex 2205 in critical applications.

Q: Is Duplex 2205 suitable for seawater service?

A: Yes. With PREN ≥ 36, Duplex 2205 provides excellent resistance to pitting and crevice corrosion in seawater, making it suitable for seawater piping, firewater systems, and offshore equipment.

Q: Can Duplex 2205 be welded?

A: Yes. Duplex 2205 is readily weldable using GTAW, GMAW, SMAW, and SAW processes. Filler metal ER2209 is recommended. Control of heat input and interpass temperature is essential to maintain proper ferrite-austenite balance and corrosion resistance.

Q: What is the maximum service temperature for Duplex 2205?

A: The recommended maximum service temperature is 300°C (572°F). Above this temperature, the alloy is susceptible to embrittlement due to sigma phase precipitation. The minimum service temperature is approximately -50°C.

Q: What is the Chinese equivalent of Duplex 2205?

A: The Chinese equivalent is 022Cr22Ni5Mo3N (GB/T 20878). It is also commonly referenced by its UNS designations S32205 and S31803.

Q: What product forms are available for Duplex 2205?

A: Womic Steel supplies Duplex 2205 in seamless pipe, welded pipe, steel bar, steel plate, steel coil, strip, flanges, pipe fittings, forgings, and valves. Complete product specifications and size ranges are listed in the product availability section.

Contact Womic Steel

Website: www.womicsteel.com
E-mail: sales@womicsteel.com

Tel / WhatsApp / WeChat:

Victor: +86 15575100681

Jack: +86 18390957568

Womic Steel – Your reliable partner for Duplex 2205 (UNS S32205 / F60) seamless pipe, welded pipe, steel bar, steel plate, steel coil, flanges, fittings, forgings, and valves for chemical tankers, offshore platforms, seawater systems, desalination plants, and chemical processing applications worldwide. Full traceability, classification society certification, and EN 10204 Type 3.1/3.2 documentation available.

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