Duplex 2205 / UNS S31803 & UNS S32205 / W.Nr. 1.4462

Duplex Steel 2205

Duplex Steel 2205

Duplex Steel 2205 is a duplex stainless steel that contains 40-50% ferrite in its annealed condition. Duplex 2205 provides a practical solution to chloride stress corrosion cracking problems, which are often encountered with traditional SS 304/304L or SS 316/316L stainless steels.

Thanks to its high chromium, molybdenum, and nitrogen content, Duplex Stainless Steel 2205 offers superior corrosion resistance compared to 316/316L and SS 317L stainless steels in most environments. However, it is not recommended for operating temperatures above 600°F.

2205 Duplex also boasts a higher design strength, making it possible for lighter wall construction in many cases. This steel has good notch impact toughness even in temperatures as low as -40°F. To ensure the best results, Duplex Steel 2205 should be welded using E2209 or ER2209 fillers.

Note: UNS S31803 is another designation for Duplex 2205 stainless steel. The UNS designation for S31803 is the same as S32205.

The key difference between UNS S31803 and UNS S32205 is the chemical composition. S32205 has a slightly higher content of chromium, molybdenum, and nitrogen than S31803. These differences result in slightly different mechanical and physical properties between the two alloys, such as increased resistance to stress corrosion cracking, improved strength and higher toughness in S32205.

2205 Duplex Steel Inventory

Product Form Size range from Size range to

2205 Duplex Steel pipe

0.5 in 8 in

2205 Duplex Steel tube

12 mm 260 mm

2205 Duplex Steel pipe fittings

0.5 in 8 in

2205 Duplex Steel flanges

0.5 in 8 in

Industries and Applications

2205 Duplex stainless steel is a versatile material with a wide range of industrial applications due to its exceptional strength, durability, and corrosion resistance. Stainless Steel Duplex 2205 offers the best of both worlds – the high strength of ferritic alloys and the ease of fabrication and corrosion resistance of austenitic alloys.

Some of the industries that utilize Duplex Steel 2205 include:

Oil and Gas: Duplex Stainless Steel 2205 is commonly used in the production of pipelines, platforms, and storage tanks in the oil and gas industry due to its exceptional resistance to corrosion from salt water and other harsh chemicals.

Chemical Processing: This steel is often used in chemical processing plants and storage tanks, as it offers exceptional resistance to harsh chemicals and high temperatures.

Paper and Pulp: 2205 Duplex is utilized in the paper and pulp industry for its excellent resistance to corrosion and high strength, making it a suitable choice for various applications, such as paper mills and processing equipment.

Mining: Stainless Steel Duplex 2205 is frequently used in the mining industry, as it offers high resistance to corrosion and abrasion, making it a reliable choice for various mining equipment and processing systems.

Marine: This steel is an ideal choice for marine applications due to its exceptional resistance to corrosion and high strength. It is often used in the construction of ships, offshore platforms, and marine infrastructure.

Resistance to Corrosion

Duplex Steel 2205 (also known as Stainless Steel Duplex 2205 or Duplex Stainless steel 2205), is renowned for its exceptional resistance to corrosion and its ability to withstand harsh environments. The high chromium, molybdenum and nitrogen content of Duplex 2205 make it highly resistant to pitting and crevice corrosion, as well as stress corrosion cracking.

This alloy is especially effective in corrosive environments that contain chloride ions, such as seawater, salt solutions and hydrochloric acid, making it an ideal choice for marine and offshore applications. Duplex 2205 is also highly resistant to intergranular corrosion, making it suitable for use in applications that require exposure to high temperatures.

In addition to its corrosion resistance, Duplex Steel 2205 also offers high strength and toughness, making it suitable for use in high-stress applications. Its high strength-to-weight ratio allows for lighter construction, and its good weldability makes it easy to fabricate and install.

Fabrication and Heat Treatment 

2205 Duplex is a versatile and easy-to-fabricate material that is ideal for use in a wide range of applications. This alloy has excellent welding properties, making it easy to join and fabricate, while its high strength and toughness make it suitable for use in high-stress applications.

In terms of fabrication, Duplex Steel 2205 can be processed using standard fabrication techniques for austenitic stainless steels, such as cutting, bending, forming, and welding. However, it is important to note that the high strength of this alloy requires greater care during fabrication to avoid cracking or deformation. Welding should be performed using appropriate filler metals, such as E2209 or ER2209, to ensure optimal results.

Heat treatment is an important aspect of the fabrication process for Duplex Steel 2205, as it can significantly affect the mechanical properties and corrosion resistance of the material. The most common heat treatment process for Duplex 2205 is solution annealing, which involves heating the material to a temperature of 1020-1100°C and then rapidly cooling it. This process helps to dissolve any precipitates that may form during fabrication and improve the mechanical properties of the material.

Duplex Steel 2205 – Applicable Specifications

Form ASTM ASME Other

Duplex Steel 2205 Sheet & Plate

A240 SA-240 EN 10088-2, EN 10088-3, NACE MR0175/ISO 15156

Duplex Steel 2205 Bar

A276 SA-276 EN 10088-3, NACE MR0175/ISO 15156

Duplex Steel 2205 Pipe

A790 SA-790 EN 10216-5, NACE MR0175/ISO 15156

Duplex Steel 2205 Fittings

A815 SA-815 EN 10253-3, EN 10253-4, NACE MR0175/ISO 15156

Duplex Steel 2205 Flange

A182 SA-182 EN 1092-1, NACE MR0175/ISO 15156

Duplex Steel 2205 Wire

A479 SA-479 N/A

Duplex Steel 2205 Fasteners

A479 SA-479 EN 1.4462, NACE MR0175/ISO 15156

Common Trade Names

Duplex 2205 is known by various trade names including Allegheny Ludlum’s LDX 2101, Outokumpu’s 2205, Sandvik’s SAF 2205, and NiDI’s LDX 2205. These trade names refer to the same duplex stainless steel alloy with similar chemical and mechanical properties.

Key Properties

(in annealed condition)

Property Alloy 2205
Tensile Strength (ksi) 85 min
Yield Strength (ksi) 44 min
Elongation 20% min
Hardness (HBW) 270 max


Chemical Composition (%)

Element Alloy 2205
Chromium 22.0 – 23.0
Nickel 4.5 – 6.5
Molybdenum 2.5 – 3.5
Manganese 1.0 – 2.0
Silicon 1.0 max
Nitrogen 0.10 – 0.20
Carbon 0.03 max
Phosphorus 0.03 max
Sulfur 0.03 max

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