ThePipingMart Blog Grades UNS S31803 Duplex Steel (2205) – Composition, Properties, and Uses

UNS S31803 Duplex Steel (2205) – Composition, Properties, and Uses

Duplex Steel UNS S31803

Duplex Steel UNS S31803 is a stainless steel alloy with many beneficial properties. It comprises two phases, austenitic and ferritic, combined to give it its excellent strength and ductility. This makes it ideal for applications requiring maximum corrosion resistance and mechanical strength, such as in the oil & gas industry or marine engineering. Let’s examine the benefits and uses of Duplex Steel UNS S31803.

What Forms is Duplex Steel S31803 Available at Piping Mart?

  • Duplex Steel S31803 Pipes
  • Duplex Steel S31803 Tubing
  • Duplex Steel S31803 Pipe Fittings
  • Duplex Steel S31803 Bolts
  • Duplex Steel S31803 Forged Fittings
  • Duplex Steel S31803 Plates
  • Duplex Steel S31803 Valves
  • Duplex Steel S31803 Flanges
  • Duplex Steel S31803 Bars
  • Duplex Steel S31803 Nuts
  • Duplex Steel S31803 Fasteners
  • Duplex Steel S31803 Screw
  • Duplex Steel S31803 Wahser

UNS S31803 Chemical Composition

Duplex Steel UNS S31803 is a key alloy in the growing steel industry. It is composed of 22% chromium, 3% molybdenum, 5-6.5% nickel, and trace amounts of other elements such as manganese, nitrogen, phosphorus, silicon, and sulfuric acid.

Element Content (%)
Iron, Fe 63.75-71.92
Chromium, Cr 21.0-23.0
Nickel, Ni 4.50-6.50
Molybdenum, Mo 2.50-3.50
Manganese, Mn 2.0
Silicon, Si 1.0
Nitrogen, N 0.080-0.20
Carbon, C 0.030
Phosphorous, P 0.030
Sulfur, S 0.020

UNS S31803 Physical Properties

UNS S31803 Duplex Steel is a highly durable, corrosion-resistant metal material with a reputation spanning centuries of use in industrial and commercial applications. It is known for its impressive tensile strength, high thermal conductivity and outstanding formability. In addition to its physical properties, UNS S31803 also provides excellent resistance to oxidation at extreme temperatures and pitting corrosion in natural environments. The combination of these traits and the availability in sheet, plate or bar make this metal an ideal choice for applications requiring excellent durability and corrosion resistance, even where operating conditions vary drastically.

Physical Property Value
Density 7.805 g/cm³
Thermal Expansion 13.7 x10^-6 /K
Modulus of Elasticity 200 GPa
Thermal Conductivity 19.0 W/m.K

UNS S31803 Chemical Properties

This stainless steel alloy has an impressive chemical makeup thanks to its combination of austenite and ferrite phases. It typically contains 21%-23% chromium, 4%-6% nickel, 2%-3% molybdenum, 1%-2% manganese, 0.8%-1.2% nitrogen, 0.-0.3% sulfur, 0.-0.04 % carbon and 62-72 KSI tensile strength with a hardness between 25-35 HRC (Rockwell C Hardness). These characteristics make it highly resistant to corrosion from acids like sulfuric acid and chlorides such as sodium chloride or seawater exposure. Additionally, its high chromium content helps protect against oxidation from high temperatures up to 925°C (1700°F).

UNS S31803 Mechanical Properties

2205 Duplex Steel has impressive mechanical strength, which can be attributed to its two phases; one phase—austenite—provides superior ductility while the other—ferrite—supplies superior strength for excellent resistance against shock loading or cyclic loading conditions that could cause deformation or fracture failure over time. Its modulus of elasticity ranges from 30-45 GPA depending on temperature, while its yield strength ranges from 225-475 MPa depending on temperature (MPa stands for megapascals). Additionally, this alloy boasts excellent fatigue behaviour due to its low coefficient of thermal expansion, which means there will be minimal distortion during welding or machining operations, making it ideal for components that need tight tolerance control even under extreme temperatures or pressure changes in their environments such as those found in the industrial sector or aerospace industry applications.

Properties Metric Imperial
Tensile strength at break 621 MPa 90000 psi
Yield strength (@strain 0.200 %) 448 MPa 65000 psi
Elongation at break (in 50 mm) 25.0 % 25.0 %
Hardness, Brinell 293 293
Hardness, Rockwell c 31.0 31.0

UNS S31803 Thermal Properties

The thermal properties of grade 2205 stainless steel are given in the following table.

Properties Metric Imperial
Thermal expansion coefficient (@20-100°C/68-212°F) 13.7 µm/m°C 7.60 µin/in°F

UNS S31803 Specifications

1.4462 BS EN 10088-3 ASTM A182 F51 X2CrNiMoN22-5-3

UNS S31803 Uses

UNS S31803 is an alloyed stainless steel with a higher chromium and nickel content than the conventional austenitic grades. This blend makes it exceptionally corrosion-resistant and the material of choice for various applications involving chemically aggressive or saline environments. It can be used in submarine sculptures, piping systems, valves and pumps, chemical industries, offshore platforms, and more. Its unique composition of high mechanical strength and corrosion resistance has made it an ideal solution for manufacturers seeking reliable products capable of performing for a long period.

Chemical Processing Equipment

Duplex Steel S31803 is an austenitic-ferritic stainless steel alloy highly resistant to corrosion and abrasion. It is often used to construct chemical processing equipment, such as tanks, pumps, valves, and piping systems. The alloy’s high strength and corrosion resistance make it ideal for harsh environments where exposure to corrosive chemicals or extreme temperatures is likely.

Oil and Gas Industry

ASTM S31803 is also widely used in the oil and gas industry due to its excellent corrosion resistance properties. It can be used for various applications, including pipeline components, offshore platforms, storage tanks, and pressure vessels. The alloy’s high strength makes it suitable for high-pressure applications where other materials may fail.

Desalination Plants

Duplex Steel 2205 is often used in the construction of desalination plants due to its superior corrosion resistance properties when exposed to saltwater. The alloy’s excellent mechanical properties make it suitable for use in components such as pumps, valves, pipes, heat exchangers, and storage tanks regularly exposed to saltwater.

Marine Applications

Due to its excellent corrosion resistance when exposed to seawater, Duplex Steel 2205 is often used in marine applications such as shipbuilding and offshore structures. The alloy’s superior mechanical properties make it suitable for use in components such as propellers, rudders, shafts, hull plating, mooring systems, and deck hardware exposed to the harsh conditions found at sea.

Heat Exchangers

Due to its excellent thermal conductivity properties, Duplex 2205 can also be used to construct heat exchangers. The alloy’s superior strength allows it to withstand extremely high temperatures without suffering from creep or deformation over time, making it ideal for use in applications where temperature fluctuations are frequent or extreme temperatures are reached regularly.

UNS S31803 Equivalent

  • ASTM A182 Grade F51
  • ASTM A240
  • ASTM A789
  • ASTM A790
  • DIN 1.4462
  • 2205
  • EN 1.4462Z
  • UNS S31803
  • UNS S32205
  • BS 318S13
  • 318

 UNS S31803 Welding

When welding this 1.4462 alloy, it is important to consider the composition of the material being joined. Since Duplex Steel UNS S31803 contains both austenitic and ferritic phases, special care must be taken when welding to prevent cracking or burn-through on the edges. Preheating to about 300°C (572°F) before welding is recommended to reduce residual stress after cooling.

UNS S31803 Corrosion Resistance

Duplex Steel UNS S31803 is highly resistant to corrosion and, therefore, greatly benefits industries dealing with aggressive and corrosive chemicals. This steel alloy features an austenitic-ferritic chrome nickel composition, resulting in a highly stable and durable compound. In addition, this versatile stainless steel makes low-temperature hardening possible, making it well-suited for use in exposed environments such as coastal regions and marine structures. As an extra layer of protection against corrosivity, UNS S31803 Steel also has excellent welding characteristics. With these features, this alloy provides long-term peace of mind when dealing with challenging environmental factors.

UNS S31803 Heat Resistance

Duplex Steel UNS S31803 is a heat-resistant variety of duplex stainless steel whose resistance to heat makes it an ideal choice for a wide range of industrial applications. This type of steel can withstand temperatures as high as 900°C, making it appropriate for use in extremely hot environments. Its excellent oxidation and corrosion resistance also means that Duplex Steel 1.4462 can be used in highly corrosive environments, further expanding the range of possible applications. Its strong mechanical properties can result in a long and reliable service life even at extreme temperatures, giving businesses the best value for their money.

UNS S31803 Heat Treatment

1.4462 duplex steel is known for its strength and corrosion resistance, so selecting the right heat treatment is important. Normalizing heat treatment works well on UNS S31803 steel, ensuring increased toughness while maintaining its superior mechanical properties. To ensure that it meets specific requirements such as good creep rupture strength, a solution annealing should be done between 1050°C – 1150°C then cooling very rapidly to obtain maximum benefits. Although these treatments are recommended for this type of steel, it’s important to conduct experiments and tests at the user’s risk to find the most suitable settings everywhere.

UNS S31803 Machining

Duplex steel UNS S31803 machining is an important process to create components and unique shapes from raw duplex steel. It consists of turning, drilling, milling, broaching, grinding, and hobbing to accurately shape the material into the desired form. Despite difficulties in machining due to its high mechanical strength and toughness, duplex steel UNS S31803 provides a highly effective solution for various industrial applications due to its excellent corrosion resistance and strength at extreme temperatures. For machinery used in industries ranging from pharmaceutical to oil & gas development and maritime operations, the properties offered by this alloy make it an ideal choice for many projects.


In conclusion, Duplex Steel Material is an incredibly versatile stainless steel alloy that offers numerous benefits due to its combination of austenitic and ferritic phases, which gives it exceptional mechanical properties such as tensile strength and ductility as well as excellent corrosion resistance against acidic solutions like sulfuric acid or chlorides like sodium chloride or seawater exposure along with superior heat resistance up to 925°C (1700°F). Its impressive chemical composition also makes it capable of machining operations with tight tolerance control requirements even under extreme temperatures or pressure changes. It is highly sought after by industries like oil & gas production facilities where maximum performance is required even under harsh conditions. With all these advantages rolled into one package, there’s no wonder why so many industries have adopted Duplex Steel UNS S31803 for their applications!

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