2205 Duplex Stainless Steel Pipe: Applications & Advantages

2205 duplex stainless steel pipe is a strong and corrosion-resistant material, useful in many piping systems. It has high mechanical strength, good fabrication, and favorable physical properties.

And because of these qualities, many industries rely on 2205 duplex. These include offshore oil and gas, chemical plants, and marine systems. It performs well in seawater, where many other steels fail. And compared to 316L stainless steel, it has nearly twice the yield strength and strong resistance to corrosion caused by chlorides.

However, no material fits every situation. The performance of 2205 steel depends on how and where you use it. So, knowing its strengths and limits helps you match it with the right use case and avoid problems over time.

What is 2205 Duplex Stainless Steel?

2205 duplex stainless steel is a dual-phase alloy that contains 50% ferrite and 50% austenite. Unlike 300 series stainless steel, this material is strong and resists corrosion easily. So, you can use it in harsh environments such as marine, oil, and gas.

But note that you will find 2205 in two specifications. First is S31803, which is the original grade. Then there’s the S32205, which has tighter controls on chromium, molybdenum, and nitrogen content. So, S32205 is an improved version of the S31803, hence it gives you better performance.

Speaking of chemical composition, 2205 duplex contains a number of elements. The most popular ones are shown in the table below:

These elements work together to exceed single-phase microstructure capabilities. For example, the 22% chromium is responsible for general corrosion resistance, while 3% molybdenum resists pitting. Other elements like nickel percentage stabilize the austenitic phase, while nitrogen optimizes the ferritic-austenitic balance.

What are the Mechanical Properties of 2205 Duplex Steel Pipe?

2205 duplex has impressive mechanical properties. That includes high toughness, yield strength, and tensile strength, all of which make it work well in hard and demanding setups.

• Tensile strength: Duplex 2205 has tensile strength that ranges from 620-655 MPa (90-95 ksi). This is high tensile enough to allow thinner walls while still handling operating pressure safely.
• Yield strength: 2205 grade stainless steel offers a 0.2% offset yield strength, which meets the minimum specifications of 450 MPa (65 ksi). That’s approximately twice the yield strength of 316L at 170 MPa. So, it provides great structural performance to your components.
• Elongation: The 2205 duplex has an elongation value exceeding 25% in a 50mm gauge length. While it’s lower than 40% in austenitic grades, it is good enough with a high degree of ductility. Thus, you can bet on the materials for safe structural and piping applications.
• Hardness: The 2205 duplex features hardness levels of up to 293 HB (Brinell) or 32 HRC (Rockwell C). That way, it is easy to machine and offers exceptional wear resistance.
• Corrosion resistance: Unlike 316L, 2205 duplex offers great resistance to pitting, stress corrosion, and crevice corrosion. Hence, that’s why you can use it in marine, oil, and gas, without worrying about corrosion.
• Impact toughness: At room temperatures, 2205 exhibits high impact toughness exceeding 100 J (Charpy V-notch). That means your component won’t fracture easily. It also offers good, stable toughness at temperatures around -50°C (-58°F), so you can use it for cryogenic applications.

What are the Main Applications of 2205 Duplex Steel Pipe?

2205 duplex stainless steel is useful in many industries, including oil and gas, chemical processing, marine, and others. Here’s how you can use the metal in each of these sectors:

1) Oil & Gas Industry

The offshore oil and gas sector leads the list of industries that depend most on 2205 duplex pipe. You can use the material for various jobs, such as produced water handling, seawater injection, and chemical injection lines. This is because 2205 can resist chloride stress corrosion cracking in seawater as well as withstand high mechanical loads.

As if that’s not enough, you can also use 2205 for subsea flowlines and risers in shallow water. Plus, in sour gas service with hydrogen sulfide, it performs well because of its resistance to sulfide stress cracking, as per the NACE MR0175 / ISO 15156-1 limits.

2) Chemical Processing

In chemical processing plants, you will find 2205 in storage tank connections, heat exchanger tubes, and pressure vessel nozzles. This is because the metal can withstand harsh conditions such as organic acids, chloride solutions, and oxidizing environments like acetic and phosphoric acids.

In pressure vessels, you can make thinner wall designs due to the duplex 2205 high-yield strength. And as a result, it cuts material use and fabrication time while avoiding the stress corrosion cracking that often affects 304L and 316L in chloride service.

3) Marine & Offshore

If you're into shipbuilding, you can use 2205 duplex steel for seawater cooling systems, ballast lines, and fire suppression systems. That way, the component lasts longer, since 2205 does not corrode in stagnant seawater.

Likewise, you can use 2205 for high-pressure reverse osmosis feed piping in desalination plants. That is because the metal can withstand both high chloride content, temperature, and mechanical stress.

4) Pulp & Paper Industry

2205 duplex can withstand chloride effects to prevent stress corrosion cracking. So, you can use it in the pulp and paper industry for bleaching operations.

Also, if your bleach plant operation involves sodium hypochlorite or chlorine dioxide, the material becomes handy. That’s unlike austenitic grades, which can experience premature pitting failures.

5) Other Industries

You can use stainless steel 2205 in many other industries that demand cleanliness and strong corrosion resistance. That includes:

• Food processing: You can use 2205 in brine lines and clean-in-place systems, since it resists corrosion, ensuring food hygiene.
• Pharmaceuticals: Duplex supports process piping that carries active ingredients in aggressive solvents. That way, you not only achieve hygienic standards but also enjoy great strengths.
• Pollution control: If you're into the pollution control industry, duplex 2205 is the cost-effective material to use. It performs well in equipment exposed to sulfuric acid and chloride-rich streams, ensuring they last longer.

What are the Limitations of 2205 Duplex Stainless Steel Pipe?

Like any other material, 2205 duplex also has its cons. First, it is only stable at temperatures of up to 300°C (572°F). That means if you expose it to heat for extended periods, sigma phase and chi phase form. As a result, it creates localized corrosion sites and makes the material brittle.

Secondly, low temperatures below -50°C bring different problems. If you work with the material at such low temperatures, the ferritic phase goes through a ductile-to-brittle transition. That phenomenon drops its impact toughness and raises the risk of brittle fracture when shock loads occur.

Another disadvantage of 2205 duplex is that it requires you to be more careful when fabricating, unlike austenitic grades. Otherwise, poor cold bending will increase springback and limit how much you can form the material before annealing.

Also, machining 2205 typically runs about 20% slower than 316L. That means your tool wears faster. So you need carbide or ceramic cutting inserts with wear-resistant coatings to keep production costs reasonable.

Lastly, welding demands tighter controls. In short, you have to use nitrogen-containing filler metals like ER2209 to keep the ferrite-austenite phases balanced and prevent too much ferrite from forming in the weld.

Frequently Asked Questions

Is 2205 duplex steel pipe cost-effective?

2205 duplex can save you money over time. For example, you can design thinner walls since the material offers high strength, which in turn reduces material and installation costs. At the same time, the ability to resist corrosion means you can use the pipe for a long time with less cost to maintain.

What is the difference between 2205 and 316 stainless steel pipe?

The 2205 and 316 differ mainly in how each material performs. The 2205 duplex steel pipe gives you nearly twice the strength of 316. Also, you get better resistance to chloride stress corrosion, which allows you to use it in corrosive setups.

316 steel pipe, on the flip side, offers you greater ductility and handles higher temperatures more reliably. So it works well for applications where corrosion exposure is moderate, and flexibility is important.

Can 2205 duplex pipe be welded?

Yes, you can weld 2205 duplex as long as you use the correct filler metal, such as ER2209. But also, you should control heat input and shield the molten weld. And by doing so, the weld remains strong and resists corrosion as the base material.

How much does 2205 duplex steel pipe cost?

2205 duplex will cost you 1.5 to 2 times more than a similar 316L pipe by weight. The actual prices vary with market conditions, order size, dimensions, and supplier. So, consider reaching out to your supplier for an exact price quote.

Conclusion

2205 duplex stainless steel pipe offers you stronger performance and better corrosion resistance than austenitic steels. It even offers you nearly twice the yield strength of 316L. So, you can use thinner walls and still meet performance requirements, which lowers material costs and system weight.

As if that is not enough, you enjoy superior chloride stress corrosion cracking and pitting resistance. So, whether you're installing offshore infrastructure, seawater systems, and chemical processing equipment, using 2205 provides durable service.

However, you must ensure you buy the materials from a reliable supplier for guaranteed performance, thanks to Voyagemetal. We ensure material traceability, proper heat treatment, and compliance with ASTM, ASME, or EN standards.