You must have observed stainless steel around you on a daily basis – it is a popular construction material due to its corrosion resistance and strength. However, it is not just one standard compound. You can get it in many types and grades, which makes buying stainless steel challenging if you do not have all the information.
Here, we introduce stainless steel 2205, or EN 1.4462, one of the most useful and strong grades of stainless steel.
What Is SS 2205?
This steel alloy is duplex stainless steel – it combines two different types of stainless steel, and its metallurgical structure has two phases. These types are austenitic and ferritic.
Austenitic stainless steel is common in many industries, and you make it by adding nickel, manganese, and nitrogen to your iron.
You can easily mold, bend, and weld this steel. It is also non-magnetic, and you can also harden them and increase their strength with heat treatment.
On the other hand, you have ferritic steel. This category consists of steels that are less weldable and hard but have excellent corrosion resistance. By composition, ferritic steels have a lower carbon percentage than iron content, so they’re called iron-based steels.
A duplex of austenitic and ferritic stainless steel will have both steels’ advantages. It will be of high strength and excellent corrosion resistance, making it ideal for infrastructure projects. Stainless steel 2205 is just one of the many duplex steel plates available.
The Components of SS 2205
This alloy’s composition varies from other steel types due to its duplex nature. It is an iron alloy, or mixture, of the following elements:
- 22-23% Chromium. This element provides corrosion resistance with the help of its oxide layer.
- 4.5% to 6.5% of Nickel: This is far less than other commonly used austenite steels like 304, which has 8-10% of nickel, or 316, which has 10-14% of nickel content. Nickel provides heat resistance to steel, which means stainless steel 2205 is unsuitable at higher temperatures.
- 3-3.5% of Molybdenum: This differentiates it from other steels and protects it from pitting and crevice corrosion. Most austenitic steels have little or no molybdenum content.
- A Maximum of 2% of Manganese: This provides it with hardness and strength.
- Less than 1% of Silicon: Silicon is a ferrite stabilizer and gives the steel its ferritic nature. It also improves the steel’s oxidation resistance.
- Maximum 0.03% of Carbon: This is low as compared to other austenitic steels like 304 and 316, which have a maximum carbon content of 0.08%. The low carbon content gives it its ferritic properties and prevents carbide precipitation.
- Around 0.08 to 0.2% of Nitrogen: This gives it high strength. Other austenitic steels have no nitrogen content, reducing their strength and toughness.
- Phosphorus and Sulfur content: Impurities that you need to keep as low as possible.
What Are the Advantages of Stainless Steel 2205?
The duplexes nature of this gives it the best qualities of both austenitic or ferritic steels:
Corrosion Resistance
SS 2205 has increased chromium content and includes molybdenum. This provides it excellent corrosion resistance – better than many other grades.
For example, this alloy can provide corrosion resistance in a chloride-rich environment. Otherwise, high chloride content stresses steel and cracks them in a process called stress corrosion cracking.
While no stainless steel is entirely resistant to chloride, SS 2205 offers good protection against it. It also resists pitting corrosion – circular burrows forming on the steel surface.
High Strength
The addition of nitrogen makes steel durable and tough. Stainless steel 2205 is one of the hardest steels, with a tensile strength of 650 to 880 MPa (94 to 128 ksi).
This toughness allows its use in structural applications where your focus is on mechanical strength and durability. So, you can use SS 2205 in infrastructural projects such as building bridges.
Weldability
Stainless steel 2205 is easy to weld. You can weld it using diverse techniques, including gas tungsten arc welding or gas metal arc welding.
This alloy has a lower thermal expansion coefficient, meaning it does not rapidly expand when heated and has high thermal conductivity. So, you don’t need to pre-heat when welding it.
A low expansion coefficient also reduces the risk of hot cracking, where cracks form due to extreme thermal expansion in a solidifying heated metal.
This grade of stainless steel has less carbon content, so it has a reduced risk of carbide precipitation when welding. Carbide precipitation can weaken the steel.
Cost-Effective
If you are low on budget, stainless steel 2205 is for you! It offers the perfect balance between performance and cost and is an economical choice of material. It is more expensive than many stainless steel grades but less expensive than high-performance ones.
SS 2205 Use-Cases
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Due to its excellent strength and high corrosion resistance, you can use SS 2205 in different industries, such as:
Oil and Gas Industry
You often use stainless steel 2205 to make oil rigs because it is sturdy and does not rust easily. Oil and gas pipelines contain valuable and flammable materials, so any deterioration is environmentally catastrophic. So, you need a strong material resistant to damage, like 2205 stainless steel, to construct oil and gas pipes. It can withstand the high pressure of oil and gas without getting damaged.
Chemical Processing Equipment
Chemical processing equipment, like tanks and heat exchangers, require durability. They also shouldn’t rust easily as the eroded compounds can interfere with the chemical processing. So, stainless steel 2205 is perfect for use in the chemical processing industry.
Marine Systems
This alloy has high-chloride environment resistance, which is helpful in oceans and seas. As it does not get cracked in stressful environments, it is perfect for use in shipbuilding and marine structures.
Pulp and Paper Industry
The paper manufacturing process utilizes chemicals like caustic soda and sulfite salts. Many of these can corrode the equipment. But as stainless steel 2205 is corrosion-resistant, you can use it in the paper industry equipment.
Structural Applications
When building bridges, buildings, and construction projects, your aim is durability and longevity. You aim to create structures that can last for centuries. Stainless steel 2205 is durable and perfect for constructing buildings and infrastructure projects like bridges.
Maintenance of Stainless Steel 2205 Products: A Handy Guide
While stainless steel 2205 is an excellent material, taking poor care of it can weaken and erode it. Ensure you follow these maintenance tips:
1. Clean It Properly
Clean your stainless steel 2205 product frequently to ensure it is not grimy and dirty. If your steel product gathers dust for a long time, it can cause corrosion.
Clean using a soft piece of cloth and a mild detergent or soap. Apply detergent to the surface, wipe it with a soft cloth or sponge, and clean it with hot water. Avoid abrasive cleaners like steel wool, as they can cause scratches.
2. Avoid Chloride-Rich Environment
Stainless steel 2205 is resistant to stress corrosion cracking that an environment rich in chloride causes. Still, no steel grade is entirely resistant to corrosion cracking, and if you store it in a high-chloride medium for no reason, it will have a shorter lifespan.
Avoid storing stainless steel 2205 beside compounds rich in chlorides, like bleach and salt water.
3. Avoid Contact with Copper or Iron
You should store stainless steel 2205 on a dry surface. Protect it from copper and iron, as they can cause galvanic corrosion.
Galvanic or bimetallic corrosion is when one metal starts corroding faster if exposed to a different metal in an electrolytic environment. When you place your stainless steel before copper or iron, it will start rusting in the right electrochemical conditions.
Limitations of Stainless Steel 2205
Despite its many benefits, stainless steel 2205 has some limitations:
1. Unsuitable at Very High Temperatures
As mentioned earlier, this grade of stainless steel contains less nickel content. As nickel provides heat resistance, stainless steel 2205 is less suitable at higher temperatures. You should not use it in environments with temperatures above 600 degrees Celsius.
2. Limited Machinability
Stainless steel 2205 has limited machinability, making cutting or molding it into different shapes hard. As it has a very high tensile strength and is incredibly hard, you require specialized and expensive tools to machine it according to your needs.
3. Hydrogen Embrittlement
Hydrogen embrittlement is a process where the metal becomes brittle when you expose it to hydrogen. Hydrogen atoms are minute and can easily insert themselves within the metallic structure. When this happens, your metal’s structural integrity is lost, and it can easily be cracked. So, you need to protect SS 2205 against it.
4. Unsuitable in Strong Acidic Environment
While stainless steel 2205 is highly corrosion resistant, continuous exposure to strong acids can damage it. While weak or mild acids don’t cause significant damage, continually exposing it to sulfuric acid or hydrochloric acid can cause pitting or crevice corrosion.
Endnote
SS 2205 is a high-performance grade; you can easily use it for multiple applications.
This alloy is very durable and corrosion-resistance. It can protect against even stress corrosion cracking in high-chloride environments like the marine environment. But it is not very machinable and is prone to hydrogen embrittlement. Make sure you study it extensively before making your choice.
Choose your stainless steel grade carefully according to your needs. If you need long-lasting steel for high-performance structural projects, consider 2205 stainless steel.
