Comprehensive Analysis of Duplex Stainless Steel 2205
High performance materials suitable for multiple fields
Duplex stainless steel 2205 (UNS S32205) is an advanced material that combines austenitic and ferritic dual-phase structures. With its high strength, corrosion resistance, and versatility in multiple fields, it has become a key material in modern industry surely.
This article will conduct a systematic analysis of duplex stainless steel 2205 from the major aspects of chemical composition to application industries.
Chemical composition of duplex 2205 stainless steel
The chemical composition of duplex stainless steel 2205 has been carefully designed, and its core elements include:
Chromium (Cr): 22.0-23.0% – enhances oxidation resistance and passivation film stability
Molybdenum (Mo): 3.0-3.5% – improves resistance to pitting and crevice corrosion
Nickel (Ni): 4.5-6.5% – balanced austenite phase ratio, optimized toughness
Nitrogen (N): 0.14-0.20% – inhibits the precipitation of harmful metal phases and enhances strength
Other elements such as carbon (C ≤ 0.03%) and manganese (Mn ≤ 2.0%) are strictly controlled at low levels to ensure material purity.
Its unique dual phase structure (approximately 50% austenite+50% ferrite). And this is formed through solution annealing process (1040-1080 ℃), which combines the toughness of austenite with the corrosion resistance of ferrite.
Physical and mechanical properties of duplex 2205 stainless steel
Strength and toughness
Tensile strength: ≥ 620 MPa, yield strength ≥ 450 MPa, twice that of ordinary austenitic stainless steel (such as 316L), significantly reducing structural weight. Elongation rate ≥ 25%, maintaining good toughness in the range of -50 ℃ to 300 ℃. And this is suitable for extreme environments.
Physical parameters
Density: 7.8 g/cm ³, similar to carbon steel, suitable for mixed structure design.
Specific heat capacity: 0.281 J (kg · K) -1
Electrical resistivity: 0.8 micro Ω m
Young’s modulus: 200 GPa
Thermal expansion coefficient: 11-13 μ m/m · K, low expansion characteristics reduce thermal stress issues.
Chemical resistance and heat resistance of duplex 2205 stainless steel
Corrosion resistance
Chloride environment:
The corrosion resistance equivalent (PREN ≥ 35) far exceeds 316L, thus suitable for seawater desalination equipment, offshore platforms, etc.
Stress Corrosion Cracking (SCC):
The dual phase structure effectively suppresses crack propagation caused by chloride ions. So from this point is superior to traditional austenitic stainless steel.
Acidic medium: It has excellent tolerance to sulfuric acid, phosphoric acid, and organic acids. So it is widely used in chemical storage tanks and pipelines.
Heat resistance
Short term temperature resistance can reach 600 ℃, and long-term use is suggested to be ≤ 300 ℃. This is aim to avoid embrittlement caused by the precipitation of intermetallic phases (such as σ phase).
Economy and processing performance
Procurement Cost
The initial cost is higher than that of ordinary stainless steel. But with its high strength and anti-rust performance, it can reduce material usage (such as reducing tank wall thickness by 30-50%) and labour maintenance. Thus the overall life cycle cost is lower.
Processability
Cold/hot forming:
It is necessary to control work hardening, thus we recommend to use low strain rate and intermediate annealing processes.
Welding:
It is better to use specialized welding materials for duplex steel (such as ER2209) and control the heat input (0.5-2.5 kJ/mm). In order to avoid an imbalance in the proportion of ferrite.
Cutting processing:
With high hardness (≤ 293 HB), it is necessary to use hard alloy cutting tools and optimize cutting parameters accordingly.
Main application industries
Oil and gas
Offshore drilling platforms, oil pipelines, valves, and pump bodies are resistant to high pressure and corrosive media specifically.
Chemical and Petrochemical Industry
Reactors, heat exchangers, and high-pressure storage tanks are suitable for strong corrosive environments such as sulfuric acid and phosphoric acid.
Desalination of seawater and environmental protection
The reverse osmosis membrane shell and seawater pump have increased their service life by more than 3 times in terms of resistance to chloride ion corrosion.
Paper and food industry
Bleach equipment and food processing containers that meet hygiene standards and chemical resistant cleaning agent requirements.
Architecture and Ocean Engineering
Cross sea bridges and coastal building structures combine lightweight and durability.
Future Development and Challenges
With the upgrading of industrial demand, the development directions for analysis of duplex stainless steel 2205 include:
Higher temperature performance:
Improve the upper limit of heat resistance through microalloying (such as adding copper and tungsten).
Cost control:
Develop low nickel and high nitrogen formulas in order to reduce dependence on raw materials.
Intelligent manufacturing:
Combining additive manufacturing technology in order to achieve efficient molding of complex components.
More info please check :SAF 2205 – Wikipedia
For Nickel Alloys and Special Stainless Steel Fasteners Series, please check: Nickel Alloys and Special Stainless Steel Fasteners Series –
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