Duplex Stainless Steel
At Stellanox Steel, we specialize in manufacturing and supplying premium-grade Duplex Stainless Steel products known for their superior strength, excellent corrosion resistance, and enhanced durability compared to standard austenitic or ferritic steels.
Engineered for critical applications across industries like oil & gas, chemical processing, marine engineering, desalination plants, and structural applications, our duplex stainless steels deliver outstanding performance in highly demanding environments.
What are Duplex Stainless Steel?
Duplex Stainless Steel is a unique material with a microstructure consisting of roughly 50% austenite and 50% ferrite. This balanced structure results in a combination of the best properties of both steel families — offering twice the strength of conventional stainless steels and significantly improved resistance to localized corrosion such as pitting and crevice corrosion.
Duplex steels are especially suited for aggressive environments where chlorides or other corrosive agents are present. Their high mechanical strength allows for thinner sections compared to conventional stainless steels, leading to significant weight savings in structural and piping systems.
| Products |
|---|
|
Stainless Steel |
|
Carbon Steel |
|
Duplex Stainless Steel |
|
Super Duplex Stainless Steel |
|
Alloy Steel |
|
Titanium |
|
Hastelloy |
|
Inconel |
|
Monel |
|
Aluminium |
|
Copper |
|
Pure Nickel |
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Flanges |
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Forged Fittings |
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Valves |
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Fasteners |
Key Features
- High Strength: Approximately twice the yield strength of 300 series stainless steels
- Excellent Corrosion Resistance: Superior resistance to pitting, crevice corrosion, and stress corrosion cracking.
- Good Weldability: Lower thermal expansion and high energy absorption properties.
- Enhanced Fatigue Resistance: Performs better under cyclic loading conditions.
- Reduced Material Thickness Needed: Strength allows thinner designs, leading to weight and cost savings.
- Cost-Effective Alternative to Nickel Alloys: Superior performance at a lower cost than high nickel-based alloys.
Duplex Stainless Steel Products
Specifications
| Property | Details |
|---|---|
|
Material Family
|
Duplex Stainless Steel
|
|
Common Grades |
UNS S31803 (2205), UNS S32205, UNS S32750 (Super Duplex 2507), UNS S32760
|
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Standards
|
ASTM A240, ASTM A790, ASTM A815, EN 1.4462, EN 1.4410
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|
Forms Available
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Plates, Sheets, Coils, Pipes, Tubes, Bars, Fittings, Flanges
|
|
Thickness Range (Plates/Sheets)
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0.5 mm to 100 mm
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Diameter Range (Pipes/Tubes)
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6 mm to 1219 mm (1/8″ NB to 48″ NB)
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Length Range
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Standard: 6 meters, 12 meters; Custom available
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Surface Finish Options
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Hot Rolled, Pickled and Passivated, Polished, Cold Finished
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Heat Treatment
|
Solution Annealed and Quenched
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Testing and Certification
|
NACE MR0175, ASTM, EN 10204 3.1/3.2, Third-Party Inspections
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Chemical Composition
| Element | Composition (%) |
|---|---|
|
Carbon (C) |
≤ 0.030
|
|
Chromium
Cr |
21.0 – 23.0
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|
Nickel
Ni
|
4.5 – 6.5
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Molybdenum
Mo
|
2.5 – 3.5
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Nitrogen
N
|
0.08 – 0.20
|
|
Manganese
Mn
|
≤ 2.0
|
|
Phosphorus
P
|
≤ 0.030
|
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Sulfur
S
|
≤ 0.020
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Iron
Fe
|
Balance |
Mechanical Properties
| Property | Value |
|---|---|
|
Tensile Strength (MPa)
|
≥ 620
|
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Yield Strength 0.2% Proof (MPa)
|
≥ 450
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Elongation (%)
|
≥ 25
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Hardness (Brinell HB)
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≤ 290
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Impact Energy (Charpy V-notch)
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≥ 100 Joules @ -46°C
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Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
|
ASTM |
A240 (Plate/Sheet), A790 (Pipe)
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UNS
|
S31803 (2205), S32205 (2205 improved)
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EN
|
1.4462
|
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DIN
|
X2CrNiMoN22-5-3
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JIS
|
SUS 329J3L
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Weight Chart (kg/m²)
| Thickness (mm) | ASTM A240 / A789 / A790 | UNS S31803 / S32205 | JIS SUS329J3L |
|---|---|---|---|
|
1 |
7.80 kg/m²
|
7.80 kg/m²
|
7.80 kg/m²
|
|
2 |
15.60
|
15.60
|
15.60
|
|
3 |
23.40
|
23.40
|
23.40
|
|
4 |
31.20
|
31.20
|
31.20
|
|
5 |
39.00
|
39.00
|
39.00
|
|
6 |
46.80
|
46.80
|
46.80
|
|
8 |
62.40
|
62.40
|
62.40
|
|
10 |
78.00
|
78.00
|
78.00
|
|
12 |
93.60
|
93.60
|
93.60
|
|
16 |
124.80
|
124.80
|
124.80
|
|
20 |
156.00
|
156.00
|
156.00
|
|
25 |
195.00
|
195.00
|
195.00
|
|
30 |
234.00
|
234.00
|
234.00
|
|
40 |
312.00
|
312.00
|
312.00
|
|
50 |
390.00
|
390.00
|
390.00
|
Applications in Various Industries
Stellanox Steel’s products are valued for their strength, machinability, and cost-effectiveness across multiple sectors:
Benefits
- Twice the Strength of Conventional Stainless Steels: Reduced weight and cost in structural designs.
- Excellent Corrosion Resistance: Especially in chloride-rich and acidic environments.
- High Resistance to Stress Corrosion Cracking: Outperforms austenitic stainless steels.
- Superior Fatigue Strength: Perfect for dynamic loading environments.
- Reduced Material Thickness: Strength advantage leads to lighter and more cost-efficient structures.
- Outstanding Toughness at Low Temperatures: Reliable even in Arctic and deep-sea applications.
Frequently Asked Questions
Duplex offers approximately twice the strength of 316 and better resistance to stress corrosion cracking and pitting, especially in chloride environments.
Yes, due to the ferritic phase, duplex stainless steels are partially magnetic.
Yes. However, controlled procedures must be used to avoid phase imbalance. Post-weld heat treatment is usually not required.
Super Duplex grades like S32750 (2507) have even higher strength and corrosion resistance compared to standard duplex grades, suitable for extremely aggressive environments like deepwater oil fields.
2025 Stellanox Steel |