Duplex Stainless Steel Tube
At Stellanox Steel, we manufacture and supply high-quality Duplex Stainless Steel Tubes designed for maximum strength, corrosion resistance, and exceptional durability. Engineered to withstand aggressive environments and mechanical stress, our duplex tubes serve a wide range of industries including offshore oil & gas, desalination plants, chemical processing, marine engineering, and structural applications.
With superior mechanical and chemical properties, Stellanox Steel’s duplex tubes provide a long-lasting, cost-efficient solution for critical, high-demand projects.
What are Duplex Stainless Steel Tubes?
Duplex Stainless Steel Tubes are precision-engineered hollow sections manufactured from duplex-grade alloys, featuring approximately equal parts austenite and ferrite.
This dual-phase structure delivers twice the strength of conventional stainless steels, outstanding resistance to pitting, crevice corrosion, and chloride stress corrosion cracking, and excellent fatigue performance under dynamic loads.
Duplex tubes are ideal where both strength and corrosion resistance are crucial, and they outperform standard austenitic stainless steel tubes (like 304L, 316L) in extreme conditions.
| Products |
|---|
|
Stainless Steel |
|
Carbon Steel |
|
Duplex Stainless Steel |
|
Super Duplex Stainless Steel |
|
Alloy Steel |
|
Titanium |
|
Hastelloy |
|
Inconel |
|
Monel |
|
Aluminium |
|
Copper |
|
Pure Nickel |
|
Flanges |
|
Forged Fittings |
|
Valves |
|
Fasteners |
Key Features
- High Strength-to-Weight Ratio: Enables thinner walls for weight reduction and material savings.
- Superior Resistance to Corrosion: Excels in chloride-rich and aggressive chemical environments.
- Excellent Mechanical Properties: High tensile and yield strengths combined with good ductility.
- Outstanding Fatigue and Impact Resistance: Handles cyclic loads and low temperatures efficiently.
- Good Weldability: Allows field installation with controlled welding procedures.
- Wide Availability of Sizes and Surface Finishes: Customization possible for special projects.
Grades
Specifications
| Property | Details |
|---|---|
|
Product
|
Duplex Stainless Steel Tube
|
|
Common Grades |
UNS S31803 (2205), UNS S32205, UNS S32750 (2507), UNS S32760
|
|
Manufacturing Standards
|
ASTM A789 (Seamless & Welded Tubes), ASTM A790 (Welded Tubes), EN 10216-5
|
|
Tube Types
|
Seamless, Welded, Cold Drawn Seamless (CDS)
|
|
Size Range (OD)
|
6 mm to 273 mm (1/4” to 10” NB)
|
|
Wall Thickness
|
0.5 mm to 12.7 mm
|
|
Length Range
|
6 meters, 12 meters, Custom Lengths Available
|
|
Surface Finish Options
|
Annealed & Pickled, Bright Annealed, Polished, Bead Blasted
|
|
Heat Treatment
|
Annealed & Pickled, Bright Annealed, Polished, Bead Blasted
|
|
Testing and Certification
|
Hydrostatic Test, Eddy Current Test, PMI Test, EN 10204 3.1/3.2, NACE MR0175 Compliance
|
Chemical Composition
| Element | Composition (%) |
|---|---|
|
Carbon (C) |
≤ 0.030
|
|
Chromium
Cr |
21.0 – 23.0
|
|
Nickel
Ni
|
4.5 – 6.5
|
|
Molybdenum
Mo
|
2.5 – 3.5
|
|
Nitrogen
N
|
0.08 – 0.20
|
|
Manganese
Mn
|
≤ 2.0
|
|
Silicon
Si
|
≤ 1.0
|
|
Phosphorus
P
|
≤ 0.030
|
|
Sulfur
S
|
≤ 0.020
|
|
Iron
Fe
|
Balance |
Mechanical Properties
| Property | Value |
|---|---|
|
Tensile Strength (MPa)
|
≥ 620
|
|
Yield Strength 0.2% Proof (MPa)
|
≥ 450
|
|
Elongation (%)
|
≥ 25
|
|
Hardness (Brinell HB)
|
≤ 290
|
|
Impact Energy (Charpy V-notch)
|
≥ 100 Joules @ -46°C
|
Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
|
ASTM |
A240 (Plate/Sheet), A790 (Pipe)
|
|
UNS
|
S31803 (2205), S32205 (2205 improved)
|
|
EN
|
1.4462
|
|
DIN
|
X2CrNiMoN22-5-3
|
|
JIS
|
SUS 329J3L
|
Weight Chart (kg/m²)
| OD (mm) | Wall Thickness (mm) | Weight per Meter (kg) | Weight per 3 m / 6 m (kg) |
|---|---|---|---|
|
6.0
|
1.0
|
0.12
|
0.36 / 0.72
|
|
8.0
|
1.0
|
0.17
|
0.51 / 1.02
|
|
10.0
|
1.0
|
0.22
|
0.66 / 1.32
|
|
12.7
|
1.2
|
0.27
|
0.81 / 1.62
|
|
15.0
|
1.2
|
0.34
|
1.02 / 2.04
|
|
19.05
|
1.5
|
0.50
|
1.50 / 3.00
|
|
25.4
|
2.0
|
0.95
|
2.85 / 5.70
|
|
30.0
|
2.0
|
1.31
|
3.93 / 7.86
|
|
38.1
|
2.5
|
1.71
|
5.13 / 10.26
|
|
50.8
|
3.0
|
2.78
|
8.34 / 16.68
|
|
63.5
|
3.0
|
3.53
|
10.59 / 21.18
|
|
76.2
|
3.5
|
4.92
|
14.76 / 29.52
|
|
89.0
|
4.0
|
6.58
|
19.74 / 39.48
|
Applications in Various Industries
Stellanox Steel’s products are valued for their strength, machinability, and cost-effectiveness across multiple sectors:
Benefits
- High Strength for High Pressure Applications: Enables thinner walls without compromising performance.
- Exceptional Corrosion Resistance: Ideal for aggressive, chloride-rich environments.
- Cost-Efficient: Lower material usage and longer service life reduce total lifecycle costs.
- Excellent Weldability: Suitable for field installations and critical piping systems.
- Superior Fatigue and Impact Strength: Handles mechanical vibration and thermal cycling.
- Environmentally Friendly: 100% recyclable with low carbon footprint during production.
Frequently Asked Questions
Technically, tubes are specified by exact outer diameter (OD) and wall thickness for mechanical applications, while pipes are specified by nominal bore (NB) for fluid transport.
Yes, duplex stainless steel has excellent resistance to seawater corrosion, especially for applications like seawater cooling or firewater systems.
Yes. With proper procedure control (low heat input and appropriate filler metals), duplex tubes can be welded efficiently.
Super Duplex grades like UNS S32750 (2507) are preferred for extremely aggressive and deepwater conditions.
2025 Stellanox Steel |