High-Performance Duplex & Super Duplex Stainless Steel Pipe
Our Duplex Stainless Steel pipes feature a balanced 50/50 microstructure of austenite and ferrite, providing significantly higher strength and superior resistance to stress corrosion cracking (SCC) compared to standard austenitic steels. Engineered for the most demanding environments, these pipes offer exceptional resistance to pitting and crevice corrosion in chloride-rich media.
-
Main Grades: S31803 (2205), S32205, S32750 (Super Duplex 2507), S32760.
-
Size Range: O.D. 6mm – 610mm | W.T. 0.5mm – 40mm | Max Length 18,000mm.
-
Standards: ASTM A789/A790, A928, EN 10216-5, EN 10217-7, JIS G3459.
-
Key Applications: Oil & gas, chemical processing, seawater desalination, offshore platforms, and pulp & paper industries.
Description
1. Product Overview & Features
Duplex Stainless Steel (DSS) is characterized by a two-phase microstructure consisting of grains of ferritic and austenitic stainless steel in roughly equal proportions (approx. 50/50 balance). This unique structure allows duplex pipes to combine the best properties of both austenitic and ferritic steels.
Key Advantages:
- Superior Strength: Approximately twice the yield strength of standard austenitic stainless steels.
- Exceptional Corrosion Resistance: Outstanding resistance to localized corrosion, particularly pitting, crevice corrosion, and stress corrosion cracking (SCC).
- Cost-Effectiveness: High mechanical strength allows for thinner wall sections, reducing weight and overall project costs.
- Low Thermal Expansion: Lower coefficient of thermal expansion than austenitic steels, providing better structural stability at varying temperatures.
2. General Specifications
| Parameter | Details |
|---|---|
| Executive Standards | ASTM A789, A790, A928; EN 10216-5, EN 10217-7; DIN 17456, 17458; JIS G3459; GOST 9941. |
| Material Grades | S31803 (2205), S32205, S32750 (Super Duplex 2507), S32760, S31500, S32304. |
| Outer Diameter (O.D.) | 6mm – 610mm |
| Wall Thickness (W.T.) | 0.5mm – 40mm |
| Length | Standard lengths or up to 18,000mm maximum. |
3. Chemical Composition & Mechanical Properties
Chemical Composition (%)
| Grade | C (Max) | Si (Max) | Mn (Max) | P (Max) | S (Max) | Ni | Cr | Mo | N |
|---|---|---|---|---|---|---|---|---|---|
| S31803 | 0.030 | 1.00 | 2.00 | 0.030 | 0.020 | 4.5-6.5 | 21.0-23.0 | 2.5-3.5 | 0.08-0.20 |
| S32205 | 0.030 | 1.00 | 2.00 | 0.030 | 0.020 | 4.5-6.5 | 22.0-23.0 | 3.0-3.5 | 0.14-0.20 |
| S32750 | 0.030 | 0.80 | 1.20 | 0.035 | 0.020 | 6.0-8.0 | 24.0-26.0 | 3.0-5.0 | 0.24-0.32 |
Mechanical Properties (Minimum Values)
| Grade | Tensile Strength Rm (MPa) | Yield Strength Rp0.2 (MPa) | Elongation A5 (%) |
|---|---|---|---|
| S31803 | 620 | 450 | 25 |
| S32205 | 655 | 450 | 25 |
| S32750 | 795 | 550 | 15 |
4. Manufacturing Process
Our duplex stainless steel pipes are manufactured using advanced metallurgical processes for both seamless and welded configurations. The process ensures a refined surface finish and precise internal structure balance.
Seamless and Welded Manufacturing Workflow
5. Applications
Due to its high performance-to-weight ratio and corrosion resistance, duplex steel is the preferred choice for:
- Petroleum & Gas: Pipeline systems, heat exchangers, and underwater equipment.
- Chemical Industry: Production of organic acids and industrial chemicals.
- Water Treatment: Seawater desalination plants and seawater handling systems.
- Environmental Protection: Flue gas desulfurization (FGD) systems.
- Infrastructure: Bridges and architectural structures in coastal environments.
6. Packing & Delivery
We provide seaworthy export packaging to prevent any mechanical damage or contamination during transit. Typical methods include:
- Steel bundled for small diameters.
- Robust wooden cases or crates for precision and large pipes.
- Protective plastic caps and waterproof wrapping as standard.
