Yes, duplex stainless steel tubes are a preferred choice for hydraulic and instrumentation systems. Their excellent mechanical strength, corrosion resistance, and long service life are factors that make these tubes suitable for applications that demand accurate and stable performance under high pressure and in harsh environments.
Duplex Stainless Steel Tube Manufacturer in China
We are Zhejiang Xintongda Special Steel (XTD), and we operate as a leading Duplex Steel Tubes manufacturer in China and a global supplier. Our tubes are made in compliance with various international standards and are designed to deliver excellent performance. These tubes contain a special mix of austenite and ferrite structures. This gives them strong mechanical strength and excellent resistance to corrosion. This alloy contains chromium, nickel, nitrogen and molybdenum. This composition enables the tubes to withstand the severe surroundings and retain their mechanical properties. Our Duplex Steel Tubes are produced as per ASTM A789, EN, JIS, GB, GOST, ISO and UNS standards and we specialise in manufacturing seamless stainless steel duplex tubes. They provide excellent longevity and are used in the most demanding industries such as oil & gas, chemical processing, and marine applications. These tubes are chosen over standard stainless steel because they are resistant to pitting, crevice corrosion, and stress corrosion cracking. We are an internationally certified manufacturer, and we put our products through strict quality testing to ensure they meet the highest standards before shipment.
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OD Range
6 - 720 mm
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Thickness Range
1 - 65 mm
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Length
≤ 22 m
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What is Duplex Stainless Steel Tube?
A duplex stainless steel tube combines the features of austenitic and ferritic stainless steel. This provides enhanced strength and outstanding corrosion resistance. The dual-phase structure improves the tube's mechanical properties, delivering approximately twice the yield strength of conventional 300 series austenitic steels and improved resistance to stress corrosion cracking. These properties make duplex stainless steel tubes ideal for industries like oil and gas, chemical processing, and marine applications, where durability is important in harsh environments.
What are the Advantages of Duplex Stainless Steel Tubes?
There are many benefits to using duplex stainless steel tubes. Due to their special microstructure, these tubes are stronger and more resistant to corrosion than standard austenitic grades.
- Extended Service Life: Our duplex steel tubes benefit from a dual-phase structure that enhances durability. The tubes are more resistant to wear and tear. They offer a longer service life than other stainless steel alloys, even in harsh chemical and marine environments.
- Lower Maintenance Requirements: Our duplex stainless steel tubes stand out from the rest with its ability to resist stress corrosion cracking and fatigue. Its properties mean it will not require as many repairs as other materials, and can withstand being exposed to unfavourable conditions for years on end without much loss in its strength.
- Improved Cost Efficiency: A duplex steel tube is a perfect option because of its high strength and good resistance to corrosion. Due to its extended service life, the replacement and maintenance cost is minimised.
- Thermal Properties: The Duplex stainless steel tube can remain highly stable in varied temperature changes. It is important for power plants and chemical processing systems to keep the mechanical strength even when the temperature rises.
- Excellent Weldability: Despite their high strength, duplex stainless steel tubes are easily weldable, making them highly versatile for various fabrication processes. Their weldability, combined with excellent corrosion resistance, allows for smooth assembly in critical applications.
Duplex Steel Tube Specification
Duplex Stainless Steel Tubes are made to order in a variety of dimensions to suit the specific demands of different industries. The strength, toughness and resilience of the tube are also influenced by the alloy, mechanical properties, size and precision of the tube, all of which affect what it can be used for. The main specifications for Duplex Steel Tubes are.
Standard
ASTM A789
Outside Diameters
6 - 720 mm
Length
≤ 22 m
Thickness Range
1 - 65 mm
Grades
S31803, S32205
Form
Round, Square, Rectangular, Hydraulic etc
End
Plain End, Beveled End, Threaded
Testing
PMI, Radiography, Mechanical, Chemical
Duplex Tubes Type & Shapes
We manufacture a wide range of Duplex stainless steel tubes to meet the specific needs of our clients. The different types and shapes are:
Duplex Steel Seamless Tube
Duplex Stainless Steel Boiler Tube
Duplex Steel Round Tube
What Grades are Available in Duplex Stainless Steel Tubes?
We offer our duplex tubes in two primary grades UNS S31803 and UNS S32205 (Duplex 2205) both suitable for a wide range of industrial applications. Most production meets the tighter S32205 composition, and dual certification (S31803/S32205) is available on request.
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UNS S31803 Tube
The UNS S31803 tube is a type of duplex stainless steel that is strong and doesn't rust easily. It has 21-23% chromium, 4.5-6.5% nickel, 2.5-3.5% molybdenum, and 0.08-0.20% nitrogen. This composition makes it strong and easy to weld. UNS S31803 Tube remains a popular choice in oil and gas, chemical processing, and marine industries due to its extended service life and performance in demanding environments.
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UNS S32205 Tube
The UNS S32205 tube is a refined-composition variant of UNS S31803, with tighter minimum ranges for chromium (22–23%), molybdenum (3.0–3.5%), and nitrogen (0.14–0.20%). Due to this improvement, the corrosion resistance of the material is better, so it can be used in highly corrosive environments. The application of the UNS S32205 tube is basically in industries such as chemical reactors and in seawater desalination plants, where the strong corrosion resistance guarantees the durability and stability of the equipment.
What are the Industrial Applications of Duplex Stainless Steel Tubes?
The following section explains the 5 main applications of Duplex Steel Tubes:
Oil & Gas
Duplex Stainless Steel Tubes are mainly employed in offshore platforms, pipelines, and refineries in the oil and gas industry. They are ideal for tough offshore environments since they do not fracture under tensile stress and are highly durable. Thus, these are the systems that can be trusted to operate for an extended period.
Chemical Processing
Duplex steel tubes are the primary choice in chemical processing plants where they are subjected to extremely corrosive substances. Such tubes are applied in reactors, heat exchangers and pressure vessels, guaranteeing safety and efficiency in operations involving aggressive chemicals.
Marine
Duplex stainless steel is used in seawater systems, shipbuilding and offshore platforms in the marine industry. These tubes are made to withstand high-strength environments in the sea due to their excellent resistance to seawater corrosion, pitting, and crevice corrosion.
Desalination
Duplex stainless steel tubes are a must in saltwater desalination facilities if you want to avoid corrosion caused by the high salt content. Their excellent resistance to pitting and crevice corrosion makes them ideal for long-term use, thus enabling the supply of clean water to arid areas.
Power Generation
Duplex steel tubes’ ability to withstand high temperatures, pressure, and corrosive environments makes them suitable for heat exchangers and boiler systems in power plants.
100% Certified Testing & Documentation
- Raw Materials Certificate
- 100% Positive Material Identification (PMI)
- Heat Treatment Charts
- Third-Party Inspection Report
- Surface roughness and size measurement
- Manufacturer Test Certificate (Impact Testing, Flattening, Flare, Bend, Hardness, Intergranular Corrosion, Pitting Corrosion, Grain size, Eddy Current (ET), Ultrasonic Testing (UT), Hydrostatic Testing (HT), etc.)
- Laboratory Test Certificate from Govt. Approved Lab
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Frequently Asked Questions
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Can duplex tubes be used in hydraulic or instrumentation systems?
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Where are duplex tubes used the most in industry?Duplex Stainless Steel Tubes are primarily utilised in industries like oil and gas, chemical processing, marine and power generation. Such tubes perform very well in conditions that require corrosion resistance, strength and reliability, which are typical of offshore, high-temperature, and high-pressure applications.
- What is Duplex Stainless Steel Tube?
- What are the Advantages of Duplex Stainless Steel Tubes?
- Duplex Steel Tube Specification
- Duplex Tubes Type & Shapes
- What Grades are Available in Duplex Stainless Steel Tubes?
- What are the Industrial Applications of Duplex Stainless Steel Tubes?
- 100% Certified Testing & Documentation
- Frequently Asked Questions