Duplex Tube

Duplex tube

The two-phase microstructure of duplex stainless steel gives rise to its name. Although exact percentages differ depending on the grade, the majority of duplex tubing are composed of around 50% ferrite and 50% austenite. The austenitic and ferritic families of alloys’ qualities are combined in duplex stainless steels, which provide the advantages of both with fewer drawbacks and frequently at a lower cost than other steel alloys.

Cost, though, is but a small portion of the overall picture. The performance of the steel for your intended usage is another important consideration when selecting the proper stainless steel.

The best course of action for you is to get NACE certified duplex stainless steel tube material.

NACE Requirements

Prequalified materials are listed in the NACE MR0175/ISO 15156 standard for use in upstream oilfield equipment where sulfide-induced stress corrosion cracking may be a problem in sour conditions, or in mixtures of oil, gas, and seawater where hydrogen sulfide (H2S) is present.

The standard permits tubing made of Duplex stainless steel to be used in control and instrumentation systems, respectively. Additionally, DSS coiled & precision tubing can be used to handle process fluids and be employed in instrumentation and control systems when they have been strain-hardened.

The document contains the following:

  • Qualifications for material usage under certain sour gas conditions;
  • Requirements for material conditions and properties;
  • Setting in which the materials are to be used

A tube that comprises equal percentage composition of ferrite and austenite is an duplex tube. This is the only reason why they show excellent resistance to corrosion cracking.

Adding to this, they comprise higher chromium contents. Hence, in the modern world, they are one of the most widely used tubes; which meets several industrial standards.

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Duplex seamless tube suppliers in UAE

Duplex Stainless Steel Tube Specification

Duplex Tube Specification

Shapes American standard for OD and thickness Duplex stainless tubing manufacturing process
  • Hot finished seamless tube
  • Cold finished seamless tube
  • Welded
  • Welded & drawn
Small tubes Duplex steel high pressure tubing DSS hydraulic tube
  • DSS Precision tubes
  • Small diameter duplex tubing
  • Duplex stainless tubing thin wall tubing
  • HPLC tubing – Up to 38.1 mm /1.5 inch
  • Size : 1.27 to 31.75 mm OD
  • wall thickness : 0.4445 to 5.5372 mm
  • Size : 3.175 to 25.4 mm
  • Wall thickness : 0.4 mm to 1.65 mm
European standard Applications & uses Duplex steel coiled tubing manufacturing type
  • EN 10216-5 (seamless & welded tubing)
  • EN 10297-2 (seamless tubing)
  • EN 10217-7 (welded tubing)
  • EN 10296-2 (welded tubing)
  • EN 10312 (welded tubing)
  • Oil and gas refining
  • Marine environments
  • Pulp & paper manufacturing
  • Duplex seamless tube
  • Duplex stainless steel  welded tube
  • Duplex SS ERW tubing
  • Duplex steel EFW tube
duplex stainless steel tubing wall thickness Meet standards Duplex steel coiled tubing surface finish and treatments
  • 4 Inch
  • Schedule 5 / 5S
  • SCH 10 duplex stainless steel tubing (Most selling)
  • SCH 20
  • SCH 30
  • SCH 40 duplex steel tube (Most selling)
  • SCH 40S
  • SCH 80 / 80S
  • SCH 120
  • SCH 160
  • Standard (SCH STD)
  • Ex-Standard (XS)
  • Double Extra Strong (XSS)
  • ASME B36.19
  • ASME B36.19M
  • EN 10217-7
  • EN 10088-2
  • EN 10088-3
  • NSF 61
  • EN 10216 – 5
  • EN 10216 – 2
  • DIN 17456
  • DIN 17458
  • Cleaned
  • Passivated
  • Pickled
  • Precleaned
Duplex stainless tubing finish QC and duplex tubes
supporting documents
List of leading duplex round tubes manufacturers
  • Solution annealed duplex SS tube
  • Annealed & Pickled (A&P)
  • Mirror
  • Bright Annealed
  • 180 grit polished
  • 2B
  • No.4
  • 400 grit
  • BA polishing
  • Matt finish
  • 320 grit
  • 600 grit
  • Cold Drawn

Refer these details before buying duplex tube from traders, manufacturers, suppliers, stockist, stockholders, or importers

  • MTC EN 10204 type 3.1
  • Duplex oval tubing material, schedule & size as per the work order
  • Verify quantity
  • Check duplex SS tubing dimensions
  • QC/ Inspection reports
  • Duplex round tubes
    detailed inspection plan (appearance, integrity, packaging etc)
  • Labeling verification
  • Origin of material

Check ready stock of these make with above verified listed duplex tubing suppliers

  • ArcelorMittal, Luxembourg (Europe)
  • Outokumpu, Finland (Europe)
  • Aperam, Luxembourg (Europe)
  • ThyssenKrupp AG, Germany
  • Jindal steel pipe, India
  • Acerinox, Spain
  • Baosteel, China
  • POSCO, South Korea
  • Nippon Steel Corporation, Japan
  • Tubecon, Pretoria (South Africa)
  • MACSTEEL, Gauteng (South Africa)
  • Tata Steel, India
  • Tenaris, Luxembourg (Europe)
  • Sandvik, Sweden
  • SMM Oman
  • JFE, Japan
  • Nippon Steel & Sumitomo Metal Corporation, Japan
  • Jiangsu Shagang, China
  • AL JAZEERA, Oman
  • Sosta, Italy
  • Steelmor, Gauteng (South Africa)
  • Nippon Yakin Kogyo Co., Ltd., Japan
  • Bristol Metals, USA
Duplex stainless tubing value added services
  • Cutting
  • Threading
  • Beveling
  • Polishing

Find reputable duplex steel tube suppliers on pipingmaterial.ae. Get quotes from multiple DSS hydraulic tube stockists in Middle East countries

While pipes are always round, Duplex tubing can have a variety of shapes, including square, rectangular, and cylindrical. The pressure force is dispersed uniformly due to the pipe’s round shape. Duplex Pipes that range in size from ½ inch to several feet can handle larger applications. For example, a 1-1/2″ Od X 2.77 mm Wall Thickness X 4926.8 mm Long Seamless Boiler Tube from SA789 Duplex stainless steel tubes fits this description. Duplex tube sizes varies according to the specific use it is for

Heat treatment has been applied to annealed tubing to eliminate internal tensions and improve ductility. To put it briefly, annealing softens the duplex tube in comparison to cold wrought, or “hard tempered,” tubing.

An annealing temperature of at least 1900 degrees Fahrenheit is required for 300-class stainless steel. Vita offers numerous methods for annealing tubing, including coil annealing in a strand annealing furnace, belt annealing, and enclosed ovens with doors. Low dew point and an oxygen-free atmosphere are required to keep the tube surface brightly finished.

Equivalent Grades of Duplex Tubing

Standard Material name EN/ DIN/ Wnr China Buttweld Fittings Flanges Fasteners Welding Electrode
  • ASTM A789 UNS S31803
  • Tube – Seamless. Welded
  • Duplex tube
  • Grade : 2205
1.4462 022Cr22Ni5Mo3N ASTM A815 UNS S31803 ASTM A182 F51 ASTM A453 Grade 660 Duplex Welding Electrode
  • Duplex tube
  • Grade : 2205
1.4462 022Cr23Ni5Mo3N ASTM A815 UNS S31803 ASTM A182 F51 ASTM A182 F51 Duplex Welding Electrode

Duplex Tube Sizes

Duplex stainless steel tubes
Duplex tubing wall thickness duplex SS tubing
  • Duplex seamless tube OD: 1mm up to 45mm (0.04″ to 1 5/8”)
  • Duplex welded, welded & drawn tubes OD: up to 38.1mm / 1 1/2″
  • Size: 6” to 24”
  • 0.25 mm up to 6.35mm (0.01″ to 0.250″)
  • Straight duplex tubing lengths : up to 14m (45ft)
  • Duplex steel coiled tubes: up to 10,000m (33,000 ft) with orbital joints

For cut to length please contact below listed Duplex Tube suppliers in UAE

Mechanical & Chemical Properties of Duplex Tube Material

Duplex Tube Properties

Grades of Duplex Steel Tube

Testing & required examination for Austenitic-Ferritic grade tubing

  • NDT ultrasonic
  • Eddy current testing
  • Tension test
  • Hydrostatic testing
  • Flaring test (for seamless duplex tubing)
  • Flange test (for welded duplex tubing)
  • Hardness test
  • Radiographic examination
  • Reverse flattening test
  • 100% PMI tested
  • Electropolishing capabilities
  • Complete physical & chemical laboratory analysis

Types of Duplex Tube

Bright annealed duplex tubing

Bright annealed duplex tubing

Solution annealed duplex tubing

Solution annealed duplex tubing

Duplex seamless tubes

Duplex seamless tubes

Welded duplex stainless tubing

Welded duplex stainless tubing

Duplex steel hydraulic tubing

Duplex steel hydraulic tubing

DSS instrumentation tubing

DSS instrumentation tubing

Duplex coiled tubing

Duplex coiled tubing

DSS sanitary tubing

DSS sanitary tubing

Duplex stainless steel mechanical tubing

Duplex stainless steel mechanical tubing

Electropolished duplex tubing

Electropolished duplex tubing

Duplex steel square tubing

Duplex steel square tubing

Round duplex stainless tubing

Round duplex stainless tubing

DSS rectangular tubing

DSS rectangular tubing

Duplex Stainless Steel Tube meaning

  • 50% austenite
  • 50% ferrite
Most recommended for
  • Chloride stress corrosion
American Standard ASTM A789
Duplex Stainless Steel short form DSS
Manufacturing types Seamless & Welded DSS Tubing
Other name Fe-Ni-Cr alloy
Temperature Limits Min (minus) -50 degrees to max 300 degrees

DSS Tubing Classification

Measured by
  • OD & ID
  • ID and Wall Thickness
Thickness In gauge
Manufacturing shapes
  • Round
  • Square
  • Rectangular
Available services
  • Cut
  • Bent
  • Flared
  • Fabricated
Manufacturing Method
  • Cold rolled
  • Hot rolled
Uses & Application
  • Instrument purpose
  • High pressure application
  • Food processing
  • Chemical processing
  • Pressure vessels

Duplex Steel Tubing Chromium Content

These DSS tube material have higher chromium (19% to 28%), refer following table to know the exact Cr content in Duplex stainless steel grade tubing

Grade Cr (% by weight)
Cr (% by weight)
2205 21.0% 23.00%
2507 24% 26%

Application Wise Duplex Tubing

  • Duplex heat exchanger tubes
  • DSS Hydraulic Tubes
  • Instrumentation Tubes
  • Control Lines
  • Coiled Tubing
  • Oil & Gas Tubing
  • Duplex Steel Capillary Tubing
  • High Pressure Tubes (Precision)

Uses of Duplex Tubes instead of a Pipe

There is various difference between a Duplex tube & pipe, project engineers required tubing in following conditions

  • For high strength & high pressure applications
  • For different shapes like square & rectangle, as Pipes comes in round shape only
  • For bending & smooth piping direction changes
  • Where small diameter tubing are required
  • If required thinner wall
  • For bent & coiled form
  • For a leak free connection with Tube fittings

Industrial uses of Duplex Stainless Steel Tubes

  • Desalination
  • Sea Water Projects & marine environments
  • Oil and Gas Industry
  • Petrochemical Plants
  • Nuclear Power & Defence sector
  • LNG
  • Mining & Minerals

Cold-drawn seamless tubes

A solid metal billet is drawn through a piercing rod to generate a hollow tube with no seams or welds in a cold-drawn seamless tube, which is a cylindrical result. They differ from other types of tubes, including welded or hot-rolled tubes, due to their seamless construction. Seamless construction improves the tube’s resilience to different loads and structural integrity, which makes it a great option for demanding applications.

Cold-drawn seamless tubes, which are commonly called seamless tubes, have become the preferred option for companies looking for precision, longevity, and dependability in various applications.

Duplex tube materials are finding more and more use as structural materials in power plants, petrochemical, and chemical applications. This is mostly because duplex tubes have great strength and hardness, as well as excellent resistance to localized corrosion.

To get your duplex tube materials, you can contact above listed Duplex tubing suppliers and it will be shipped to you anywhere in Middle East including Turkey, Saudi Arabia, Egypt, Iraq, Qatar, Algeria, Kuwait, Oman, and Libya.

If you are looking for a good quality and top notch duplex seamless tube, highly advisable that you contact the suppliers of pipingmaterial.ae; where:

Reasonable pricing is quoted. So, customers pay only for their needs and standards.

These suppliers are listed and verified. So, customer confidentiality and product genuineness is not affected.

Looking for specific sizing of the seamless tube, the contact details of each suppliers are also open for free. So, customers can contact and place their necessary demands to them.

Confused whether your product meets your daily standards? Suppliers also would help you with their personal suggestions.

For them, customer comfort and suitability are the primary factors. Hence, until today, they are one of the most prominent and leading duplex tube suppliers in UAE, covering wide range of industrial standards.

Both ID and OD refer to the diameter of duplex tubing.

But being centric around to the terms, ID refers to the internal diameter of the tube. Whereas, OD refers to the outer diameter of the tubing.

In most industrial standards, OD is one of the factors which are most commonly used to perform most of the measurements.

Duplex stainless steel tubes and DSS boiler tubes are known for very good stress corrosion cracking

With the presence of higher chromium contents, Duplex tubing shows excellent resistance to corrosive environments.

Not only to general corrosions, but you would also see it resisting intergranular corrosions too. Adding to this, in environments comprising sulphide and chloride, excellent stress corrosion cracking resistance is shown.

Want to purchase DSS superheater tubes? Check the minimum order quantity with several GCC stockists of duplex tubing

duplex tube material offers simplicity in their welding, with the help of standard welding methods.

With that said, it shows good weldability. But very important aspect to be noted here is that duplex steel welded tube cannot be welded easily; as that of austenitic grades.

On the other hand, because they have low thermal expansion, it reduces residual stress and distortion; after welding process.

Purchase duplex stainless steel extruded tube and welded tube that complies with standards in a variety of sizes and custom lengths

With excellent strength and corrosion resistance properties, below are some ideal applications of DSS boiler tube:

  • Used for the purpose of processing of chemical.
  • Marine applications; where resistance to corrosion and durability are considered.
  • Refineries of oil and gas, thanks to their excellent strength characteristics and high level temperature tolerance.
  • DSS superheater tubes used as an equipment in pollution control.