Duplex Steel Tubes Manufacturer
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Midland Alloys Inc. is a reputable Indian producer and international supplier of Duplex Steel Tubes known for excellent performance in critical industrial applications. Duplex Steel Tubes are made from a type of stainless steel that includes both austenitic, and ferritic parts, giving them an exceptional combination of corrosion resistance and strength. These tubes exhibit excellent mechanical strength and are ideal for corrosive and high-pressure applications. We offer a wide range of grades including UNS S31803, UNS S32205, and UNS S32750, available in both duplex welded steel tubes and duplex seamless steel tubes. These tubes, also known as 22 Cr Duplex Steel Schedule 5S Tubes, have a chemical composition that balances chromium (21–23%), nickel (4.5–6.5%), molybdenum (2.5–3.5%), and nitrogen (0.14–0.20%). They provide strong performance in various industries by delivering high tensile strength (up to 620 MPa), and excellent elongation (minimum 25%). Hot Finished Duplex Tubes are part of our product line to increase dependability in challenging conditions.
Benefits of Duplex Steel Tubes
22 Cr Duplex Steel Schedule 5S Tube offers a balanced solution for industries demanding high strength, corrosion resistance and cost efficiency. Its dual-phase structure provides performance advantages not found in traditional stainless steel grades.
- High resilience to heat and mechanical stress
- Exceptional resistance to corrosion in acidic, and chloride-rich environments
- Good weldability and low intergranular corrosion risk
- Cost-effective substitute for high-nickel alloys in key systems
- Outstanding resistance to stress corrosion cracking, pitting, and crevice corrosion
- High strength-to-weight ratio for offshore and structural designs
- Longer service life in demanding process settings
- Lower thermal expansion compared to austenitic steels
Duplex Stainless Steel Tubes Specifications
Seamless Tube OD : 1 / 2" NB - 16" NB Welded Tube OD : 6.35 to 114.3 mm EFW Tube Size : 6″ NB – 24″ NB
ASTM A790 / ASME SA790
Seamless / Welded / ERW / Fabricated / CDW / 100% X Ray Welded
Round, Square, Rectangular, Hydraulic Etc
Single Random, Double Random, Standard & Cut length
Plain Ends (PE), Threaded Ends (TE), Bevelled Ends (BW), Grooved Mechanical Joints or Grooved Ends, TBE (Treaded Both Ends)
SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS
Bright, Polish, and Black
Difference Between Duplex Steel Tubes vs Nickel Alloy Tubes
Duplex Steel Tubes and Nickel Alloy Tubes have very different composition and functions. Duplex stainless steel tubes provide a two-phase microstructure with relatively moderate nickel content (about 5–6%), whereas nickel alloy tubes are sometimes found to have more than 60% nickel. This ensures that the nickel alloys are more resilient to high-temperature oxidation and highly corrosive acids, but they are also expensive. Duplex tubes provide a practical balance of mechanical strength and corrosion resistance, especially in environments involving chlorides, without the high cost of nickel-based materials. While nickel alloys outperform in extreme temperatures above 600°C, duplex tubes are ideal for most mid-range industrial applications where strength and corrosion resistance are essential at a lower cost.
Contact us today to discuss how Duplex Stainless Steel Tubes can benefit your application. Whether you need guidance in selecting the right pipes or have specific requirements, our team of experts is here to help you find the optimal solution.
Duplex Stainless Steel Tubes Grades We Offer
Round Bar
Analytic
Cut to Length
Centering
Heating
Perforation
Inspection of Size
Pickling
Inspection of Surface
Lubricating
Cold Drawing (Cold Rolling)
Degreasing
Annealing
Straightening
Cut
Pickling / Passivating
Inspection
Analytic
Marking
Packing & Shipping
Applications of Duplex Stainless Steel Tubes
Duplex stainless steel pipes are extensively utilized in industries requiring high mechanical strength, higher corrosion resistance, and cost-effective materials. Duplex pipes are utilized in pipelines, risers and subsea systems in the oil and gas industry subjected to chloride and sulfide stress. Chemical processing plants use these tubes in heat exchangers, pressure vessels, and storage tanks. Desalination plants rely on duplex seamless steel tubes for their resistance to saltwater corrosion. Power generation units, especially those using seawater cooling, benefit from their longevity and thermal stability. In pulp and paper industries, duplex tubes withstand aggressive bleaching chemicals. They also find use in marine structures, offshore platforms, and pharmaceutical and food processing units, where hygiene and corrosion resistance are essential.
Why Choose Duplex Steel Tubes from Midland Alloys Inc.
Midland Alloys Inc. is a prominent Indian duplex UNS S31803 tube manufacturer and exporter, providing precision made products to international buyers. As an ISO certified company we maintain rigorous standards of ASTM, ASME and EN specifications for manufacturing processes. Cut-to-length tubing, unique surface treatments, personalized schedules, and customized end finishes are some of our customization options provided by us. In order to satisfy a wide range of consumer requirements, we export to global markets like the Gulf, Europe, Africa and Southeast Asia. Each batch undergoes optional third-party inspections, mill certification and internal testing. We provide effective logistics, and prompt project-specific services for both small orders and bulk exports of products. We focus on long-term partnerships, delivering consistent quality and dependable service. All duplex tubes are marked per ASTM/ASME standards and supplied with Mill Test Certificates (MTCs) confirming full chemical and mechanical compliance.
FAQ’S
Duplex tubes are manufactured from duplex stainless steel with an austenitic and ferritic structure, usually with 22–25% chromium, 5–7% nickel, and 2–3.5% molybdenum.
Duplex steel can be detected using PMI (Positive Material Identification), magnetic testing (it responds to partial magnetism) and microstructure examination that indicates the presence of ferrite and austenite phases.
Steel tube is sized according to its outer diameter (OD), and wall thickness (WT), usually in mm. An example would be a 25 mm OD x 2 mm wall tube would be quoted as 25 x 2 mm.
