Duplex Flanges
Duplex Flanges are precision-engineered components manufactured from duplex stainless steel, a material known for its exceptional strength and corrosion resistance. These flanges combine the benefits of both austenitic and ferritic stainless steels, offering superior durability in harsh industrial environments. Typically produced through forging or casting processes, they serve as critical connectors in piping systems, ensuring leak-proof joints and structural integrity under high pressure and temperature conditions.
Available in various types such as weld neck, slip-on, blind, and threaded, these fittings accommodate diverse installation requirements. The duplex alloy composition, often including elements like chromium, nickel, and molybdenum, enhances resistance to chloride stress corrosion cracking and pitting. This makes them ideal for use in chemical processing plants, offshore oil and gas platforms, desalination units, and marine applications where exposure to aggressive media is frequent.
From an engineering perspective, these flanges conform to international standards including ASME, ASTM, and DIN, ensuring compatibility and quality assurance across global markets. Their dimensional accuracy and surface finish are tailored to meet stringent industry specifications, facilitating easy integration with existing pipeline infrastructure. The mechanical properties of the material provide excellent tensile strength and toughness, which are crucial for maintaining safety and operational efficiency in demanding industrial setups.
In terms of export readiness, these components undergo rigorous quality control protocols such as non-destructive testing, hardness verification, and chemical analysis to certify compliance with global trade requirements. Packaging is designed to protect against corrosion and mechanical damage during transit, making them suitable for shipment to international destinations. Suppliers often provide comprehensive documentation, including mill test reports and certification, to support seamless customs clearance and project implementation worldwide.
Industrial buyers seeking reliable flange solutions for critical applications will find the duplex stainless steel variants particularly advantageous due to their longevity and performance in challenging environments. Their adaptability across sectors such as petrochemical, power generation, and water treatment underscores their value as a dependable choice for enhancing pipeline system resilience and operational uptime.
Lead Time
2–7 weeks depending on size
Delivery Terms
FOB, CIF, DDP
Shipping Modes
Sea / Air / Express
Why Duplex Flanges Are Preferred by Global Buyers
- ✔ Factory Pricing: Direct manufacturer rates with bulk stock
- ✔ Certified Quality: ISO & 3rd-party tested, EN 10204 certified
- ✔ Export-Ready: Sea-worthy packaging for on-time delivery
- ✔ Fast RFQs: Quick quotes for custom sizes & quantities
- ✔ Traceability: 100% heat number tracking from raw material to finished product
Trusted by industries like oil & gas, petrochemicals, power, marine, and heavy engineering.
- Manufacturing Capacity: 500 MT / Month
- Export Experience: 15+ Years
- Countries Served: 50+
- Annual Export Volume: 5,500 MT
Table of Contents
- 1. What is Duplex Flanges
- 2. How to Choose the Right Manufacturer
- 3.Comparison of Duplex Flanges
- 4. Why Global Buyers Source from Ragnar Metals and Tubes
- 5. Features
- 6. Technical Overview
- 7. Specifications
- 8. Available Grades
- 9. Available Sizes
- 10. Chemical Properties
- 11. Mechanical Properties
- 12. Physical & Thermal Properties
- 13. Electrical Resistivity
- 14. Equivalent Grades
- 15. Manufacturing Process & Heat Treatment
- 16. Various Types
- 17. Applications & Uses
- 18. Industries We Serve
- 19. Latest Price List
- 20. MOQ & Payment Terms
- 21. Export Packaging & Shipping
- 22. Cities We Supply in India
- 23. Countries We Export Worldwide
- 24. Our Certifications
- 25. Quality Inspection & Testing
- 26. Our Other Product Types
- 27. People Also Search For
- 28. Frequently Asked Questions
- 29. About Ragnar Metals and Tubes
How to Choose the Right Duplex Flanges
India is home to hundreds of manufacturers ranging from small job shops to large ISO-certified exporters. International and domestic buyers typically evaluate manufacturers based on quality compliance, production capacity, export experience, and pricing transparency.
- Certification & international standards (ASME, ASTM, EN)
- Manufacturing capability vs trading activity
- Export documentation & inspection support
- Stock availability & lead time reliability
- Past supply experience in oil & gas, EPC & heavy industries
Comparison Factors Among Duplex Flanges
| Evaluation Factor | Small Local Suppliers | Trading Companies | ISO-Certified Manufacturers |
|---|---|---|---|
| Manufacturing Control | Limited | None | Full in-house / audited partners |
| International Standards | Basic | Depends on source | ASME / ASTM / EN |
| Inspection & MTCs | Limited | Inconsistent | EN 10204 3.1 / 3.2 |
| Export Experience | Low | Medium | 50+ countries |
| Risk for EPC Projects | High | Medium | Low |
International buyers typically prefer ISO-certified manufacturers for large-scale or critical applications due to better quality control, documentation, and lower project risk.
Why Global Buyers Choose Ragnar Metals and Tubes
Ragnar Metals and Tubes is a trusted ISO 9001:2015 certified manufacturer and global exporter of ferro alloys and metal products, supplying consistent, high-quality materials to customers across USA, UK, Europe, Middle East, Africa, and Asia-Pacific. Our focus on quality assurance, cost efficiency, and on-time delivery makes us a preferred sourcing partner for international buyers.
| Key Advantage | Buyer Benefit |
|---|---|
| ISO 9001:2015 Certified Manufacturing | Consistent quality with documented QA systems and process control |
| ASME / ASTM / EN Compliant Products | Globally accepted standards with EN 10204 3.1 / 3.2 MTCs |
| Lower Manufacturing & Sourcing Costs | Save up to 15–20% compared to European suppliers |
| Favorable Exchange Rate Advantage | Reduced landed cost for international importers |
| In-House Testing & Inspection Facilities | Strict chemical, mechanical & dimensional quality checks |
| Bulk Stock & High Production Capacity | Fast order fulfillment and stable supply for large projects |
| Custom Sizes & Drawing-Based Manufacturing | Products manufactured exactly to buyer specifications |
| Export-Grade Packaging & Global Logistics | Sea-worthy packing, palletization & worldwide shipping support |
| Faster Global Shipping Routes | Optimized logistics for Middle East, Africa & Southeast Asia |
| Technical & After-Sales Support | Project assistance, documentation & responsive RFQ handling |
| Trusted by Global Steel & EPC Companies | Proven export experience across 50+ countries |
Features of Duplex Flanges
- ✔ High corrosion resistance in aggressive environments
- ✔ Excellent mechanical properties at both room and elevated temperatures
- ✔ Cost-effective alternative to nickel-based alloys
- ✔ Superior weldability and fabrication characteristics
- ✔ Enhanced strength-to-weight ratio
- ✔ Versatile applications across various industries including oil and gas, chemical, and marine
Technical Overview of Duplex Flanges
| Product | Composition | Usage | Standards |
|---|---|---|---|
| Duplex 2205 Flange | 22% Chromium, 5% Nickel, 3% Molybdenum | Used in oil and gas, chemical processing, and marine applications | ASTM A182, ASTM A240 |
| Duplex 2507 Flange | 25% Chromium, 7% Nickel, 4% Molybdenum | Ideal for seawater and chloride environments | ASTM A182, ASTM A240 |
| Duplex UNS S31803 Flange | 22% Chromium, 5% Nickel, 3% Molybdenum | Commonly used in pulp and paper, and wastewater treatment | ASTM A182, ASME SA182 |
Specifications Table
| Material | Duplex Stainless Steel |
|---|---|
| Grades | UNS S32205, UNS S31803 |
| Standard | ASTM A182, ASME B16.5 |
| Size Range | 1/2" to 24" |
| Length | Variable, based on size and class |
| Form | Slip-On, Weld Neck, Blind, Socket Weld |
Available Grades Table
| Product | Composition | Applications |
|---|---|---|
| Duplex 2205 | 22% Cr, 5% Ni, 3% Mo | Oil and gas, chemical processing, marine applications |
| Duplex 2507 | 25% Cr, 7% Ni, 4% Mo | Desalination plants, offshore oil rigs, pulp and paper industry |
| Duplex 2304 | 23% Cr, 4% Ni | Food processing, storage tanks, water treatment |
| Super Duplex 2507 | 25% Cr, 7% Ni, 4% Mo, 0.3% N | High chloride environments, oil and gas, seawater applications |
| Duplex 31803 | 24% Cr, 6% Ni, 3% Mo | Structural components, chemical processing, offshore projects |
Available Sizes of Duplex Flanges (MM)
| Size (MM) | Size (MM) |
|---|---|
| 15 | 20 |
| 25 | 32 |
| 40 | 50 |
| 65 | 80 |
| 100 | 125 |
| 150 | 200 |
| 250 | 300 |
| 350 | 400 |
| 450 | 500 |
| 600 | 700 |
Chemical Properties of Duplex Flanges
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 22.0 - 25.0 |
| Nickel (Ni) | 4.5 - 8.0 |
| Molybdenum (Mo) | 3.0 - 5.0 |
| Iron (Fe) | Balance |
| Manganese (Mn) | 1.0 max |
| Silicon (Si) | 1.0 max |
| Carbon (C) | 0.03 max |
| Sulfur (S) | 0.01 max |
Mechanical Properties of Duplex Flanges
| Property | Value |
|---|---|
| Tensile Strength | 620 MPa (90 ksi) |
| Yield Strength | 450 MPa (65 ksi) |
| Elongation | 25% |
| Hardness (Brinell) | 250 HB |
| Impact Toughness | ≥ 40 J at -50°C |
Duplex Flanges – Physical & Thermal Properties
Density of Duplex Flanges
| Property | Metric | Imperial |
|---|---|---|
| Density | 7,800 kg/m³ | 0.28 lb/in³ |
Melting Point of Duplex Flanges
| Property | Metric | Imperial |
|---|---|---|
| Melting Point | 1,450 °C | 2,642 °F |
Specific Heat of Duplex Flanges
| Specific Heat of Duplex Flanges | ||
|---|---|---|
| Specific Heat (J/kg·K) | Temperature Range (°C) | Condition |
| 500 | 20 - 100 | Solid |
| 650 | 100 - 600 | Solid |
| 700 | 600 - 1,000 | Solid |
Electrical Resistivity of Duplex Flanges
| Electrical Resistivity | ||
|---|---|---|
| Value (µΩ·m) | Temperature (°C) | Treatment or Condition |
| 0.80 | 20 | As-Received |
| 0.82 | 100 | |
| 0.85 | 200 | |
| 0.88 | 300 | |
| 0.90 | 400 | |
Equivalent of Duplex Flanges
| Standard | Werkstoff Nr. | UNS |
|---|---|---|
| ASTM A182 | 1.4462 | S31803 |
| EN 10088-3 | X2CrNiMoN22-5-3 | S32205 |
Manufacturing Process & Heat Treatment of Duplex Flanges
Annealing
Annealing of duplex flanges involves heating the material to a temperature range of 1020°C to 1100°C, followed by a slow cooling process. This treatment reduces internal stresses, enhances ductility, and improves the overall microstructure of the steel, ensuring optimal performance in service conditions.
Forging
The forging process for duplex flanges includes heating the steel to a temperature between 1100°C to 1200°C and then mechanically deforming it to achieve the desired shape. This process enhances the material's mechanical properties, such as strength and toughness, by refining the grain structure.
Hardening & Tempering
| Process | Temperature Range (°C) | Quenching Medium | Purpose |
|---|---|---|---|
| Hardening | 1000 - 1050 | Oil | To increase hardness and strength |
| Tempering | 600 - 700 | Air | To relieve stresses and reduce brittleness |
| Stress Relief | 300 - 400 | Air | To minimize residual stresses after machining |
The combination of these manufacturing and heat treatment processes ensures that duplex flanges possess the necessary mechanical properties and corrosion resistance required for demanding applications in various industries.
Various Types
Duplex Steel Slip-On Flanges
- Dimensions: 1" to 24" NPS
- Condition: ASTM A182, A240
- Applications: Piping systems, oil and gas industry
Duplex Steel Blind Flanges
- Dimensions: 1" to 30" NPS
- Condition: ASTM A182, A240
- Applications: End of a piping system, pressure vessels
Duplex Steel Weld Neck Flanges
- Dimensions: 1" to 36" NPS
- Condition: ASTM A182, A240
- Applications: High-pressure systems, chemical processing
Duplex Steel Socket Weld Flanges
- Dimensions: 1/2" to 4" NPS
- Condition: ASTM A182, A240
- Applications: Small diameter piping, high-pressure applications
Applications & Uses
- Oil & Gas Industry: Pipelines, process piping, and high-pressure fluid handling systems.
- Petrochemical & Refineries: Reactors, heat exchangers, and chemical processing units.
- Water Treatment Plants: Filtration systems, storage tanks, and corrosion-resistant piping.
- Pharmaceutical Industry: Hygienic piping, sanitary fittings, and cleanroom equipment.
- Food & Beverage: Processing lines, storage vessels, and contamination-free pipelines.
- Automobile & Engineering: Exhaust systems, structural parts, and precision components.
- Power & Energy Sector: Boilers, condensers, and turbine piping systems.
- Marine & Offshore: Shipbuilding, offshore platforms, and coastal infrastructure.
- Construction & Infrastructure: Structural frameworks, bridges, and industrial buildings.
Industries We Serve
Our stainless steel, alloy steel, and high-performance metal products are widely used across the following industries:
Latest Price List of Duplex Flanges
| Material Grade | Thickness | Price (USD / Kg) | Price (INR / Kg) |
|---|---|---|---|
| Duplex 2205 | 3 mm | $2.50 – $3.00 | ₹210 – ₹250 |
| Duplex 2205 | 6 mm | $2.80 – $3.30 | ₹235 – ₹270 |
| Duplex 2205 | 10 mm | $3.00 – $3.50 | ₹250 – ₹295 |
Note: Prices are indicative and may vary based on size, quantity, raw material cost, and delivery location. Contact us for the latest quotation for Duplex Flanges.
MOQ & Payment Terms
Minimum Order Quantity: 25–100 Kg depending on part size and grade.
Payment Terms: Depending On Grade and Quantity Size
Export Packaging & Shipping
- Seaworthy, fumigated wooden crates with waterproof inner lining
- Palletised packing with clear shipping marks and heat number identification
- Container stuffing supervision with loading photographs available on request
We Exported to 50+ Countries Worldwide
| Global Export Destinations | |||||
|---|---|---|---|---|---|
| United States | Canada | Mexico | United Kingdom | Germany | Netherlands |
| Italy | Spain | South Africa | Australia | India | Korea |
| United Arab Emirates | Saudi Arabia | Qatar | Kuwait | Oman | Bahrain |
| Singapore | Malaysia | Indonesia | Dubai | Riyadh | Dammam |
Our Certifications
We are a certified manufacturer and exporter, committed to strict quality control and international compliance standards. Below are our key certifications.
GST Registered
ISO 9001:2015
ISO 1002:2018
Udyam MSME Registration
Testing Process & Quality Assurance – Ragnar Metals & Tubes
At Ragnar Metals & Tubes, our testing process ensures the safety, reliability, and performance of stainless steel and alloy steel products supplied for global industrial and infrastructure projects. Each batch is verified from raw material selection to final dispatch under internationally recognized standards including ASTM, ASME, ISO, DIN, and EN.
Detects internal flaws using high-frequency sound waves
Measures yield strength, elongation, and material durability
Evaluates toughness under low-temperature and high-stress conditions
Ensures smoothness, coating quality, and visual compliance
Enhances hardness, strength, and corrosion resistance
Measures resistance to deformation and wear
Documentation & Global Compliance
- ✔ EN 10204 3.1 / 3.2 Mill Test Certificates (MTC)
- ✔ Batch-wise quality traceability and inspection records
- ✔ Third-party inspection by SGS, TUV, Bureau Veritas & Lloyd’s
- ✔ Export documentation support for customs and international shipping
Supporting supply for oil & gas, petrochemical, power generation, marine, infrastructure, and heavy engineering industries worldwide.
Related Products
Explore our full range of stainless steel and alloy steel products including pipes, tubes, fittings, flanges, sheets, plates, spools, fasteners, round bars, and special grades manufactured for industrial, infrastructure, and global export applications.
People Also Search For
- Duplex Stainless Steel
- Flange Types and Applications
- Pipe Flanges
- Weld Neck Flanges
- Blind Flanges
Frequently Asked Questions
About Ragnar Metals & Tubes
- ✔ Leading manufacturer, stockist, and exporter of stainless steel and alloy steel products for industrial and infrastructure projects
- ✔ ISO 9001:2015 certified quality management system ensuring consistent product reliability and compliance
- ✔ Specialized in precision pipes, tubes, fittings, flanges, sheets, plates, fasteners, and round bars
- ✔ Modern processing and testing facilities with advanced manufacturing and inspection equipment
- ✔ Custom-engineered solutions based on client drawings and technical specifications
- ✔ Full material traceability with EN 10204 3.1 / 3.2 mill test certification
- ✔ Compliance with ASTM, ASME, DIN, EN, and ISO international standards
- ✔ Trusted global supplier supporting oil & gas, petrochemical, power, marine, and heavy engineering industries