Description
Product Detail
A duplex welding neck flange is a forged flange with a long tapered hub that is butt welded to pipe, providing smooth flow transition, strong joint integrity and excellent resistance to pressure, temperature fluctuation and cyclic loading. Duplex and super duplex grades combine high mechanical strength with superior resistance to chloride stress corrosion cracking, pitting and crevice corrosion, making them suitable for offshore, subsea, desalination, chemical and power piping systems.
SASA FLANGE supplies duplex welding neck flanges in standard and customized sizes according to ASME B16.5, ASME B16.47, EN 1092-1, DIN, JIS and GB requirements. Each batch can be supported with chemical analysis, mechanical testing, dimensional inspection, PMI testing, EN 10204 3.1 certificate and full heat number traceability to meet project and end-user specifications.
- ✓Product Name: Duplex Welding Neck Flange
- ✓Material Grade: ASTM A182 F51, F53, F55, F60, F61
- ✓Product Type: Forged Weld Neck Flange
- ✓Main Feature: High strength, butt weld connection, excellent chloride and seawater corrosion resistance
- ✓Applications: Oil and gas, offshore, chemical processing, desalination, power generation and water treatment
Product Parameters
| Product Name | Duplex Welding Neck Flange |
| Material Grade | ASTM A182 F51, F53, F55, F60, F61 |
| Material Type | Duplex Stainless Steel / Super Duplex Stainless Steel |
| Product Form | Forged Weld Neck Flange with tapered hub and butt weld end |
| Size Range | DN15 – DN1500 (1/2 inch – 60 inch) |
| Pressure Class | Class 150 – 2500 / PN10 – PN160 |
| Sealing Face | RF, FF, RTJ, TG, MFM |
| Surface Treatment | Natural machined, pickling, passivation, face protection, anti-rust oil on carbon steel contact areas if required |
| Standard | ASME B16.5, ASME B16.47 Series A/B, EN 1092-1, DIN, JIS B2220, GB/T 9119 or customer specification |
| Inspection | Chemical Analysis, Mechanical Test, PMI Test, Dimensional, Hydrostatic |
| Certificate | EN 10204 3.1 Material Certificate available |
| Processing Service | Cutting, CNC Machining, Custom Drilling, Custom Size Processing |
Chemical Composition
Typical chemical composition shown below is for reference for common duplex grade ASTM A182 F51 / UNS S31803-S32205. Final composition depends on the ordered grade, applicable standard and mill test certificate. For project orders, SASA FLANGE verifies chemistry through raw material certification and positive material identification before shipment.
| Element | C | Si | Mn | P | S | Cr | Ni | Mo | Other |
|---|---|---|---|---|---|---|---|---|---|
| Content % | 0.03 max | 1.00 max | 2.00 max | 0.03 max | 0.02 max | 21.0-23.0 | 4.5-6.5 | 2.5-3.5 | N 0.14-0.20 |
Mechanical Properties
Mechanical properties below are typical reference values for annealed duplex and super duplex forging materials used for weld neck flanges. Actual values can vary by grade, heat treatment condition, product thickness and standard requirements. Final certified values are confirmed by test reports and EN 10204 3.1 material certificate.
| Grade | Tensile Strength | Yield Strength | Elongation | Hardness | Density |
|---|---|---|---|---|---|
| ASTM A182 F51 | 620 MPa min | 450 MPa min | 25% min | 290HB max | 7.80 g/cm3 |
| ASTM A182 F55 | 795 MPa min | 550 MPa min | 15% min | 310HB max | 7.80 g/cm3 |
Common Size Table
| Size Range | Pressure Class | Sealing Face | Material | Availability |
|---|---|---|---|---|
| DN15 – DN50 | Class 150 – 600 | RF | A182 F51 / F60 | Stock / Production |
| DN65 – DN300 | Class 150 – 1500 | RF / RTJ | A182 F51 / F53 / F55 | Stock / Production |
| DN350 – DN600 | Class 150 – 2500 | RF / RTJ | A182 F51 / F55 | Production |
| DN700 – DN1500 | Class 150 – 900 | RF | A182 F51 / F53 / F55 | Made to Order |
Different Specifications Comparison
| Type | Description | Typical Use |
|---|---|---|
| ASME Weld Neck Flange | Forged flange with tapered hub and butt weld end manufactured to ASME B16.5 or B16.47 dimensions | Oil and gas, refinery, petrochemical and high-pressure process lines |
| EN Welding Neck Flange Type 11 | European standard welding neck flange produced to EN 1092-1 with PN rating system | Water treatment, chemical plants, utility and industrial pipe systems in Europe |
| RTJ Duplex Weld Neck Flange | Ring type joint face for high-pressure sealing performance in critical duty service | Offshore, high-pressure injection, gas processing and severe service pipelines |
| Custom Duplex Weld Neck Flange | Non-standard dimensions, drilling, bore or facing produced according to drawing or project specification | Skid packages, OEM equipment, replacement flanges and special engineered systems |
Equivalent Standards and International Names
Duplex welding neck flanges are supplied to international dimensional standards, while the material grade is specified separately according to forging standards such as ASTM A182. Equivalent naming may differ by region, but common duplex grades include 2205 and super duplex 2507. SASA FLANGE can match project specifications across American, European, Japanese and Chinese systems.
| Standard / Region | Standard Code | Typical Grade / Equivalent |
|---|---|---|
| USA | ASME B16.5 | ASTM A182 F51 / F53 / F55 |
| Europe | EN 1092-1 | 1.4462 / 1.4410 |
| Germany | DIN 2633 / 2635 / 2637 | X2CrNiMoN22-5-3 / X2CrNiMoN25-7-4 |
| Japan | JIS B2220 | SUS329J3L / duplex equivalent by project specification |
| China | GB/T 9119 | 022Cr22Ni5Mo3N / 022Cr25Ni7Mo4N |
Production Process Flow
Strict manufacturing control is essential for duplex stainless steel flanges to maintain phase balance, corrosion resistance and dimensional accuracy. SASA FLANGE monitors each production stage from raw material verification to final marking and export packing.
- 1. Raw Material Selection
- 2. Forging / Cutting
- 3. Heat Treatment
- 4. Rough Machining
- 5. Finish Machining
- 6. Drilling
- 7. Surface Treatment
- 8. Inspection
- 9. Marking
- 10. Packing
- 11. Delivery
| Process Step | Description | Quality Control Point |
|---|---|---|
| Raw Material | Select certified forging billets or plates | Material certificate and traceability |
| Forging | Hot forging to achieve required shape | Forging temperature and reduction ratio |
| Heat Treatment | Solution annealing and rapid cooling as required for duplex grades | Temperature and holding time control |
| Machining | Sealing face, bolt holes, dimensions | Dimensional accuracy and surface finish |
| Inspection | Final inspection before shipment | Dimension, surface, PMI, hydrostatic |
Product Inspection
1. Chemical Composition Inspection
Chemical analysis is performed to confirm that chromium, nickel, molybdenum, nitrogen, carbon, sulfur and phosphorus meet the specified duplex or super duplex grade. This verification is based on raw material certificates and can be cross-checked by spectrometer analysis to ensure corrosion resistance and compliance with ASTM A182 and project requirements.
2. Mechanical Properties Testing
Mechanical testing verifies tensile strength, yield strength, elongation and hardness of the forging material after proper heat treatment. These tests help confirm that the duplex welding neck flange has the required strength for high-pressure service while maintaining suitable ductility for fabrication, welding and long-term performance in aggressive industrial environments.
3. Dimensional Inspection
Each flange is checked for outside diameter, thickness, hub dimensions, bore size, bolt circle, bolt hole quantity, hole diameter and raised face or RTJ profile. Dimensional inspection ensures full conformity with ASME, EN, DIN, JIS or GB standards so the flange fits correctly with mating pipe, gasket and bolting assemblies at site.
4. PMI Testing and Hydrostatic Testing
PMI testing is available to confirm alloy identity and prevent material mix-up, which is critical for duplex stainless steel service. Hydrostatic or system pressure testing can be arranged according to order requirements. SASA FLANGE provides EN 10204 3.1 material certificate, inspection records and traceable heat numbers for reliable project documentation and quality assurance.
Product Packaging
- ✓Wooden Case Packaging: Suitable for high-pressure and large-diameter products
- ✓Pallet Packing with Shrink Wrap: Suitable for batch shipments and standard sizes
- ✓Anti-rust Oil Coating + Waterproof Paper: Used for ocean freight protection
- ✓Individual Plastic Bag + Carton: Used for small fittings and threaded products
- ✓Clear Marking: Grade, size, pressure class, heat number and PO number
Applications
Duplex welding neck flanges are widely used where high strength and corrosion resistance are required at the same time. They are especially suitable for chloride-bearing, seawater and aggressive process media, where conventional stainless steel or carbon steel flanges may have reduced service life or higher maintenance requirements.
| Industry | Typical Applications | Why This Product Is Used |
|---|---|---|
| Oil and Gas | Process piping, produced water systems, injection lines, topside modules and refinery units | High strength, pressure resistance and excellent resistance to chloride corrosion and SCC |
| Chemical Processing | Acid handling lines, reactors, storage transfer lines and corrosive chemical piping | Good pitting and crevice corrosion resistance with reliable welded joint performance |
| Power Generation | FGD systems, cooling water lines, condensate systems and auxiliary process piping | Durable performance under pressure, temperature variation and corrosive media exposure |
| Water Treatment | Desalination plants, seawater intake, RO skids and brine handling pipelines | Duplex grades perform well in seawater and high-chloride service environments |
| Marine and Offshore | Shipboard piping, offshore platforms, subsea support systems and firewater lines | Strong corrosion resistance, long service life and reduced maintenance in marine atmosphere |
Why Choose SASA FLANGE?
- ✓Professional manufacturer of Weld Neck Flange for global industrial projects
- ✓Customized size, pressure class and material grade according to drawings
- ✓Full standard support: ASME, EN, DIN, JIS, GB, GOST and customer specifications
- ✓Material traceability with heat number control and EN 10204 3.1 material certificate
- ✓Chemical analysis, mechanical testing, PMI testing, hydrostatic and dimensional inspection
- ✓Stock availability for standard items, lead time 3-7 days; custom production 15-30 days
- ✓Export-grade packaging for sea, air and land transportation
- ✓15+ years experience supplying 50+ countries worldwide
FAQ
Q: What is a duplex welding neck flange?
A: A duplex welding neck flange is a forged flange with a long tapered hub and butt weld end, manufactured from duplex stainless steel. It is designed to provide strong mechanical performance, smooth flow transition and reliable sealing in high-pressure or corrosive piping systems. It is commonly used in offshore, chemical, desalination and process plant applications.
Q: What materials are available for duplex welding neck flanges?
A: SASA FLANGE supplies duplex and super duplex forged grades including ASTM A182 F51, F60, F53, F55 and F61. Equivalent material designations such as 2205 and 2507 can also be supported depending on project requirements. Material selection depends on chloride level, design pressure, temperature and corrosion allowance required by the final service condition.
Q: What pressure class is supported?
A: Duplex welding neck flanges can be supplied in ASME Class 150, 300, 600, 900, 1500 and 2500, as well as EN PN10 to PN160 depending on standard and size. For larger diameters, ASME B16.47 Series A or B is available. The correct class should match the pipeline design pressure, temperature and gasket arrangement.
Q: Can SASA FLANGE supply custom sizes?
A: Yes. SASA FLANGE can manufacture custom duplex welding neck flanges according to drawings or project specifications, including non-standard bore, wall match, hub dimensions, drilling pattern, facing type and special material grades. RF, FF, RTJ and other sealing faces can be machined, and PMI plus dimensional reports can be included for critical orders.
Q: What certificate is provided?
A: Standard supply can include EN 10204 3.1 material certificate with full heat number traceability. Additional documentation may include raw material MTC, chemical composition report, mechanical test report, dimensional inspection report and PMI records. Hydrostatic or third-party inspection can also be arranged according to project, end-user or EPC documentation requirements.
Contact Us
If you are looking for flange duplex welding neck or related custom flange products, please contact SASA FLANGE with your required size, pressure class, material grade, standard, surface treatment, quantity and inspection requirements. Our team will provide professional technical solutions and competitive quotation within 24 hours.
- 📧 Email: sales@sasaflange.com
- 📱 WhatsApp: +86 13764965049
- ☎️ Tel: +86 21 52236361
- 🌐 Website: www.sasaflange.com
