Understanding Duplex Stainless Steel Flanges: Strength, Corrosion Resistance & Applications
Introduction
In industries where corrosion resistance and mechanical strength are non-negotiable, duplex stainless steel flanges have become the preferred solution. Combining the benefits of both austenitic and ferritic stainless steels, these flanges offer outstanding performance in aggressive environments.
As a trusted manufacturer and supplier in India, Steel Flange MFG provides duplex flanges engineered to meet international standards, including ASME, ANSI, and DIN.
What Are Duplex Stainless Steel Flanges?
Duplex stainless steel contains approximately equal parts of ferrite and austenite, giving it dual-phase properties. This composition results in:
- Twice the strength of regular stainless steel (304/316)
- Superior corrosion resistance, especially against chloride stress-corrosion cracking
- Good weldability and workability
Common grades include:
- UNS S31803 (2205)
- UNS S32205
- Super Duplex – UNS S32750 / S32760
Applications of Duplex Stainless Steel Flanges
Duplex flanges are widely used in:
- Oil & Gas pipelines – Excellent resistance to sour gas and high-pressure conditions
- Chemical processing plants – Withstand aggressive acids and solvents
- Marine industries – Ideal for offshore rigs and seawater environments
- Desalination plants – Resist chloride corrosion and scaling
- Power plants – Tolerant of high heat and pressure fluctuations
Types of Duplex Flanges We Manufacture
At Steel Flange MFG, we offer a full range of duplex stainless steel flanges:
- Weld Neck Flanges (WN) – High-stress systems
- Slip-On Flanges (SO) – Easy installation
- Blind Flanges (BL) – For sealing pipes
- Socket Weld Flanges (SW) – For small-diameter pipelines
- Threaded Flanges (TH) – For non-welded systems
- Lap Joint Flanges (LJ) – For frequent maintenance access
All are available in Class 150, 300, 600, and 900 pressure ratings.
Advantages Over Regular SS Flanges
| Feature | Regular SS (304/316) | Duplex Stainless Steel |
|---|---|---|
| Tensile Strength | Medium | High (up to 2x stronger) |
| Corrosion Resistance | Good | Excellent |
| Chloride Stress Cracking | Moderate Risk | Very Low Risk |
| Temperature Range | -196°C to 870°C | -50°C to 300°C (optimal) |
| Cost | Lower | Moderate but better lifecycle |
Why Choose Steel Flange MFG for Duplex Flanges?
In-house machining & testing IBR & ISO certified Global shipping: UAE, Saudi Arabia, USA, Europe Custom solutions with drawings and quick delivery Third-party inspections on request
Packaging, Shipping & Compliance
All flanges are shipped with:
- Heat numbers & mill test certificates
- Stamped material grade and pressure class
- Rust-proof packaging and export-safe crates
Compliance with:
- ASME B16.5 / B16.47
- DIN 2501 / EN 1092
- API 6A (for oilfield applications)
Conclusion
Whether you’re sourcing for an offshore oil rig, a chemical plant, or a high-pressure steam line, duplex stainless steel flanges offer unmatched reliability. With Steel Flange MFG, you get flanges that are precision-engineered, globally certified, and ready to perform under pressure.
Need Help Choosing the Right Duplex Flange?
Could you let our experts help you?
Email: info@steelflangemfg.com
Website: www.steelflangemfg.com Phone: +91 93511 11359