Overview
Duplex and Super Duplex Steel Flanges combine the strength of ferritic steel with the corrosion resistance of austenitic steel. They are widely used in offshore, marine, chemical processing, and desalination plants, where superior performance in harsh and chloride-rich environments is required.
Types of Duplex Steel Flanges
Technical Specifications
| Standard | Size Range | Pressure Rating | Face Type |
|---|---|---|---|
| ASME / ANSI B16.5 & B16.47 | ⅛” to 48” | 150# to 2500# | RF, RTJ |
| DIN | DN10 to DN2000 | PN6 to PN400 | RF, FF |
| JIS | 10A to 1500A | 5K to 30K | FF, RF |
Material Grades: Duplex 2205, Super Duplex 2507
UNS: S31803, S32750, S32760, S32900
Chemical & Mechanical Properties
- Tensile Strength: 620 MPa min
- Yield Strength: 450 MPa min
- Hardness: 250 HB max
- Excellent pitting & crevice corrosion resistance
- Balanced ferrite-austenite microstructure
Applications & Industries
Key Features & Benefits
- High resistance to chloride stress corrosion cracking
- Superior strength compared to standard stainless steel
- Excellent performance in seawater & harsh chemicals
- Leak-proof, durable & long service life
- Available in Duplex (2205) & Super Duplex (2507)
Certifications & Quality Assurance
- ISO Certified
- PED & IBR Approved
- Third-party inspection (TPI) available
- Mill Test Certificates (MTC) provided
Frequently Asked Questions
What is the difference between Duplex and Super Duplex flanges?
Super Duplex (2507) offers higher strength and better corrosion resistance than Duplex (2205), especially in seawater and aggressive environments.
Are Duplex Steel Flanges suitable for marine applications?
Yes, Duplex and Super Duplex flanges are ideal for marine and offshore applications due to their excellent chloride resistance.
Which UNS grades are available?
Available grades include UNS S31803, S32750, S32760, and S32900.
Difference Between Duplex 2205 and Super Duplex 2507 Flanges
| Property | Duplex 2205 Flanges | Super Duplex 2507 Flanges |
|---|---|---|
| UNS Grade | S31803 / S32205 | S32750 |
| Chromium Content | 22% – 23% | 24% – 26% |
| Molybdenum Content | 3.0% Approx. | 4.0% Approx. |
| PREN Value | 35 – 40 | Above 40 |
| Corrosion Resistance | Excellent resistance to pitting and stress corrosion cracking. | Superior resistance to pitting, crevice corrosion and chloride attack. |
| Mechanical Strength | Approximately twice the strength of austenitic stainless steels. | Higher strength than Duplex 2205, suitable for extreme service conditions. |
| Marine Performance | Suitable for most offshore and marine applications. | Preferred for highly aggressive seawater and offshore environments. |
| Cost | More economical | Higher cost due to enhanced alloy content and performance. |
| Typical Applications | Oil & Gas Pipelines, Chemical Processing, Heat Exchangers, Pressure Vessels. | Desalination Plants, Offshore Platforms, Marine Systems, High-Chloride Processing Facilities. |
Selection Guide: Duplex 2205 flanges are the preferred choice for general industrial, chemical, and offshore applications requiring excellent strength and corrosion resistance at a competitive cost. Super Duplex 2507 flanges offer significantly higher corrosion resistance and mechanical strength, making them ideal for severe chloride, seawater, and highly aggressive processing environments.
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