Super Duplex Blind Flange: Grades, Specifications & Applications
Super Duplex Blind Flange: Grades, Specifications & Applications
If your piping system needs a blind flange that can withstand chloride-induced stress corrosion cracking, heavy loads, and high pressure, super duplex is the grade to specify. These SD flanges are typically available in grades such as S32750 (also known as F53) and S32760 (F55), offering excellent corrosion resistance and mechanical properties compared to standard duplex stainless steel. This guide covers the grades, specifications, types, and testing methods that make this component and its related fittings a reliable choice for demanding piping systems.
What Makes a Super Duplex Blind Flange Stand Out?
It is resistant to a wide range of corrosive conditions, including chloride-induced stress corrosion cracking, and offers high strength that can withstand heavy loads and pressures. These stainless flanges have higher yield and tensile strength compared to standard duplex stainless steel, and they also show excellent resistance to fatigue, making them suitable for cyclic loading applications.
Blind Flange vs Other Types: Forged, Threaded, Lap Joint & More
Beyond this option, super duplex is manufactured into several other flange stainless types, each suited to different piping needs:
- Forged flanges – feature a raised or flat face with bolt holes, allowing easy welding to pipes or other flanges
- Threaded flanges – have internal threads, providing a secure connection without requiring welding
- Lap joint flange – used with a stub end for applications requiring frequent disassembly
- Slip-on flanges – slide over the pipe end before welding
- Weld neck flanges – provide a tapered hub for smooth flow and high-pressure service
- Socket weld flanges – offer a secure, leak-free connection when properly welded to pipes
Specifications & Size Range
Duplex Pipeline Solutions supplies these super duplex flanges to the following specifications:
- Tensile strength: approximately 415 MPa
- Yield strength: approximately 290 MPa
- Coating: oil varnish
- Pressure class: 150 – 2500
- Size: 1/2″ – 48″
- Face type: RTJ, RF, FF, T&G
- Elongation: 50mm
- Application: aerospace and industrial piping systems
Quality Testing for Super Duplex Blind Flanges
Several inspection methods are used to verify quality before this component leaves the mill:
- Visual inspection – checks for surface irregularities and cracks
- Dimensional inspection – verifies diameter, thickness, and other tolerances
- Magnetic particle testing – detects surface defects such as cracks or discontinuities
- Radiographic testing (RT) – uses X-rays or gamma rays to examine internal structure and defects.
Corrosion Resistance & Piping System Efficiency
Super duplex weld neck flanges and other stainless flanges offer excellent corrosion resistance, especially in aggressive environments, considerably reducing the risk of corrosion-related failures and leaks in the piping system. The chromium layer in these flanges acts as a barrier against corrosive agents, while molybdenum further enhances resistance in chloride-containing environments by increasing resistance to pitting and crevice corrosion.
Why Choose Duplex Pipeline Solutions for Stainless Flanges
- Leading manufacturer of super duplex stainless steel flanges in India
- Available in multiple equivalent grades for broad system compatibility
- Full chemical and mechanical property documentation available on request
