Everything You Need to Know About Steel Flanges: Types, Uses & Industry Standards
Steel flanges are critical components in the industrial piping world. They serve as connecting elements in pipelines, enabling secure, leak-proof, and accessible joints between pipes, valves, pumps, and other equipment. Used across diverse industries—from oil and gas to shipbuilding—flanges must be manufactured with precision and from high-quality materials to ensure long-term reliability.
What Are Steel Flanges?
A steel flange is a flat, round, or square metal ring that is bolted to the end of a pipe. It is typically used in systems where frequent assembly or disassembly is required. Steel flanges allow components to be easily connected or separated for cleaning, inspection, or maintenance. Unlike welded joints, flanged joints offer modularity and flexibility.
️ Common Applications of Steel Flanges
Steel flanges are widely used in:
- Oil & Gas pipelines
- Petrochemical and chemical plants
- Water treatment and wastewater systems
- Power generation plants (thermal, hydro, nuclear)
- Pharmaceutical & food-grade piping systems
- Firefighting systems
- HVAC (Heating, Ventilation, Air Conditioning)
Types of Steel Flanges
Understanding the different types of flanges is essential to choosing the right one for your application:
1. Weld Neck Flange (WNRF)
- Recognized by its long, tapered hub.
- Ideal for high-pressure and high-temperature applications.
- Butt-welded to the pipe, providing excellent stress distribution.
2. Slip-On Flange (SORF)
- Slides over the pipe and is fillet-welded inside and outside.
- Easier to align but slightly less robust than weld neck flanges.
- Common in low-pressure systems.
3. Socket Weld Flange (SWRF)
- The pipe is inserted into a socket and then fillet-welded.
- Best for small-diameter high-pressure piping systems.
4. Blind Flange (BLRF)
- Used to seal the end of a pipeline or valve.
- Enables pressure testing and future pipeline extensions.
5. Threaded Flange
- Screwed onto threaded pipes without welding.
- Suitable for low-pressure and non-critical applications.
6. Lap Joint Flange
- Used with a stub end and preferred in systems requiring frequent dismantling.
- Not suitable for high-pressure environments.
️ Material Grades and Standards
Steel flanges are available in various materials based on the environment and fluid medium. Common grades include:
- Carbon Steel (ASTM A105, A350)
- Stainless Steel (SS304, SS316, SS321)
- Alloy Steel (ASTM A182 F11, F22, F91)
- Duplex and Super Duplex Steel
Industry standards include:
- ASME B16.5
- ANSI B16.47
- DIN EN 1092-1
- BS4504
- JIS B2220
How to Choose the Right Steel Flange
When selecting a flange, consider:
- Pressure Rating: ANSI 150, 300, 600, 900, 1500, and 2500 classes
- Pipe Size and Schedule: To ensure a perfect fit
- Material Compatibility: For corrosion, temperature, and fluid resistance
- Surface Finish & Gasket Selection: To achieve proper sealing
- Bolting and Torque Requirements: To avoid leakage or over-tightening
Benefits of Using Steel Flanges
- Strength & Reliability in high-pressure, high-temperature environments.
- Corrosion Resistance with stainless and alloy steels.
- Ease of Installation & Maintenance, thanks to bolted connections.
- Wide Range of Sizes & Designs to suit various industries.
- Custom Fabrication Available to meet specialized needs.
Why Choose [Your Company Name] for Steel Flanges?
We are a trusted manufacturer and supplier of industrial-grade steel flanges, catering to national and international clients. Our flanges are:
- Manufactured under strict quality controls.
- Tested for pressure, tensile strength, corrosion, and durability.
- Delivered on time with competitive pricing.
- Customizable to your drawings or sample specifications.
Contact Us Today
Looking for a reliable partner for your piping needs?
Let’s discuss how we can support your project with precision-engineered steel flanges.