When it comes to piping systems and sheet-metal assemblies, “flange” and “flange plate” are terms you’ll hear all the time. They may sound similar, but knowing their exact differences can save you time, money, and headaches on the job. Here’s an easy-to-read breakdown to help you choose the right component for your stainless steel project.
What Is a Flange?
A flange is a projecting rim or edge, often used to:
- Connect pipes: Flanges join two pipe sections securely with bolts and a gasket.
- Attach valves and fittings: You’ll see flanges on pumps, compressors, and instrument connections.
- Serve as end caps: Blind flanges seal off the end of a pipe.
Key features of flanges:
- Standardized dimensions
Flanges conform to ANSI, DIN, or JIS standards, ensuring compatibility across manufacturers. - Variety of types
Common styles include weld-neck, slip-on, socket-weld, threaded, and lap-joint. - Pressure ratings
Rated by classes (e.g., 150, 300, 600), each flange can withstand specific pressures and temperatures.
What Is a Flange Plate?
A flange plate—sometimes called a flat flange or welding neck ring—is essentially a stripped-down flange without the hub or raised face. It’s a simple, flat, circular disc with bolt holes and often used when:
- Space is limited: No protruding hub means a slimmer profile.
- Cost is a concern: Less material and simpler machining lowers price.
- Custom shapes are needed: Easier to cut and drill in-house for one-off jobs.
Key features of flange plates:
- Uniform thickness
Every flange plate is cut to a precise thickness, making it ideal for sheet-metal applications. - Customizable
You can order stock plates and drill them to match any bolt pattern. - Versatile materials
Available in stainless steel grades like 304, 316, duplex, and more—just like full-fledged flanges.
Flange vs. Flange Plate: When to Use Which
| Criterion | Flange | Flange Plate |
|---|---|---|
| Application | High-pressure piping systems | Light-duty connections, covers, gaskets |
| Installation | Requires welding or threaded joint | Bolt-on or tack weld, minimal prep |
| Cost | Higher (more material, machining) | Lower (simpler design) |
| Profile | Raised face/hub for gasket seating | Flat, thin profile |
| Standards | ANSI/DIN/JIS certified | Custom or standard drilled patterns |
Tips for Seamless Integration
- Match material grade
For corrosive environments, choose 316 or duplex stainless steel for both flanges and plates. - Confirm bolt patterns
Always double-check hole count, diameter, and pitch circle diameter (PCD) before fabrication. - Mind the pressure class
If you’re working above 150 psi, a full flange with a raised face is usually safer. - Consider stock vs. custom
Keep a selection of standard flange plates on hand for quick turnarounds and fabricate custom flanges for critical runs.
Why Marley Metal Technology Co., Ltd. for Stainless Steel Processing?
At Marley Metal Technology Co., Ltd., we specialize in stainless steel fabrication, sheet-metal processing, and custom flanges for export markets worldwide. Whether you need off-the-shelf ANSI flanges or precision-drilled flange plates, our in-house CNC machining and welding teams ensure rapid, high-quality delivery.