In industrial piping infrastructure, the connection point is the most critical area for potential failure. Whether you are in oil and gas, chemical processing, or power generation, ASME B16.5 flanges are the global benchmark for safety and performance.
At RAYOUNG, we have spent years manufacturing and exporting high-precision industrial pipe fittings to global projects. In this guide, we dive deep into the technical specifications, flange types, and the procurement insights every project manager needs to know.
1. What is the ASME B16.5 Standard?
ASME B16.5 is the standard for Pipe Flanges and Flanged Fittings, covering sizes from NPS 1/2 to NPS 24. It establishes the baseline for:
- Pressure-Temperature Ratings: Determining how much pressure a flange can hold at specific temperatures.
- Materials: Defining acceptable steel grades (ASTM A105, A182, etc.).
- Dimensions: Bolt hole patterns, flange thickness, and outer diameters.
- Marking: Mandatory requirements for traceability (Material grade, heat number, manufacturer logo).
2. Common ASME B16.5 Flange Types
At RAYOUNG, our most requested B16.5 flange categories include:
- ASME B 16.5 Weld Neck Flanges (WN): Designed for high-pressure and high-temperature services. They feature a long tapered hub that reinforces stress distribution.
- ASME B 16.5 Slip-On Flanges (SO): Popular for their ease of alignment and installation. They slide over the pipe and are fillet-welded at the base.
- ASME B 16.5 Blind Flanges (BL): Used to seal the ends of piping systems, valves, or pressure vessel openings.
- ASME B16.5 Socket-Weld Flanges (SW): Ideal for small-diameter, high-pressure piping.
- ASME B 16.5 Lap Joint Flanges: Typically used with stub ends, ideal for systems that require frequent dismantling for cleaning or inspection.
- ASME B 16.5 Threaded Flanges: Used in specialized applications where welding is not an option (e.g., explosive environments).
ASME B16.5 Flanges Actually Used
3. Technical Specifications & Pressure Classes
ASME B16.5 flanges are categorized by Pressure Classes, which indicate the maximum allowable working pressure. The standard includes the following classes:
- Class 150 / 300 / 400 / 600 / 900 / 1500 / 2500
Quick Reference Guide (Common Dimensions):
- NPS 1/2 to 24: B16.5 scope.
- Bolt Holes: Strictly standardized to ensure international compatibility.
- Facing Types: Raised Face (RF) is the most common, followed by Flat Face (FF) and Ring Type Joint (RTJ) for high-pressure sealing.
(Need a detailed datasheet for a specific class? Contact RAYOUNG for our full technical catalog.)
4. Comparisons: B16.5 vs. B16.36 vs. B16.47 Flanges
- ASME B16.5 vs. B16.36 Flanges: B16.5 flange is for general use. B16.36 flange is specifically for Orifice Flanges, featuring internal pressure taps to measure flow rates in pipes.
- ASME B16.5 vs. B16.47 Flanges: Size is the main factor. B16.5 flange covers up to 24 inches. B16.47 flange covers large diameter flanges from 26 to 60 inches.
5. Our Success Case
At RAYOUNG, we aren’t just a manufacturer; we are a solution provider.
- Water Treatment – Southeast Asia: Delivered a complete set of ASME B16.5 flanges for a seawater desalination plant. Our anti-corrosion packaging guaranteed that the materials arrived in pristine condition, despite the humid maritime climate.
6. How to Choose a Reliable Steel Flange Manufacturer
Sourcing from overseas requires trust. When evaluating your supplier, ensure they offer:
- Full Traceability: Can they provide MTC (Mill Test Certificates) for every batch?
- On-Site Inspection: Do they allow third-party inspections?
- Manufacturing Flexibility: Can they handle both standard mass production and custom-engineered orders?
- Logistics Know-How: Proper crating (fumigated wood) and moisture protection are non-negotiable for overseas shipping.
Rayoung–A leading Butt Weld pipe fittings, flanges, and steel pipes supplier& factory in China.
We’re here to help with your industrial piping and flange needs. Rayoung has been in the business of industrial pipe fittings since 1983, and we’re confident we can help you find a solution more quickly, affordably, and with greater expertise than the competition.
7. ASME B16.5 Flanges FAQ
Q: Can I use a Class 150 flange for a 300 psi system?
A: No. You must consult the B16.5 pressure-temperature rating table, as the maximum rating for a Class 150 flange at elevated temperatures is significantly lower than 300 psi.
Q: What is the difference between Raised Face (RF) and Ring Type Joint (RTJ)?
A: RF uses a gasket between the flange faces. RTJ uses a metal ring inside a grooved face, providing a superior seal for high-pressure, high-temperature applications.
Q: Does RAYOUNG provide custom markings?
A: Yes, we provide full laser-marked branding (Company logo, heat number, size, class, and standard) as per client requirements.
Partner with RAYOUNG – Your Trusted Flange Supplier China
Are you looking for high-quality ASME B16.5 flanges that meet your project’s stringent specifications? RAYOUNG is your factory-direct partner, offering competitive bulk pricing and technical excellence.
Don’t let subpar fittings compromise your project safety.
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📧 Email us at: info@hb-steel.com
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