At API International, we support large diameter ANSI/ASME B16.47 flange requests for NPS 26 to 60 inches in pressure classes 150 through 300, including blind and weld neck styles. Our team can help confirm specifications, bolt patterns, and lead times for your project.
Important note:
Series B
| ASME Pressure Class | Typical Pressure Range (psi) | Common Applications and Service Characteristics |
|---|---|---|
| Class 75 | Low pressure | Water transmission, low pressure utility piping, and general service in large diameter systems (NPS 26–60). |
| Class 150 | Low to moderate pressure | Water systems, HVAC, low pressure steam, fire protection, and general industrial piping. |
| Class 300 | Moderate pressure | Process piping, compressed air, hydrocarbons, and light chemical service. |
| Class 400 | Intermediate pressure | Less common class typically specified for specialized or legacy systems where Class 300 is insufficient but Class 600 is not required. |
| Class 600 | High pressure | Oil and gas processing, steam systems, chemical plants, and power generation. |
| Class 900 | Very high pressure | Refinery service, high pressure process lines, and severe hydrocarbon applications. |
* Pressure depends on material group and operating temperature. Always confirm allowable pressure using ANSI/ASME B16.47 pressure temperature rating tables for the specified material.
Blind flanges serve as the definitive endpoint for a piping system, used to terminate lines or isolate specific process equipment.
Weld neck flanges are a premier choice for high-pressure systems and remain one of the most commonly used flange types.
Slip-ons, threaded, and socket weld flanges are not covered by ASME B16.47 and are instead manufactured to industry (non-ASME) standards. These “industry standard” designs are based on B16.47 bolt patterns, with dimensions varying by manufacturer.
ASME B16.47 covers large diameter flanges from NPS 26 through 60 and includes pressure classes 75, 150, 300, 400, 600, and 900. Final allowable pressure depends on the selected material group and operating temperature, so always confirm using the B16.47 pressure temperature rating tables.
ANSI/ASME B16.47 is divided into Series A and Series B.
Key differences:
Key Similarities:
Series B flanges typically use a smaller bolt circle and commonly use more bolts of a smaller size, while Series A flanges tend to use fewer bolts in larger sizes. Bolt size and quantity are defined by the standard for the specific NPS and class, so always verify the bolt pattern and hardware requirements per the specified Series and pressure class.
ASME B16.5 covers “standard” pipe flanges and flange fittings through NPS 24 (and includes the higher classes up to 2500, depending on size/material).
ASME B16.47 covers large-diameter blind and weld neck steel flanges from NPS 26 through NPS 60. ASME B16.47 covers pressure classes 75, 150, 300, 400, 600, and 900. Additionally, this standard features two dimensional series of flange configurations, Series A and Series B. Because these series have different dimensions, weights, and applications, they are not interchangeable.
Contact API International’s experienced sales team, and we will help you select the right flange for your application. You can also explore our full range of ANSI and ASME flanges in our online product catalog, or contact us for custom flange options designed to meet your project specifications. Get connected with a dedicated sales representative today, or call us at 503.692.3800
• Custom Bolt Holes, Overbore, Counterbore, Tapped, Welds, O-ring Grooves, Threads, Special Serrations, Bevels, Chamfers
• Metric Parallel, Metric Tapered, Parallel (BSPP), Taper Thread (BSPT), UN/UNF/UNC Thread, NPT (National Pipe Thread)
• MWD
• Contact API’s engineering department for exact specifications and tolerances.
Plastic: Delrin, POM, Lexan, Nylon 66, Nylon 6, PEEK, PP, PE, Acetal
Rubber: EPDM, Neoprene, Buna-N, Viton
Aluminum: A2011, A2024, A2017, A5052, A5056, A6061, A6063, A6463, A6082, A7075
Copper: 3600, 3604, 3771
Titanium: 1-28
Steel Series:
• Ductile Iron: ASTM A536
• Carbon/Mild Steel: A105, A36, A516-70, A572-50, etc.
• Stainless Steel:
- 300 Series – 303, 304, 304L, 316, 316L
- 400 Series – 420J2, 430, 434, 442
Special Metals: Hastelloy, Inconel, Incoloy, Duplex 2205, Super Duplex 2507, Chrome Steel, alloys, or their equivalents
Stock Finish, Spiral Serrated (Phonographic), Concentric Serrated, Smooth Finish, Cold Water Finish, MWD, Phonographic
Dipped, Nickel Plating, Zinc Plating (clear, yellow, black, red, blue), Super Agitine, Powder, Painted, Galvanized, Epoxy, Lacquer
Water/Wastewater, Irrigation, Agriculture, HVAC, Marine, Exhaust, Mining, Energy/Power Generation/Oil
• Forged:
- Ring Rolling:
• Materials: Carbon Steel, Stainless Steel, Duplex
• Size: 2–202”
• Cast:
- Centrifugal Casting (Industrial):
• Material: Stainless Steel
- Continuous Casting:
• Stainless Steel
- Sand Casting:
• Material: A536, Stainless Steel, Ductile Iron
- Investment/Lost-Wax/Precision Casting
• Stainless Steel
Machining: Milling, Turning, Facing, Boring, Drilling, Tapping, Counter Sinking, Laser Cutting, Water Jet, Plasma Cutting
Products | Type | Materials | Size Range |
|---|---|---|---|
Flanges | Flat-Face, Raised-Face, & Plate: Slip-On/Ring Weld, Neck, Blind, Socket Weld, Orifice, Reducing, Threaded | See Materials List | 5–202″ |
Gaskets | Molded, Extruded, sheet | EPDM, Buna-N, NBR, Non-Asbestos (GNA), Red Rubber (GRR), Viton | 5–60″ |
Screens For Filters | Basket Screens and Cone Screens (Perforated, Mesh) | Galv. Carbon Steel, Carbon Steel, Stainless Steel | 6”D x 8’-H |
Rings | Exhaust Rings (Marmon Flanges for DPF Filters) | Carbon Steel, Stainless Steel, Aluminum | 1–16” |
Seamless Rolled Rings | Forged | Carbon Steel, Stainless Steel, Aluminum | 1–165” |
Square Hole Rings | Repair Couplers | Stainless Steel, Carbon Steel, Galvanized, Epoxy Coated | 3–32” |
Fabricated Assemblies | Weldments, Pipe Spools, Valve Bodies, Silencer Housings | Carbon Steel, Stainless Steel | 2–24” |
Long/Short Radius Elbows | EN 10253-2–S235, P235GH–P265GH–P265NL and ASTM A234, WPB, WPC/ A420 WPL6, WPL3/ A860 WPHY52/ ASTM A234 WP11, WP22, WP5, WP9–16Mo3 | 304L & 316L Stainless Steel | (45° & 90°): OD: 21.3mm (1/2”)–3048mm (120”) WT: Up to SCH. XXS/160 |
Miscellaneous | Tubesheets / Diffuser Plates / Baffles / Ferrules / Sleeves / Pins | Carbon Steel, Stainless Steel, Duplex | 5–104” |
Who we are
API International is a manufacturer and wholesale distributor of flanges, expansion joints, valves, other pipe fittings and custom fabricated parts. We offer a wide variety of AIS & imported flanges along with other industrial pipe fitting and accessories. Customers turn to us when they need quick delivery of parts and are looking for a higher level of customer service. Standard parts are stocked in one of our conveniently located warehouses for quick distribution throughout the United States.
