ASME B16.47 Flange Standard

Series A & B Flanges Suppliers

ASME B16.47 Flange Standard

ASME B16.47 Standard Flanges: Dimensions | Specifications | Material Grade | Standards | About B16.47 Series A & B Flanges | All Product Types

ASME B16.47 Series A & B Flanges are large-diameter industrial flanges used in high-pressure and high-flow piping systems ranging from 26″ to 60″ nominal bore (DN650 to DN1500). This standard covers weld neck flanges and blind flanges specifically designed for demanding environments like oil & gas, petrochemical, refining, offshore, and power generation sectors. The flanges conform to strict pressure ratings from Class 75 to Class 900, ensuring performance reliability in critical applications.

ASME B16.47 is split into two series:

  • Series A (formerly MSS SP-44): Heavier construction, wider bolt circle diameter, and higher load capacity — suitable for critical service and high-stress environments.
  • Series B (formerly API 605): Lighter, more compact, and cost-effective — widely used where space or weight is a concern without compromising performance.

The standard defines not just dimensions and pressure-temperature ratings, but also tolerances, bolt hole alignment, flange thickness, and gasket compatibility. Each flange is precision machined to meet tight specifications ensuring leak-proof connections and compatibility with international pipe schedules and fittings.

We manufacture and supply both Series A & B flanges with custom drilling templates, surface finishes (Stock Finish, Spiral Serrated, Smooth), and coating options on request. Our flanges are tested as per international quality protocols and supplied with full EN 10204 3.1 / 3.2 certification and NACE, PED, IBR approvals.

Whether you're looking for ASME B16.47 flange dimensions, weight chart, or a reliable exporter of large diameter flanges, Nutech offers a complete solution with global delivery and technical support.

ASME B16.47 Flange Dimensions, Weight Chart, Pressure Ratings, Drilling Templates, and Tolerance Guidelines for Industrial Applications

For complete technical details, including dimensions, pressure rating classes, weight charts, sizes, tolerances, and material specifications of our ANSI B16.47 Series A & B Standard Flanges, please download the full Catalog PDF below.

Large Diameter Weld Neck and Blind Flanges as per ASME B16.47 Series A & B – Sizes 26″ to 60″, Pressure Class 75 to 900, for Oil, Gas, Petrochemical, and Marine Piping Systems

Technical Specifications of ASME / ANSI B16.47

Specification Details
Flange Standard ASME B16.47 Series A (MSS SP-44), ASME B16.47 Series B (API 605)
Flange Types Weld Neck (WN), Blind (BL)
Size Range 26″ to 60″ (DN650 to DN1500)
Pressure Ratings Class 75, 150, 300, 400, 600, 900
Face Types Raised Face (RF), Ring Type Joint (RTJ)
Design Features Defined bolt circle diameters, wall thicknesses, facing finishes, and tolerances as per ASME B16.47
Drilling Template Matches companion flanges according to B16.47 bolt hole specifications (Series A & B)
Surface Finish Stock Finish (125–250 AARH), Spiral Serrated, Smooth Face, RTJ Grooves
Inspection & Testing Hydro Test, PMI, Dimensional Inspection, UT/MPI on request
Applicable Gaskets Spiral Wound, RTJ Ring, Full Face, Raised Face Gaskets
Marking Standard marking per ASME B16.47 including size, pressure class, heat number, and manufacturer’s logo
Application Industries Oil & Gas, Petrochemical, Refinery, LNG Terminals, Offshore Platforms, Power Plants, Marine Infrastructure
Origin Made in India (by Nutech Overseas)
Export Network USA, Europe, and Middle East

Complete Material Grade Chart - Class 150 ANSI B16.47

Material Category B16.47 Flange Grades
Stainless Steel B16.47 Flange ASTM A182 F304 / F304L / F304H, F316 / F316L / F316Ti, F310, F309S, F317 / F317L, F321 / F321H, F347 / F347H, F904L, ASTM A351 CF3 / CF3M / CF8 / CF8M / CF8C, DIN 1.4301, 1.4306, 1.4307, 1.4311, 1.4401, 1.4404, 1.4408, 1.4409, 1.4541, 1.4571, 1.4550, 1.4435, 1.4539
Duplex Steel B16.47 Flange ASTM A182 F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61, UNS S31803 / S32205
Super Duplex Steel B16.47 Flange ASTM A182 F53 / F55 / F57 / F59 / F60 / F61, UNS S32750 / S32760
Carbon Steel B16.47 Flange ASTM A105 / A105N, ASTM A350 LF2, ASTM A694 F52 / F56 / F60 / F65 / F70 / F80, ASTM A216 WCB, DIN 1.0460 / 1.0402 / 1.0619, Die Steel, Mild Steel
Alloy Steel B16.47 Flange ASTM A182 F5 / F9 / F11 / F12 / F22 / F91, AISI 4130 / 4140
Nickel Alloy B16.47 Flange Nickel 200 / 201, ASTM B564
Monel B16.47 Flange Monel 400 (UNS N04400), Monel K500 (UNS N05500), ASTM B564
Inconel B16.47 Flange Inconel 600 / 601 / 625 / 690 / 718 / 783 / X750, ASTM B564
Incoloy B16.47 Flange Incoloy 800 / 800H / 800HT (UNS N08800), Incoloy 825 (UNS N08825), Incoloy 925, ASTM B564
Hastelloy B16.47 Flange Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X, ASTM B564
Alloy 20 B16.47 Flange Alloy 20 / 20Cb-3, Carpenter® 20, ASTM B462
254 SMO B16.47 Flange SMO 254 / 6Mo, UNS S31254, DIN 1.4547, ASTM A182
Copper Nickel B16.47 Flange Copper Nickel 90/10 (C70600), 70/30 (C71500), UNS C71640, ASTM B61 / B62 / B151 / B152
Copper B16.47 Flange TP1, TP2, T1, T2, C10100–C12300, C14200–C17200, C21000–C71520, including C10930, C11000, C11400, C12000, C12200, C26000, C28000, C33000, C44300, C70600, etc.
Brass B16.47 Flange Grades 3602, 2604, H59, H62, etc.
Aluminium B16.47 Flange Aluminium Grades 5052, 6061, 6063, 2017, 7075, etc.
Titanium B16.47 Flange ASTM B381 Gr.1 / Gr.2 / Gr.4 / Gr.5 / Gr.7, UNS R50250 / R50400 / R50550 / R50700 / R52400 / R53400 / R56320 / R56400
Other Special Grades Al6XN, Tin Bronze, Aluminium Bronze, Lead Bronze, Nimonic 75 / 80A / 90

International Flange Standards We Manufacture & Supply

What is ASME B16.47 and why is it used in large diameter flange connections?

ASME B16.47 is a standard that governs the dimensions, pressure ratings, and tolerances for large diameter steel flanges ranging from 26″ to 60″ nominal bore (DN650–DN1500). It is primarily used in industries where high flow capacity, strength, and sealing reliability are critical.

Key reasons ASME B16.47 flanges are used:

  • Covers both Series A & B flanges (formerly MSS SP-44 & API 605)
  • Designed for high-pressure and high-temperature piping systems
  • Ensures uniform bolt circle dimensions, flange thickness, and drilling templates
  • Compatible with Weld Neck (WN) and Blind (BL) flange types
  • Used in applications like oil & gas transmission, LNG terminals, offshore platforms, petrochemical pipelines, and water treatment

This standard ensures that large-diameter connections remain leak-proof, durable, and interchangeable across international projects.

What is the difference between ASME B16.47 Series A and Series B flanges?

The main difference between ASME B16.47 Series A and Series B flanges lies in their design dimensions, bolt patterns, and load capacity, even though both cover sizes from 26″ to 60″ and are used for similar applications.

Parameter Series A Series B
Bolt Circle Diameter (BCD) Wider bolt circle for enhanced strength Smaller bolt circle for compact design
Flange Thickness Thicker and heavier flange design Thinner and lighter flange construction
Bolt Hole Configuration Fewer bolts with larger diameter More bolts with smaller diameter
Load Capacity Higher mechanical strength and rigidity Sufficient strength with reduced weight
Applications Used in critical services like offshore, refining, and petrochemicals Used in process piping where economy and space are key
Compatibility Newer industry standard with higher performance Maintains compatibility with older API 605 systems

Engineers often choose Series A for higher mechanical strength, while Series B is selected for cost-effectiveness and compatibility with older systems.

How do I select between Series A and Series B flanges in a project?

Selecting between ASME B16.47 Series A and Series B flanges depends on several technical and project-specific factors, such as space constraints, pressure requirements, system design, and legacy compatibility.

Key Factors to Consider:

  • Pressure & Load Conditions:
    • Choose Series A when the system requires higher mechanical strength and operates under more critical pressure loads.
  • Space & Weight Considerations:
    • Choose Series B when installation space is limited or weight reduction is a priority — ideal for compact piping layouts.
  • Project Specification or Legacy Systems:
    • Use Series B if your system follows older API 605 standards or existing flanges are Series B.
    • Use Series A for newer specifications or EPC projects that call for stronger, thicker flange profiles.
  • Cost & Material Optimization:
    • Series B flanges are more economical due to reduced material volume.

Always check the design pressure, gasket type, and companion flange compatibility before making a final selection. For custom projects, consulting the project piping class or a qualified engineer is essential.

What are the pressure ratings available in ASME B16.47 flanges?

ASME B16.47 flanges are available in a range of pressure classes that determine their maximum allowable pressure under different temperature conditions. These ratings are defined by ASME standards and are critical when selecting flanges for high-performance piping systems.

Pressure Class Breakdown:

  1. Series A (MSS SP-44 based):
    • Available in Class 150, 300, 400, 600, and 900
  2. Series B (API 605 based):
    • Available in Class 75, 150, 300, 400, 600, and 900

Key Points:

  • The pressure class determines the wall thickness, number and size of bolts, and flange dimensions.
  • These classes also relate to the flange’s temperature-pressure rating as per ASME B16.47 pressure-temperature charts.
  • Higher class = greater strength and sealing capacity.

Always consult the ASME pressure-temperature rating tables to ensure the selected flange class meets the operational pressure at the specified service temperature.

Are ASME B16.47 flanges interchangeable with ASME B16.5 flanges?

No, ASME B16.47 flanges are not interchangeable with ASME B16.5 flanges, as they are designed for different size ranges and dimensional standards.

Key Differences:

  • Size Range:
    • ASME B16.5: Covers flanges from ½″ to 24″ (DN15 to DN600)
    • ASME B16.47: Starts from 26″ to 60″ (DN650 to DN1500)
  • Bolt Hole Patterns & Dimensions:
    • The bolt circle diameters, number of bolts, and flange thicknesses differ completely and cannot be matched or bolted together.
  • Applicable Standards:
    • These two flange types are governed by distinct technical criteria, and their usage depends on system design specifications.

If a pipeline or equipment has a 24″ or smaller nozzle, B16.5 flanges must be used. For anything larger, B16.47 is required. Adapters or transition flanges may be needed if connecting across standards.

What gaskets are suitable for ASME B16.47 Series A & B flanges?

The gasket selection for ASME B16.47 Series A & B flanges depends on the flange facing type, operating pressure, temperature, and media compatibility. Both Series A and Series B flanges are commonly available in Raised Face (RF) or Ring Type Joint (RTJ) facings.

Compatible Gasket Types:

  • For Raised Face (RF) Flanges:
    • Spiral Wound Gaskets (with or without inner/outer rings)
    • Soft Gaskets (Compressed Non-Asbestos, PTFE)
    • Metal Jacketed Gaskets
    • Corrugated Gaskets
  • For Ring Type Joint (RTJ) Flanges:
    • RTJ Ring Gaskets — typically Oval or Octagonal, as per API 6A / ASME B16.20

Selection Notes:

  • Ensure the gasket material is compatible with the temperature and pressure class of the flange.
  • Gasket dimensions must match the Series A or Series B bolt circle and groove specs exactly.
  • Always refer to ASME B16.20 for metallic gasket construction guidelines.

Proper gasket selection ensures leak-free sealing and long-term performance in critical service applications like oil & gas, offshore, and chemical processing.

Which countries does Nutech Overseas export ASME B16.47 flanges to?

Nutech Overseas is a trusted global exporter of ASME B16.47 Series A and Series B flanges, supplying premium-quality Weld Neck and Blind flanges to customers across oil & gas, petrochemical, marine, and power sectors in more than 40 countries.

Key Export Destinations Include:

  • Middle East: United Arab Emirates (UAE), Saudi Arabia, Oman, Qatar, Kuwait, Bahrain
  • Asia: Singapore, Malaysia, Indonesia, Vietnam, Philippines
  • Europe: Germany, Italy, Spain, Netherlands, Poland, France
  • North America: United States, Canada, Mexico
  • Africa: Egypt, Nigeria, South Africa, Algeria
  • South America: Brazil, Chile
  • CIS & Russia: Kazakhstan, Uzbekistan, Russia

We provides custom packaging, documentation (EN 10204 3.1/3.2, PED, NACE), and logistics support to ensure seamless and timely delivery of flanges globally.

Browse The Products

ASME B16.11 Forged Fittings

Forged Fittings

PDF Icon

Forged Fittings

Get More Details
ASME B16.5 Flanges

Flanges