API 605 Flanges Suppliers

Dimensions & Pressure Ratings

API 605 Flanges Suppliers

API 605 Standard Flanges: Dimensions | Specifications | Material Grade | Standards | About API 605 | All Product Types

API 605 flanges, once a standard for large-diameter steel pipe flanges, have now been officially replaced by ASME B16.47 Series A flanges. However, many industries still refer to these high-diameter flanges as "API 605 flanges" in technical specifications, making it an essential keyword in procurement and design.

At Nutech, we manufacture and export a wide range of API 605-type flanges, strictly following the dimensional and tolerance requirements of ANSI/ASME B16.47 Series A. These flanges are designed for pipelines with sizes ranging from 26″ to 60″ NB and are available in pressure classes Class 150, 300, 400, 600, and 900.

Our large diameter flanges are engineered for critical applications such as oil & gas transmission lines, petrochemical process systems, seawater intakes, and pressure vessel connections. The flange face types include Raised Face (RF) and Ring Type Joint (RTJ) to meet the sealing needs of different industries.

We ensure full compliance with international codes, pressure rating charts, weight tolerances, and bolt-hole patterns. Every flange is manufactured with tight dimensional control, high-grade materials, and surface finishes suitable for spiral wound gaskets or RTJ rings, based on your specifications.

Our production is backed by comprehensive documentation, EN 10204 3.1 / 3.2 certification, and NACE MR0175 compliance for sour service applications.

API 605 Flanges (ASME B16.47 Series A) – Dimensions, Pressure Ratings, Tolerances, Face Types & Industrial Applications in Large-Diameter Pipeline Systems.

For complete technical details, including dimensions, pressure rating classes, weight charts, sizes, tolerances, and material specifications of our API 605 Standard Flanges, please download the full Catalog PDF below.

Sizes from 26″ to 60″ NB, Pressure Classes 150 to 900, Raised Face & RTJ Face Options, Bolt-Hole Drilling Templates, and Design as per B16.47 Series A Guidelines.

Technical Specifications of API 605 Standard Flange

Specification Details
Standard API 6A
Flange Types API 605 (ASME B16.47 Series A)
Pressure Ratings Weld Neck Flange, Blind Flange
Size Range 26″ to 60″ NB (DN 650 to DN 1500)
Pressure Ratings Class 150, 300, 400, 600, 900
Face Type Raised Face (RF), Ring Type Joint (RTJ)
Drilling Templates As per ASME B16.47 Series A bolt-hole pattern
Dimensional Tolerances Conforming to ASME B16.47 Series A specifications
Surface Finish Stock finish (3.2–6.3 µm), Spiral Serrated, Smooth Face
Marking According to ASME B16.47 Series A – includes class, size, heat number, and material grade
Coating & Protection Black Paint, Rust Preventive Oil, Galvanized
Applications Oil & Gas, Refineries, Petrochemical Plants, Offshore, Power Generation, Marine Piping Systems
Origin Made in India (by Nutech Overseas)
Export Network USA, Europe, and Middle East

Complete Material Grade Chart - API 605 Flange

Material Category API 605 Flange Grades
Stainless Steel API 605 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 API 605 Flange ASTM A182 F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61, UNS S31803 / S32205
Super Duplex Steel API 605 Flange ASTM A182 F53 / F55 / F57 / F59 / F60 / F61, UNS S32750 / S32760
Carbon Steel API 605 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 API 605 Flange ASTM A182 F5 / F9 / F11 / F12 / F22 / F91, AISI 4130 / 4140
Nickel Alloy API 605 Flange Nickel 200 / 201, ASTM B564
Monel API 605 Flange Monel 400 (UNS N04400), Monel K500 (UNS N05500), ASTM B564
Inconel API 605 Flange Inconel 600 / 601 / 625 / 690 / 718 / 783 / X750, ASTM B564
Incoloy API 605 Flange Incoloy 800 / 800H / 800HT (UNS N08800), Incoloy 825 (UNS N08825), Incoloy 925, ASTM B564
Hastelloy API 605 Flange Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X, ASTM B564
Alloy 20 API 605 Flange Alloy 20 / 20Cb-3, Carpenter® 20, ASTM B462
254 SMO API 605 Flange SMO 254 / 6Mo, UNS S31254, DIN 1.4547, ASTM A182
Copper Nickel API 605 Flange Copper Nickel 90/10 (C70600), 70/30 (C71500), UNS C71640, ASTM B61 / B62 / B151 / B152
Copper API 605 Flange TP1, TP2, T1, T2, C10100–C12300, C14200–C17200, C21000–C71520, including C10930, C11000, C11400, C12000, C12200, C26000, C28000, C33000, C44300, C70600, etc.
Brass API 605 Flange Grades 3602, 2604, H59, H62, etc.
Aluminium API 605 Flange Aluminium Grades 5052, 6061, 6063, 2017, 7075, etc.
Titanium API 605 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 the API 605 flange standard and how is it related to ASME B16.47 Series A?

API 605 was a standard issued by the American Petroleum Institute for large-diameter steel flanges, primarily covering sizes from 26″ to 60″ NB in pressure classes ranging from Class 150 to Class 900. It was commonly used in oil, gas, and petrochemical pipelines requiring high-integrity flange connections.

However, the API 605 standard has been officially withdrawn, and its scope has been absorbed into ASME B16.47 Series A, which now governs these dimensions, tolerances, and pressure ratings.

Key Points of Transition:

  • API 605 flanges are now technically referred to as ASME B16.47 Series A flanges.
  • The dimensional characteristics, bolt-hole patterns, and face finishes are maintained in the transition.
  • Most global procurement documents still reference "API 605" for identification, even though the standard in use is ASME.

If your specifications mention API 605, you should source flanges compliant with ASME B16.47 Series A for full compatibility and code compliance.

Why are API 605 (ASME B16.47 Series A) flanges preferred for large-diameter pipeline systems?

API 605 flanges — now governed by ASME B16.47 Series A — are specifically designed to handle the mechanical and sealing challenges of large-diameter piping (from 26″ to 60″ NB), commonly found in high-capacity, high-pressure pipeline networks.

Key reasons for their preference:

  1. Structural Integrity: The large weld neck hub ensures smooth stress distribution, reducing the risk of fatigue or failure in high-pressure lines.
  2. Leak Prevention: Available in RF and RTJ face types, these flanges support strong sealing with spiral wound or metal ring gaskets.
  3. Custom Bolt Patterns: Precision-drilled holes provide reliable alignment and gasket compression in large flange diameters.
  4. International Compatibility: Dimensions conform to ASME standards, enabling global use without customization.
  5. Ease of Maintenance: Ideal for process pipelines where large flanges must be disassembled during inspections or repairs.

This makes them a top choice in oil & gas terminals, refinery header lines, seawater intake pipelines, and offshore riser systems.

What are the key considerations when installing API 605 (ASME B16.47 Series A) flanges?

Installing large-diameter flanges like API 605 / ASME B16.47 Series A requires proper planning, equipment, and technical oversight due to their heavy weight and critical sealing role in high-pressure systems.

Important installation considerations include:

  • Proper Alignment: Ensure precise bolt hole and gasket face alignment to avoid leaks and mechanical stress during tightening.
  • Gasket Compatibility: Use spiral wound, metal jacketed, or RTJ ring gaskets suited to the selected flange face (RF or RTJ).
  • Torque Sequencing: Apply torque in a crisscross pattern using calibrated torque wrenches to ensure uniform gasket compression.
  • Face Surface Check: Inspect flange surface finish (typically 125–250 AARH) and flatness for sealing efficiency.
  • Lifting Equipment: Use appropriate rigging or cranes, as sizes up to 60″ may weigh several hundred kilograms per piece.
  • Fastener Grade: Use ASTM A193 / A194 bolts and nuts, compatible with the flange pressure class and temperature rating.

Correct installation ensures leak-proof operation, joint longevity, and safety compliance in critical service environments.

What materials and coatings are commonly used for API 605 flanges in industrial applications?

API 605 flanges (now ASME B16.47 Series A) are available in a wide range of materials and surface protection options to match the demanding requirements of various industries such as oil & gas, offshore, and chemical processing.

Common Materials Used:

  1. Carbon Steel: ASTM A105, A350 LF2 (for low temperature), A694 F52/F60/F65 (for high pressure pipeline service)
  2. Stainless Steel: ASTM A182 F304, F316, F321 – used in corrosive or high-temperature environments
  3. Duplex & Super Duplex: ASTM A182 F51, F53, F55 – ideal for offshore and seawater service
  4. Alloy Steel: ASTM A182 F11, F22 – suitable for high-temperature and pressure environments
  5. Nickel Alloys & Inconel: For highly corrosive or special applications (available on request)

Typical Surface Coatings:

  • Black Paint – for general rust prevention during shipping/storage
  • Yellow Transparent Varnish – offers short-term protection in controlled environments
  • Hot Dip Galvanizing – zinc coating for long-term corrosion resistance (especially for CS flanges)
  • Anti-Rust Oil Coating – applied internally and externally on carbon steel flanges
  • Customized Coatings – epoxy, PTFE, or ceramic as per client request or project requirement

Selecting the right material and protective finish depends on pressure rating, fluid media, operating temperature, and project location.

Which countries does Nutech export API 605 / ASME B16.47 Series A flanges to?

At Nutech Overseas, we are a trusted global supplier of API 605 (ASME B16.47 Series A) large-diameter flanges, catering to a wide range of industries and EPC contractors around the world.

Our export network spans across:

  1. United States (USA)
  2. Germany, Spain, Italy, France (Europe)
  3. United Arab Emirates (UAE), Saudi Arabia, Oman, Qatar, Kuwait (Middle East)
  4. South Africa, Egypt, Nigeria (Africa)
  5. Indonesia, Malaysia, Philippines, Vietnam (Southeast Asia)
  6. Australia, New Zealand
  7. Brazil, Mexico, Chile (South America)

With a reputation for on-time delivery, strict quality control, and technical compliance, we ensure our flanges meet international codes and client-specific requirements. All export consignments are supported by full inspection documents, MTCs, test reports, and global shipping support.

Whether for offshore, refinery, petrochemical, or pipeline projects — We delivers reliable flange solutions across the globe.

Browse The Products

ASME B16.11 Forged Fittings

Forged Fittings

PDF Icon

Forged Fittings

Get More Details
ASME B16.5 Flanges

Flanges