Type 6B/6BX Flanges
API 6A Standard Flanges: Dimensions | Specifications | Material Grade | Standards | About API 6A | All Product Types
API 6A flanges are high-performance, pressure-rated components used in wellhead systems, Christmas Tree assemblies, and other critical equipment in upstream oil and gas production. These flanges are designed to meet the rigorous requirements of the API 6A standard, which governs wellhead and tree equipment. At Nutech, we manufacture and export API 6A flanges that conform to the latest edition of the specification, including Type 6B and Type 6BX flanges, supporting pressure classes from 2,000 psi to 20,000 psi.
Our product range includes weld neck, blind, companion, and studded flanges for various wellhead configurations. These are manufactured in compliance with PSL 1 to PSL 4 (Product Specification Levels) and tested as per PR1 and PR2 requirements. We also supply EE and FF designated flanges with metal-to-metal sealing suitable for sour service environments and NACE MR0175/ISO 15156 compliance.
API 6A Type 6B flanges are bolted with ring gaskets and are widely used in upstream pipelines and manifolds, while Type 6BX flanges are compact, high-pressure-rated, and feature a gasket-less metal seal for critical pressure applications such as blowout preventers (BOPs) and Xmas Tree assemblies.
Each flange is forged from high-strength alloy steel and undergoes rigorous non-destructive testing, including hydrostatic testing, ultrasonic inspection, and hardness checks. Material traceability and certification as per EN 10204 3.1/3.2 are provided.
As a reputed API 6A flange manufacturer and exporter, Nutech supplies equipment to global markets including USA, Saudi Arabia, UAE, Qatar, Iraq, Indonesia, and Europe, supporting oilfield service contractors, EPC firms, and rig OEMs with custom machining, fast lead times, and strict adherence to API standards.
For complete technical details, including dimensions, pressure rating classes, weight charts, sizes, tolerances, and material specifications of our API 6A Standard Flanges, please download the full Catalog PDF below.
Specification | Details |
---|---|
Standard | API 6A |
Flange Types | Type 6B, Type 6BX, Weld Neck, Blind, Companion, Studded Face Flanges |
Pressure Ratings | 2,000 psi to 20,000 psi (Class 2000 – 20000) |
Size Range | 1 13/16″ to 26 3/4″ |
Product Specification Levels | PSL 1, PSL 2, PSL 3, PSL 3G, PSL 4 |
Material Classes | AA, BB, CC, DD, EE, FF, HH (NACE-compliant grades available) |
Temperature Ratings | Grades L, P, R, S, T, U, V, X (as per API 6A Annex) |
Testing Levels | PR1 and PR2 (Performance Rating Levels) |
Sealing Type | Metal-to-Metal Seal (for 6BX), Ring Joint (for 6B) |
Surface Finish | As per API 6A requirements – Stock Finish, Spiral Serrated |
Applications | Wellhead Assemblies, Christmas Tree Equipment, Blowout Preventers (BOP), Choke & Kill Manifolds, Subsea Equipment |
Documentation | EN 10204 3.1 / 3.2, NACE MR0175 / ISO 15156, Mill Test Certificates |
Application Industries | Oil & Gas, Petrochemical, Power Generation, Water Treatment, Food & Beverage, Fire Protection Systems, Pulp & Paper, Shipbuilding, HVAC, Offshore |
Origin | Made in India (by Nutech Overseas) |
Export Network | USA, Europe, and Middle East |
Material Category | API 6A Flange Grades |
---|---|
Stainless Steel API 6A 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 6A Flange | ASTM A182 F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61, UNS S31803 / S32205 |
Super Duplex Steel API 6A Flange | ASTM A182 F53 / F55 / F57 / F59 / F60 / F61, UNS S32750 / S32760 |
Carbon Steel API 6A 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 6A Flange | ASTM A182 F5 / F9 / F11 / F12 / F22 / F91, AISI 4130 / 4140 |
Nickel Alloy API 6A Flange | Nickel 200 / 201, ASTM B564 |
Monel API 6A Flange | Monel 400 (UNS N04400), Monel K500 (UNS N05500), ASTM B564 |
Inconel API 6A Flange | Inconel 600 / 601 / 625 / 690 / 718 / 783 / X750, ASTM B564 |
Incoloy API 6A Flange | Incoloy 800 / 800H / 800HT (UNS N08800), Incoloy 825 (UNS N08825), Incoloy 925, ASTM B564 |
Hastelloy API 6A Flange | Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X, ASTM B564 |
Alloy 20 API 6A Flange | Alloy 20 / 20Cb-3, Carpenter® 20, ASTM B462 |
254 SMO API 6A Flange | SMO 254 / 6Mo, UNS S31254, DIN 1.4547, ASTM A182 |
Copper Nickel API 6A Flange | Copper Nickel 90/10 (C70600), 70/30 (C71500), UNS C71640, ASTM B61 / B62 / B151 / B152 |
Copper API 6A 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 6A Flange | Grades 3602, 2604, H59, H62, etc. |
Aluminium API 6A Flange | Aluminium Grades 5052, 6061, 6063, 2017, 7075, etc. |
Titanium API 6A 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 |
The key differences between API 6A 6B and 6BX flanges lie in their design, sealing mechanism, and pressure ratings:
Type 6B Flanges:
Type 6BX Flanges:
In general, 6BX flanges are more compact and robust, making them suitable for critical pressure systems like subsea trees, BOPs, and kill lines.
Product Specification Levels (PSL) in API 6A flanges define the technical and quality requirements for materials, testing, and documentation based on the intended application’s severity. They are critical in oil & gas to ensure performance, traceability, and safety.
Here’s a breakdown:
Choosing the correct PSL is vital to ensure long-term reliability of flanged connections under extreme pressure and temperature variations.
API 6A flanges are designed for high-pressure wellhead and Xmas tree equipment, and their selection depends on operating pressure, temperature, and service conditions.
The available pressure ratings (classes) under API 6A are:
Selection Criteria:
API 6A strictly regulates these pressure classes, ensuring flanges are matched correctly with other equipment such as valves and connectors.
API 6A flanges are manufactured using strictly controlled material grades, defined by Material Class Codes such as AA, BB, DD, EE, and so on. These classes indicate mechanical strength, corrosion resistance, and NACE compliance.
Here are the commonly used material classes:
These materials are tested to meet:
Nutech offers full traceability and documentation for all materials, compliant with PSL levels and application requirements.
API 6A flanges are engineered for use in high-pressure, high-risk environments typically found in upstream oil & gas operations. Their robust design, PSL classifications, and sealing types make them suitable for:
Primary Applications:
These flanges are selected for their sealing integrity under cyclic pressure, corrosion resistance, and API 6A standardization, which ensures interoperability across OEM components.
In critical zones like offshore rigs, desert fields, and sour service reservoirs, API 6A flanges are essential for system safety and performance.
We are a trusted manufacturer and global exporter of high-performance API 6A flanges, catering to the stringent requirements of the oil & gas, drilling, and offshore sectors across continents.
Key Export Destinations Include:
With on-time delivery, PSL-certified documentation, and tailored packaging, Nutech ensures its API 6A flanges meet global project specifications for both onshore and offshore installations.