API 6A Flanges

Handling extreme pressure and sour service in oilfield setups requires flanges that meet exact standards and ensure secure sealing. Our API 6A Flanges follow 21st Edition standards, supporting 2000 psi to 20000 psi ratings across PSL1 to PSL4.

Standard Specification

API 6A (21st Edition), ISO 10423, ASME B16.5 (Supplementary)

Pressure Rating

2000 psi to 20000 psi (13.8 MPa to 138 MPa) [PSL1-PSL4]

Material

Carbon Steel (A694 F60/F65), Stainless Steel (A182 F6a/F6NM), Duplex (A995 4A/5A)

Nominal Size

1-13/16″ to 21-1/4″ (46mm to 540mm) [Through-bore sizes]

Flange Type

6B (Studded), 6BX (Ring Groove), Blind, Weld Neck [No slip-on/socket weld]

Product Description

Incorrect flange selection can risk joint failure and cause operational delays. We manufacture these flanges using forged carbon steel, stainless steel, or duplex alloys, with RTJ faces for controlled metal-to-metal sealing.

Facing Type

Ring-Type Joint (RTJ) R/RX/BX [No raised face options]

Dimensions

API 6A Table 5.1 (Hub lengths), Table 5.2 (Flange thickness)

Bolt Circle Diameter

API 6A Table 5.3 (e.g., 7-1/16″ 5000psi: 11.00″)

Number & Size of Bolt Holes

Studded connections (e.g., 7-1/16″ 5000psi: 8×1-1/8″ studs) [ASTM A193 B7/B16]

Surface Finish

63-125 μin RA (RTJ grooves), 125-250 μin RA (non-sealing) [API 6A §5.5.5]

Corrosion Resistance

NACE MR0175 compliant materials required for sour service

Temperature Rating

-50°F to +250°F (-46°C to +121°C) [Material/PSL dependent]

Material Certification

API Q1 (mandatory), PSL2+ requiring full traceability

Gasket Compatibility

API 6A RX/BX gaskets only [No spiral-wound/spiral-wound options]

Coating/Plating

Phosphate coating (API 6A §5.5.6), No organic coatings permitted

Manufacturing Method

Forged (ASTM A182) + CNC machining [No castings permitted]

Technical Advantages

API 6A Flanges must resist high-pressure cycling, sour fluid exposure, and temperature shifts. We supply flanges in through-bore sizes from 1-13/16″ to 21-1/4″, CNC machined to meet API 6A Table 5 specifications. 
These flanges maintain a surface finish of 63-125 μin RA in sealing grooves for RX/BX compatibility. Bolt circle and stud sizing match API 6A Table 5.3, with stud grades as per ASTM A193 B7 or B16. 

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Industry Applications

Wellhead Assemblies

Connects casing and tubing heads with ring joint sealing to handle high axial and pressure loads. 

High-Pressure Production Headers

Joins flowline outputs through 6BX flanges, maintaining structural integrity during continuous multiphase fluid transfer in surface production facilities. 

Frac Equipment Manufacturing

Integrates 20000 psi flanges for high-pressure pumping applications, with material compliance to NACE MR0175. 

Manifold Systems

Enables flow routing through studded flanges and BX gasket faces, minimizing leak points in critical areas. 

Blowout Preventer (BOP) Stacks

Uses 6B and blind flanges for safe shutoff, supporting full traceability and PSL4 requirements.

Test Skids and Choke Panels

Interfaces with ring joint flanges for repeatable sealing under cyclic load conditions. 

API 6A Flanges

Flanges Built for Critical Oilfield Sealing

Your upstream operations depend on flange joints that offer safety and compliance without delays. We control each stage of forging, machining, and coating in-house, ensuring conformance to API Q1 and full traceability. 
With no slip-on or socket weld options, we limit your risk of improper installation in pressure-rated applications. These flanges fit into your systems with standard RTJ gaskets, reducing gasket mix-ups during assembly. 

API 6A Flanges

Having Doubts? Our FAQ

Check all our Frequently Asked Question

Are API 6A flanges compatible with standard ASME B16.5 piping?

No, API 6A flanges do not align with ASME B16.5 bolt patterns or gasket styles. They are built for high-pressure oilfield use and follow completely different dimensional charts. Mixing both types risks leakage or joint failure. 

Do your flanges support full material traceability as per API Q1?

Yes, every flange includes heat number mapping, MTRs, and inspection stamps as per API Q1 guidelines. We record all production stages from forging to final CNC machining. This traceability supports PSL2 and higher procurement requirements. 

Do you supply BX gaskets along with BX-type flanges?

We do not supply gaskets by default with flange orders. However, we support sourcing guidance for API 6A BX-type ring gaskets. Each flange is machined to suit only the matching BX profile with no substitutes. 

How are your flanges tested before dispatch?

We conduct dimensional inspection, RTJ surface roughness checks, and hydrostatic pressure tests based on PSL level. Test certificates and visual records are shared with every lot. These checks meet API 6A 21st Edition criteria.

What should we consider before choosing between 6B and 6BX types?

Choose 6B for lower pressures up to 5000 psi and 6BX for compact high-pressure designs up to 20000 psi. 6BX needs BX gaskets and supports metal-to-metal sealing under ring groove tension. Selection depends on your working pressure and field installation layout. 

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LOCATIONS

Global Sales Office

818, Preakness lane, Coppell, Texas, USA – 75019

Registered Office

10-A, First Floor, V.V Complex, Prakash Nagar, Thiruverumbur, Trichy-620013, Tamil Nadu, India.

Operations Office

9/1, Poonthottam Nagar, Ramanandha Nagar, Saravanampatti, Coimbatore-641035, Tamil Nadu, India. ㅤ

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API 6A Flanges

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API 6A Flanges

Need reliable Machining for your next project? Get in touch with us today, and we’ll help you find exactly what you need!

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