API 6A Ring Gaskets
API 6A Ring Gaskets are high-pressure sealing elements used in wellhead equipment, Christmas trees, and valve flange connections in the oil and gas industry. They comply with the API 6A (Wellhead and Christmas Tree Equipment) standard.
Types: R type (oval or octagonal), RX type, and BX type
Materials: Soft iron, carbon and low alloy steels, stainless steels, and other CRAs
Standards: API 6A, ASME B16.20
In the oil & gas industry, reliability and safety are non-negotiable — especially in high-pressure wellhead systems. One critical component that ensures leak-free performance is the API 6A Ring Gasket, also known as the API 6A metal ring joint gasket. These gaskets are engineered for extreme pressure, high temperature, and corrosive environments, providing dependable sealing performance for wellhead and Christmas tree equipment.
An API 6A Ring Gasket is a precision-machined metal sealing ring used in high-pressure RTJ (Ring Type Joint) flanges. It conforms to the API 6A Wellhead and Christmas Tree Equipment standard, ensuring compatibility and reliability in upstream oil & gas operations.
These gaskets achieve sealing by metal-to-metal deformation, where the ring gasket is compressed into the RTJ groove of mating flanges under bolting load.
Types of API 6A Ring Gaskets
API 6A covers several commonly used ring gasket profiles. The three most widely used types are:
✔ R-Type (Oval or Octagonal)
- Used for standard pressure RTJ flanges
- Ideal for moderate to high pressure
- Simple and widely available
✔ RX-Type
- Pressure-energized design
- Automatically increases sealing performance as pressure rises
- Suitable for higher pressure ratings
✔ BX-Type
- Used for very high pressure service (up to 20,000 psi)
- Seals both internal pressure and external forces
- Designed for API 6A high-pressure flanges
These profiles ensure proper sealing integrity depending on system pressure and operational conditions.
API 6A Ring Gasket Dimensions
Materials Used for API 6A Ring Gaskets
- Soft Iron
- Carbon Steel & Low Alloy Steels
- Stainless Steel
In the oil and gas, chemical, and seawater system industries, CRA (Corrosion-Resistant Alloy) refers to special metallic materials with high corrosion resistance, such as:
- Inconel series (e.g., 625, 718)
- Incoloy series (e.g., 825, 925)
- Monel 400
- Hastelloy series (e.g., C276, C22)
- Duplex / Super Duplex (e.g., 2205, 2507)
- 904L
- Alloy 20
- Titanium alloys
| Material | Maximum Hardness HRB |
|---|---|
| Soft iron | 56 |
| Carbon and low alloys | 68 |
| Stainless steel | 83 |
| Nickel alloy UNS N08825 | 92 |
| Other CRAs | Hardness shall meet manufacturer's written specification |
Application
API 6A ring gaskets are widely used in upstream oil & gas operations, especially in high-pressure sealing systems. Typical applications include:
- Wellhead equipment
- Christmas trees
- Valves (gate valves, choke valves)
- Spools, casing heads, tubing heads
- RTJ flange connections
Their exceptional sealing performance prevents leaks in critical systems, protecting the environment and ensuring operational safety.
Markings & Identification
Each ring gasket is typically marked with:
- API 6A compliance
- Gasket size (e.g., R-47, RX-70, BX-155)
- Material grade (e.g., 316, Inconel 625)
- Heat treatment condition
- Heat number / batch traceability
Why Choose MillsForge for API 6A Ring Gaskets?
MillsForge provides high-quality API 6A ring gaskets backed by API certification and ISO 9001:2005 quality management. No matter the profile (R, RX, BX) or the material requested (carbon steel, stainless steel, or high-end CRA alloys), MillsForge can meet your engineering, offshore, and high-pressure application requirements.
What We Offer
- Certified API 6A & ISO 9001 products
- Full range of ring gasket profiles
- Custom materials for sour-service and offshore corrosion resistance
- Precision machining with strict tolerance control
- Fast delivery and global supply capability
MillsForge ensures that every gasket meets the highest industry standards for durability, accuracy, and safety.
