API 6A Gate Valve

Design and tested in accordance API 6A, high-pressure, heavy-duty valves designed for oil and gas wellhead, Christmas tree, and manifold applications, adhering to American Petroleum Institute (API) specifications. They feature forged steel bodies, bidirectional sealing, and metal-to-metal seating for reliable, durable performance in severe service, with pressure ratings typically from 3,000 to 10,000 psi and PSL 1-3.

 

Key Features and Specifications

• Design Standards: Conforms to API Spec 6A for material, design, and testing, often including API Q1 and ISO 9001 quality management.
• Structure: Usually forged (AISI 4130/4140) or cast, utilizing a slab gate or expanding gate design for tight sealing.
• Sealing: Metal-to-metal sealing between gate and seat, with pressure-energized stem packing and bonnet gaskets.
• Pressure/Temperature: Rated for high pressures 3,000 to 10,000 psi and temperatures ranging from −46∘C to 180∘C.
• Operation: Non-rising stem with needle roller bearings for ease of operation.
• Maintenance: Designed for in-line repairability, with some models allowing for seat and gate replacement without removing the valve from the line.

Applications

• Oil and gas production wellheads.
• Christmas tree equipment.
• High-pressure choke and kill manifolds.
• Severe service, including corrosive and abrasive fluids.

Common Types

• Slab Gate Valves: Single gate unit, often used for general high-pressure applications.
• Expanding Gate Valves: Provides positive mechanical sealing at both high and low pressures.
• Parallel Slide Valves: Provides low torque operation and consistent sealing.

Components & Materials

• Body/Bonnet: Forged steel (e.g., AISI 4130).
• Trim: Often clad or coated with corrosion-resistant alloys (e.g., Inconel, stainless steel) for harsh environments.
• Seats: Metal-seated for durability, with options for soft inserts.

 

 

 

 

Gate Valve Trim Chart

SERVICE CONDITIONS	TRIM	BODY	BONNET	GATE	SEAT	STEM	BSR
General / non-corrosive	AA	A487 4D/4130	4130	4130	4130	4140	1018
General / Slightly Corrosive	BB	A487 4D/4130	4130	410SS	410SS	17-4SS	316SS
General, Moderately Corrosive, CO2	CC	CA6NM / 410SS	410SS	410SS	410SS	17-4SS	316SS
Sour, non-corrosive	DD-NL	A487 4D/4130	4130	4130	4130	4140	1018 ZINC
Sour, non-corrosive	DD-0,5	A487 4D/4130	4130	4130	4130	17-4SS	1018 ZINC
Sour, Slightly Corrosive	EE-0,5	A487 4D/4130	4130	410SS	410SS	17-4SS	316SS
Sour Highly Corrosive, MOD Abrasive, CO2	EE-1,5	A487 4D/4130	4130	410SS	410SS	410SS	316SS
Sour Highly Corrosive, CO2, High Abrasive	EE-NL	A487 4D/4130	4130	410SS	410SS	NITRONIC 50*1	316SS
Sour, Moderately Corrosive, H2S	FF-0,5	CA6NM / 410SS	410SS	410SS	410SS	17-4SS	316SS
Sour, Highly Corrosive, CO2 and H2S	FF-1,5	CA6NM / 410SS	410SS	410SS	410SS	410SS	316SS
Sour, Highly Corrosive, CO2 and H2S	FF-NL	CA6NM / 410SS	410SS	410SS	410SS	NITRONIC 50*1	316SS
High Corrosion Extreme Service	HH-NL *3	4130 w/625 Inlay	4130 w/625 Inlay	INCONEL 718 *2	INCONEL 718 *2	INCONEL 718 *2	316SS

NOTES:

1. INCONEL 718 IS AVAILABLE AS AN UPGRADE.
2. INCONEL 718 IS ONLY “NL” FOR TEMPERATURES K THRU U. INCONEL 725 CAN BE USED UP TO TEMP X.
3. CRA MATERIAL IS NOT AVAILABLE FOR TEMP Y SERVICE.
4. STANDARD TRIM PARTS ARE QPQ NITRIDED.
5. TUNGSTEN CARBIDE, HVOF, HARDFACED GATES AND SEATS ARE AVAILABLE FOR ANY TRIM UPON REQUEST.

TRIM CODE API SPEC.6A RETAINED FLUID RATING MATERIAL CLASS EXPLANATION   T-21 AA STANDARD TRIM For essentially noncorrosive liquids or gases. Typical examples are crude and refined oils, natural or refined gases and processed hydrocarbons. Typical uses are wellheads, manifolds, flowlines and other similar installations requiring a through conduit valve. The temperature limitations ar 0 degrees to 250 degrees F. T-22 BB STAINLESS TRIM  For substantially the same service as T-21 but where the corrosion resistance of 13 Chrome Stainless Steel internal parts are desirable. Also usable for mildly corrosive fluids and gases when limited corrosion of the internal body surfaces can be tolerated. The temperature limitations are 0 degrees to 250 degrees F. Recommended when partial pressure of CO2 is greater than 30. T-23 CC FULL STAINLESS TRIM For any liquid or gaseous product for which the resistance of the 13 Chrome Stainless is adequate. Also used where the resistance of Stainless Steel is desirable from the standpoint of product purity. The temperature limitations are 0 degrees to 250 degrees F. Recommended when partial pressure of CO2 is greater than 30. T-24 EE SOUR GAS AND OIL Primarily for sour gas and oil where resistance to Hydrogen Sulphide embrittlement is required. Also suitable for other chemicals, products or hydrocarbons when H2S is present. May be used when CO2 is present in smaller amount than H2S. The temperature limitations are 0 degrees to 250 degrees F. T-26 FF STAINLESS SOUR GAS AND OIL TRIM Primarily for sour gas and oil when the CO2 content exceeds the H2S content. It is intended to provide resistance to the metal loss type of corrosion usually associated with CO2 plus resistance to Hydrogen Sulphide embrittlement. The temperature limitations are 0 degrees to 250 degrees F. T-27 WATERFLOOD (UNINHIBITED)  Primarily for use in untreated or uninhibited brackish saline water typically associated with oilfield waterflood projects and/or disposal wells in which the internal plastic coating of the body surfaces provides resistance to saltwater corrosion. The internal parts are also resistant to Sulphide embrittlement and corrosion. The temperature limitations are 0 degrees to 250 degrees F. T-36 AA LOW TEMPERATURE – STANDARD TRIM – GENERAL OILFIELD For essentially noncorrosive liquids or gases. Typical examples are crude and refined oils, natural or refined gases and processed hydrocarbons. Typical uses are wellheads, manifolds, flowlines and other similar installations requiring a through conduit valve. The temperature limitations are -50 degrees to 180 degrees F. T-37 EE LOW TEMPERATURE -SOUR GAS AND OIL Primarily for sour gas and oil where resistance to Hydrogen Sulphide embrittlement is required. Also suitable for other chemicals, products or hydrocarbons when H2S is present. May be used when CO2 is present in smaller amount than H2S. The temperature limitations are -50 degrees to 180 degrees F.