Description
API 6A Flanged Gate Valve for Wellheads, Christmas Trees, Flowheads, Manifolds and Replacement Projects
SGPE supplies API 6A flanged gate valves for oil and gas wellheads, Christmas trees, surface test trees, flowheads, injection wellheads and high-pressure manifold systems.
Built for on-off pressure isolation, the valve combines an API ring-type-joint connection with a full-opening or through-conduit bore. Typical installation positions include lower and upper master valves, production and kill wing valves, swab valves, annulus outlet valves and manifold isolation valves.
Oilfield buyers may also refer to this product as an API 6A flange-end gate valve, flange-to-flange gate valve, double-flanged wellhead valve, API RTJ gate valve, flanged master valve or replacement Christmas tree valve.
Correct valve selection involves more than nominal size and working pressure. The flange designation, ring-gasket number, minimum bore, face-to-face dimension, bolt-hole orientation and operator clearance must also suit the adjoining wellhead equipment.
Available configurations include API 6B and API 6BX connections, manual or hydraulic operation, rising or non-rising stems and forged or selected cast pressure-containing bodies. Wells containing sand, H₂S, CO₂, chlorides or other aggressive media may require hardfaced sealing surfaces, CRA trim, corrosion-resistant stems, ring-groove inlay or Alloy 625 overlay.
Common rated working pressures range from 2,000 to 20,000 psi. Final availability depends on the valve size, bore, end connection, gate design, material class, temperature class, Product Specification Level, Performance Requirement and approved manufacturing range.
API 6A Flanged Gate Valve Highlights
API 6A flanged gate valves are available with API 6B or API 6BX RTJ connections in flange-to-flange and double-flanged arrangements. Depending on the approved design, the valve can provide a full-opening or through-conduit bore, bidirectional isolation and metal-to-metal primary sealing.
Manual versions can use a handwheel or gearbox, while hydraulic configurations can support remote operation and selected fail-safe functions. Pressure-containing bodies may use forged construction or selected approved cast designs according to the size, pressure class and project requirements.
For abrasive well fluids, hardfaced gates and seats can improve resistance to sand, scale and proppant. Defined sour or corrosive environments may require CRA trim, corrosion-resistant stem materials, stainless-steel ring-groove inlay or Alloy 625 overlay.
The supply scope can also include dimensional matching for existing wellhead equipment, compatible ring gaskets, flange bolting, spare parts, technical drawings, test records and factory or approved third-party inspection.
Reference Technical Specifications
The following data provides preliminary selection guidance. Final values are confirmed in the approved technical data sheet and general arrangement drawing.
| Parameter | Typical Supply Options |
|---|---|
| Product | API 6A Flanged Gate Valve |
| Alternative Names | Flange-end, flange-to-flange, double-flanged or RTJ wellhead gate valve |
| Primary Function | On-off pressure isolation |
| Main Applications | Wellheads, Christmas trees, test trees, flowheads and manifolds |
| Applicable Standard | Applicable requirements of API Specification 6A and ISO 10423 |
| Valve Design | Selected slab or expanding gate configuration |
| Common Nominal Size | Approximately 1-13/16 in. to 7-1/16 in. |
| Working Pressure | 2,000 to 20,000 psi, subject to configuration |
| Bore | Full opening or through conduit |
| End Connection | API 6B or API 6BX RTJ flange |
| Connection Layout | Flanged × flanged or approved project-specific arrangement |
| Bonnet | Bolted or design-specific bonnet |
| Operation | Handwheel, gearbox or hydraulic actuator |
| Stem Type | Rising or non-rising stem |
| Body Construction | Forged or selected cast body |
| Sealing Direction | Bidirectional in applicable designs |
| Seat System | Pressure-energized or design-specific arrangement |
| Product Specification Level | PSL 1, PSL 2, PSL 3, PSL 3G or PSL 4, as specified |
| Performance Requirement | PR1 or PR2, as specified |
| Material Class | AA, BB, CC, DD, EE, FF or HH, according to the approved design |
| Temperature Rating | API temperature class or project-specific range |
| Service Fluids | Oil, gas, condensate, produced water, injection fluid and multiphase flow |
| Sour Service | Materials reviewed for defined H₂S conditions |
| Abrasive Service | Hardfaced gate and seat options |
| CRA Options | CRA trim, ring-groove inlay or Alloy 625 overlay |
| Position Indication | Local indicator, limit switch or remote feedback |
| Testing | Hydrostatic, seat and functional testing |
| Inspection | Factory or approved third-party inspection |
| Documentation | Drawings, certificates and reports according to the purchase order |
Not every nominal size is available with every pressure class, material class, PSL, PR or gate design. The final combination is confirmed after review of the project specification.
API 6A Working-Pressure Classes
| Rated Working Pressure | Metric Equivalent | Typical Oilfield Use |
| 2,000 psi | 13.8 MPa | Conventional lower-pressure wellheads and manifolds |
| 3,000 psi | 20.7 MPa | Production trees, outlets and gathering systems |
| 5,000 psi | 34.5 MPa | Production trees, injection wellheads and well-test systems |
| 10,000 psi | 69.0 MPa | High-pressure trees, flowheads and manifolds |
| 15,000 psi | 103.5 MPa | High-pressure gas, offshore and well-test service |
| 20,000 psi | 138.0 MPa | Selected extreme high-pressure configurations |
These applications are illustrative only. The required pressure class must follow the approved wellhead design and project specification.
The valve body, end connections, ring gasket, bolting and adjoining equipment must use compatible pressure ratings. Matching the nominal size alone does not create a suitable pressure-containing connection.
What Is an API 6A Flanged Gate Valve?
An API 6A flanged gate valve isolates pressure in upstream surface equipment.
The valve uses a ring-type-joint flange at one or both ends. A metal ring gasket sits inside machined grooves on the mating flange faces, while studs and nuts hold the connection under the required preload.
When fully open, the gate port aligns with the body bore and creates a straight flow passage. Depending on the application, the valve may carry crude oil, natural gas, condensate, produced water, completion fluid, kill fluid, injection water, injection gas or multiphase well flow.
When the valve closes, the solid gate section moves across the bore and isolates pressure.
Unlike a general industrial flange-end valve, a wellhead gate valve may encounter high pressure, full differential pressure, sour gas, produced water, chlorides, formation sand, scale and completion debris. It may also operate in offshore marine environments, desert locations or low-temperature regions.
The valve should normally remain fully open or fully closed. It provides isolation, while an adjustable or positive choke controls pressure reduction and flow rate.
API Flange and RTJ Connection Interface
A complete API flange interface includes the flange body, ring groove, metal ring gasket, bolt-hole pattern, studs, nuts and internal bore.
Each part affects assembly, sealing and compatibility with the adjoining equipment.
| Interface Element | Main Function | Information Required |
| Flange Designation | Defines the pressure-containing connection | Flange type, nominal size and pressure class |
| Ring Groove | Locates the metal sealing ring | Groove profile, condition and overlay requirement |
| Ring Gasket | Seals the mating flange faces | R, RX or BX type and exact ring number |
| Studs and Nuts | Apply connection preload | Size, grade, length and coating |
| Bolt-Hole Pattern | Controls assembly and orientation | Bolt circle and clocking |
| Minimum Bore | Maintains the internal flow path | Bore size, alignment and drift |
| Face-to-Face Dimension | Controls installation fit | Approved GA drawing or field measurement |
| Mating Equipment | Defines the adjoining interface | Tree, spool, manifold or companion-flange drawing |
The valve must match the adjoining tree cross, wellhead spool, manifold or companion flange in connection type, pressure class, ring groove, ring number, bolt pattern and bore.
For this reason, an API 6A flanged gate valve should never be selected from nominal size alone.
Flange-End, Double-Flanged and Flange-to-Flange Valves
Oilfield RFQs often use several names for the same basic connection arrangement.
A purchaser may request an API 6A flange-end gate valve, flange-ended valve, flange-to-flange gate valve, double-flanged wellhead valve, RTJ gate valve or ring-joint isolation valve.
“Double flanged” and “flange-to-flange” normally mean that both valve ends use flanged connections. These descriptions do not confirm the exact flange design, ring gasket, minimum bore or installation length.
A complete inquiry should identify the nominal size, working-pressure class, flange designation, ring-gasket number, minimum bore, face-to-face dimension, bolt-hole orientation and required operator position. For an existing installation, photographs and drawings of the mating equipment should also be included.
API 6B and API 6BX Flange Options
| Flange Type | Typical Use | Ring-Gasket Arrangement | Main Selection Data |
| API 6B | Conventional production wellheads, tree outlets and manifolds | R or RX, depending on designation | Size, pressure, ring number and installation length |
| API 6BX | High-pressure trees, flowheads, injection and offshore equipment | BX pressure-energized ring gasket | Size, pressure, BX number, bore and bolt orientation |
API 6B connections commonly appear on production wellheads, casing-head outlets, tubing-head outlets, conventional Christmas trees and manifold systems. Depending on the designation, the connection may use an R or RX ring gasket.
API 6BX connections commonly use BX pressure-energized rings. They often appear on high-pressure gas wellheads, surface test trees, flowheads, offshore production equipment and injection systems.
Similar-looking flanges may use different grooves, bolting patterns or internal bores. Always provide the complete connection designation and ring number.
RTJ Ring-Gasket Selection
RTJ means ring-type joint. A metal ring fits into the grooves on two mating flange faces and creates the pressure-sealing interface.
| Ring-Gasket Family | Common Association | Selection Requirement |
| R | Selected conventional RTJ connections | Match the exact flange designation and ring number |
| RX | Selected pressure-energized RTJ connections | Confirm compatibility with the mating groove |
| BX | High-pressure API 6BX systems | Match the size, pressure class and BX number |
The sealing ring should not be selected from nominal valve size alone. An incorrect ring can prevent assembly or cause leakage during pressure testing.
Once the interface has been confirmed, compatible ring gaskets, flange studs and nuts can be supplied with the valve.
Mating Flanges and Companion Equipment
An API 6A flanged gate valve may connect to another valve, a Christmas tree cross, wellhead spool, adapter spool, double-studded adapter, manifold block or companion flange.
The adjoining component must match the valve in connection type, nominal size, working pressure, ring number, bore diameter, bolt-hole pattern and flange-face orientation.
A companion flange or adapter should not reduce the working-pressure rating or minimum bore of the complete system.
When a new valve connects to existing or non-standard equipment, the mating drawing, surrounding piping and available installation space should be reviewed before final approval.
Face-to-Face Dimension and Installation Fit
The face-to-face dimension, also referred to here as the valve installation length, measures the distance between the two flange faces.
This dimension becomes critical when a new valve must fit an existing Christmas tree, wellhead or manifold without changing nearby equipment.
Installation length varies with nominal size, pressure rating, flange design, minimum bore, body construction, gate arrangement, bonnet design and manufacturer series.
For new wellhead packages, the dimensions are confirmed in the approved GA drawing.
For existing equipment, provide the current face-to-face dimension, overall valve height, bore centerline, handwheel diameter, actuator envelope, bolt-hole orientation and available operating clearance.
Generic catalog dimensions should not be used to approve a replacement valve.
Bolt-Hole Clocking and Operator Orientation
Bolt-hole clocking can change the final position of the handwheel, gearbox or hydraulic actuator.
An incorrect orientation may place the operator against nearby piping, restrict handwheel access, block the position indicator or make flange studs difficult to install.
For replacement and brownfield projects, the flange clocking, stem direction and operator envelope should be checked before the final drawing is issued.
Full-Opening and Through-Conduit Bore
A full-opening or through-conduit bore helps maintain a straight flow path through the valve and adjoining wellhead equipment.
When fully open, the valve reduces unnecessary restriction, pressure loss and turbulence. The straight bore also improves alignment through the Christmas tree and reduces areas where sand or debris can collect.
Where the complete system bore permits, the valve may support slickline, wireline or coiled-tubing access.
However, nominal flange size does not always equal minimum bore. For intervention, drift or replacement applications, state both the required bore and drift diameter.
Gate Valve Operating Principle
The gate moves vertically between two seat assemblies.
In the open position, the gate port aligns with the body bore. In the closed position, the solid gate section blocks the flow path and isolates pressure.
Selected configurations may use a parallel slab gate with pressure-energized seats or a ported gate with an expanding segment. The approved internal design determines sealing direction, body-cavity behavior, operating torque, stem movement and maintenance requirements.
The flange defines the external connection. It does not define the complete internal valve design.
Further information about internal construction and operation is available on the related SGPE pages for API 6A FC Gate Valves, API 6A FLS Gate Valves, API 6A Slab Gate Valves, API 6A Expanding Gate Valves, API 6A Manual Gate Valves and API 6A Hydraulic Gate Valves. These pages explain the differences between the available gate designs, body configurations and operating methods.
Typical Oil and Gas Applications
| Valve Position or System | Main Function | Key Selection Data |
| Lower Master Valve | Provides primary vertical well isolation | Tree bore, flange, pressure and service fluid |
| Upper Master Valve | Provides secondary vertical isolation | Face-to-face dimension and operator clearance |
| Production Wing Valve | Isolates the production outlet | Fluid, sand content and shutdown requirement |
| Kill Wing Valve | Provides kill or circulation access | Fluid compatibility and reopening torque |
| Swab Valve | Controls vertical intervention access | Minimum bore and drift |
| Annulus Outlet Valve | Isolates the casing or tubing annulus | Outlet connection and orientation |
| Surface Test Tree Valve | Controls flow during well testing | Hydraulic operation and fail position |
| Flowhead Valve | Isolates production and kill branches | Bore alignment and connection interface |
| Production Manifold Valve | Isolates well inlets and headers | Branch orientation and operator access |
| Injection Wellhead Valve | Controls water, gas or chemical injection | Fluid chemistry and temperature |
| Flowback Isolation Valve | Isolates choke and separator branches | Solids content and erosion conditions |
| Replacement Valve | Fits existing tree or manifold equipment | Exact interface and dimensional data |
Wellhead and Christmas Tree Isolation
Master, wing and swab valves provide isolation at key positions in a Christmas tree.
The master valve sits in the main vertical bore. Many trees use a lower and an upper master valve to create two pressure barriers.
The production wing valve isolates the tree outlet before the production choke. During normal production, the gate valve remains fully open, while the downstream choke controls flow rate.
The kill wing valve provides access for well killing, circulation, stimulation, pressure equalization or chemical injection. Because it may remain closed for long periods, reliable sealing and reopening performance remain important.
The swab valve controls vertical access for slickline, electric-line, wireline and coiled-tubing work. Its minimum bore must match the intervention equipment.
Surface Test Trees and Flowheads
Surface test trees and flowheads control the well during testing, cleanup, temporary production and intervention.
Flanged gate valves may isolate the main bore, production outlet, kill inlet, swab access or emergency shutdown path.
Hydraulic operation often supports remote control and repeated cycling. Actuator selection should account for control pressure, fail position, opening and closing time, hydraulic volume, maximum differential pressure and position-feedback requirements.
Production and Test Manifolds
Flanged gate valves isolate well inlets, production headers, test headers, separator branches, choke branches, bypass lines and pressure-test connections.
Consistent connection sizes, installation lengths and operator positions simplify manifold fabrication and field installation. They can also reduce spare-parts complexity across multi-well facilities.
The gate valve provides isolation only. A choke should control normal pressure reduction and flow rate.
Injection, Flowback and Well Cleanup
API 6A flanged gate valves can support water injection, produced-water reinjection, gas injection, chemical injection, gas lift and disposal-well service.
Injection fluids may create different corrosion risks from production fluids. The technical review should consider pressure, chlorides, dissolved oxygen, H₂S, CO₂, chemical additives, temperature and scaling tendency.
During flowback or well cleanup, the valve may encounter oil, gas, completion fluid, produced water, sand, scale and proppant. Hardfaced trim can improve wear resistance, although the gate valve should still operate fully open or fully closed.
Replacement, Retrofit and Brownfield Projects
Older wellheads may use discontinued valve series, manufacturer-specific dimensions or limited installation envelopes. A suitable replacement therefore requires more than the same nominal size and pressure rating.
A project-specific drop-in replacement remains subject to dimensional and engineering approval.
| Required Information | Why It Matters |
| Valve Nameplate | Identifies the original model, size and pressure |
| Full Valve Photographs | Show the body, bonnet, operator and orientation |
| Nominal Size and Bore | Confirm the internal flow path |
| Working Pressure | Confirms the pressure class |
| Flange Designation | Confirms the mating connection |
| Ring-Gasket Number | Confirms the RTJ sealing interface |
| Ring-Groove Condition | Identifies repair or overlay requirements |
| Face-to-Face Dimension | Determines fit within the existing assembly |
| Overall Height | Confirms available clearance |
| Bolt-Hole Orientation | Prevents operator misalignment |
| Stem and Operator Type | Confirms the operating arrangement |
| Existing Drawing | Supports dimensional comparison |
| Fluid and H₂S Data | Supports material selection |
SGPE can review standard replacement valves, custom dimensional requirements and replacements for existing OEM-installed wellhead equipment.
Available Valve Configurations
The flanged connection can be combined with several internal designs and operating arrangements. A slab gate configuration uses a parallel gate and pressure-energized seats for wellhead, Christmas tree and manifold isolation, while an expanding gate configuration uses a gate and segment to create mechanical seating in selected manual applications.
Manual valves can use a handwheel for direct operation or a gearbox where the required torque is higher. Hydraulic versions can use double-acting actuators for remote opening and closing or spring-return fail-close actuators for selected emergency shutdown duties.
Rising-stem designs provide visible stem movement where adequate vertical clearance is available, while non-rising-stem versions help reduce the external operating envelope in compact tree and manifold layouts. Pressure-containing bodies may use forged construction for high-pressure and traceability-focused projects or selected approved cast construction within the applicable design range.
Common RFQ Descriptions
| Common Inquiry | Typical Application |
| 2-1/16 in. 5,000 psi API 6A flanged gate valve | Wellhead outlet or manifold branch |
| 2-1/16 in. 10,000 psi API 6BX gate valve | High-pressure tree or injection wellhead |
| 3-1/16 in. 5,000 psi flange-to-flange gate valve | Christmas tree master or wing valve |
| 3-1/16 in. 10,000 psi hydraulic gate valve | High-pressure wing or test-tree valve |
| 4-1/16 in. 5,000 psi flanged master valve | Production tree or manifold inlet |
| 4-1/16 in. 10,000 psi full-bore RTJ valve | High-pressure tree or manifold |
| Valve with matching companion flange | Package supply or interface conversion |
| Hydraulic fail-close double-flanged valve | Emergency shutdown service |
| Sour-service flanged wellhead valve | Defined H₂S service |
| Custom-dimensional replacement valve | Brownfield retrofit |
| Replacement Christmas tree valve | Existing tree maintenance or upgrade |
These examples reflect common RFQ wording rather than a universal manufacturing matrix. Availability is confirmed after review of the connection, bore, pressure, materials and operating requirements.
Valve Body, Bonnet and Maintenance
Selected designs use a bolted bonnet that provides workshop access to the stem, gate, seats and internal seals.
Depending on the valve series, serviceable components may include the gate, seat assemblies, stem, packing, bonnet seal, thrust bearing, handwheel, gearbox and hydraulic actuator seals.
Technicians must not service a live or pressurized valve simply because the design contains replaceable components. All maintenance must follow the operation manual and approved site-isolation procedure.
Operating torque changes with valve size, differential pressure, seat design, stem arrangement, packing friction, temperature, lubrication condition and operating history. Larger or higher-pressure valves may require a gearbox or hydraulic actuator.
Service-Specific Materials and Trim
| Component | Typical Material Options | Main Selection Factor |
| Body and Bonnet | Heat-treated alloy steel, including selected 4130-type material or equivalent | Pressure, PSL and temperature |
| Gate | Alloy steel, stainless steel or CRA | Corrosion and wear |
| Seats | Alloy steel, stainless steel or CRA | Sealing direction and abrasion |
| Stem | Stainless steel, precipitation-hardening stainless steel or CRA | Strength and corrosion |
| Hardfacing | Qualified wear-resistant system | Sand, scale and proppant |
| Stem Packing | Elastomeric or thermoplastic system | Temperature and service fluid |
| Seals | HNBR, FKM or another qualified compound | Chemical compatibility |
| Body-Bonnet Seal | Metal or design-specific pressure seal | Pressure and valve design |
| Ring Grooves | Base material, stainless inlay or CRA overlay | Connection corrosion protection |
| Wetted Cavities | CRA or Alloy 625 overlay | H₂S, CO₂ and chlorides |
| Bolting | Alloy steel selected for pressure and environment | Strength and sour-service conditions |
| External Coating | Land, desert, marine or project-specific system | Ambient environment |
Sour and Corrosive Service
The phrase “H₂S service” does not provide enough information for final material selection.
A proper review requires the H₂S and CO₂ concentration or partial pressure, water cut, chloride content, fluid pH, operating temperature and design temperature. Produced-water chemistry, material class, applicable NACE MR0175 or ISO 15156 requirements and customer hardness limits may also influence the final selection.
These conditions affect the body, bonnet, gate, seats, stem, seals, bolting and ring grooves.
Sand and Abrasive Fluids
Formation sand, scale, rust, proppant and completion debris can damage the gate and seats during operation.
Abrasive service may require hardfaced gates, hardfaced seats, qualified wear-resistant systems, replaceable internal parts and recommended spare kits.
For trim selection, provide the expected solids content, particle-size range, flow rate, flow regime, differential pressure and service duration.
CRA and Overlay Options
Wells with high H₂S, CO₂ or chloride levels may require CRA gates and seats, corrosion-resistant stems, stainless-steel ring-groove inlay, Alloy 625 overlay or project-specific wetted-surface cladding.
The final material package should balance corrosion risk, pressure, temperature, expected service life, inspection requirements and project cost.
PSL and Performance Selection
| Requirement | Practical Meaning |
| PSL 1 | Base product specification level where permitted |
| PSL 2 | Increased material and quality controls |
| PSL 3 | Additional inspection and testing controls |
| PSL 3G | PSL 3 with additional gas-testing requirements where applicable |
| PSL 4 | Highest listed API 6A PSL for selected critical applications |
| PR1 | Standard performance-validation requirement where specified |
| PR2 | More demanding performance-validation requirement where specified |
PSL and PR can affect material requirements, NDT scope, hardness testing, documentation, validation, price and delivery schedule.
Special configurations remain subject to the selected valve series, approved manufacturing scope and project-specific technical review.
Quality Control, Testing and Documentation
| Stage | Typical Activities |
| Material Control | MTC review, heat traceability, chemistry, mechanical properties and hardness |
| Dimensional Inspection | Bore, flange, ring groove, face-to-face length and overall dimensions |
| Nondestructive Examination | UT, MT, PT, visual and overlay inspection as required |
| Assembly Control | Gate, seat, stem, bonnet, operator and actuator checks |
| Pressure Testing | Body hydrostatic and seat pressure tests |
| Gas Testing | Low- or high-pressure gas testing when required |
| Functional Testing | Opening, closing, fail-safe and position-indication checks |
| Final Inspection | Marking, coating, flange protection, preservation and packing |
| Standard Documents | Data sheet, GA drawing, MTC, test report, COC and O&M manual |
| Optional Records | ITP, NDT reports, hardness reports, dimensional report and MRB |
| Third-Party Inspection | Witness and hold points according to the approved ITP |
The final document package can include the technical data sheet, GA drawing, interface drawing, sectional drawing, bill of materials, material certificates, NDT reports and dimensional inspection report.
Where required by the purchase order, the package can also include ring-groove inspection records, hydrostatic and seat test reports, functional test reports, a certificate of conformity, an operation and maintenance manual, an inspection and test plan and a manufacturing record book.
Why Choose SGPE?
SGPE reviews the flange designation, sealing ring, minimum bore, face-to-face dimension, bolt orientation and operator envelope before quotation. This interface-matching process helps reduce installation problems when the valve connects to a wellhead spool, Christmas tree, flowhead or manifold.
For replacement and brownfield work, existing nameplates, drawings, photographs and field measurements can be reviewed before the final configuration is selected. The valve is evaluated according to its actual system position, pressure direction, service fluid, temperature and operating method rather than nominal size and pressure alone.
The available supply scope can include manual or hydraulic operators, selected slab or expanding gate designs, forged or approved cast bodies, hardfaced trim, CRA components and Alloy 625 overlay. Related wellhead spools, Christmas tree components, chokes, manifolds, ring gaskets, flange bolting, adapter components and spare parts can also be supplied as part of the agreed package.
Drawings, technical data sheets, test reports and manufacturing records are prepared according to the confirmed purchase order, quality level and inspection scope.
Frequently Asked Questions About API 6A Flanged Gate Valves
1. What is an API 6A flanged gate valve?
An API 6A flanged gate valve provides on-off pressure isolation in oil and gas wellheads, Christmas trees, surface test trees, flowheads and high-pressure manifold systems. The valve uses an API ring-type-joint flange at one or both ends and normally creates a full-opening or through-conduit flow path when fully open.
Depending on its position in the pressure-control system, the valve may serve as a lower master valve, upper master valve, production wing valve, kill wing valve, swab valve, annulus outlet valve or manifold isolation valve. Buyers may also describe the product as an API 6A flange-end gate valve, flange-to-flange gate valve, double-flanged wellhead valve or API RTJ gate valve.
The final specification should define the nominal size, minimum bore, working pressure, flange designation, ring-gasket number, gate design, operating method, material class, PSL, PR and service conditions.
2. What flange information should I provide when requesting a quotation?
Provide the flange designation, nominal size, rated working pressure, ring-gasket number, minimum bore, face-to-face dimension and bolt-hole orientation. These details show whether the valve will connect correctly to the adjoining tree cross, tubing head, casing head, wellhead spool, adapter spool or manifold block.
For a new Christmas tree or wellhead package, the approved equipment drawing normally contains the required interface data. For a replacement or brownfield project, also send the existing valve nameplate, clear photographs, overall height, operator position, actuator envelope and available installation space.
Nominal valve size alone cannot confirm compatibility. Two valves with the same nominal flange size may use different pressure classes, ring grooves, bolt patterns, internal bores or installation lengths.
3. What is the difference between API 6B and API 6BX flanges?
API 6B and API 6BX flanges use different connection geometries, ring grooves, bolting arrangements and pressure-sealing systems. They are not interchangeable simply because they share the same nominal size.
Operators commonly install API 6B connections on conventional production wellheads, casing-head outlets, tubing-head outlets, Christmas trees and production manifolds. Depending on the flange designation, an API 6B connection may use an R or RX ring gasket.
API 6BX connections normally use BX pressure-energized ring gaskets. High-pressure gas wellheads, surface test trees, flowheads, injection wellheads and offshore pressure-control equipment often use this connection type.
Before selecting the valve, confirm the complete flange size, pressure class, ring number, minimum bore and bolt-hole orientation.
4. Is a double-flanged gate valve the same as an RTJ gate valve?
No. The two terms describe different features.
“Double flanged” or “flange-to-flange” means that the valve has a flanged connection at both ends. “RTJ” describes the ring-type-joint sealing method between the valve flange and the mating equipment.
Most API 6A double-flanged gate valves use RTJ connections. However, the term “double flanged” does not identify whether the valve uses an API 6B or API 6BX flange, nor does it confirm the correct R, RX or BX ring-gasket number.
A double-flanged RTJ gate valve may serve as a master valve, wing valve, flowhead valve or manifold isolation valve. Buyers should still check the exact connection and dimensional requirements against the wellhead or Christmas tree drawing.
5. What sizes and pressure ratings are available?
Lower-pressure valves often serve conventional production wellheads and gathering systems. Operators commonly use 5,000 and 10,000 psi valves on production trees, injection wellheads, surface test systems and high-pressure manifolds. Selected 15,000 and 20,000 psi configurations may suit high-pressure gas wells, offshore projects and demanding well-test applications.
Not every size supports every pressure class, minimum bore, gate design, body material, PSL or PR. SGPE confirms the final valve range after reviewing the project specification and available manufacturing scope.
6. Is an API 6A flanged gate valve full bore?
Many API 6A flanged gate valves use a full-opening or through-conduit bore.
When the valve opens fully, the gate port aligns with the body bore and creates a straight flow passage through the valve.
A full-bore wellhead gate valve helps reduce unnecessary pressure loss and turbulence in production, injection, well-test and flowback systems. It also reduces areas where sand, scale or completion debris may accumulate.
Where the complete Christmas tree or wellhead bore permits, the valve may support slickline, electric-line, wireline or coiled-tubing access. However, nominal flange size does not always equal the actual minimum bore.
State both the required bore and drift diameter in the RFQ.
7. Can SGPE supply manual and hydraulic flanged gate valves?
Yes. Manual API 6A flanged gate valves use a handwheel or gearbox, depending on valve size, operating torque and available installation space. These configurations suit accessible production wellheads, Christmas trees and manifold systems where operators can work locally.
Hydraulic flanged gate valves use double-acting, fail-close or selected fail-open actuators. Surface test trees, flowheads, offshore wellheads, emergency shutdown systems and remotely operated production facilities often require hydraulic operation.
For hydraulic actuator selection, provide the available control pressure, required fail position, maximum differential pressure, opening and closing time, hydraulic volume, operating frequency and position-feedback requirements.
The actuator envelope and orientation must also fit the surrounding piping and wellhead structure.
8. Can SGPE supply an API 6A flanged gate valve for H₂S sour service?
Yes, subject to a complete service review.
“H₂S service” alone does not provide enough information for final material selection. Provide the H₂S and CO₂ concentration or partial pressure, water cut, chloride content, fluid pH, operating temperature, design temperature and produced-water chemistry.
Depending on the defined environment, the valve may require suitable body and bonnet materials, corrosion-resistant gate and seat components, CRA stems, qualified elastomers, controlled hardness, stainless-steel ring-groove inlay or Alloy 625 overlay.
The material package may also need to follow the applicable requirements of NACE MR0175 or ISO 15156.
Operators commonly use sour-service flanged gate valves on gas wellheads, production trees, injection wellheads, offshore systems and high-pressure manifolds. The final material selection must match the actual process conditions rather than a general sour-service description.
9. Can SGPE supply a replacement Christmas tree gate valve?
Yes. SGPE reviews dimensional replacement valves for existing Christmas trees, wellheads, test trees and manifold systems. A suitable replacement must match more than the nominal size and working pressure.
The technical review checks the flange designation, ring-gasket number, minimum bore, face-to-face dimension, overall valve height, bolt-hole orientation, stem arrangement, handwheel or actuator position and available operating clearance.
For the most accurate review, send the existing valve nameplate, full product photographs, original GA drawing, field measurements and details of the mating equipment.
SGPE confirms any project-specific drop-in replacement after completing the dimensional and engineering review.
10. Can SGPE provide a custom face-to-face dimension?
Yes. SGPE can review a custom or existing-equipment face-to-face dimension when a standard valve will not fit the available installation space.
Christmas tree replacement, wellhead upgrades, offshore maintenance and brownfield manifold projects often require this type of dimensional review.
The requested installation length must remain within an approved valve design and manufacturing range. Changes to the face-to-face dimension may affect the body pattern, flange thickness, bore alignment, overall height, operating torque and operator clearance.
Before quotation, provide the required face-to-face length, flange designation, minimum bore, overall dimensions, bolt-hole clocking and surrounding equipment layout.
The drawing review will confirm final feasibility.
11. Can SGPE supply matching ring gaskets, flange bolting and companion equipment?
Yes.
SGPE can quote matching API ring gaskets, flange studs, nuts, selected companion flanges, adapter spools and other wellhead interface components with the API 6A flanged gate valve.
The ring gasket must match the exact flange designation and groove profile. Depending on the connection, the valve may require an R, RX or BX sealing ring.
The bolting must also match the flange size, working pressure, material requirements and service environment.
Supplying the valve together with the correct ring gasket and flange bolting can simplify installation on Christmas trees, wellhead spools, surface test trees, flowheads and high-pressure manifolds.
Before shipment, the technical team should still check the complete package against the approved interface drawing.
12. What testing, inspection and documents can SGPE provide?
SGPE can provide material traceability, dimensional inspection, bore and drift checks, flange and ring-groove inspection, hardness testing, nondestructive examination, body hydrostatic testing, seat testing and functional operation checks according to the confirmed inspection scope.
For hydraulic valves, the inspection plan may also include actuator cycling, fail-safe verification, opening and closing time checks and position-indicator testing.
SGPE can include low- or high-pressure gas testing when the approved specification and selected quality level require it.
The document package may include the technical data sheet, general arrangement drawing, interface drawing, material certificates, NDT reports, dimensional inspection report, hydrostatic and seat test reports, certificate of conformity, operation and maintenance manual, inspection and test plan and manufacturing record book.
SGPE can also arrange approved third-party inspection according to the purchase order and ITP.
Information Required for Quotation
For a new API 6A flanged gate valve, the inquiry should identify the valve position and application, nominal size, minimum bore, drift, working pressure, flange designation, ring-gasket number and operating method. The required face-to-face dimension, bolt-hole orientation, sealing direction, service fluid, design temperature, material class, PSL, PR and inspection scope should also be provided.
For hydraulic operation, state the available control pressure, required fail position, operating time and any position-feedback requirement. Sour or abrasive applications should include the H₂S and CO₂ conditions, water chemistry, chloride concentration, solids content and any hardfacing, CRA or overlay requirements.
When the valve will replace existing equipment, send the valve nameplate, clear photographs, GA drawing, field measurements, overall height, operator envelope and details of the mating connection. The quantity, delivery destination and required schedule should also be included so that the technical and commercial proposal can be prepared on the same basis.
Request an API 6A Flanged Gate Valve Quotation
Send us your valve data sheet, flange drawing, wellhead drawing, manifold layout, face-to-face dimensions or existing valve nameplate.
The technical review will confirm the connection designation, ring-gasket number, minimum bore, installation dimensions, bolt-hole orientation, valve configuration, materials and operating method before quotation.
The available supply scope includes API 6A flange-end gate valves, API 6B and API 6BX RTJ gate valves, full-bore wellhead isolation valves, manual and hydraulic flanged valves, sour-service configurations, custom-dimensional valves and matching ring gaskets, flange studs, nuts, companion flanges and adapter components.
E-Mail:
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