ASTM A694 F70 Weld Neck Flange | WNRF & WNRTJ
ASTM A694 F70 Weld Neck Flanges are high-yield forged steel flanges designed for high-pressure transmission pipelines and critical oil and gas piping systems.
Grade F70 provides a minimum yield strength of 70 ksi / 485 MPa, making it suitable for high-strength pipeline systems where API 5L X70 line pipe and ASTM A860 WPHY70 butt-weld fittings may also be specified.
Available configurations include Weld Neck Raised Face (WNRF) and Weld Neck Ring Type Joint (WNRTJ) flanges manufactured to ASME B16.5, ASME B16.47 or MSS SP-44 as applicable.
ASTM A694 F70 Weld Neck Flange Overview
| Item | Specification |
|---|---|
| Material | ASTM A694 Grade F70 |
| Product | Weld Neck Flange |
| Flange Types | WNRF, WNRTJ |
| Yield Strength | 485 MPa / 70 ksi min |
| Tensile Strength | 565 MPa / 82 ksi min |
| Elongation | 18% min |
| Standards | ASME B16.5, ASME B16.47, MSS SP-44 |
| Facing | RF, RTJ |
| Typical Service | High-Pressure Transmission Pipelines |
| Sour Service | Available when specified |
| HIC Testing | Available when specified |
What Is ASTM A694 F70?
ASTM A694-A694M covers carbon and alloy steel forgings for pipe flanges, fittings, valves and related components intended for high-pressure transmission service.
F70 is one of the highest-strength commonly specified grades within ASTM A694 and is identified by its 70 ksi minimum yield strength.
F70 may be produced from suitable carbon steel, high-strength low-alloy steel or alloy steel capable of meeting the specified mechanical properties after heat treatment.
Typical heat-analysis requirements include:
| Element | Requirement |
|---|---|
| Carbon, C | 0.30% max |
| Manganese, Mn | 1.60% max |
| Phosphorus, P | 0.025% max |
| Sulfur, S | 0.025% max |
| Silicon, Si | 0.15–0.35% |
Additional alloying elements are reported as applicable.
ASTM A694 F70 Mechanical Properties
| Property | Requirement |
|---|---|
| Yield Strength | 485 MPa / 70 ksi min |
| Tensile Strength | 565 MPa / 82 ksi min |
| Elongation in 50 mm | 18% min |
Where low-temperature service, offshore service or a specified MDMT applies, Charpy impact testing should be defined separately by the project specification.
ASTM A694 F70 WNRTJ Flange
ASTM A694 F70 Weld Neck RTJ Flanges are used in high-pressure piping systems where a metallic Ring Type Joint gasket is required.
The Weld Neck configuration provides a tapered hub and butt-weld connection to the pipe, while the RTJ facing uses a precision-machined ring groove for the metallic gasket.
Typical applications include:
- High-pressure transmission pipelines
- Compressor stations
- Offshore piping systems
- Pipeline manifolds
- Gas processing facilities
- High-pressure process piping
- Critical isolation connections
Common pressure classes include Class 600, 900, 1500 and 2500 where applicable to the specified size and standard.
Typical order description:
ASTM A694 F70 Weld Neck Flange, NPS 8″, Class 1500, RTJ, Sch 160 Bore, ASME B16.5
The RTJ groove and corresponding ring gasket must match the applicable flange standard and project requirement.
ASTM-A694-F70 WNRF Flange
F70 Weld Neck Raised Face Flanges are commonly used in welded high-pressure pipeline connections using conventional gasketed Raised Face joints.
The tapered Weld Neck hub provides a gradual transition between flange and pipe, helping distribute stresses around the welded connection.
Typical order:
ASTM A694 F70 Weld Neck Flange, NPS 16″, Class 600, RF, Sch STD Bore, ASME B16.5
The bore should be specified to match the connected pipe wall thickness where required.
ASME B16.5, B16.47 and MSS SP-44
ASTM A694 specifies the material requirements, while the flange dimensions and pressure-class system are specified separately.
ASME B16.5
Used for flange sizes from NPS 1/2 through NPS 24, subject to the available Class and size combination.
Applicable pressure classes include:
150, 300, 400, 600, 900, 1500 and 2500
ASME B16.47
Used for large-diameter steel flanges from NPS 26 through NPS 60.
Configurations include:
- Series A
- Series B
with applicable Classes from 75 through 900.
MSS SP-44
MSS SP-44 Steel Pipeline Flanges is particularly relevant to high-strength pipeline applications and may also be specified for ASTM A694 F70 Weld Neck Flanges.
F70 Flanges for API 5L X70 Pipeline Systems
ASTM A694 F70 is commonly selected as a flange grade in high-yield pipeline systems containing API 5L X70 pipe.
| Component | Typical Specification |
|---|---|
| Line Pipe | API 5L X70 |
| Weld Neck Flange | ASTM A694 F70 |
| Butt-Weld Fitting | ASTM A860 WPHY70 Pipe Fittings |
These grades are commonly selected where comparable high-yield strength levels are required throughout the pipeline system.
However, ASTM A694 F70, API 5L X70 and ASTM A860 WPHY70 are separate product specifications and are not directly equivalent or interchangeable materials.
Each component must comply with its own applicable specification.
Heat Treatment
ASTM A694 F70 forgings are supplied in a heat-treated condition.
Depending on material chemistry, section size and required properties, carbon steel and high-strength low-alloy steel forgings may be supplied in conditions such as:
- Normalized
- Normalized and Tempered
- Quenched and Tempered
The final heat-treatment route must produce the specified F70 mechanical properties.
NACE Sour-Service F70 Flanges
ASTM A694 F70 Weld Neck Flanges can be supplied for projects specifying NACE MR0175 / ISO 15156 requirements.
Sour-service suitability is project specific and may require control of:
- Material chemistry
- Heat treatment
- Hardness
- Manufacturing condition
- H₂S exposure
- Service temperature
- Project-specific acceptance requirements
ASTM A694 F70 designation alone does not automatically establish NACE compliance.
HIC Tested ASTM A694 F70 Flanges
Hydrogen-Induced Cracking testing can be performed to NACE TM0284 when specified.
HIC testing is an additional project requirement rather than a mandatory ASTM A694 requirement.
The required test condition and acceptance criteria should be defined by the purchaser or project specification.
Inspection and Certification
Available inspection and documentation include:
- EN 10204 Type 3.1 MTC
- EN 10204 Type 3.2 when specified
- Chemical Analysis
- Mechanical Testing
- Hardness Testing
- Charpy Impact Testing when specified
- Ultrasonic Testing
- Magnetic Particle Testing
- HIC Testing when specified
- PMI where required
- Dimensional Inspection
- RTJ Groove Inspection
- Third-Party Inspection
- Full Heat-Number Traceability
Related ASTM A694 F70 Products
- ASTM A694 F70 Blind Flange – RF and RTJ blind flanges for pipeline closure and isolation.
- ASTM A694 F70 Slip-On Flange – available where Slip-On flange construction is permitted by the piping specification.
- ASTM A694 F70 RTJ Flanges – available in Weld Neck and Blind configurations for high-pressure metallic ring-gasket connections.
- ASTM A860 WPHY70 Pipe Fittings – high-yield butt-weld fittings for X70-strength pipeline systems.
How to Order ASTM A694 F70 Weld Neck Flanges
A complete RFQ should include:
- ASTM A694 F70
- Weld Neck Flange
- Nominal pipe size
- Pressure class
- RF or RTJ
- Pipe bore / wall thickness
- ASME or MSS standard
- Quantity
- Sour-service requirement if applicable
- HIC or impact testing if required
- Certification and inspection requirements
Example
ASTM A694 F70 Weld Neck Flange, NPS 10″, Class 900, RTJ, Sch 120 Bore, ASME B16.5, NACE MR0175 / ISO 15156 and HIC testing as specified
ASTM A694 F70 Weld Neck Flange Manufacturer and Supplier
We manufacture and supply ASTM A694 F70 Weld Neck Flanges for high-pressure oil and gas transmission, offshore and pipeline applications.
Available products include F70 WNRF and WNRTJ flanges to ASME B16.5, ASME B16.47 and MSS SP-44, with project-specific NACE, HIC, impact testing, NDE and third-party inspection available when required.
