ASTM A694 F56
ASTM A694 F56 Flanges & Fittings
ASTM A694 F56 is a high-strength carbon steel forging grade engineered for high-pressure and high-temperature pipeline applications. It is commonly used for manufacturing forged flanges, fittings, and pipeline components in industries such as oil & gas, LNG, petroleum refining, offshore drilling, and chemical processing.
Grade F56 offers a combination of enhanced mechanical strength, impact resistance, and weldability, making it ideal for demanding transmission systems, compressor stations, and critical flow line assemblies.
Key Features
High tensile & yield strength for pressure-critical systems
Excellent toughness & ductility
Reliable performance in pipeline environments
Suitable for low-temperature & moderate-temperature service
Good forgeability & weldability
Efficient for long-distance oil & gas transportation pipelines
Specification
| Standard | ASTM A694 |
|---|---|
| Grade | F56 |
| Product Form | Forged Flanges, Fittings & Components |
| Delivery Condition | Normalized / Quenched & Tempered |
| Service | High-pressure pipeline systems (Oil, Gas, LNG) |
Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM | A694 F56 |
| ASME | SA694 F56 |
| API | API 6A (Comparable Class) |
| EN / DIN | — (No direct equivalent) |
| Product | Size Range |
|---|---|
| Flanges | ½” – 60” NB |
| Forged Fittings | ½” – 4” NB |
| Rings / Discs / Blocks | Custom Orders |
| Machined Parts | As per Drawing / EPC Specs |
Chemical Composition
| Element | % |
|---|---|
| Carbon (C) | 0.30 Max |
| Manganese (Mn) | 0.60 – 1.35 |
| Silicon (Si) | 0.15 – 0.40 |
| Phosphorus (P) | 0.025 Max |
| Sulfur (S) | 0.025 Max |
| Vanadium (V) | 0.08 Max |
| Niobium (Nb) | 0.05 Max |
| Titanium (Ti) | 0.04 Max |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 485 MPa Min |
| Yield Strength | 390 MPa Min |
| Elongation | 20% Min |
| Hardness | 197 HB Max |
| Impact (Charpy V-Notch) | Required |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Elastic Modulus | ~200 GPa |
| Thermal Conductivity | ~45 W/m-K |
| Melting Point | ~1425 – 1540°C |
Type of ASTM A694 F56 Flanges
Types of ASTM A694 F56 Products
Weld Neck Flanges
Blind Flanges
Slip-On Flanges
Ring Type Joint (RTJ) Flanges
Socket-Weld & Threaded Flanges
Lap Joint & Orifice Flanges
Forged Pipe Fittings
Custom Forged Pipeline Components
Corrosion Resistance
Good atmospheric corrosion resistance
Suitable for sweet (non-sour) media
Surface coating recommended for marine/offshore & sour service
Compatible with cathodic protection systems
Heat Resistance
Performs effectively up to ~450°C
Suitable for moderate-temperature high-pressure services
Not recommended for prolonged high-temperature creep conditions
Heat Treatment
Normalizing
Quenching & Tempering
Stress Relief on request
Heat treatment improves toughness and grain structure.
Welding
Good weldability with low-hydrogen welding processes
Pre-heating recommended for heavy-section welds
PWHT may be required depending on thickness & service design
Fabrication
Excellent forgeability & machinability
Made to project drawings & industry standards
CNC machined for accuracy & sealing integrity
Applications
Oil & Gas Transmission Pipelines
Natural Gas & LNG Facilities
Refineries & Petrochemical Plants
Subsea & Offshore Platforms
Compressor & Pumping Stations
Valves, Flanges, Elbows & Tees in Pipeline Networks