ASTM A350 LF1
ASTM A350 LF1 Carbon Steel – Low Temperature Forgings
ASTM A350 LF1 is a Carbon Steel grade specifically designed for low-temperature service applications. It is widely used in pressure systems, piping components, and flanges that require toughness and ductility at sub-zero temperatures. This material offers excellent impact strength, weldability, and machinability, making it an ideal choice for cryogenic and refrigerated environments.
At Emirerri Steel, we manufacture and supply ASTM A350 LF1 flanges, fittings, and round bars with superior surface finish and dimensional accuracy to meet international standards.
Key Features
Excellent performance in low-temperature environments
Good mechanical strength and impact toughness
Superior weldability and machinability
High-dimensional stability and pressure resistance
Suitable for cryogenic and sub-zero temperature applications
Available in various forged forms, including flanges, fittings, and bars
ASTM A350 LF1 – Specification
| Standard | ASTM A350 / ASME SA350 |
|---|---|
| Grade | LF1 |
| Product Forms | Forged flanges, forged fittings, valves, and other pressure parts |
| Type | Carbon Steel (Low Temperature Service) |
| Forging Method | Open Die / Closed Die / Ring Rolled |
| Heat Treatment | Normalized, Quenched & Tempered |
| Size Range | NPS ½” to 48” (Flanges & Fittings) / Dia 10mm to 300mm (Bars) |
| Pressure Rating | Class 150 to 2500 |
| Standards Covered | ASME B16.5, B16.47, B16.11, MSS-SP-79, 83, 95 |
Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| EN | C22.8 |
| DIN | 1.0460 |
| BS | 1503-161-400 |
| JIS | SF440A |
| ISO | P245GH |
Available Sizes
Flanges: ½” to 48” NB
Forged Fittings: ½” to 4”
Round Bars: 10mm to 300mm diameter
Custom dimensions available upon request
Chemical Composition
| Element | Percentage (%) |
|---|---|
| Carbon (C) | 0.30 max |
| Manganese (Mn) | 0.60 – 1.35 |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.040 max |
| Silicon (Si) | 0.15 – 0.30 |
| Nickel (Ni) | 0.40 max |
| Chromium (Cr) | 0.30 max |
| Molybdenum (Mo) | 0.12 max |
| Copper (Cu) | 0.40 max |
Mechanical Properties
| Property | Unit | Value |
|---|---|---|
| Tensile Strength | MPa | 415 min |
| Yield Strength | MPa | 205 min |
| Elongation | % | 22 min |
| Reduction of Area | % | 35 min |
| Impact Energy (Charpy V-Notch) | J | 27 min at -46°C |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Melting Point | 1450°C (approx.) |
| Modulus of Elasticity | 200 GPa |
| Thermal Conductivity | 43 W/m·K |
| Specific Heat | 486 J/kg·K |
Types of ASTM A350 LF1 Products
ASTM A350 LF1 Flanges (Weld Neck, Blind, Slip-On, Socket Weld, Threaded, Lap Joint, Long Weld Neck)
ASTM A350 LF1 Forged Fittings (Elbow, Tee, Coupling, Union, Cap, Plug, Cross)
ASTM A350 LF1 Round Bars / Shafts / Blocks
Corrosion Resistance
Although ASTM A350 LF1 is not a stainless steel, it provides good resistance to general corrosion in neutral or mild environments. For aggressive or acidic service, protective coatings or painting is recommended.
Regular maintenance and surface protection significantly enhance its service life and corrosion performance in outdoor or marine conditions.
Heat Resistance
ASTM A350 LF1 exhibits moderate oxidation and scaling resistance up to 425°C (800°F). However, it is primarily designed for low-temperature service, not high-temperature exposure.
Heat Treatment
Normalizing: 860–940°C followed by air cooling
Tempering: 590–675°C depending on mechanical property requirements
Annealing: Optional for stress relief after machining
Proper heat treatment ensures uniform mechanical properties and improved toughness at low temperatures.
Welding
ASTM A350 LF1 can be readily welded using standard welding techniques such as SMAW, GTAW, or GMAW. Preheating before welding and post-weld heat treatment (PWHT) may be recommended to minimize residual stress and improve joint integrity.
Fabrication
This grade is easy to machine, forge, and form, allowing manufacturers to produce custom-designed components. Proper temperature control during forging enhances its grain structure and ensures optimum toughness.
Applications
ASTM A350 LF1 is widely used in low-temperature and cryogenic service industries, including:
LNG Processing Plants
Refrigeration Units
Pressure Vessels & Cryogenic Tanks
Offshore Oil & Gas Platforms
Petrochemical Refineries
Power Generation Units
Pipeline Components