1. Specifications & Capability
FUSHUN METAL forges low-temperature steel components in A350 LF2, LF3 and LF6, for service from -46 C down to -101 C. These are the flanges, tubesheets and fittings of cryogenic and low-temperature plants, quenched and tempered with Charpy V-notch impact verified at the design temperature.
The grades are selected by their nickel content, which lowers the ductile-to-brittle transition temperature so the steel remains tough at cryogenic temperatures.
| Grade | Standard | Service Temperature |
|---|---|---|
| A350 LF2 | ASTM A350 | -46 C |
| A350 LF3 | ASTM A350 | -101 C |
| A350 LF6 | ASTM A350 | -51 C |
2. Components & Service Conditions
These forgings are the flanges, tubesheets and fittings of LNG plants, cryogenic storage tanks and low-temperature process piping. At sub-zero temperatures carbon steel becomes brittle and can fracture without warning, so the controlling requirement is notch toughness at the design temperature.
Nickel is the key alloying element: LF2 relies on fine grain and heat treatment for -46 C, while the 3.5% nickel of LF3 lowers the transition temperature enough for -101 C service. Each heat is quenched and tempered and Charpy V-notch tested at the design temperature to confirm the toughness the code requires.
3. Grade Equivalents – A350 LF2 / LF3 / LF6
| Designation | Standard | Notes |
|---|---|---|
| A350 LF2 | ASTM A350 | Carbon steel, -46 C |
| A350 LF3 | ASTM A350 | 3.5% Ni steel, -101 C |
| A350 LF6 | ASTM A350 | Low-alloy steel, -51 C |
| 16MnD / 09MnNiD | GB/T 3531 | Reference only, not used in certification |
| Grade | C | Si | Mn | Ni |
|---|---|---|---|---|
| A350 LF2 | 0.30 max | 0.15-0.30 | 0.60-1.35 | 0.40 max |
| A350 LF3 | 0.20 max | 0.15-0.35 | 0.90 max | 3.25-3.75 |
| A350 LF6 | 0.22 max | 0.15-0.30 | 0.60-1.35 | 1.00-1.50 |
The 3.25-3.75% nickel of LF3 is what extends serviceability down to -101 C by lowering the ductile-to-brittle transition temperature.
4. Manufacturing Process
Melting. FUSHUN METAL melts in an electric arc furnace with refining to keep phosphorus and sulfur low, which is essential for notch toughness.
Forging. Components are forged with a minimum 4:1 reduction ratio to refine the grain, then quenched and tempered.
Testing. Charpy V-notch impact tests at the design temperature, plus tensile and ultrasonic testing, with full traceability.
Certification. Inspection certificates under EN 10204 3.1, with ISO 9001 and AS9120B quality system certification.
5. Standards & Certification
Low-temperature forgings are supplied to ASTM A350, with Charpy V-notch impact verification at the design temperature and inspection certificates under EN 10204 3.1. FUSHUN METAL holds ISO 9001 and AS9120B certification.
Related forging: duplex stainless forgings.
6. Typical Applications
LNG plants
Flanges and fittings for LNG liquefaction and storage.
Cryogenic storage
Tubesheets and flanges for cryogenic tanks.
Low-temperature piping
Forged fittings for sub-zero process piping.
Ethylene plants
Low-temperature forgings for ethylene processing.
7. Inquiry Essentials
To quote your low-temperature forging, please provide the design temperature, the impact requirements, and the required grade.
