China ASTM A350 LF1, LF2, LF3 Carbon/Alloy Steel Pipe Suppliers & Factory
General Characteristics
These grades of steel are used as pipeline steels and also in the production of forged flanges. They are suitable for use down to –20ºF (LF1), –50ºF (LF2) and –150ºF (LF3).
| Mat. No. | DIN | EN | AISI |
|---|---|---|---|
| 1.5622 | 14Ni6 | - | A350 |
Chemical Analysis
| C% | Mn% | Si% | S% | P% | Cr% | Ni% |
|---|---|---|---|---|---|---|
| 0.30 max | 0.6/1.35 | .15/.30 | .040 max | .035 max | 0.30 max | 0.40 max |
| C% | Mn% | Si% | S% | P% | Cr% | Ni% |
|---|---|---|---|---|---|---|
| 0.30 max | 0.6/1.35 | .15/.30 | .040 max | .035 max | 0.30 max | 0.40 max |
| C% | Mn% | Si% | S% | P% | Cr% | Ni% |
|---|---|---|---|---|---|---|
| 0.20 max | 0.90 | .20/.35 | .040 max | .035 max | 0.30 max | 3.3/3.7 |
Applications & Technical Processing
These steels are primarily used for pipelines and forged flanges.
LF1 and LF2 grades would ideally be forged at around 2250-2300ºF (1230-1260ºC) and can't be forged below 1650-1700ºF (900-925ºC).
The LF3 grade would be forged at around 2150-2200ºF (1175-1205ºC) and can't be forged below 1700ºF (925ºC).
Heat treatment of pipeline steels will be done on a continuous basis after welding. The structure of these steels will be initially determined by the rolling/forging process. The pipeline itself will be supplied from hot-rolled steels, the flanges etc. from forgings.
The actual welding process will be primordial in ensuring the suitability and security of the pipeline and its subsequent performance. Preheat and post heat treatments are essential. The three grades listed here are easily weldable by all tried and tested methods.
In the case of forged fittings and flanges, these grades can be machined as required. Ongoing experience will determine if machining is best done on an as-forged structure, a normalized structure or an annealed structure. In view of the critical nature of the end use, advice should be taken from a recognized heat treatment company.