ASTM A350
Carbon and low-alloy steel forgings for low-temperature piping components
Covers carbon and low-alloy steel forgings for low-temperature piping components, with notch-toughness testing — LF2 is the common grade.
- Flanges & forgings
- ASME SA-350
- 1 grade supplied to it
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is ASTM A350?
ASTM A350 is the specification for carbon and low-alloy steel forgings that require notch-toughness (impact) testing for low-temperature piping components such as flanges and forged fittings. LF2 is the common carbon steel grade: class 1 is impact tested at −46 °C (−50 °F). It is the low-temperature counterpart of ASTM A105.
ASTM A350 at a glance
| Products | Flanges, forged fittings, valves |
|---|---|
| Material | Carbon and low-alloy steel, impact tested |
| Common grades | LF2 class 1 and 2, LF3 |
| ASME designation | SA-350 |
Low-temperature carbon steel system
| Component | Specification |
|---|---|
| Pipe | ASTM A333 Gr 6 |
| Buttweld fittings | ASTM A420 WPL6 |
| Flanges | ASTM A350 LF2 class 1 |
| Bolting | ASTM A320 L7 with A194 nuts |
How to write ASTM A350 on a purchase order
Name the product, size, material specification and grade, the dimensional standard and the certificate. An example line:
Illustrative only — sizes, tests, inspection level and any project values come from your purchase specification.
ASTM A350 edition and verification status
Which edition we have confirmed, and what is still being checked before any numerical requirement is published here.
| Current edition | Not yet confirmed against the publisher listing |
|---|---|
| Full-text verification | In progress — numerical requirements are not published on this page |
| Edition on your order | The edition named in your purchase order or design code governs — confirm it with your enquiry |
What to know before ordering to ASTM A350
The points that decide whether material to ASTM A350 is accepted at inspection.
- LF2 Class 1 is impact-tested at −46 °C.
- A350 LF2 flanges match A333 Gr 6 pipe.
- Dimensions follow ASME B16.5 or B16.47.
Grades and products we supply to ASTM A350
| Grade | Product | Designation on the certificate |
|---|---|---|
| ASTM A333 Gr 6 | Fittings · Flanges | ASTM A350 LF2 |
How ASTM A350 fits into an order
A purchase order line is only complete when it names the material standard, the dimensional standard and the inspection document. Miss one and the mill, the inspector and the buyer can each read the order differently.
ASTM A350 — questions buyers ask
What is ASTM A350?
ASTM A350 is the specification for carbon and low-alloy steel forgings that require notch-toughness (impact) testing for low-temperature piping components such as flanges and forged fittings. LF2 is the common carbon steel grade: class 1 is impact tested at −46 °C (−50 °F). It is the low-temperature counterpart of ASTM A105.
At what temperature is A350 LF2 impact tested?
Class 1 at −46 °C (−50 °F). Class 2 is tested at a higher temperature (−18 °C / 0 °F).
Can A350 LF2 replace A105?
Generally yes — LF2 meets similar strength and adds impact testing — but confirm with your piping class.
Which grades do you supply to ASTM A350?
ASTM A333 Gr 6 — see the table on this page for the exact product and designation.
What is the difference between ASTM A350 and ASME SA-350?
ASME SA-350 is the ASME Boiler and Pressure Vessel Code (Section II) adoption of ASTM A350. The technical requirements are usually identical to a specific ASTM edition; pressure-equipment codes call for the ASME designation, and most mill certificates show both.
Do you supply certificates to this standard?
Yes. Material is supplied with mill test certificates to EN 10204 3.1 showing the standard, grade and heat number; 3.2 with third-party inspection on request.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026