ASTM A420
Carbon and alloy steel piping fittings for low-temperature service
Covers carbon and alloy steel wrought piping fittings for low-temperature service, such as WPL6, with Charpy impact testing.
- Pipe fittings
- ASME SA-420
- 1 grade supplied to it
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is ASTM A420?
ASTM A420 is the specification for wrought carbon steel and alloy steel pipe fittings for low-temperature service. WPL6 is impact tested at −46 °C (−50 °F) and matched with ASTM A333 Gr 6 pipe; WPL3 (3½Ni) is tested at −101 °C. Dimensions follow ASME B16.9. ASME adopts it as SA-420.
ASTM A420 at a glance
| Products | Wrought buttweld fittings |
|---|---|
| Common grades | WPL6, WPL3, WPL8, WPL9 |
| WPL6 impact test | −46 °C (−50 °F) |
| ASME designation | SA-420 |
Carbon steel fittings by temperature
| Service | Fitting | Pipe |
|---|---|---|
| Ambient / high temperature | ASTM A234 WPB | ASTM A106 Gr B |
| Low temperature | ASTM A420 WPL6 | ASTM A333 Gr 6 |
How to write ASTM A420 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 A420 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 A420
The points that decide whether material to ASTM A420 is accepted at inspection.
- WPL6 matches A333 Grade 6 pipe.
- The impact test temperature must suit your minimum design temperature.
- Dimensions follow ASME B16.9.
Grades and products we supply to ASTM A420
| Grade | Product | Designation on the certificate |
|---|---|---|
| ASTM A333 Gr 6 | Fittings | ASTM A420 WPL6 |
How ASTM A420 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.
Standards used with ASTM A420
Same family
ASTM A420 — questions buyers ask
What is ASTM A420?
ASTM A420 is the specification for wrought carbon steel and alloy steel pipe fittings for low-temperature service. WPL6 is impact tested at −46 °C (−50 °F) and matched with ASTM A333 Gr 6 pipe; WPL3 (3½Ni) is tested at −101 °C. Dimensions follow ASME B16.9. ASME adopts it as SA-420.
What is the difference between WPL6 and WPB?
WPL6 is impact tested for low-temperature service; WPB is not.
Which grades do you supply to ASTM A420?
ASTM A333 Gr 6 — see the table on this page for the exact product and designation.
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