ASTM A335 P22 CapASTM A234 · ASME B16.9 · Manufacturer, trader & exporter, India
SA-335 P22 · 2¼Cr-1Mo alloy pipe
An ASTM A335 P22 cap is a fitting that closes the end of a pipe, for use with ASTM A335 P22 pipe. ASTM A335 P22 itself is a pipe or plate specification, so the matching cap is made to ASTM A234 WP22 (buttweld) · ASTM A182 F22 (forged) — which is what we supply for P22 lines. Buttweld caps are dished ends welded to the pipe; forged caps are threaded or socket-weld. Used at dead ends and future connection points.
- ASTM A234
- ASME B16.9
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an ASTM A335 P22 Cap?
- What it is
- A fitting that closes the end of a pipe
- Material
- ASTM A234 WP22 (buttweld) · ASTM A182 F22 (forged)
- Dimensions
- ASME B16.9 · B16.11
- Grade
- ASTM A335 P22
- Best at
- High-pressure steam and hydrogen service up to about 580 °C
ASTM A335 P22 Cap Specification
| Product | ASTM A335 P22 Cap |
|---|---|
| Material standard | ASTM A234 WP22 (buttweld) · ASTM A182 F22 (forged) |
| Dimensional standard | ASME B16.9 · B16.11 |
| Sizes | Buttweld ½" – 48" · forged ⅛" – 4" |
| Wall / class | Schedule to match pipe · Class 3000 / 6000 (forged) |
| Ends | Bevelled to ASME B16.25 |
| Testing | Chemical & mechanical per heat · NDT · impact where specified |
| Documents | EN 10204 3.1 or 3.2 on request / as specified in the PO |
When to Choose a Cap
Buttweld caps are dished ends welded to the pipe; forged caps are threaded or socket-weld. Used at dead ends and future connection points.
- Buttweld dished caps
- Threaded and socket-weld caps
- Wall to match the pipe
More on choosing: Cap guide.
ASTM A335 P22 Cap: Why P22 for caps
Buttweld caps are dished ends welded to the pipe; forged caps are threaded or socket-weld. Used at dead ends and future connection points. In ASTM A335 P22, the choice usually comes down to the medium and temperature — the rows here are the points buyers check for this exact combination.
| Why this grade | Carbon and low-alloy fittings suit hydrocarbon, steam and utility lines. ASTM A335 P22 is picked for high-pressure steam and hydrogen service up to about 580 °C. |
|---|---|
| Typical service | Power plants — High-pressure steam lines. |
| Welding to carbon steel | Matching carbon or low-alloy filler is used; joints to stainless need ER309L |
| Matching filler | ER90S-B3 / E9018-B3 |
ASTM A335 P22 Cap Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Chromium | As specified |
| Molybdenum | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Phosphorus | As specified |
| Sulphur | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM A335 Grade P22.
ASTM A335 P22 Cap Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM A335 Grade P22 — condition per order.
Full chemistry, properties and equivalents are on the ASTM A335 P22 grade page.
Other ASTM A335 P22 pipe fittings
ASTM A335 P22 Cap dimensions — ASME B16.9
Values in mm, the same for every material; the wall thickness matches the pipe schedule.
| NPS | OD | Cap length E |
|---|---|---|
| ½" | 21.3 | 25 |
| ¾" | 26.7 | 25 |
| 1" | 33.4 | 38 |
| 1½" | 48.3 | 38 |
| 2" | 60.3 | 38 |
| 3" | 88.9 | 51 |
| 4" | 114.3 | 64 |
| 6" | 168.3 | 89 |
| 8" | 219.1 | 102 |
| 10" | 273.1 | 127 |
| 12" | 323.9 | 152 |
| 16" | 406.4 | 178 |
| 20" | 508.0 | 229 |
| 24" | 610.0 | 267 |
Full chart: ASME B16.9 fitting dimensions.
ASTM A335 P22 Cap — questions buyers ask
Can a cap take full line pressure?
Yes — a buttweld cap of matching schedule is rated like the pipe it closes.
Can ASTM A335 P22 caps be welded to carbon steel?
Yes — matching carbon or low-alloy filler is used; joints to stainless need ER309L.
Which standard covers ASTM A335 P22 caps?
The material is ASTM A234 WP22 (buttweld) · ASTM A182 F22 (forged); dimensions follow ASME B16.9 · B16.11. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a ASTM A335 P22 cap?
The steel price, the size and schedule or class, quantity, and the testing and documents required. Send your list and we quote the same working day.
What documents do you supply?
EN 10204 3.1 or 3.2 certificates available on request / as specified in the PO; dimensional reports as required. PMI can be arranged depending on product and requirements, as specified in the PO.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026