SS 321 Seamless PipeASTM A312 · ASME B36.19 · Manufacturer, trader & exporter, India
AISI 321 · UNS S32100
An SS 321 seamless pipe is pipe made without a weld seam, by piercing and drawing, made from SS 321 to ASTM A312 TP321. Seamless pipe is the choice for high pressure, high temperature and critical service where a weld seam is not wanted.
- ASTM A312
- ASME B36.19
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an SS 321 Seamless Pipe?
- What it is
- Pipe made without a weld seam, by piercing and drawing
- Material
- ASTM A312 TP321
- Dimensions
- ASME B36.19 · B36.10
- Grade
- SS 321 · UNS S32100
- Best at
- High-temperature service between 425 and 815 °C
SS 321 Seamless Pipe Specification
| Product | SS 321 Seamless Pipe |
|---|---|
| Material standard | ASTM A312 TP321 |
| Dimensional standard | ASME B36.19 · B36.10 |
| Sizes | NPS ⅛" – 24", Sch 5S – XXS |
| Length | Random, double random or cut lengths |
| Testing | PMI (as specified in the PO) · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 or 3.2 on request / as specified in the PO |
When to Choose a Seamless Pipe
Seamless pipe is the choice for high pressure, high temperature and critical service where a weld seam is not wanted.
- No weld seam
- NPS ⅛" – 24"
- Schedules 5S – XXS
More on choosing: Seamless pipe guide.
SS 321 Seamless Pipe: Why 321 for seamless pipes
Seamless pipe is the choice for high pressure, high temperature and critical service where a weld seam is not wanted. In SS 321, 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 | Stainless tubulars are the default for corrosive and hygienic service. SS 321 is picked for high-temperature service between 425 and 815 °C. |
|---|---|
| Typical service | Aircraft exhaust — Manifolds, bellows and exhaust systems. |
| Welding to carbon steel | ER309L (or E309L electrode) is the usual filler when joining it to carbon steel |
| Matching filler | ER347 (AWS A5.9) |
SS 321 Seamless Pipe Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Chromium | As specified |
| Nickel | As specified |
| Titanium | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Nitrogen | As specified |
| Phosphorus | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM A240 for UNS S32100.
SS 321 Seamless Pipe Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
| Hardness | 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 A240 for UNS S32100 — Annealed plate & sheet.
Full chemistry, properties and equivalents are on the SS 321 grade page.
Other SS 321 pipes & tubes
SS 321 Seamless Pipe — questions buyers ask
Why choose seamless over welded pipe?
No longitudinal weld means uniform strength and corrosion resistance — preferred for pressure and critical service.
Can SS 321 seamless pipes be welded to carbon steel?
Yes — ER309L (or E309L electrode) is the usual filler when joining it to carbon steel.
Which standard covers SS 321 seamless pipes?
The material is ASTM A312 TP321; dimensions follow ASME B36.19 · B36.10. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a SS 321 seamless pipe?
The alloy price, the size and dimensions, 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