SS 321 Round TubeASTM A213 · Tube specification · Manufacturer, stockist & exporter, India
AISI 321 · UNS S32100
An SS 321 round tube is tube ordered by exact OD and wall thickness, made from SS 321 to ASTM A213. Round tube is used for heat exchangers, boilers and instruments, with tighter tolerances than pipe.
- ASTM A213
- Tube specification
- 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 Round Tube?
- What it is
- Tube ordered by exact OD and wall thickness
- Material
- ASTM A213
- Dimensions
- Tube specification
- Grade
- SS 321 · UNS S32100
- Best at
- High-temperature service between 425 and 815 °C
SS 321 Round Tube Specification
| Product | SS 321 Round Tube |
|---|---|
| Material standard | ASTM A213 |
| Dimensional standard | Tube specification |
| Sizes | OD × wall to order |
| Length | Random, double random or cut lengths |
| Testing | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose a Round Tube
Round tube is used for heat exchangers, boilers and instruments, with tighter tolerances than pipe.
- OD × wall ordering
- Seamless or welded
- Straight or U-bent
More on choosing: Round tube guide.
SS 321 Round Tube: Why 321 for round tubes
Round tube is used for heat exchangers, boilers and instruments, with tighter tolerances than pipe. 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 Round Tube Chemical Composition
| Element | Weight % |
|---|---|
| Chromium | 17.0 – 19.0 |
| Nickel | 9.0 – 12.0 |
| Titanium | 5 × (C + N) min, 0.70 max |
| Carbon | 0.08 max |
| Manganese | 2.00 max |
| Silicon | 0.75 max |
| Nitrogen | 0.10 max |
| Phosphorus | 0.045 max |
SS 321 Round Tube Mechanical Properties
| Annealed plate & sheet | Value |
|---|---|
| Tensile strength | 515 MPa · 75 ksi |
| Yield strength 0.2% | 205 MPa · 30 ksi |
| Elongation | 40% |
| Hardness | 217 HB max |
Full chemistry, properties and equivalents are on the SS 321 grade page.
Other SS 321 pipes & tubes
SS 321 Round Tubes for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 321 Round Tube — questions buyers ask
What is the difference between tube and pipe?
Tube is specified by exact OD and wall; pipe by nominal size and schedule.
Can SS 321 round tubes 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 round tubes?
The material is ASTM A213; dimensions follow Tube specification. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a SS 321 round tube?
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 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026