SS 321 Capillary TubeASTM A213 · ASTM A269 / A632 · Manufacturer, stockist & exporter, India
AISI 321 · UNS S32100
An SS 321 capillary tube is small-bore tube for instruments and medical use, made from SS 321 to ASTM A213. Capillary tubes have very small diameters and walls for instrumentation, thermometry and medical devices.
- ASTM A213
- ASTM A269 / A632
- 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 Capillary Tube?
- What it is
- Small-bore tube for instruments and medical use
- Material
- ASTM A213
- Dimensions
- ASTM A269 / A632
- Grade
- SS 321 · UNS S32100
- Best at
- High-temperature service between 425 and 815 °C
SS 321 Capillary Tube Specification
| Product | SS 321 Capillary Tube |
|---|---|
| Material standard | ASTM A213 |
| Dimensional standard | ASTM A269 / A632 |
| 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 Capillary Tube
Capillary tubes have very small diameters and walls for instrumentation, thermometry and medical devices.
- Very small OD
- Bright annealed
- Coils or cut lengths
More on choosing: Capillary tube guide.
SS 321 Capillary Tube: Why 321 for capillary tubes
Capillary tubes have very small diameters and walls for instrumentation, thermometry and medical devices. 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 Capillary 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 Capillary 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 Capillary Tubes for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 321 Capillary Tube — questions buyers ask
What sizes are capillary tubes?
Commonly 0.3 – 6 mm OD with thin walls, supplied in coils or cut lengths.
Can SS 321 capillary 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 capillary tubes?
The material is ASTM A213; dimensions follow ASTM A269 / A632. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a SS 321 capillary 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