Stainless Steel 316L Ultra-High-Purity (VAR / VIM-VAR) Seamless Tubing Manufacturer & Supplier
SS 316L UHP is a controlled-chemistry 316L produced by Vacuum Arc Remelting (VAR) or VIM-VAR to minimise non-metallic inclusions, with sulphur controlled to 0.005-0.017% for consistent orbital weldability. Delivered electropolished (Ra 0.25 um / 10 Ra-in or better), helium leak-tested, nitrogen-purged, capped and double-bagged for cleanroom entry, it is the standard tubing for semiconductor gas and high-purity fluid systems. Stancor supplies UHP tubing through qualified electropolishing partners, with an in-house EP line on the investment roadmap.
UNS: S31603 | Category: Austenitic Stainless Steel - UHP Grade | Werkstoff Nr: 1.4404 / 1.4435 | EN Name: X2CrNiMo17-12-2 (controlled chemistry)
Size Range
Outer Diameter: 1/8" to 2" OD (3.18mm to 50.8mm OD)
Wall Thickness: 0.035" to 0.083" (0.89mm to 2.11mm)
Chemical Composition (%)
| C | Mn | Si | Cr | Ni | Mo | S | P | O | N |
|---|---|---|---|---|---|---|---|---|---|
| 0.030 max | 2.00 max | 0.75 max | 16.0-18.0 | 10.0-15.0 | 2.0-3.0 | 0.005-0.017 (controlled) | 0.030 max | 50 ppm max (VAR) | 0.10 max |
Mechanical Properties
- Tensile Strength
- 485 MPa min
- Yield Strength
- 170 MPa min
- Elongation
- 35% min
- Hardness
- 90 HRB max
Physical Properties
- Density
- 7.98 g/cm3
- Melting Range
- 1375-1400 C
- Thermal Conductivity
- 16.3 W/m-K
- Electrical Resistivity
- 740 nOhm-m
- Specific Heat
- 500 J/kg-K
- Coeff. of Thermal Expansion
- 15.9 um/m-C
Corrosion Resistance
- Pitting Resistance (PREN)
- ~24-26
- Max Service Temp (Oxidizing)
- 870 C
- Intergranular Corrosion
- Resistant (low carbon)
- Stress Corrosion Cracking
- Better than 304L in chlorides
- General Corrosion Rate
- <0.05 mm/yr; Cr/Fe-enriched passive layer after electropolishing
- Seawater Resistance
- Moderate
Applicable Standards
- SEMI F20 (UHP tubing chemistry & cleanliness)
- SEMI F19 (surface finish Ra)
- ASTM A269 / A270
- ASTM A632
- ASTM A213 / ASME SA213
Applications
- UHP specialty and bulk gas distribution (N2, Ar, He, H2, O2, SiH4, NF3)
- Gas cabinets, valve manifold boxes and gas sticks
- CMP slurry and DI water distribution
- Sub-fab process cooling water (PCW) loops
- Orbital-welded cleanroom process piping
- Pharmaceutical WFI and biotech high-purity lines
Industries Served
- Semiconductor & Electronics
- Pharmaceutical
- Solar & Photovoltaic
- Display Manufacturing
- Biotechnology
Key Advantages
- VAR / VIM-VAR melting minimises inclusions that seed particle generation
- Controlled sulphur for repeatable orbital-weld penetration
- Electropolished Cr-rich passive layer for moisture dry-down and low outgassing
- Full SEMI F20-type documentation: heat chemistry, inclusion rating, surface Ra
- Cleanroom-compatible packaging: N2 purge, caps, double bag
- Fully traceable heat-to-tube certification (EN 10204 3.1)
Equivalent Grades
- ASTM
- TP316L (controlled S)
- SEMI
- F20 Type 1 / Type 2
- DIN
- 1.4404 / 1.4435