Instrumentation systems require absolute accuracy, zero leaks, and smooth, contamination-free tubing to ensure reliable transmission of pressure, flow, and chemical signals.
This is exactly where ASTM A269 / ASME SA269 stainless-steel tubing excels.
These tubes are engineered for:
INOX STEEL INDIA manufactures A269/SA269 tubes with extreme dimensional precision, tight OD/WT tolerances, bead-rolled welds, and bright annealed or polished finishes.
ASTM A269 tubes are austenitic stainless-steel welded or seamless tubes used primarily for instrumentation, hydraulic, pneumatic, and polished applications.
They are specified where the following are non-negotiable:
These tubes undergo bright annealing, polishing, and strict inspection processes to maintain the required cleanliness for precise industrial operation.
Instrumentation fittings (compression, ferrule, double-ferrule) require precision.
Instrumentation often carries:
A269 tubes offer bright annealed ID, weld bead removal or bead rolling, and clean, low Ra surface.
Depending on the grade:
A269 also covers polished tubes used in:
Available finishes:
| Grade | Ideal Use | Advantages |
| 304 / 304L | General hydraulic & pneumatic lines | Economical, corrosion-resistant |
| 316 / 316L | Chloride-rich, corrosive fluids | Molybdenum improves pitting resistance |
| 321 | High-temperature lines | Titanium stabilization prevents carbide formation |
| Outside Diameter (OD) | Wall Thickness (WT) | Application Use |
| 3.18 mm (1/8″) | 0.28 – 1.00 mm | Impulse lines, control panels |
| 6.35 mm (1/4″) | 0.40 – 1.20 mm | Hydraulic & pneumatic circuits |
| 9.52 mm (3/8″) | 0.50 – 1.50 mm | Chemical dosing, sampling |
| 12.7 mm (1/2″) | 0.60 – 2.00 mm | Instrumentation manifolds |
| 15.88 mm (5/8″) | 0.70 – 2.50 mm | High-pressure fluid systems |
| 19.05 mm (3/4″) | 0.90 – 3.00 mm | HVAC & pneumatic lines |
| 25.4 mm (1″) | 1.00 – 3.00 mm | Process instrumentation |
| 31.75 – 50.8 mm | 1.20 – 3.50 mm | Polished / architectural |
| Property | A269 (Instrumentation) | A249 (Heat Exchanger) | A213 (Seamless Boiler) |
| Surface Finish | ★★★★★ (BA / Polished) | ★★★★★ (BA) | ★★★ |
| Weld Bead | Removed / Rolled | Removed / Rolled | NA |
| ID Cleanliness | Very High | High | Medium |
| Pressure Rating | High | Medium | Very High |
| Ideal Use | Instrumentation, hydraulic | Heat exchangers | High-pressure boilers |
| Grade | Price (INR/kg) | Price (USD/kg) |
| 304 / 304L | ₹260 – ₹380 | $3.0 – $4.5 |
| 316 / 316L | ₹360 – ₹520 | $4.5 – $6.5 |
| 321 | ₹420 – ₹650 | $5.0 – $8.0 |