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Instrumentation Tubes

Instrumentation Tubes – ASTM A269 / A632 Manufacturer in India

Stainless Steel Precision Tubes for Instrumentation, Control Lines & High-Purity Fluid Systems
Inox Steel India

Inox Steel India is a leading manufacturer, stockist, and exporter of Instrumentation Tubes conforming to ASTM A269 and ASTM A632.

These tubes are designed for high-purity, high-precision, and corrosion-critical environments, ensuring reliable performance in control systems, measurement lines, chemical dosing systems, pneumatic circuits, and offshore subsea control lines.

Instrumentation tubes must deliver:

  • Tight dimensional tolerance
  • High corrosion resistance
  • Smooth internal surface (clean-bore finish)
  • Reliable bending & flaring performance
  • Absolute leak-tight integrity

Our tubes are supplied in:

  • Bright Annealed (BA) finish
  • Cleaned & Passivated
  • Coiled or straight lengths
  • Orbital welding compatible
  • OD tolerance class: ±0.05 mm or as specified

Table of Contents

Understanding ASTM A269 & ASTM A632 Standards

ASTM A269 — Stainless Steel Seamless/Welded Instrumentation Tubes

Best for: Medium-size precision tubing used in instrumentation, hydraulic & pneumatic control.

Grades:

  • TP304 / TP304L
  • TP316 / TP316L
  • TP321 / TP347

Characteristics:

  • Smooth ID for accurate media flow
  • Corrosion resistance in chemicals, steam, water & oil
  • Excellent for bending, double flaring & ferrule fittings

Used in: Instrumentation panels · Hydraulic lines · Gas sampling · Steam lines

ASTM A632 — Small Diameter Stainless Instrumentation Tubes

Best for: High-purity, small OD control lines & sensitive instrumentation systems.

Grades:

  • SS 304 / 304L
  • SS 316 / 316L
  • Nickel Alloys: Inconel 625/600, Monel 400

Characteristics:

  • Very small diameters
  • Ultra-smooth bore
  • Electropolished / Bright Annealed
  • Exceptional corrosion resistance

Used in: Panel instruments · Chemical dosing · Gas lines · Offshore umbilicals

Where Instrumentation Tubes Are Used

  • Oil & Gas (Upstream, Midstream, Refinery)
  • Petrochemicals
  • Chemical Process Plants
  • Offshore Platforms & FPSO Units
  • Power Plants
  • Pharmaceutical & Biotech
  • Food & Beverage CIP/SIP systems
  • Marine & Subsea Systems
  • OEM Hydraulic & Pneumatic Panels

Typical Applications

  • Pressure gauges
  • Flow transmitters
  • Level controls
  • Pneumatic control valves
  • Chemical injection lines
  • Analyzer shelters

Manufacturing Process — Instrumentation Tubes

1. Cold Drawing / Cold Rolling
Achieves tight tolerance & uniform mechanical strength.

2. Bright Annealing (BA Furnace)
Ensures clean ID, low carbon, corrosion resistance.

3. Pickling & Passivation
Removes scale & impurities for clean-bore finish.

4. ID/OD Polishing
Ensures smooth internal surface and accurate flow.

5. Coil-forming (Optional)
For long continuous control lines.

6. NDT Testing
Eddy current + hydrotest ensure leak-free performance.

Applications by Standard / Media / Industry

ASTM A269 – Medium OD Instrumentation Tubes

Application Media Industries
Impulse Lines Steam · Gas · Liquid Oil & Gas · Power
Hydraulic Instrumentation Hydraulic Oil Machinery
Gas Sampling Lines Natural Gas Analyzer Shelters
Panel Tubing Air · Nitrogen Process Panels
Steam Trace Tubing Saturated Steam Thermal Power

Dimensional Range

  • ASTM A269: OD 6 mm – 50.8 mm | WT 0.8 – 4.0 mm
  • ASTM A632: OD 1.59 mm – 12.7 mm | WT 0.20 – 2.11 mm
  • Forms: Straight lengths or coils

Indicative Price Range — 2025

Standard Grade Price (INR/kg) Price (USD/kg)
ASTM A269 304/304L ₹250 – ₹350 $3.30 – $4.60
ASTM A269 316/316L ₹280 – ₹420 $3.50 – $5.35
ASTM A632 316/316L ₹320 – ₹490 $4.00 – $6.00
Nickel Alloys 625/600/400 ₹1,500 – ₹3,200 $18 – $38

Testing & Quality Assurance

  • Tensile, yield & hardness tests
  • Clean-bore inspection
  • Eddy current & hydrostatic tests
  • Pneumatic leak test
  • Dimensional accuracy checks
  • EN 10204 3.1 / 3.2 certification

Call to Action — Get a Quick Instrumentation Tube Quote

ASTM A269 is most commonly used, while ASTM A632 is selected for small-diameter or high-precision applications.

Yes. ASTM A269 and A632 welded tubes are specifically designed for instrumentation and control service.

Proper OD tolerance ensures leak-free sealing with compression fittings and stable signal transmission.

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