ASTM A213 / ASME SA213 TP316L Stainless Steel Seamless Tube Bright Annealed Tube

Bright annealing stainless steel seamless tubes can result in a bright, clean surface finish with improved aesthetics and increased resistance to corrosion and oxidation. The process also helps in achieving tight dimensional tolerances and improving the mechanical properties of the tube.

Instrumentation tubing provides the critical connection between primary process piping and measurement or control devices. This small-diameter conduit facilitates the transfer of pressure, fluid, or gas signals to components including control systems, valves, and pressure gauges. Its dimensions are characterized by outside diameter and wall thickness. While typically constructed from stainless steel (common grades are 304/304L and 316/316L) for its corrosion resistance, it is also available in materials such as mild steel, copper, and nickel alloys.

Available Materials

Key Characteristics

1. Small Diameter: Typically ranges from 1/4 inch to 1/2 inch (6 mm to 12 mm) in outside diameter (OD). This small size allows for neat, compact tubing runs in control panels and field installations.

2. Precision-Made: Manufactured to much tighter tolerances than standard pipe or tubing. This ensures consistent performance, reliable connections, and predictable fluid flow.

3. Measured by OD: Its size is always specified by its Outside Diameter (OD) and wall thickness (e.g., 1/4" OD x 0.035" wall).

4. Material: Chosen for corrosion resistance, strength, and cleanliness.

   • Stainless Steel (most common): Grades 304/304L and 316/316L are the industry standard for their excellent corrosion resistance.

   • Other Materials: Carbon steel, copper, nickel alloys (e.g., Inconel®, Hastelloy®) for specific high-temperature or highly corrosive services.

5. Pressure Rating: Designed to handle high pressures relative to its small size, ensuring the integrity of the control system.

Primary Functions

• Transmit Signals: Carries pneumatic (air) or hydraulic (fluid) signals from a controller to an actuator to open or close a valve.

• Sample Lines: Transports small samples of a process fluid (like steam, oil, or chemicals) to an analyzer for quality testing.

• Gauge Lines: Connects a process line to a pressure or temperature gauge for local reading.

• Impulse Lines: The specific tubing that connects a process vessel or pipe to a pressure transmitter or differential pressure (DP) transmitter.

Industries and Applications

Stainless steel instrumentation tubing is essential in any industry where process control and reliability are paramount:

• Oil & Gas: Wellhead controls, compressor stations, refinery process lines.

• Chemical & Petrochemical: Transporting samples and signals for aggressive chemicals.

• Power Generation: Boiler controls, steam lines, turbine systems.

• Pharmaceutical & Biotech: Requires ultra-clean, sterilizable tubing (often electropolished 316L).

• Food & Beverage: For sanitary processes and clean-in-place (CIP) systems.

• Pulp & Paper: Resisting corrosive chemicals used in the pulping process.

• Semiconductor Manufacturing: For high-purity gas and chemical delivery.