Stainless Steel Capillary Tube
Stainless Steel Capillary Tubes are high-precision, corrosion-resistant tubes essential for applications requiring accurate flow control and durability.
Their production involves cold drawing, annealing, surface finishing, and careful inspection to meet stringent dimensional and performance standards.
- Description
Stainless Steel Capillary Tubes are thin-walled, small-diameter tubes used in applications requiring precise fluid control, high corrosion resistance, and durability.
They are widely used in refrigeration systems, HVAC, medical devices, instrumentation, hydraulic systems, and laboratory equipment.
Capillary tubes require high precision in diameter, wall thickness, and surface finish, which demands specialized manufacturing and processing techniques.
Manufacturing Process
1. Material Selection
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High-quality stainless steel, typically 304, 304L, or 316, is selected for corrosion resistance, ductility, and cleanliness.
2. Tube Extrusion or Drawing
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Stainless steel billets or tubes are cold-drawn through precision dies to reduce the diameter to capillary size.
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Multiple passes are used to achieve tight tolerances and uniform wall thickness.
3. Annealing
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Solution annealing is performed to relieve internal stresses caused by cold drawing.
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Enhances ductility, corrosion resistance, and mechanical stability.
4. Surface Treatment
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Internal and external surfaces are polished to reduce roughness, ensuring smooth fluid flow.
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Pickling and passivation may be applied for enhanced corrosion resistance.
5. Straightening and Cutting
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Tubes are straightened to prevent kinks or bends.
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Cut to standard or custom lengths, depending on application requirements.
6. Inspection
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Dimensional checks for outer diameter, wall thickness, and roundness.
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Surface quality inspection ensures smooth finish for fluid flow and precision applications.
Common Size Specifications
Outer Diameter and Wall Thickness
| Outer Diameter (mm) | Wall Thickness (mm) | Typical Length (m) |
|---|---|---|
| 0.5 – 1.0 | 0.05 – 0.10 | 1 – 6 |
| 1.0 – 2.0 | 0.05 – 0.20 | 1 – 6 |
| 2.0 – 3.0 | 0.10 – 0.30 | 1 – 6 |
| 3.0 – 5.0 | 0.15 – 0.50 | 1 – 6 |
Imperial Units (inch)
| Outer Diameter (in) | Wall Thickness (in) | Typical Length (ft) |
|---|---|---|
| 0.020 – 0.039 | 0.002 – 0.010 | 3 – 20 |
| 0.040 – 0.079 | 0.002 – 0.015 | 3 – 20 |
| 0.080 – 0.118 | 0.004 – 0.020 | 3 – 20 |
Custom diameters and lengths are available for specific industrial or medical applications.
Applications
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Refrigeration and air conditioning capillary lines
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Hydraulic and pneumatic precision systems
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Medical devices such as catheters and microfluidic tubing
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Laboratory and analytical instruments
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Fuel and gas metering systems
Advantages
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High dimensional accuracy for precise fluid control
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Excellent corrosion resistance
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Smooth internal surface for laminar flow
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Compatible with welding, bending, and coiling
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Available in a wide range of diameters, wall thicknesses, and lengths
