Premium Quality Capillary Tubes in SS, Hastelloy, Inconel & Titanium – ASTM B165, B163, B338 Certified. Sizes from 0.3mm OD with Ultra-Thin Wall Thickness. Ideal for High-Precision, Corrosion-Resistant Applications in Pharma, Lab & Gas Distribution Systems. Supplied with MTC & Third-Party Inspection on Request.
Capillary Tubes are small-diameter tubes with thin walls, designed to carry fluids with precision under controlled flow conditions. These tubes are typically manufactured using high-quality stainless steel, copper, or other non-ferrous materials, and are produced through cold-drawing and annealing processes to achieve tight dimensional tolerances and a smooth internal surface. The manufacturing process ensures a consistent inner diameter and uniform wall thickness, which is critical for accurate fluid transfer in sensitive systems.
Technically, capillary tubes are available in outer diameters ranging from 0.5 mm to 6 mm, with wall thickness as low as 0.1 mm, and are often supplied in coil or straight length form. They comply with international standards such as ASTM A269, A213, A632 (for stainless steel) and ASTM B280 (for copper). These tubes are manufactured in grades like SS 304, 304L, 316, and 316L, offering high corrosion resistance and excellent mechanical properties. Surface finishes can range from bright annealed to polished, and tolerances are maintained to ±0.01 mm for critical applications.
Capillary tubes are widely used in medical instruments, refrigeration systems, pressure measuring devices, chemical processing, analytical instruments, and gas chromatography equipment. In refrigeration and air conditioning systems, capillary tubes function as expansion devices to regulate refrigerant flow. In the medical field, they are used in catheters, IV lines, and fluid measurement systems due to their precision and cleanliness. Their ability to handle low-flow and high-precision applications makes them ideal for laboratory and analytical systems as well.
The key features of capillary tubes include tight dimensional control, corrosion resistance, smooth internal bore, high-pressure resistance, and excellent formability. They are typically packaged in clean-room conditions, using sealed coils, plastic sleeves, or polyethylene bags, ensuring contamination-free delivery for sensitive applications. Our capillary tubes are exported to demanding markets across Europe, the Middle East, the USA, and Asia, where quality and reliability are paramount for performance-critical systems.
Stainless Steel & Nickel Alloy Capillary Tubes, Sizes 0.3mm to 6mm OD, in SS 304, 316L, 321, Monel 400, Inconel 625, and Hastelloy C22. Meets ASTM A269, B165, B163 Standards. MTC Provided as per EN 10204 3.1 / 3.2. Ready Stock & Custom Cut Lengths Available.
Capillary Tubes Specifications
| Specification | Details |
|---|---|
| Product Type | Capillary Tubes |
| Outer Diameter (OD) | 0.5mm to 4.76mm (1/32” to 3/16”) |
| Wall Thickness | 0.2mm to 1.2mm |
| Length | Standard Lengths (1m to 6m), Custom Cut Lengths Available |
| Material | Stainless Steel (SS 304, 304L, 316, 316L), Copper (ASTM B68, B75), Brass |
| Standards | ASTM A213, A269, A632, B75, DIN 2391, EN 12449 |
| Stainless Steel Grades | SS 304, 304L, 316, 316L, 321 |
| Copper Grades | C12200 (Deoxidized High Phosphorus), C11000 |
| Brass Grades | IS 319 / ASTM B135 |
| End Type | Plain End, Deburred |
| Surface Finish | Bright Annealed, Mill Finish, Polished, Pickled |
| Tolerance | OD ±0.02mm, WT ±10% or as per customer request |
| Testing & Inspection | Eddy Current Test, Hydrostatic Test, PMI Test, Dimensional Check, Surface Finish Inspection |
| Certification | Mill Test Certificate (MTC) as per EN 10204 3.1 / 3.2 |
| Applications | Medical & Surgical Instruments, Refrigeration & Air Conditioning, Analytical Instruments, Gas Delivery Systems, Laboratory Equipment |
Types of Pipes & Tubes
Hot rolled and defect-free – Seamless Pipes & Tubes built for strength and longevity.
Strong, smooth, and reliable – Welded Pipes & Tubes for every industrial need.
Seamless look, welded strength — ERW Pipes & Tubes built to perform.
Tubing is the backbone of modern construction and manufacturing
Oval pipes offer a unique shape ideal for modern design and efficient flow systems.
Square and rectangular pipes are essential in construction, fabrication, and structural design.
Their versatility and durability make them a go-to choice for frames, supports, and structural components.
Their small diameter allows accurate flow regulation and heat exchange efficiency.
Capillary Tubes Size Chart
| Gauge | Outside Diameter Tolerance mm | Regular Wall (RW) mm | Thin Wall (TW) mm | Extra Thin Wall (XTW) mm | Ultra Thin Wall (UTW) mm |
|---|---|---|---|---|---|
| 30 | 0.304 – 0.317 | 0.064 – 0.089 | |||
| 29 | o.330 – 0.342 | 0.064 – 0.089 | |||
| 28 | 0.355 – 0.368 | 0.076 – 0.102 | |||
| 27 | 0.406 – 0.419 | 0.089 – 0.115 | 0.064 – 0.089 | ||
| 26 | 0.457 – 0.469 | 0.089 – 0.114 | |||
| 25 | 0.508 – 0.520 | 0.115 – 0.140 | 0.089 – 0.114 | ||
| 24 | 0.558 – 0.571 | 0.114 – 0.140 | 0.089 – 0.114 | 0.051 – 0.102 | |
| 23 | 0.635 – 0.647 | 0.140 – 0.165 | 0.089 – 0.114 | 0.051 – 0.102 | |
| 22 | 0.711 – 0.723 | 0.140 – 0.165 | 0.096 – 0.121 | 0.077 – 0.102 | 0.051 – 0.102 |
| 21 | 0.812 – 0.825 | 0.140 – 0.165 | 0.102 – 0.127 | 0.051 – 0.102 | |
| 20 | 0.901 – 0.914 | 0.108 – 0.165 | 0.108 – 0.134 | ||
| 19 | 1.054 – 1.079 | 0.166 – 0.216 | 0.102 – 0.140 | 0.070 – 0.108 | |
| 18 | 1.257 – 1.282 | 0.191 – 0.241 | 0.127 – 0.165 | 0.083 – 0.121 | 0.051 – 0.102 |
| 17 | 1.460 – 1.485 | 0.177 – 0.229 | 0.115 – 0.152 | 0.083 – 0.127 | 0.057 – 0.102 |
| 16 | 1.638 – 1.663 | 0.204 – 0.254 | 0.127 – 0.165 | 0.096 – 0.133 | 0.070 – 0.121 |
| 15 | 1.816 – 1.841 | 0.204 – 0.254 | 0.127 – 0.165 | 0.096 – 0.134 | 0.070 – 0.121 |
| 14 | 2.082 – 2.133 | 0.216 – 0.292 | 0.165 – 0.229 | 0.114 – 0.165 | 0.076 – 0.134 |
| 13 | 2.387 – 2.438 | 0.267 – 0.343 | 0.191 – 0.267 | ||
| 12 | 2.743 – 2.749 | 0.267 – 0.321 | |||
| 11 | 3.023 – 3.073 | 0.293 – 0.368 | 0.216 – 0.292 | ||
| 10 | 3.378 – 3.429 | 0.318 – 0.394 | 0.216 – 0.292 |
Capillary Tubing Pressure Rating
| External Dimensions | Wall Thickness Mm | |||||||
|---|---|---|---|---|---|---|---|---|
| A X A Mm | 5 | 4 | 3 | 2,5 | 2 | 1,5 | 1,2 | 1 |
| 10 X 10 | – | – | – | – | – | 0,422 | 0,347 | 0,294 |
| 15 X 15 | – | – | – | – | 0,857 | 0,661 | 0,538 | 0,453 |
| 16 X 16 | – | – | – | – | 0,921 | 0,709 | 0,576 | 0,485 |
| 20 X 20 | – | – | – | – | 1,176 | 0,901 | 0,729 | 0,613 |
| 25 X 25 | – | – | 2,167 | 1,837 | 1,495 | 1,140 | 0,921 | 0,772 |
| 30 X 30 | – | – | 2,645 | 2,236 | 1,814 | 1,379 | 1,112 | 0,932 |
| 35 X 35 | – | – | 3,124 | 2,635 | 2,133 | 1,618 | 1,304 | 1,091 |
| 40 X 40 | – | 4,703 | 3,602 | 3,033 | 2,452 | 1,858 | 1,495 | 1,251 |
| 45 X 45 | – | 5,341 | 4,081 | 3,432 | 2,771 | 2,097 | 1,686 | 1,410 |
| 50 X 50 | 7,349 | 5,979 | 4,559 | 3,831 | 3,090 | 2,336 | 1,878 | – |
| 60 X 60 | 8,943 | 7,255 | 5,516 | 4,628 | 3,728 | 2,814 | – | – |
| 70 X 70 | 10,538 | 8,531 | 6,473 | 5,426 | 4,366 | 3,293 | – | – |
| 80 X 80 | 12,133 | 9,807 | 7,430 | 6,223 | 5,004 | 3,771 | – | – |
| 100 X 100 | 15,323 | 12,359 | 9,344 | 7,818 | 6,279 | 4,728 | – | – |
| 120 X 120 | 18,513 | 14,910 | 11,258 | 9,413 | 7,555 | – | – | – |
| 150 X 150 | 23,298 | 18,738 | 14,129 | 11,805 | 9,469 | – | – | – |
| 200 X 200 | 31,272 | 25,118 | 18,913 | 15,793 | 12,659 | – | – | – |
| 250 X 250 | 39,247 | 31,497 | 23,698 | – | – | – | – | – |
Capillary Tubes Dimensional Tolerances
| SIZE OD | NOMINAL WALL THICKNESS | OUTSIDE DIAMETER TOLERANCE | LENGTH TOLERANCE | WALL THICKNESS TOLERANCE | ||||
|---|---|---|---|---|---|---|---|---|
| (in) | (mm) | (in) | (mm) | (in) | (mm) | (in) | (mm) | (%) |
| ½ | 12.7 | 0.065 | 1.65 | +/-0.005 | +/-0.13 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| ¾ | 19.1 | 0.065 | 1.65 | +/-0.005 | +/-0.13 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| 1 | 25.4 | 0.065 | 1.65 | +/-0.005 | +/-0.13 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| 1½ | 38.1 | 0.065 | 1.65 | +/-0.008 | +/-0.20 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| 2 | 50.8 | 0.065 | 1.65 | +/-0.008 | +/-0.20 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| 2½ | 63.5 | 0.065 | 1.65 | +/-0.010 | +/-0.25 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| 3 | 76.2 | 0.065 | 1.65 | +/-0.010 | +/-0.25 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| 4 | 101.6 | 0.083 | 2.11 | +/-0.015 | +/-0.38 | +⅛, -0 | +3.18, -0 | +/-10.0% |
| 6 | 152.4 | 0.109 | 2.77 | +/-0.030 | +/-0.76 | +1, -0 | +25.4, -0 | +/-10.0% |
Worldwide Supply of Capillary Tubes
Russia, Bahrain, Cyprus, Egypt, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Palestine, Qatar, Saudi Arabia, Syria, Turkey, United Arab Emirates (UAE), Yemen, United States of America (USA), Albania, Andorra, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Moldova, Monaco, Montenegro, Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, San Marino, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, United Kingdom, Vatican City.
