1/4" Capillary Tube

Stainless Steel 316L

0.049" Wall

Due to our unique manufacturing processes and strict quality control, our 1/4” capillary tube outperforms the best on the market.

Capillary Tube (0.250 Pair) [Web] GEO PSI

0.250″ Capillary Tube Stainless Steel 316L 0.049″

Our Stainless Steel 316L Capillary Line is ideal for use in oil and natural gas wells due to its higher strength, resistance to pitting, corrosion, and chloride stress corrosion cracking. For injection applications, the tubing is self-supporting inside the production casing and facilitates the injection of chemicals to enhance production flow rate, inhibit corrosion and de-water. In control line applications, the tubing is strapped to the production casing and facilitates the hydraulic actuation of surface-controlled subsurface equipment such as valves.

General Properties

316L is an austenitic stainless steel possessing excellent mechanical properties (strength and hardness). Compared to other chromium-nickel austenitic stainless steels, 316L provides higher creep, stress to rupture and tensile strength at elevated temperatures.

The high amounts of nickel and chromium provide outstanding corrosion resistance to most chemicals, salts and acids. This is improved further by the molybdenum content, particularly with higher resistance to pitting and crevice corrosion in chloride environments.

Forming & Annealing Process

The strip is passed through a series of rollers to form it into a tubular cross-section. The tubing is continuously welded along the seam with a gas tungsten arc welding (GTAW) process. To achieve the desired length of tubing, individual lengths are joined by orbital welding. Continuous eddy current testing is performed to detect holes. Exiting the tube mill, the tubing is passed through an induction coil and annealed at between 1,070°C – 1,100°C.


Additional Information

We recommend the use of SwageLok™ or DK-Lok™ compression fittings to ensure reliable grip and seal with the Stainless Steel 316L Capillary Tubing.


Stainless Steel 316L Chemistry

(by weight)

Carbon (C)


Manganese (Mn)


Silicon (Si)


Chromium (Cr)


Nickel (Ni)


Molybdenum (Mo)


Phosphorus (P)


Sulfur (S)


Iron (Fe)


Nitrogen (N)


Physical & Mechanical Properties

Outer Diameter

0.250” (1)

Wall Thickness

0.049” (1)


0.1074 lbs/ft

Burst Pressure

29,400 psi (2)

Internal Pressure

11,700 psi (3)

Collapse Pressure

9,400 psi (4)

Working Pressure

8,400 psi (5)

Test Pressure

9,700 psi (6)


(Pitting Resistance Equivalent Number)

24.45 (7)

Metal Cross Section

0.0310 in2

Flow Cross Section

0.0182 in2

Minimum Tensile Strength

75,000 psi (8)

Minimum Yield Strength

30,000 psi (8)

Minimum Elongation

35% (8)

Hardness (HRB Max)

95 (9)

(1) Dimension Tolerances per ASTM A632-19: O.D. +0.004”, -0.000”; I.D. +0.000”, -0.004”; WT ± 10%
(2) Calculated using Barlow’s formula at Tensile Strength (ASTM A312).
(3) Calculated using Barlow’s formula at Minimum Yield Strength.
(4) Collapse pressure calculated per API 5C3.
(5) Working pressure is defined as Internal Pressure x 0.72 Fd (design factor).
(6) Testing recommended at 15% above Working Pressure.
(7) (%Cr + 3.3%Mo + 16%N), API Technical Report 938-C, 2nd Edition, 2011.
(8) Tensile tests conform to ASTM A370-20, using yield strength method 0.2% offset.
(9) Vickers 500g (HV0.5) hardness test conforms to ASTM E384-17. Rockwell Hardness conversion per ASTM E140-12b (2019).
* The data are typical and subject to normal manufacturing tolerances. The data are provided for information purposes and should not be construed as maximum or minimum values for specification or design purposes. The data are subject to change at any time without notice.

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