Stainless Steel 316 Seamless Capillary Tubes Manufacturer India

Stainless Steel 316 Seamless Capillary Tubes Manufacturer & Supplier in India

Amardeep Steel Centre is a Mumbai-based manufacturer, stockist and exporter of stainless steel 316 seamless capillary tubes, producing to ASTM A213 and ASTM A269 specifications in outer diameters from 0.3 mm to 6 mm and wall thicknesses from 0.08 mm to 1.5 mm. Every tube is cold-drawn from solid SS 316 billet under UNS S31600, with no seam or weld line, and is available in straight-cut lengths or continuous coil, plain or bevelled end, and bright annealed, pickled or polished finish. As a direct manufacturer with ex-stock inventory, we supply instrumentation, pharmaceutical, HPLC, medical device and aerospace customers across more than 40 countries, with every batch backed by an EN 10204 3.1 Mill Test Certificate for full traceability.

Why Choose Seamless SS 316 Capillary Tube Over Welded

Instrument lines built for critical duty cannot afford internal leakage or a blocked bore. A welded capillary tube carries a seam, and that seam is where stress corrosion cracking tends to start once vibration and temperature cycling get involved. A seamless 316 capillary tube has a continuous structure through the full wall thickness, which gives it a higher working pressure limit, steadier flow and better fatigue life over the life of the installation. Where the budget allows and the duty justifies it, seamless is the safer specification for high-pressureS sensing, chromatography and hydraulic control.

Technical Data

Stainless Steel 316 Seamless Capillary Tube Specification

Specification	Detail
Standard	ASTM A213 ASTM A269 with ASTM A688 and ASTM A803 available on request
Grade	SS 316 UNS S31600 Werkstoff 1.4401 JIS SUS 316
Outer diameter	0.3 mm to 6 mm larger sizes on request
Wall thickness	0.08 mm to 1.5 mm
Length	Cut length fixed length single random double random or continuous coil
Type	Seamless
Form	Round straight or coiled
End finish	Plain end or bevelled end
Surface finish	Bright annealed pickled polished or electropolished
Certification	EN 10204 3.1 Mill Test Certificate standard 3.2 on request

To review standard tolerance limits and wall thickness schedules across larger industrial sizes, reference the complete ASTM A269 stainless steel seamless tubing specs.

Chemical Composition of Stainless Steel 316 Seamless Capillary Tubes

Grade	UNS	C max	Mn max	Si max	P max	S max	Cr	Ni	Mo
TP316	S31600	0.08	2.00	0.75	0.045	0.030	16.0 to 18.0	10.0 to 14.0	2.0 to 3.0

SS 316 Seamless Capillary Tubes Mechanical Properties

Property	Value
Tensile strength minimum	515 MPa (75000 psi)
Yield strength 0.2 percent proof minimum	205 MPa (30000 psi)
Elongation in 50 mm minimum	35 percent
Hardness maximum	95 HRB
Solution annealing temperature	Approximately 1040 C followed by rapid cooling
Maximum continuous service temperature	Approximately 870 C in oxidising atmospheres

Equivalent Grades for Stainless Steel 316 Seamless Capillary Tube

Standard	UNS	Werkstoff	EN name	JIS
SS 316	S31600	1.4401	X5CrNiMo17 12 2	SUS 316

Dimensions and Gauge Chart for SS 316 Seamless Capillary Tubes

Outer diameter (mm)	Wall thickness (mm)	Inner diameter (mm)
0.30	0.08	0.14
0.50	0.10	0.30
0.80	0.15	0.50
1.00	0.20	0.60
1.60	0.20 to 0.51	0.58 to 1.20
2.00	0.30	1.40
3.00	0.50	2.00
4.00	0.50	3.00
6.00	1.00	4.00

Dimensional Tolerances for Stainless Steel 316 Seamless Capillary Tubes

Size range	Outer diameter tolerance	Wall thickness tolerance	Length tolerance
Up to 1.6 mm OD	Plus or minus 0.02 mm	Plus or minus 10 percent	Plus 3 mm minus 0 mm
1.6 mm to 3 mm OD	Plus or minus 0.03 mm	Plus or minus 10 percent	Plus 3 mm minus 0 mm
3 mm to 6 mm OD	Plus or minus 0.05 mm	Plus or minus 10 percent	Plus 3 mm minus 0 mm

SS 316 Seamless Capillary Tube’s Working Pressure

Outer diameter (mm)	Wall thickness (mm)	Indicative working pressure (bar)
1.60	0.20	Approximately 220
1.60	0.30	Approximately 380
3.00	0.50	Approximately 430
6.00	1.00	Approximately 480

Seamless vs Welded SS 316 Capillary Tubes

Factor	Seamless SS 316 capillary tube	Welded SS 316 capillary tube
Construction	Drawn from solid billet, no weld line	Strip formed, welded and drawn to final size
Wall uniformity	Very consistent around the full circumference	Good, with a defined weld line along the length
Pressure rating	Higher for a given wall thickness	Suitable for most instrumentation and sensing duty
Typical use	High pressure sensing, chromatography, hydraulic control	General instrumentation, chemical and marine sensing lines
Relative cost	Higher per metre	More economical

Applications of Stainless Steel 316 Seamless Capillary Tube

Instrumentation and pressure sensing lines
High-performance liquid chromatography (HPLC) and laboratory analytical equipment
Medical hypodermic needles, diagnostic tools and surgical equipment
Aerospace sensing systems and military hydraulic control assemblies
Marine chemical injection lines and subsea sampling units
Petrochemical power generation and offshore oil and gas process monitoring

Get a Competitive Quote for Stainless Steel 316 Seamless Capillary Tubes

Amardeep Steel Centre supplies stainless steel 316 seamless capillary tubes with complete technical documentation, including the EN 10204 3.1 Mill Test Certificate. Request a quote today by specifying your outer diameter, wall thickness, length and total required quantity

Frequently Asked Questions

What is a stainless steel 316 seamless capillary tube?

It is a fine bore precision tube generally under 6 mm outer diameter, drawn from solid grade 316 billet with no seam or weld line It is manufactured to ASTM A213 or ASTM A269 under UNS S31600 and is chosen when a system requires an accurate, pressure-resistant passage that withstands corrosive fluids better than standard 304 material.

What sizes are available in SS 316 seamless capillary tube?

We stock outer diameters starting from 0.3 mm up to 6 mm with wall thicknesses ranging from 0.08 mm to 1.5 mm in both straight cut lengths and continuous coils. Custom wall combinations and non-standard dimensions are produced on order.

What is the difference between a seamless and welded capillary tube?

Seamless tube is cold drawn from a solid steel hollow billet without any longitudinal weld line, resulting in uniform wall strength, smooth interior bore dimensions and higher pressure capacity. Welded tube is formed from flat strip material welded along the seam and drawn down, while economical welded tubing is less suitable for severe cyclic pressure or ultra-high-purity fluid paths

What is the difference between a capillary tube and a precision tube?

Capillary tubes represent the small-diameter end of precision tubing, usually defined by outer diameters below 6 mm. 'Precision tube' is an umbrella term covering any tube made to tight dimensional tolerances, regardless of overall size. Every capillary tube is a precision tube but not every precision tube is small enough to be classed as capillary.

What is the maximum working pressure for SS 316 capillary tubing?

Working pressure depends on the ratio of wall thickness to outer diameter as well as the operating temperature. Heavier wall thicknesses relative to outer diameter increase working pressure capability. Significantly higher pressures can be sustained safely in 316 grade compared to lower alloyed steels due to superior mechanical strength and resistance to localised pitting.

Which industries use SS 316 seamless capillary tubes?

Major consuming sectors include analytical instrumentation, marine process plants, oil and gas sampling lines, medical equipment manufacturing, aerospace hydraulic systems and pharmaceutical fluid transfer lines, where chemical purity and corrosion resistance are mandatory.

Stainless Steel 316 Seamless Capillary Tubes