SS304 / SS316L / SS321 Stainless Steel Capillary Tubes

Stainless steel capillary tubes are essential in industries where precision, corrosion resistance, and cleanliness are critical. Whether used in instrumentation, medical equipment, aerospace systems, or chemical processing, these small-diameter tubes deliver reliable performance in the most demanding environments.

At Gnee, we supply SS304, SS316L, and SS321 stainless steel capillary tubes in stock, offering tight dimensional control, mirror-clean inner surfaces, and customizable lengths to meet your exact requirements. All products comply with ASTM A269 / A213 / EN 10216-5 standards and come with full mill test certificates (MTC 3.1).

 

What's the difference between 304, 316L, and 321 capillary tubes?
304 is economical and widely used in clean and non-aggressive environments.
316L has added molybdenum for excellent chloride resistance.
321 contains titanium for superior high-temperature oxidation resistance.

SS304 / SS316L / SS321 Stainless Steel Capillary Tubes in stock

Specification	Details
Standards	ASTM A269 / ASTM A213 / EN 10217-7 / JIS G3459
Grades Available	SS304, SS316L, SS321
Outer Diameter (OD)	0.3 mm – 6.35 mm (1/8 inch or smaller)
Wall Thickness	0.05 mm – 1.2 mm
Length	Up to 12 meters (custom cut available)
Surface Finish	Bright Annealed / Polished / Pickled
Tolerance	OD ±0.05 mm, Wall Thickness ±10%
Testing	Eddy Current, Hydrostatic, Air Under Water, and Dimensional Inspection
Form	Straight, Coil, or U-bend Type

 

Tolerance of SS Capillary Tubes

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%

 

Chemical Composition of SS316

Stainless Steel Capillary Tube Grades	UNS	C	Mn	P	S	Si	Cr	Ni	Mo	Ti	Nb	N
TP316	S3160	0.08	2	0.045	0.03	1	16-18	11-14	2-3
TP316L	S31603	0.035	2	0.045	0.03	1	16-18	10-14	2-3

 

SS capillary tube Mechanical Characteristics

Material	Heat	Temperure	Tensile Strength	Yield Strength	Elongation %, Min
	Treatment	Min.	Ksi (MPa), Min.	Ksi (MPa), Min.
TP316	Solution	1900(1040)	75(515)	30(205)	35
TP316L	Solution	1900(1040)	70(485)	25(170)	35

 

SS304 / SS316L / SS321 Stainless Steel Capillary Tubes Price Reference (2025 Market)

SS304 Capillary Tube: USD 6.5–7.5/kg

SS316L Capillary Tube: USD 7.8–9.2/kg

SS321 Capillary Tube: USD 8.0–9.5/kg

 

Gnee is a professional supplier of SS304 / SS316L / SS321 stainless steel capillary tubes, offering:

✅ What We Can Provide
Ready stock in a wide range of diameters and wall thicknesses
Custom production according to ASTM, EN, or JIS standards
Processing services: precision cutting, polishing, coiling, and bending
Testing: Hydrostatic, Eddy current, Dimensional, and PMI
Certificates: ISO 9001, SGS, BV, EN 10204 3.1/3.2
Delivery: Within 7–15 days worldwide
MOQ: Flexible - small orders accepted
Packaging: Vacuum-sealed, moisture-proof wooden boxes or coils