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Utilizing 26 high-precision cold rolling mills and 6 cold drawing machines, we ensure dimensional accuracy and superior mechanical properties.
Small Diameter Stainless Steel Tubing
ASTM A269 / A213 | OD 1.0mm - 25.4mm | TP304L / TP316L / S32205 / Inconel 625 | Precision Grades
ISO 9001 | PED | Swagelok CompatibleRelated Products
Introduction
In the precision-demanding world of analytical instrumentation, process control systems, medical device manufacturing, semiconductor fabrication, and hydraulic engineering, the humble small-bore tube performs a function that belies its modest physical dimensions — carrying critical process fluids, instrument signals, reference gases, and hydraulic power through the intricate networks of connections that form the nervous system of modern industrial and medical technology. Small Diameter Stainless Steel Tubing, defined here as seamless austenitic tubing with outside diameters from 1.0mm to 25.4mm (1 inch) with wall thicknesses from 0.1mm to 3.0mm, represents one of the most technically demanding product categories in the global stainless steel tube market — demanding because the combination of very small dimensions and the tight tolerances required for reliable compression fitting seals, instrument connection integrity, and medical device dimensional precision requires manufacturing process control capabilities far beyond those needed for standard process piping production. The precision cold-drawing and cold-pilgering processes used to produce small diameter stainless tubing achieve outside diameter tolerances of ±0.02mm and wall thickness tolerances of ±5% in the most demanding precision grades — dimensional precision levels that approach the capabilities of precision-turned bar rather than conventionally produced tubular products, and that require continuous investment in precision tooling, in-process measurement systems, and statistical process control programs to maintain consistently across production lots.
The application landscape for small diameter stainless steel tubing is remarkably diverse, spanning industries with dramatically different technical requirements that converge on the common need for corrosion-resistant, dimensionally precise, smooth-bore tubing in small outside diameter ranges. In the process instrumentation and control sector, 6.35mm (1/4 inch) OD and 3.18mm (1/8 inch) OD TP316L tubing in wall thicknesses of 0.89mm and 0.71mm respectively represent the global standard for instrument impulse lines, sample conditioning system tubing, and analyzer connections — dimensions specifically chosen to match the standard ferrule geometry of the most widely deployed compression tube fitting systems including Swagelok, Parker A-Lok, and equivalent metric compression fitting series. In semiconductor wafer fabrication facilities, ultra-high-purity small diameter TP316L tubing with electropolished internal bore achieving Ra values below 0.25μm serves as the distribution medium for ultra-pure process gases, deionized water, and high-purity chemical reagents where sub-part-per-trillion metallic contamination targets require surface quality levels that only electropolished stainless and polished nickel alloy tube surfaces can reliably achieve. In medical device manufacturing, 316L small diameter tubing produced to ASTM A269 with supplementary biocompatibility requirements provides the structural and fluid-handling elements of endoscopic instruments, catheter reinforcement sleeves, and surgical tool components where dimensional precision and corrosion resistance in body fluid environments are simultaneous design requirements that the austenitic stainless small-bore tube uniquely satisfies.
The grade selection for small diameter stainless steel tubing is typically straightforward for standard industrial and instrumentation applications — TP316L is the default specification for the majority of process, instrumentation, and industrial fluid service applications due to its combination of adequate corrosion resistance in most industrial aqueous environments, well-characterized mechanical properties that are understood by fitting and connection system designers, and global availability in the standard instrumentation dimensions. However, specific application requirements drive grade diversification across the small diameter tube product family: TP304L serves cost-sensitive instrumentation applications in low-chloride environments where TP316L's molybdenum addition provides no meaningful corrosion resistance benefit; duplex S32205 small-bore tubing serves high-pressure hydraulic and umbilical applications where the higher yield strength of duplex grades reduces wall thickness requirements relative to austenitic alternatives; and Inconel 625 small diameter tubing is specified for subsea umbilical hydraulic tubes, offshore control system connections, and aerospace fuel system lines where the combination of high strength, corrosion resistance, and fatigue performance requirements exceed the capability of standard austenitic grades in the required dimensional range.
Our small diameter stainless steel tubing program covers outside diameters from 1.0mm to 25.4mm with wall thicknesses from 0.10mm to 3.0mm, available in TP304L, TP316L, TP321, duplex S32205, and Inconel 625 grades to ASTM A269 and A213 standards. Precision tolerance Class 1 (±0.02mm OD) is standard for sizes below 12.7mm OD, with bright annealed finish (Ra ≤ 0.4μm internal) standard for instrumentation grades and electropolished finish (Ra ≤ 0.25μm) available for semiconductor and pharmaceutical UHP applications. Coils, straight lengths, and custom-cut pieces are supplied with full EN 10204 3.1 Mill Test Reports and Swagelok/Parker compression fitting compatibility verification documentation. Bulk coil supply in standard instrumentation dimensions is available from stock for rapid delivery to instrumentation installation projects worldwide.
Specifications
| Available Grades | TP304L, TP316L, TP321, S32205, Inconel 625 |
| Standard | ASTM A269, A213, ASTM A632 |
| Outer Diameter | 1.0mm - 25.4mm |
| Wall Thickness | 0.10mm - 3.0mm |
| Supply Form | Straight Lengths / Coils / Custom Cut Pieces |
| Finish | Bright Annealed (BA) / Electropolished (EP) |
Chemical Composition (TP316L)
| Element | C | Cr | Ni | Mo | Mn | Si | N |
| Value (%) | ≤0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 | ≤2.00 | ≤0.75 | ≤0.10 |
±0.02mm OD ToleranceCompression Fitting ReadyEP / BA Surface
Mechanical Strength (TP316L)
Comprehensive Info
| MOQ | 10m per size (Coil or Cut Lengths) |
| Lead Time | 10 - 20 Days (Stock Sizes) |
| Packaging | Coils / Straight Bundles with End Caps |
| Certifications | ISO 9001, PED, ASTM A269 Class 1 |
| Raw Materials | Premium Low-Carbon Austenitic Melt |
| Customization | Grade, OD/WT, Finish (BA/EP), Coil/Straight |
Applications
Process Instrumentation Lines1/4" and 1/8" OD TP316L impulse tubing, sample lines, and analyzer connections with compression fitting compatibility
Semiconductor UHP DistributionElectropolished TP316L ultra-high-purity process gas and chemical distribution tubing in wafer fab facilities
Medical Device Components316L precision small-bore tubing for catheter reinforcement, endoscopic instrument channels, and surgical tool bodies
Subsea Hydraulic Control LinesS32205 and Inconel 625 small-bore tubing for subsea Christmas tree hydraulic control and chemical injection umbilical lines
Pharmaceutical CIP/SIP TubingBA-finish TP316L small-bore tubing for clean-in-place and steam-in-place circuit connections in pharmaceutical manufacturing
Aerospace Hydraulic & Fuel LinesInconel 625 and TP321 precision small-bore tubing for aircraft hydraulic, fuel, and bleed air system connections
Advantages
±0.02mm Precision OD
Class 1 precision cold-drawing achieves ±0.02mm OD tolerance — the dimensional precision required for reliable compression fitting ferrule bite and leak-free seal formation in critical instrument and process connections.
Electropolished UHP Surface
Internal bore electropolishing to Ra ≤ 0.25μm removes micro-peaks that trap contamination, achieving the ultra-smooth surface required for semiconductor UHP gas distribution and pharmaceutical high-purity fluid systems.
Coil Supply for Long Runs
Continuous coil supply in 30m, 50m, and 100m coil lengths minimizes field joints in long instrument tubing runs — each joint is a potential leak point, so coil supply directly reduces system leak risk in critical instrumentation installations.
Multi-Grade Single Source
TP316L, S32205, and Inconel 625 all available in matching small-bore dimensions — enabling single-source procurement for complex instrumentation projects requiring multiple alloy grades across the same OD range.
About Jiangsu Jend Tube Co.,Ltd.
As China Small Diameter Stainless Steel Tubing Manufacturers and Wholesale Small Diameter Stainless Steel Tubing Factory, Established in 2011 and is a manufacturing enterprise with a complete manufacturing cycle from raw material selection to finished product delivery. The company currently has more than 100 employees, covers an area of 30015 square meters, and has a registered capital of 48 million yuan, annual production capacity of 3800 tons.
The company has passed ISO9001:2015 quality certification, domestic pressure vessel TS certification, and foreign pressure vessel PED certification. With rich experience and mature technology, we have been expanding our market internationally. At present, our products are exported to more than 50 countries and regions including Europe, America, Southeast Asia, and the Middle East.
The company adheres to different production norms and standards such as the American standard (ASTM), the European standard (EN), the German standard (DIN), the Japanese standard (JIS), the Russian standard (GOST), and the Chinese standard (GB).
Our company specializes in and customizes various specifications of Martensite TP410 (0Cr13, 1Cr13), Ferrite TP405 (1Cr13Al), TP430 (1Cr17), TP444 (0Cr18Mo2), TP439, TP409 (0Cr11Ti), It is also proficient in manufacturing Austenitic seamless stainless steel pipes of series such as TP304(L/H), TP316(L/H/Ti), TP310S, TP317, TP321(H) and TP347(H). Duplex such as S31803, S2205, S32750, S32304, and Nickel-based alloys Monel400, Monel600, Monel800, GH3030, 904L, Inconel 625, etc.
The company mainly produces seamless steel pipes with the following specifications: outer diameter: 3.18mm to 406.4mm, wall thickness: 0.3mm to 20mm, and the longest length is 25000mm. Additionally, it can customize seamless steel pipes with special materials and specifications according to customer requirements. The company attaches great importance to scientific innovation. The staff of the company vigorously develop technological research and development.
Jiangsu Jend Tube Co.,Ltd. will continuously accumulate professional knowledge and capabilities, striving to become a leader in the domestic market and even the world market. Strive to be the most reassuring pipe manufacturing enterprise for customers.
Precision Manufacturing and Process Optimization
We rely on precision equipment and optimized production technologies to achieve outstanding mechanical performance and consistent product quality.
Cold Rolling and Cold Drawing
Solution Heat Treatment
Natural gas solution treatment furnaces and BA solution treatment furnaces optimize the material's grain structure, enhancing corrosion resistance.
Precision Straightening and Polishing
10 straightening machines and 8 finishing polishing machines guarantee product surface smoothness and dimensional accuracy.
Automated Inspection and Quality Assurance
Real-time monitoring systems ensure the stable quality of every batch of products.
Product Usage Tips
Compression Fitting Installation
For reliable compression fitting seals on small diameter TP316L tube, verify tube hardness is within the fitting manufacturer's specified range (typically Rockwell B 80–95 for standard stainless tube). Over-annealed tube that is too soft will not develop sufficient ferrule bite for rated working pressure. Cut tube ends squarely with a dedicated tube cutter — hacksaw or abrasive cutting creates burrs and out-of-round ends that prevent full ferrule engagement and cause chronic leak-back at the joint face.
UHP Electropolish Handling
After electropolishing, handle UHP small diameter tubing only with clean nitrile gloves — bare hand contact deposits skin oils and sodium chloride that initiate chloride pitting on the polished surface during storage. Store in sealed polyethylene bags with nitrogen purge to prevent atmospheric moisture and particulate contamination of the electropolished bore before installation in the ultra-pure process system.
Cutting Thin-Wall Small Bore Tube
For wall thicknesses below 0.5mm, use a dedicated orbital tube cutting wheel rather than standard pipe cutters — standard cutters apply excessive radial force that collapses thin-wall small bore tubes, creating an out-of-round cut end that cannot be correctly engaged by compression fitting ferrules. Orbital cutters maintain tube roundness through the cutting cycle and produce the square, burr-free cut ends required for reliable compression fitting assembly.
Pressure Rating Calculation
For small diameter tubing used in high-pressure instrument and hydraulic applications, calculate maximum allowable working pressure using Barlow's formula: P = 2S×T/OD, where S is the allowable stress at operating temperature per ASME B31.3, T is wall thickness, and OD is outside diameter. Verify that the calculated MAWP exceeds the system design pressure with the specified safety factor before finalizing tube OD and wall thickness selection for the application.
Value-Added Processing Services
We provide precision processing services tailored to instrumentation, semiconductor, and medical device small-bore tube requirements:
Precision Custom Cutting
±0.2mm length tolerance cutting with square-end verification for direct compression fitting or orbital weld assembly.
Electropolishing
Internal and external electropolishing to Ra ≤ 0.25μm with surface roughness verification report for UHP semiconductor and pharma applications.
Coil Winding
Custom coil winding to specified coil OD and length for instrumentation project-specific supply configurations.
Helium Leak Testing
Mass spectrometer helium leak testing to 10⁻⁹ mbar·L/s for semiconductor and aerospace ultra-high-purity tube qualification.
Payment & Shipping
Payment Terms
- T/T (Telegraphic Transfer)
- L/C at Sight (Letter of Credit)
- Western Union
- Flexible terms for long-term partners
Shipping Options
- Sea Freight (FCL/LCL)
- Air Freight for urgent instrumentation orders
- Express courier for small sample and urgent coil orders
- Polyethylene-sealed coils or straight bundles with end caps
Certifications & Standards
Our small diameter stainless steel tubing is manufactured and tested to precision instrumentation and process standards:
ISO 9001:2015
ASTM A269 Class 1
ASTM A632
PED Certification
SEMI F20 UHP Compatible
EN 10204 3.1 MTR
Frequently Asked Questions
What OD tolerance is required for compression fitting compatibility?
Standard compression tube fitting systems (Swagelok, Parker A-Lok) are designed for tube OD tolerances of ±0.05mm for 1/4" OD tube and proportionally tighter for smaller sizes. Our ASTM A269 Class 1 precision tubes meet ±0.02mm OD tolerance — well within compression fitting ferrule design limits for reliable seal formation at rated working pressure without under- or over-engagement of the ferrule bite geometry.
What is the difference between bright annealed and electropolished finish?
Bright annealing in a hydrogen or nitrogen-hydrogen reducing atmosphere produces an oxide-free, smooth surface with Ra typically 0.4–0.8μm — adequate for standard instrumentation and most process applications. Electropolishing removes additional surface micro-peaks through electrochemical dissolution, achieving Ra below 0.25μm with a highly passive chromium-enriched surface layer — required for semiconductor UHP gas distribution and pharmaceutical high-purity fluid applications where the lowest possible metallic contamination and particle generation are critical.
Can small diameter tubing be supplied in coil form?
Yes, coil supply is our standard format for sizes below 12.7mm OD, available in 30m, 50m, and 100m coil lengths as standard, with custom coil lengths on request. Coil supply minimizes the number of field joints required in long instrument tubing runs, directly reducing system leak risk. Coils are wound to a minimum bend radius that prevents cold working of the tube wall and maintains the annealed mechanical properties throughout the coil length.
Is TP316L the best choice for all small-bore instrumentation applications?
TP316L is the optimal choice for the majority of process instrumentation applications in aqueous, acidic, and mild corrosive service. In high-pressure applications above 400 bar, S32205 duplex offers significantly higher yield strength that reduces required wall thickness. In seawater and subsea environments, Inconel 625 provides superior corrosion resistance and fatigue life. In high-temperature service above 400°C, TP321 offers better sensitization immunity under long-term thermal exposure.
What minimum wall thickness is practical for small diameter tubes?
We produce small diameter tubes with wall thicknesses as thin as 0.10mm for the smallest OD sizes, and 0.50mm minimum wall for instrumentation grades requiring pressure rating. For structural integrity in process and instrumentation service, a minimum D/t ratio (OD/wall) of approximately 10:1 is recommended to prevent tube ovalization during bending and compression fitting installation. For 6.35mm OD tube, this corresponds to a minimum 0.64mm wall thickness.
Do you supply small diameter tubing for medical device applications?
Yes, we supply ASTM A269 TP316L small diameter tubing for medical device structural and fluid-handling applications, with supplementary biocompatibility documentation available including ISO 10993-1 material class reference and confirmation of compliance with ASTM F899 stainless steel for surgical instruments where applicable. Custom dimensional tolerances to medical device engineering drawings are available on request.
What is the typical lead time for small diameter precision tubing?
Standard instrumentation dimensions (1/4" OD × 0.035" WT, 6mm OD × 1mm WT, 12mm OD × 1mm WT) in TP316L bright annealed are available from stock within 10–15 days. Electropolished finish adds 5–7 days for electropolishing processing. Non-standard dimensions or less common grades in small-bore format require production lead times of 20–35 days.
Can you supply small diameter tubing with helium leak test certification?
Yes, mass spectrometer helium leak testing to 10⁻⁹ mbar·L/s is available as a supplementary test for semiconductor and aerospace UHP small diameter tube qualification. Each tube is individually pressure-tested with helium tracer gas and scanned with a calibrated mass spectrometer detector, with individual tube serial number and test result recorded on the supplementary test certificate.
Ready to Order Small Diameter Stainless Steel Tubing?
Precision instrumentation grades, electropolished UHP finish, coil supply — contact us for compression fitting compatible stainless tube
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