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Utilizing 26 high-precision cold rolling mills and 6 cold drawing machines, we ensure dimensional accuracy and superior mechanical properties.
Precision Instrumentation Stainless Steel Tubing
ASTM A269 Class 1 / A632 | TP316L / S32205 | OD ±0.025mm | BA & Electropolished
ISO 9001 | NACE MR0175 | Swagelok CompatibleRelated Products
Introduction
The reliable transmission of process measurements — pressure, flow, level, temperature, and analytical composition — from the point of measurement in a chemical, oil and gas, or power generation process to the control system that governs process safety and production efficiency depends on an often-overlooked but critically important element of the instrumentation architecture: the impulse line and sample conditioning tubing through which the process signal is physically transmitted. Precision Instrumentation Stainless Steel Tubing is the engineered solution for this application — a family of seamless austenitic stainless tubes produced to dimensional tolerances, surface quality standards, and mechanical property consistency levels that exceed standard process tubing requirements and are specifically optimized for the compression fitting connections, orbital weld joints, and small-bore manifold assemblies that constitute the instrumentation tubing infrastructure of modern industrial process control systems. Manufactured to ASTM A269 Class 1 and ASTM A632 dimensional precision standards, with outside diameter tolerances of ±0.025mm for the critical 6.35mm (1/4 inch) and 12.7mm (1/2 inch) instrumentation standard sizes, precision instrumentation tubing provides the dimensional consistency required for reliable compression fitting ferrule engagement across the complete range of industrial instrumentation connection systems — from the widely deployed Swagelok and Parker A-Lok compression systems to the orbital welding tube-to-fitting connections increasingly specified in high-purity pharmaceutical and semiconductor instrumentation installations where compression fitting leak integrity under cyclic thermal and pressure loading is considered insufficient for the application's reliability requirements.
The process industries deploy instrumentation tubing in environmental conditions that place demands on the material far beyond simple dimensional precision. Offshore platform instrument lines must simultaneously withstand marine atmospheric corrosion on the exterior, process fluid corrosion on the interior, mechanical vibration from rotating machinery and wave motion, and the cumulative fatigue damage that can develop in small-bore tubing subjected to millions of pressure cycles from process upsets and normal operating variation over a 25-year design life. These combined requirements — corrosion resistance, fatigue strength, dimensional precision, and surface quality — drive the specification of TP316L as the near-universal standard grade for industrial instrumentation tubing, with its 2–3% molybdenum addition providing the chloride pitting resistance required for both marine atmosphere exterior protection and moderate chloride-containing process fluid interior service. The low carbon maximum of 0.030% ensures complete immunity to sensitization at the weld heat-affected zones of the orbital welds and manual TIG welds used to connect tubing to instrument manifolds, valve blocks, and transmitter connections — a critical reliability feature in applications where sensitization-induced intergranular attack at weld zones has been identified as a primary failure mechanism in long-term offshore instrumentation tubing performance reviews. For the most demanding applications — subsea chemical injection metering systems, offshore safety instrumentation valve actuator supply lines, and high-pressure analyzer sample conditioning systems — duplex S32205 instrumentation tubing is specified to provide the combination of higher pressure rating, superior corrosion resistance, and excellent fatigue life that the requirements of these critical safety instrumentation applications demand.
The surface quality of precision instrumentation stainless tubing is a performance parameter as important as dimensional tolerance for applications where tube interior surface condition directly influences measurement accuracy and system cleanliness. In analytical instrumentation sample conditioning systems, where process fluid samples are transported from the process tap point to on-line analytical instruments for composition measurement, the tube interior surface roughness determines the extent of sample carryover between consecutive sample flushes — higher surface roughness creates dead zones where previous sample composition is retained, contaminating the fresh sample being presented to the analyzer and introducing composition measurement lag that can mislead process control decisions. Bright annealed instrumentation tubing (Ra ≤ 0.8μm internal) provides the surface quality adequate for most standard industrial sample conditioning applications. For pharmaceutical clean utility instrumentation systems and semiconductor process gas distribution instrumentation where cross-contamination between consecutive process batches or measurement cycles is unacceptable, electropolished TP316L precision tubing (Ra ≤ 0.38μm) provides the smooth, highly passive surface required for rapid purge-down between samples and validation of cleanliness to the regulatory standards of GMP and semiconductor ultra-high-purity process systems.
Our precision instrumentation stainless steel tubing program is the most comprehensively stocked product category in our stainless tubing portfolio, maintaining immediate availability of the highest-demand instrumentation sizes — 6.35mm × 1.24mm WT (1/4" × 0.049" WT), 9.53mm × 1.65mm WT (3/8" × 0.065" WT), and 12.7mm × 1.65mm WT (1/2" × 0.065" WT) — in TP316L bright annealed condition, with electropolished grades available on short lead times. The program covers OD sizes from 3.18mm (1/8 inch) to 25.4mm (1 inch) in both imperial (fractional inch) and metric OD dimensions to serve the complete global instrumentation market. Coil supply in 30m and 50m coil lengths for field instrumentation installation and straight lengths from 3,000mm to 9,000mm for workshop prefabrication are both stocked. All material ships with EN 10204 3.1 Mill Test Reports, and NACE MR0175 sour service compliance documentation is available for offshore instrumentation tubing where H₂S-containing process fluid service is a design requirement.
Specifications
| Available Grades | TP316L (Primary), TP304L, S32205 |
| Standard | ASTM A269 Class 1, ASTM A632 |
| OD Range | 3.18mm (1/8") to 25.4mm (1") — Imperial & Metric |
| OD Tolerance | ±0.025mm (Class 1) for sizes ≤12.7mm |
| Supply Form | Coil (30m/50m) or Straight (3000–9000mm) |
| Finish | Bright Annealed (BA) or 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 |
±0.025mm OD PrecisionBA Ra≤0.8μm / EP Ra≤0.38μmNACE Sour Service
Mechanical Strength (TP316L)
Comprehensive Info
| MOQ | 10m coil or 10 straight lengths per size |
| Lead Time | 7 - 20 Days (Stock Sizes) |
| Packaging | PE-Sealed Coils / End-Capped Straight Bundles |
| Certifications | ISO 9001, ASTM A269, NACE MR0175 |
| Raw Materials | Premium Low-Carbon Austenitic Melt |
| Customization | Imperial/Metric OD, WT, Finish, Coil Length |
Applications
Process Impulse LinesPressure transmitter, differential pressure, and flow measurement impulse tubing in chemical and petrochemical plant control systems
Analyzer Sample ConditioningSample transport tubing in on-line process chromatograph and spectrometer conditioning systems for industrial quality measurement
Offshore Platform InstrumentationMarine-atmosphere exposed instrument lines on offshore oil and gas platforms requiring TP316L corrosion resistance and fatigue life
Pharmaceutical Process MonitoringEP-finish TP316L tubing for process monitoring points and CIP circuit sensing connections in GMP pharmaceutical manufacturing
Power Plant Instrument ConnectionsSteam and feedwater impulse tubing and instrument root valve connections in fossil fuel and nuclear power plant control rooms
Subsea Chemical Injection MeteringS32205 duplex precision tubing for subsea chemical injection metering unit connections and flow assurance chemical distribution lines
Advantages
Fitting System Compatible
±0.025mm OD tolerance verified against Swagelok and Parker A-Lok ferrule engagement specifications — ensuring reliable leak-free compression fitting seals at first make-up without the dimensional inconsistency that causes chronic re-make requirements in field instrumentation installation.
Dual Surface Finish Options
Bright annealed (Ra ≤ 0.8μm) for standard process and offshore instrumentation; electropolished (Ra ≤ 0.38μm) for pharmaceutical GMP and analytical instrument sample conditioning — both grades stocked for rapid delivery to mixed-specification instrumentation projects.
Fatigue Life Assurance
Seamless precision tube construction, verified hardness in the Rb 65–90 range, and absence of weld seams or surface defects collectively maximize fatigue life in vibration-exposed offshore and rotating machinery instrumentation environments.
Immediate Stock Availability
The broadest stocked range of standard instrumentation sizes in TP316L BA — enabling same-week delivery for urgent instrumentation replacement, maintenance, and small project requirements without the production lead time of non-stocked sizes.
About Jiangsu Jend Tube Co.,Ltd.
As China Precision Instrumentation Stainless Steel Tubing Manufacturers and Wholesale Precision Instrumentation 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 Make-Up Procedure
For initial compression fitting make-up on precision instrumentation tube, insert the tube fully to the tube stop and advance the nut 1-1/4 turns from finger-tight for Swagelok fittings (1-1/2 turns for Parker A-Lok) — this is the precise engagement required to set the ferrule bite without over-compression. Mark the nut position with a marker pen before make-up to verify the exact rotation achieved. Over-tightening reduces fitting re-make capacity and can permanently deform the tube OD, preventing reliable re-seal on subsequent connections.
Tube Cutting for Instrumentation
Use only a sharp, dedicated tube cutter designed for the tube OD — a dull or incorrect-size cutter applies radial forces that slightly flatten the tube end, compromising ferrule engagement. For EP-finish tubing, use a stainless steel cutter wheel to avoid carbon steel contamination of the tube bore at the cut face. Deburr the internal edge with a tube reamer immediately after cutting — internal burrs create turbulence that increases sample carryover in analyzer connections and can trap process debris that causes plugging in impulse lines.
Sour Service Instrumentation
For instrumentation systems contacting H₂S-containing process fluids, verify NACE MR0175 compliance of all wetted components including the tube material. TP316L precision instrumentation tubing in the annealed condition typically meets NACE MR0175 hardness requirements (maximum 22 HRC). For duplex S32205 instrumentation lines in sour service, verify actual hardness against the 36 HRC maximum and PREN ≥ 34 chloride pitting resistance requirement before specifying for sour offshore service environments.
Freeze Protection for Impulse Lines
In cold climate installations where impulse line freezing is a risk, install heat tracing on TP316L precision instrumentation tubing rather than specifying carbon steel impulse lines for their perceived freeze damage tolerance — stainless tubes are as susceptible to freeze damage as carbon steel at comparable wall thicknesses, and the corrosion resistance advantage of TP316L is lost if the impulse line is replaced with carbon steel to manage freeze risk. Steam or electric heat tracing with insulation is the correct engineering solution for freeze protection.
Value-Added Processing Services
We provide instrumentation-ready processing services for offshore, pharmaceutical, and process plant instrumentation projects:
Precision Custom Cutting
±0.5mm length cutting with deburring for direct instrumentation manifold and valve block assembly.
Electropolishing
Internal EP to Ra ≤ 0.38μm with surface roughness verification for pharmaceutical and UHP instrumentation applications.
Custom Coil Winding
Project-specific coil lengths from 10m to 100m for pre-fabricated instrumentation tubing skid supply programs.
NACE MR0175 Documentation
Sour service compliance documentation for offshore instrumentation qualification in H₂S-containing process service.
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 coil and urgent replacement orders
- PE-sealed coils and end-capped straight bundles for contamination protection
Certifications & Standards
Our precision instrumentation stainless tubing is certified to process control and offshore instrumentation standards:
ISO 9001:2015
ASTM A269 Class 1
ASTM A632
NACE MR0175
PED Certification
EN 10204 3.1 MTR
Frequently Asked Questions
What OD tolerance does Swagelok require for compatible tube?
Swagelok compression fittings require tube OD within ±0.05mm of nominal for standard fittings below 1/2" OD. Our ASTM A269 Class 1 precision instrumentation tubing at ±0.025mm OD tolerance is well within Swagelok's and Parker A-Lok's ferrule design envelope, ensuring reliable first-make-up ferrule bite without the reworking or re-make that occurs with out-of-tolerance tube.
What is the difference between bright annealed and electropolished instrumentation tubing?
Bright annealed (BA) tubing has an oxide-free smooth surface with Ra ≤ 0.8μm, achieved by annealing in a hydrogen-nitrogen reducing atmosphere — adequate for process instrumentation, offshore, and most industrial applications. Electropolished (EP) tubing achieves Ra ≤ 0.38μm with a chromium-enriched passive surface through electrochemical surface removal — required for pharmaceutical GMP and analytical sample conditioning where cross-contamination and sample carryover must be minimized.
Is TP316L suitable for sour service (H₂S) instrumentation lines?
Yes, TP316L precision instrumentation tubing in the annealed condition typically meets NACE MR0175 / ISO 15156 hardness requirements (maximum 22 HRC / 248 HBW) for sour service. Our NACE MR0175 documentation package confirms actual hardness values on the specific heat supplied, providing the traceability required for sour service material qualification in offshore and refinery instrumentation systems.
When should S32205 duplex be specified for instrumentation instead of TP316L?
Specify S32205 duplex instrumentation tubing when the combination of higher pressure rating, superior chloride pitting resistance (PREN ≥ 34 versus TP316L PREN ≈ 23), and better fatigue life in vibration service justifies the premium over TP316L. For subsea chemical injection metering, offshore safety system instrument lines, and high-pressure analyzer sample systems above 200 bar, S32205 provides the engineered performance advantage that the increased cost represents.
Can instrumentation tubing be orbital welded?
Yes, precision TP316L instrumentation tubing is widely orbital welded in pharmaceutical and semiconductor instrumentation systems where compression fitting leak integrity under cyclic thermal loading is considered insufficient. The smooth BA or EP surface finish, controlled hardness, and dimensional precision of our instrumentation tubing are specifically optimized for consistent orbital weld quality with the standard orbital welding heads used in pharmaceutical and UHP process installations.
What is the most common instrumentation tubing specification for offshore oil and gas?
The dominant offshore instrument tubing specification is 1/2" OD × 0.065" WT (12.7mm × 1.65mm) TP316L seamless, bright annealed, ASTM A269 Class 1, NACE MR0175 compliant, supplied in 50m coils. Secondary sizes include 1/4" × 0.049" WT for small instrument connections and 3/8" × 0.065" WT for medium manifold runs. We maintain all three sizes in TP316L BA from stock for rapid offshore project delivery.
Do you supply instrumentation tubing in imperial (inch) dimensions?
Yes, we stock the complete range of standard imperial instrumentation OD dimensions (1/8", 3/16", 1/4", 5/16", 3/8", 1/2", 5/8", 3/4", 1") with standard wall thicknesses matching Swagelok and Parker catalog tube specifications for compression fitting systems. Metric OD instrumentation dimensions (6mm, 8mm, 10mm, 12mm) are also stocked for European and metric-standard instrumentation projects.
What is the typical delivery time for standard instrumentation tubing sizes?
Stock sizes in TP316L BA (1/4", 3/8", 1/2" OD in standard wall thicknesses) are available for dispatch within 3–7 days. Electropolished grades add 5–7 days for EP processing. Non-standard OD dimensions, S32205 duplex instrumentation sizes, or custom coil lengths require production lead times of 15–25 days. Air freight is available for urgent offshore platform maintenance requirements.
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Swagelok-compatible precision, NACE certified, BA and EP grades stocked — your instrumentation tubing specialist
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