Stainless Steel Coil Tube — Precision Wound Coil for Analytical & Process Instrumentation
Product Overview
The Stainless Steel Coil Tube (Coil Tube / 盘管) is a precision-engineered tubular component manufactured by Wenzhou Jixing Metal Materials Co., Ltd., designed for demanding applications in analytical instrumentation, chemical process control, fluid transport, and heat exchange systems. This product is fabricated from high-grade austenitic stainless steel and wound into a consistent helical or spiral geometry to optimize surface-area-to-volume ratios, pressure distribution, and thermal performance.
Coil tubes find extensive use in amino acid analyzers (e.g., Hitachi 835-50 type), sample injection pump stop valves, chromatography systems, gas-liquid chromatography (GLC), high-performance liquid chromatography (HPLC), and other precision analytical and process instrumentation where fluid path integrity, chemical resistance, and repeatable performance are critical.
Material & Properties
Primary Material Grades
- 304 / 304L (UNS S30400 / S30403): General-purpose austenitic stainless steel with excellent corrosion resistance, formability, and weldability. Suitable for most analytical and food-grade applications.
- 316 / 316L (UNS S31600 / S31603): Enhanced corrosion resistance due to 2–3% molybdenum (Mo) content. Preferred for aggressive chemical environments, chloride-containing media, and pharmaceutical-grade applications.
- 321 (UNS S32100): Titanium-stabilized grade offering superior resistance to intergranular corrosion, suitable for elevated-temperature process applications.
- 316Ti (UNS S31635): Titanium-stabilized variant of 316, providing enhanced resistance to stress corrosion cracking (SCC) in high-temperature aqueous environments.
Key Material Properties
- Chemical Resistance: Resistant to organic acids, diluted inorganic acids, alkalis, and a wide range of chemical reagents used in analytical sample preparation.
- Mechanical Strength: High tensile strength and yield strength ensuring structural integrity under repeated pressure cycling.
- Thermal Stability: Maintains dimensional stability and mechanical properties across a wide temperature range (–196 °C to 870 °C for 304/316 grades).
- Hygienic Surface Finish: Available in polished (Ra ≤ 0.4 μm), electropolished (Ra ≤ 0.25 μm), or passivated finishes to minimize protein adsorption and biofilm formation.
- Non-Magnetic / Low Magnetic Permeability: Austenitic structure ensures negligible magnetic interference in sensitive analytical environments.
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (盘管 / Coil Tube) |
| Product Code | No. 1620 |
| Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd. |
| Material Grades | 304, 304L, 316, 316L, 321, 316Ti |
| Outer Diameter (OD) | 1.0 mm – 25.0 mm (customizable) |
| Wall Thickness | 0.1 mm – 2.0 mm (customizable) |
| Coil Diameter | 5 mm – 200 mm (spiral / helical winding) |
| Coil Length / Turns | 0.5 m – 50 m; multi-turn configurations available |
| Winding Pitch | 0.5 mm – 5.0 mm (adjustable per application) |
| Surface Finish | Mirror polished, electropolished, passivated, or as-rolled |
| End Connections | Butt-weld, socket-weld, threaded, flanged, or capillary fittings |
| Operating Pressure | Up to 40 MPa (application-dependent) |
| Operating Temperature | –196 °C to 870 °C |
| Applicable Standards | ASTM A269 / A270, ASME BPE, ISO 15530, DIN 11850 |
| Customization | Available for OEM/ODM — custom geometry, length, finish, and end connections |
Manufacturing Process
1. Raw Material Selection & Inspection
High-purity austenitic stainless steel seamless tubes are sourced from certified mills and subjected to incoming quality inspection, including chemical composition analysis (via Optical Emission Spectroscopy, OES), mechanical property verification, and dimensional tolerance checks.
2. Cutting & End Preparation
Tubes are precision-cut to required lengths using automated CNC cutting systems. End faces are deburred, chamfered, and prepared for welding or fitting installation to ensure leak-tight connections.
3. Coil Winding
The straight tube is wound into a helical or spiral coil using computerized coil-winding machines. The winding parameters — coil diameter, pitch, number of turns, and total length — are controlled programmatically to achieve dimensional accuracy within ±0.5 mm tolerance. Uniform winding ensures consistent flow distribution and pressure drop characteristics.
4. Heat Treatment & Stress Relief
Where applicable, the coiled tube undergoes solution annealing (typically at 1050–1150 °C followed by rapid water quench) to restore full austenitic structure, relieve residual stresses from forming, and enhance corrosion resistance.
5. Surface Finishing
The coil is processed through one or more of the following finishing operations:
- Acid Pickling: Removal of surface oxide scale and contamination.
- Passivation: Chemical treatment (typically nitric acid or citric acid based) to enrich the chromium oxide passive layer.
- Electropolishing: Electrochemical dissolution of the surface to achieve Ra ≤ 0.25 μm finish, enhancing biocompatibility and chemical resistance.
- Mechanical Polishing: For mirror-finish requirements in optical or hygienic applications.
6. Quality Control & Testing
Each batch undergoes rigorous quality assurance including:
- Dimensional inspection (OD, wall thickness, coil diameter, pitch)
- Pressure testing (hydrostatic or pneumatic, typically 1.5× working pressure)
- Leak testing (helium mass spectrometry for high-integrity applications)
- Surface finish verification (surface roughness tester)
- Chemical composition verification (OES or XRF)
- Visual inspection for weld quality, surface defects, and geometric conformity
7. Packaging & Traceability
Finished coil tubes are individually packaged in protective, moisture-proof containers with accompanying material certificates (Mill Test Certificates, MTC), traceability codes, and batch documentation to ensure full supply chain traceability.
Applications
1. Analytical Instrumentation
Coil tubes serve as critical components in amino acid analyzers (such as the Hitachi 835-50 type), where they function as reaction coil tubes and sample injection pump stop valve tubing. In these applications, the coil tube provides a controlled reaction pathway for amino acid separation and detection, requiring exceptional chemical inertness, minimal dead volume, and resistance to repeated cleaning cycles (including acid/base washes and organic solvent flushing).
2. Chromatography Systems
Used as guard columns, inline reactors, and transfer tubing in HPLC, GLC, and ion chromatography (IC) systems where low adsorption and high purity are paramount.
3. Process & Chemical Engineering
Employed as heat exchangers, reactors, and flow control elements in chemical processing plants, pharmaceutical manufacturing, and food & beverage industries where sanitary-grade fluid handling is required.
4. Medical & Pharmaceutical Devices
Utilized in infusion systems, dialysis equipment, and bioreactors where biocompatibility and sterility are non-negotiable requirements.
5. Semiconductor & Electronics
Applied in ultra-pure water (UPW) distribution systems and chemical delivery systems (CDS) where metallic contamination must be minimized to parts-per-trillion (ppt) levels.
6. Aerospace & Energy
Used in fuel systems, hydraulic lines, and cryogenic applications where corrosion resistance, mechanical integrity, and thermal stability under extreme conditions are essential.
Quality Certifications & Standards Compliance
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
- ISO 13485 — Medical device quality management (where applicable for medical-grade applications).
- ASME BPE — Bioprocessing Equipment standards for pharmaceutical-grade sanitary design and fabrication.
- ASTM A269 / A270 — Standard specifications for austenitic stainless steel seamless, welded, and heavy-wall tubing and pipe.
- ISO 15530 — Sanitary fittings and piping systems for the dairy, food, and pharmaceutical industries.
- CE Marking — Conformity with European health, safety, and environmental protection standards.
- Material Certificates: EN 10204 Type 3.1 / Type 3.2 Mill Test Certificates (MTC) provided with every shipment.
Unique Selling Points
- Precision Winding Accuracy: Computer-controlled coil winding ensures dimensional repeatability within ±0.5 mm, guaranteeing consistent flow characteristics across production batches.
- Ultra-Low Adsorption Surface: Electropolished and passivated finishes minimize protein and analyte adsorption, critical for analytical accuracy in amino acid analysis and chromatography.
- Full Customization Capability: OEM/ODM services allow clients to specify exact coil geometry, material grade, surface finish, and end connections tailored to their specific instrument or process requirements.
- Multi-Grade Material Availability: Six austenitic stainless steel grades available to match varying levels of corrosion resistance, mechanical strength, and temperature tolerance.
- End-to-End Traceability: Each product is accompanied by full material certification, batch documentation, and test reports ensuring complete supply chain transparency.
- Cleaning & Maintenance Compatibility: Designed to withstand repeated cleaning protocols — including acid washes, base flushes, organic solvent rinses, and autoclaving — without degradation, as validated in amino acid analyzer service applications.
- Sanitary & Hygienic Design: Compliant with ASME BPE and ISO 15530 standards, suitable for pharmaceutical, food, and medical-grade applications.
Technical Note: For amino acid analyzer applications (e.g., Hitachi 835-50 type), regular cleaning of reaction coil tubes and sample injection pump stop valves is essential to prevent analyte carryover and maintain separation efficiency. Recommended cleaning protocols include sequential flushing with 0.1 N NaOH, 0.1 N HCl, and deionized water, followed by verification of baseline stability. Wenzhou Jixing Metal Materials Co., Ltd. coil tubes are engineered to endure these rigorous cleaning cycles without surface degradation or dimensional change.