Re-Cold Drawn Seamless Stainless Steel Coil Tube for Precision Instrumentation and EP Processes
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. presents its premium Re-Cold Drawn Seamless Stainless Steel Coil Tube (Product No. 57), a high-precision tubing solution engineered through a secondary cold-drawing process applied to seamless stainless steel stock. This advanced manufacturing technique delivers exceptional dimensional accuracy, superior surface finish, and enhanced mechanical properties, making it the ideal feedstock for high-end instrumentation tubing, electronic packaging (EP) tube mother tubes, and other precision-critical applications.
Unlike standard seamless tubes, this product undergoes an additional cold-drawing pass that refines the already tight tolerances of the initial seamless extrusion or piercing process. The result is a coil tube with dramatically improved roundness, wall uniformity, and surface integrity—meeting the most demanding specifications in aerospace, semiconductor, medical, and analytical instrumentation industries.
Material & Properties
The re-cold drawn coil tube is available in a comprehensive range of austenitic and specialty stainless steel grades, each selected to meet specific corrosion, mechanical, and thermal requirements:
- 304 / 304L (UNS S30400 / S30403) — General-purpose corrosion resistance with excellent formability; the workhorse grade for instrumentation and food-grade applications.
- 316 / 316L (UNS S31600 / S31603) — Superior resistance to pitting and crevice corrosion due to molybdenum content; preferred for chemical processing and marine environments.
- 310S (UNS S31008) — High-temperature oxidation resistance up to 1150 °C (2094 °F); suitable for furnace and heat-treatment applications.
- 321 (UNS S32100) — Titanium-stabilized austenitic grade offering resistance to intergranular corrosion at elevated temperatures.
- 904L (UNS N08904) — Ultra-high corrosion resistance for aggressive chemical and acid environments.
- Custom Alloy Grades — Upon request, including duplex (2205, 2507), precipitation-hardening (17-4PH), and custom compositions.
Key Mechanical Properties (Typical, Cold-Drawn Condition)
- Tensile Strength: ≥ 520 MPa (75,400 psi)
- Yield Strength: ≥ 205 MPa (29,730 psi)
- Elongation: ≥ 40%
- Hardness: ≤ 210 HV
- Grain Size: Fine and uniform, typically ASTM No. 7–10
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | 1.0 mm – 50.0 mm (0.039" – 1.969") |
| Wall Thickness | 0.10 mm – 3.0 mm (0.004" – 0.118") |
| OD Tolerance | ±0.01 mm (±0.0004") — Precision grade; ±0.05 mm (±0.002") — Standard grade |
| Wall Thickness Tolerance | ±5% of nominal — Precision grade; ±10% — Standard grade |
| Roundness | ≤ 2% of OD tolerance |
| Surface Finish | Bright annealed (BA), Ra ≤ 0.4 μm; Polished, Ra ≤ 0.2 μm; Pickled, Ra ≤ 0.8 μm |
| Coil Length | 50 m – 500 m (164 ft – 1,640 ft) per coil |
| Coil Weight | Up to 2,000 kg (4,409 lbs) per coil |
| Delivery Condition | Cold-drawn, cold-drawn & annealed (CD/CA), cold-drawn & pickled |
| Standards | ASTM A269, ASTM A213, EN 10216-5, JIS G3459, GB/T 14976 |
| Available Grades | 304, 304L, 316, 316L, 310S, 321, 904L, 2205, 2507, 17-4PH, custom |
| Surface Treatment Options | Bright Annealed (BA), Electropolished, Passivated, Custom coating |
Manufacturing Process
The production of the re-cold drawn seamless coil tube follows a rigorous multi-stage process that ensures precision at every step:
- Raw Material Selection — Virgin stainless steel ingots or billets are sourced from certified mills with full traceability documentation (Mill Test Certificates per EN 10204 3.1).
- Seamless Forming — Billets are heated to forging temperature (1100–1200 °C / 2012–2192 °F) and pierced via rotary or Mannesmann piercing to produce seamless tube blanks.
- Primary Cold Drawing — The seamless blanks are cold-drawn through calibrated tungsten carbide (WC) or diamond dies to achieve initial dimensional specifications.
- Intermediate Annealing — Tubes are annealed in a controlled atmosphere (protective gas, dew point ≤ −60 °C / −76 °F) at 1050–1100 °C (1922–2012 °F) to relieve cold-work stresses and restore ductility.
- Re-Cold Drawing (Secondary Drawing) — The core differentiating step: tubes undergo a second, precision cold-drawing pass through ultra-fine tolerance dies. This step reduces dimensional tolerances to ±0.01 mm, improves roundness, and enhances surface finish to Ra ≤ 0.4 μm. Lubrication systems using food-grade or chemical-grade drawing compounds ensure contamination-free processing.
- Final Annealing & Surface Treatment — Tubes are bright annealed in vacuum or controlled-atmosphere furnaces, followed by acid pickling (HNO₃/HF blend) and passivation to remove surface oxides and maximize corrosion resistance.
- Coiling — Finished tubes are wound onto precision coils with controlled tension to prevent deformation, kinking, or surface damage during storage and transport.
- Quality Inspection — Every coil undergoes 100% inspection including ultrasonic testing (UT), eddy current testing (ECT), hydrostatic testing, dimensional verification, and surface defect examination.
Applications
The re-cold drawn seamless coil tube is purpose-built for applications where dimensional precision, surface quality, and material integrity are non-negotiable:
- High-End Instrumentation Tubes — Feedstock for precision pressure sensors, flow meters, level gauges, and analytical instruments requiring tight bore tolerances and smooth internal surfaces.
- EP (Electronic Packaging) Tube Mother Tubes — Primary raw material for manufacturing electronic packaging housings, connector shells, and precision components in the semiconductor and telecommunications industries.
- Aerospace Components — Hydraulic lines, fuel system tubing, and instrumentation conduits where lightweight, high-strength, corrosion-resistant tubing is critical.
- Medical Devices — Surgical instruments, endoscopes, and implant-grade tubing requiring biocompatibility and ultra-smooth surfaces.
- Semiconductor Manufacturing — Gas delivery lines, vacuum system tubing, and chemical vapor deposition (CVD) components.
- Automotive & Racing — Precision fuel lines, brake lines, and sensor housings.
- Chemical & Pharmaceutical Processing — Reaction vessel instrumentation, CIP/SIP lines, and process control tubing.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework to ensure product excellence:
- ISO 9001:2015 — Quality Management System certification ensuring consistent process control and continuous improvement.
- ISO 14001 — Environmental Management System certification demonstrating commitment to sustainable manufacturing.
- EN 10204 Type 3.1 — Full mill test certificates with traceable chemical and mechanical data for every heat.
- ASTM / EN Compliance — Products manufactured and tested in accordance with ASTM A269, ASTM A213, EN 10216-5, and equivalent international standards.
- RoHS & REACH Compliance — Certified free of restricted hazardous substances for global market access.
- Third-Party Inspection Available — SGS, BV, TÜV, and DNV inspection services available upon customer request.
- NADCAP / AS9100 — Available for aerospace-grade applications upon qualification.
Unique Selling Points
Superior Precision Through Dual Cold-Drawing: The re-cold drawing process delivers dimensional tolerances up to 5× tighter than single-pass cold-drawn tubes, enabling downstream customers to eliminate or reduce their own machining operations—saving cost and cycle time.
- Exceptional Surface Finish — Ra values as low as 0.2 μm achieved without additional polishing, reducing post-processing requirements for instrument and EP applications.
- Full Traceability — Every coil is linked to its heat number, chemical analysis, and mechanical test results, providing complete supply chain transparency.
- Customization Capability — Flexible tolerance, surface finish, and grade options tailored to specific customer specifications and application requirements.
- Coil Format Efficiency — Delivered in continuous coil format for maximum feed efficiency in automated tubing processing lines, reducing waste and improving throughput.
- One-Stop Solution — From raw material sourcing through final coiling and inspection, Wenzhou Jixing provides integrated manufacturing with consistent quality control at every stage.
Conclusion
The Re-Cold Drawn Seamless Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. represents the pinnacle of precision tubing manufacturing. By combining seamless forming with a proprietary secondary cold-drawing process, this product delivers unmatched dimensional accuracy, surface quality, and material performance—making it the preferred choice for demanding instrumentation, electronic packaging, aerospace, and medical applications worldwide.