Stainless Steel Coil Tube — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (Product Code: 672) is a precision-engineered cold-drawn tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is supplied in continuous coil form, offering superior flexibility, dimensional consistency, and corrosion resistance compared to conventional straight-length stainless steel tubing. The coil configuration enables seamless integration into automated cutting, forming, and welding lines, thereby reducing material waste and improving production efficiency in downstream manufacturing operations.
Designed to meet the stringent requirements of modern industrial applications, this coil tube product leverages advanced cold-drawing technology to achieve tight tolerances on both inner and outer diameters, as well as wall thickness uniformity. The product is particularly suited for applications requiring hygienic-grade surfaces, thermal cycling resistance, and long-term mechanical integrity.
2. Material & Properties
2.1 Grade Classification
The coil tube is available in multiple austenitic and duplex stainless steel grades, selected according to the specific service environment and performance requirements of the end application:
- Austenitic Grades — AISI 304 (UNS S30400), AISI 316 (UNS S31600), AISI 316L (UNS S31603), AISI 321 (UNS S32100), AISI 304L (UNS S30403)
- Duplex Grades — UNS S31803 (2205), UNS S32750 (2507)
- Super-Austenitic Grades — AISI 904L (UNS N08904), Alloy 625 (UNS N06625)
2.2 Mechanical Properties (Typical — Annealed Condition)
| Property | 304 / 304L | 316 / 316L | 321 | 2205 Duplex |
|---|---|---|---|---|
| Tensile Strength (MPa) | ≥ 515 | ≥ 515 | ≥ 515 | ≥ 550 |
| Yield Strength (MPa, 0.2% offset) | ≥ 205 | ≥ 205 | ≥ 205 | ≥ 450 |
| Elongation (% at break) | ≥ 40 | ≥ 40 | ≥ 35 | ≥ 25 |
| Hardness (HB max) | 217 | 217 | 217 | 275 |
| Corrosion Resistance (Pitting — ASTM G48) | Good | Excellent | Good | Outstanding |
| Maximum Service Temperature (°C) | 870 | 870 | 925 | 315 (continuous) |
2.3 Surface Finish Options
- 2B Finish — Cold-rolled and annealed in a protective atmosphere; general-purpose surface with moderate reflectivity
- No. 4 Hairline Finish — Uniform unidirectional grain pattern; suitable for decorative and architectural applications
- Mirror Finish (8K) — Polished to high gloss; used in food-grade and pharmaceutical equipment
- Electropolished (EP) Finish — Electrochemical dissolution achieving Ra ≤ 0.4 μm; critical for bioprocessing and sanitary piping
- Pickled & Passivated (P&P) — Removal of heat-tint oxide layers followed by passivation to enhance passive film integrity
3. Specifications
| Parameter | Specification |
|---|---|
| Product Designation | Stainless Steel Coil Tube (盘管 / Coil Tube) |
| Product Code | 672 |
| Manufacturing Standard | ASTM A213 / ASTM A269 / EN 10216-5 / GB/T 14976 |
| Outer Diameter (OD) | 3.0 mm – 108.0 mm (custom sizes available upon request) |
| Wall Thickness | 0.25 mm – 4.00 mm |
| OD Tolerance | ±0.05 mm (precision grade); ±0.10 mm (standard grade) |
| Wall Thickness Tolerance | ±10% (standard); ±5% (precision grade) |
| Coil Inner Diameter | 500 mm / 600 mm / 750 mm / 1000 mm (customizable) |
| Coil Length | Up to 500 m per coil (continuous length) |
| Coil Weight | Typically 200 kg – 1,500 kg per coil |
| Forming Method | Cold-drawn (CD) / Seamless |
| Heat Treatment | Solution Annealed (SA) or Annealed & Pickled (A&P) |
| End Condition | Plain ends / Beveled ends / Flanged (custom) |
| Packaging | Wooden pallet with moisture-proof wrapping; export-grade packaging available |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube follows a rigorous multi-stage manufacturing workflow designed to ensure metallurgical integrity, dimensional precision, and surface quality:
- Raw Material Selection & Inspection — Virgin stainless steel ingots or continuous-cast billets are sourced from certified mills. Incoming material undergoes spectroscopic analysis (OES) and mechanical testing to verify chemical composition and base properties prior to processing.
- Piercing & Hot Rolling — Solid billets are heated to 1,150–1,250°C and pierced to form seamless hollow tubes. Hot rolling reduces cross-sectional dimensions to near-final specifications while establishing initial microstructure.
- Pickling & Descaling — The hot-rolled tube is passed through an acid pickling line (typically HNO₃/HF mixed acid) to remove oxide scale and restore a clean, passive surface.
- Cold Drawing — The tube is cold-drawn through calibrated dies using a mandrel-die or capstan-die system. This process achieves precise dimensional tolerances, improves grain flow alignment, and enhances mechanical properties through work hardening.
- Intermediate Annealing — For multi-pass drawing operations, intermediate annealing at 1,050–1,100°C relieves accumulated residual stresses and restores ductility, preventing cracking during subsequent deformation passes.
- Final Cold Drawing & Sizing — The final drawing pass achieves the target OD, wall thickness, and roundness tolerances. Precision sizing ensures uniformity along the entire coil length.
- Final Annealing & Pickling — A final solution-annealing cycle in a protective atmosphere (or vacuum) ensures full austenitic transformation. Subsequent pickling and passivation restore the corrosion-resistant chromium oxide passive film.
- Coiling & Winding — The processed tube is wound onto precision-controlled reels to form the final coil configuration. Tension control systems ensure uniform coil stacking without deformation or kinking.
- Non-Destructive Testing (NDT) — Each coil undergoes 100% eddy current testing (ECT) for internal and external surface defects, supplemented by hydrostatic pressure testing (typically 30–50 MPa) to verify structural integrity.
- Final Inspection & Packaging — Dimensional verification, surface finish assessment, and chemical composition confirmation are performed. Approved coils are packaged in moisture-barrier wrapping on treated wooden pallets for shipment.
5. Applications
The Stainless Steel Coil Tube (Product Code 672) is engineered for demanding industrial environments where corrosion resistance, dimensional precision, and hygienic surface integrity are paramount:
- Food & Beverage Industry — Sanitary-grade piping systems, CIP (Clean-In-Place) circuits, dairy processing lines, and beverage transfer systems requiring FDA/3-A compliance
- Pharmaceutical & Biotechnology — Sterile fluid transfer lines, bioreactor connections, and process instrumentation tubing subject to repeated autoclave sterilization cycles
- Chemical Processing — Corrosive fluid handling in acid, alkali, and halide environments; reactor internals and heat exchanger tubing
- Oil & Gas Industry — Downhole tubing, chemical injection lines, and marine/offshore applications requiring resistance to chloride-induced stress corrosion cracking (SCC)
- Automotive & Aerospace — Fuel lines, exhaust components, hydraulic systems, and cryogenic applications
- Medical Devices — Endoscopic instrument tubing, surgical tool housings, and implant-grade components
- Architectural & Decorative — Handrails, structural elements, and facade components in coastal or high-humidity environments
- Heat Exchanger & HVAC — Coil winding for air handling units, refrigeration coils, and thermal management systems
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains an internationally recognized quality management system ensuring full traceability and compliance with global standards:
| Certification / Standard | Scope of Applicability |
|---|---|
| ISO 9001:2015 | Quality Management System — Full manufacturing process |
| ISO 14001:2015 | Environmental Management System |
| ISO 45001:2018 | Occupational Health & Safety Management |
| CE Marking (EU) | Compliance with European Pressure Equipment Directive (PED 2014/68/EU) |
| EN 10204 3.1 | Material Test Certificate — Third-party verified |
| ASTM A213 / A269 | American Society for Testing and Materials — Seamless & welded tube specifications |
| GB/T 14976 | Chinese National Standard — Seamless steel tubes for fluid transport |
| 3-A Sanitary Standards | International Dairy/Food/Pharmaceutical Equipment compliance |
| FDA 21 CFR 177 | Food Contact Materials — Stainless steel certification |
7. Unique Selling Points
- Superior Dimensional Precision — Cold-drawing process achieves ±0.05 mm OD tolerance, enabling direct use in precision assembly without secondary machining
- Continuous Coil Supply — Eliminates butt-weld joints inherent in straight-length tube, reducing leak points and improving system reliability in hygienic and pressure-critical applications
- Multi-Grade Flexibility — Full range of austenitic, duplex, and super-austenitic grades available from a single source, simplifying supply chain management
- Custom Surface Engineering — Electropolished finish achieving Ra ≤ 0.4 μm supports pharmaceutical GMP compliance and reduces microbial adhesion
- Full Traceability — Each coil is heat-numbered with complete mill test data, enabling end-to-end material traceability from raw ingot to final product
- Cost Efficiency — Coil format reduces cutting waste by up to 30% compared to straight-length tube, offering significant lifecycle cost savings for high-volume applications
Note: All specifications listed above represent typical values. Actual performance characteristics may vary based on grade selection, manufacturing batch, and heat treatment condition. Customers are advised to request a Material Test Certificate (MTC) and confirm specifications with Wenzhou Jixing Metal Materials Co., Ltd for project-specific requirements.