Stainless Steel Coil Tube — Wenzhou Jixing Metal Materials Co., Ltd.
Product Overview
The Stainless Steel Coil Tube (盘管 / Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a continuous-length stainless steel tube formed into a coil configuration, designed for seamless downstream processing including cutting, bending, forming, and welding. This product category (Internal Reference No. 927) falls under the industrial piping and tubing segment of the company's product portfolio, serving as a critical intermediate and end-use material across multiple engineering disciplines.
Coil tubes offer distinct advantages over cut-length straight pipe: they eliminate the need for butt-welding during fabrication, reduce material waste significantly, and enable rapid deployment in high-volume production environments. The coil form factor also facilitates automated processing through continuous manufacturing lines, making it particularly suitable for mass-production applications in HVAC, automotive, chemical processing, and food-grade equipment industries.
Material & Properties
Base Material Grades
Wenzhou Jixing Metal Materials Co., Ltd. offers coil tubes in the following standard stainless steel grades, selected to meet diverse corrosion resistance, mechanical strength, and temperature tolerance requirements:
- 304 (UNS S30400 / 1.4301) — The most widely used austenitic stainless steel; excellent general-purpose corrosion resistance, good formability, and weldability. Suitable for food processing, chemical, and architectural applications.
- 316 (UNS S31600 / 1.4401) — Molybdenum-enhanced austenitic grade offering superior resistance to pitting and crevice corrosion in chloride-containing environments. Ideal for marine, pharmaceutical, and chemical processing applications.
- 321 (UNS S32100 / 1.4541) — Titanium-stabilized austenitic grade providing excellent resistance to intergranular corrosion at elevated temperatures (450–850 °C). Suitable for high-temperature structural and exhaust applications.
- 316L (UNS S31603 / 1.4435) — Low-carbon variant of 316 with enhanced weldability and resistance to carbide precipitation in the heat-affected zone (HAZ).
- 304L (UNS S30403 / 1.4307) — Low-carbon variant of 304 for improved welding performance and resistance to sensitization.
Mechanical Properties (Typical — Annealed Condition)
| Property | 304 / 304L | 316 / 316L | 321 |
|---|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 515 | ≥ 515 |
| Yield Strength (0.2% Proof Stress, MPa) | ≥ 205 | ≥ 170 | ≥ 170 |
| Elongation (≥ %) | 40 | 40 | 40 |
| Hardness (HBW, max) | 217 | 217 | 217 |
| Density (g/cm³) | 8.00 | 8.03 | 8.01 |
| Thermal Conductivity (W/m·K @ 100 °C) | 16.3 | 16.3 | 16.3 |
| Maximum Service Temperature (°C) | 870 (oxidizing) / 870 (reducing) | 870 (oxidizing) / 925 (reducing) | 900 (oxidizing) / 925 (reducing) |
Chemical Composition (wt% — Maximum)
| Element | 304 / 304L | 316 / 316L | 321 |
|---|---|---|---|
| Carbon (C) | 0.08 / 0.03 | 0.08 / 0.03 | 0.08 |
| Chromium (Cr) | 18.0–20.0 | 16.0–18.0 | 17.0–19.0 |
| Nickel (Ni) | 8.0–10.5 | 10.0–14.0 | 9.0–12.0 |
| Molybdenum (Mo) | — | 2.0–3.0 | — |
| Titanium (Ti) | — | — | 5×C to 0.70 |
| Sulfur (S) | 0.03 | 0.03 | 0.03 |
| Phosphorus (P) | 0.045 | 0.045 | 0.045 |
| Silicon (Si) | 0.75 | 0.75 | 0.75 |
Specifications
Dimensional Parameters
| Parameter | Range / Tolerance | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 168.3 mm (1/8" – 6") | ASTM A269 / A213 |
| Wall Thickness (WT) | 0.30 mm – 8.00 mm | ASTM A269 / GB/T 12771 |
| Coil Length (per coil) | 50 m – 300 m (customizable) | Manufacturer specification |
| Coil Inner Diameter (ID) | 300 mm – 600 mm | Standard packaging |
| OD Tolerance | ±0.05 mm – ±0.20 mm (depending on diameter) | ASTM A269 |
| Wall Thickness Tolerance | ±10% of nominal | ASTM A269 |
| Surface Finish | Bright annealed (BA), No. 1 pickled, 2B, hairline, or custom | ASTM A269 |
| End Condition | Plain cut, beveled (45°/60°), or threaded | Per customer specification |
| Coil Weight (typical) | 500 kg – 2,000 kg per coil | Logistics-dependent |
Applicable Standards
- ASTM A269 / A269M — Standard Specification for Seamless and Wrought Stainless Steel Tubing, Instrument and Orifice Tube
- ASTM A213 / A213M — Standard Specification for Seamless Ferritic, Austenitic, and Ferritic-Austenitic (Duplex) Stainless Steel Tubing for Heat-Transfer and Similar Applications
- GB/T 12771 — Technical Conditions for Delivery of Stainless Steel Seamless Tubes
- GB/T 21832 — Technical Conditions for Delivery of Stainless Steel Welded Tubes
- EN 10217-7 — Technical Delivery Conditions for Stainless Steel Tubes for Pressure-Purposes
- JIS G3459 — Specifications for Stainless Steel Tubes
Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Steel Strip Preparation — Cold-rolled stainless steel strip is supplied by certified mill sources (e.g., POSCO, Outokumpu, TISCO, or Baosteel). Incoming material undergoes spectroscopic verification (OES) to confirm chemical composition within specified limits.
- Edge Milling and Surface Cleaning — Strip edges are milled to remove surface defects, scale, and oxide layers. The strip is degreased and cleaned to ensure uniform weld formation and surface quality.
- Tubing Forming (Roll Forming) — The prepared strip is fed through a series of progressively die-set rolls that gradually form the flat strip into a tubular shape. This cold-forming process preserves the austenitic microstructure while achieving precise dimensional control.
- Welding — The formed tube is welded using either:
- Argon Gas Shielded Welding (TIG / GTAW) — For high-purity welds with minimal oxidation, using internal and external inert gas shielding.
- Laser Welding — For high-precision, high-speed production with narrow heat-affected zones.
- Ultrasonic Welding — For certain thin-wall applications requiring solid-state bonding without filler material.
- Weld Heat Treatment — The weld seam is subjected to solution annealing (1050–1150 °C, water quench) to restore full austenitic properties and eliminate any sensitization or carbide precipitation in the heat-affected zone (HAZ).
- Pickling and Passivation — Tubes are immersed in a mixed acid solution (HNO₃/HF) to remove surface oxide scale. Subsequent passivation treatment (HNO₃-based) establishes a stable chromium oxide passive film, enhancing corrosion resistance.
- Coiling — The continuous tube is wound onto precision coiling drums at controlled tension to maintain dimensional stability and prevent deformation or kinking.
- Non-Destructive Testing (NDT) — Electromagnetic (Eddy Current) inspection is performed to detect internal and external defects. Hydrostatic pressure testing verifies weld integrity at 1.5× the maximum working pressure.
- Final Inspection and Packaging — Each coil undergoes dimensional measurement, surface quality inspection, and chemical verification. Coils are wrapped in protective film, strapped, and packaged for export or domestic delivery.
Applications
The stainless steel coil tube produced by Wenzhou Jixing Metal Materials Co., Ltd. finds extensive application across multiple industrial sectors:
| Industry | Application Details | Recommended Grade |
|---|---|---|
| Food & Beverage Processing | Hygienic piping, condensate lines, pasteurization systems, CIP (Clean-in-Place) circuits, brewing equipment | 304L, 316L |
| Pharmaceutical & Biotechnology | Sterile fluid transfer, bioreactor connections, chromatography systems, USP Class VI compliant piping | 316L |
| Chemical & Petrochemical | Process piping, heat exchanger tubes, chemical dosing lines, reactor internals | 316, 321 |
| Automotive | Exhaust system components, fuel lines, turbocharger piping, brake lines | 321, 304 |
| HVAC & Refrigeration | Heat exchanger coils, condensate drainage, refrigerant lines, air handling unit components | 304, 316 |
| Marine & Offshore | Ballast water systems, seawater cooling circuits, desalination plant piping | 316, 316L |
| Architectural & Decorative | Handrails, balustrades, structural supports, decorative trim, elevator components | 304 |