Stainless Steel Coil Tube — Wenzhou Jixing Metal Materials Co., Ltd.
Product Code: No. 828 | Category: Stainless Steel Coiled Tubing | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. (温州吉兴金属材料有限公司)
1. Product Overview
The Stainless Steel Coil Tube (SSCT) produced by Wenzhou Jixing Metal Materials Co., Ltd. is a precision cold-worked tubular product delivered in continuous coil configuration. This form factor offers significant advantages over traditional cut-to-length pipe in terms of material utilization, processing efficiency, and inventory management. The coil tube is manufactured from high-purity austenitic and duplex stainless steel grades, conforming to international standards including ASTM, EN, and GB specifications.
Unlike conventional seamless pipe or welded pipe delivered in straight lengths, the coil tube is wound into a controlled helical configuration on a steel or aluminum spool, enabling downstream fabricators to perform automated cutting, bending, and forming operations with minimal waste. This product line is particularly suited for high-volume manufacturing environments where just-in-time processing and reduced handling costs are critical.
2. Material & Properties
2.1 Available Grades
- Austenitic Grades: 304 (UNS S30408), 304L (UNS S30403), 316 (UNS S31608), 316L (UNS S31603), 321 (UNS S32108), 310S (UNS S31008)
- Duplex Grades: 2205 (UNS S31803/S32205), 2507 (UNS S32750)
- Super-Austenitic Grades: 904L (UNS N08904), Alloy 20 (UNS N08200)
- Custom Grades: Available upon request with specified chemical composition
2.2 Mechanical Properties (Annealed Condition)
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HV) |
|---|---|---|---|---|
| 304 / 304L | ≥520 | ≥205 | ≥40 | ≤200 |
| 316 / 316L | ≥515 | ≥205 | ≥40 | ≤200 |
| 321 | ≥515 | ≥205 | ≥40 | ≤200 |
| 2205 | ≥550 | ≥450 | ≥25 | ≤310 |
| 904L | ≥550 | ≥220 | ≥40 | ≤220 |
2.3 Physical Properties
- Density: 7.93 g/cm³ (austenitic grades)
- Thermal Conductivity: 16.3 W/(m·K) at 100°C (Grade 304)
- Thermal Expansion Coefficient: 17.3 × 10⁻⁶ /K (20–100°C, Grade 304)
- Operating Temperature Range: −196°C to +870°C (austenitic); up to +350°C (duplex)
2.4 Corrosion Resistance
The coil tubes exhibit outstanding resistance to general corrosion, pitting corrosion, crevice corrosion, and intergranular corrosion. The low-carbon variants (304L, 316L) are specifically designed to resist sensitization during welding operations, maintaining full corrosion resistance in the heat-affected zone (HAZ). Molybdenum-bearing grades (316, 904L) provide superior resistance to chloride-induced pitting and stress corrosion cracking (SCC).
3. Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | Φ3.0 mm – Φ50.8 mm (custom sizes available) |
| Wall Thickness (WT) | 0.3 mm – 5.0 mm |
| OD Tolerance | ±0.05 mm (precision grade); ±0.1 mm (standard grade) |
| WT Tolerance | ±0.03 mm (precision grade); ±0.05 mm (standard grade) |
| Coil Inner Diameter (ID) | Φ150 mm / Φ200 mm / Φ300 mm / Φ500 mm |
| Coil Weight | 200 kg – 2,000 kg per coil |
| Surface Finish | No. 1 (annealed), 2B (cold-rolled & annealed), BA (bright annealed), No. 4 (hairline), Mirror (8K) |
| Welding Process | TIG (GTAW) longitudinal seam; full penetration weld |
| Weld Quality | 100% radiographic inspection (RT) or ultrasonic inspection (UT) on weld seam |
| Delivery Condition | Annealed (A), Pickled & Passivated (P&P), Cold Worked (CW) |
| Standards | ASTM A269 / A213, EN 10216-5, GB/T 12771, JIS G3459 |
| Packaging | Steel spool with wooden pallet; plastic film wrapping; desiccant included |
4. Manufacturing Process
4.1 Process Flow
- Steel Coil Procurement: Cold-rolled stainless steel strip (CRSS) is sourced from certified mills with full chemical and mechanical certification.
- Strip Inspection & Slitting: Incoming strip undergoes visual inspection, thickness verification via ultrasonic gauging, and precision slitting to target coil tube dimensions.
- Tube Forming: The flat strip is fed through a multi-roll forming system (typically 12–16 pass rolls) to progressively shape the tube cross-section. Forming rollers are precision-ground to ensure dimensional accuracy.
- Longitudinal Welding: TIG (Tungsten Inert Gas) welding is performed on the formed tube seam under continuous argon shielding (internal and external) at a controlled welding speed. Weld parameters are maintained within validated windows.
- Weld Inspection: 100% online ultrasonic testing (UT) or radiographic testing (RT) detects weld defects including lack of fusion, porosity, and undercuts.
- Pipe Milling / Weld Bead Grinding: The internal and external weld beads are milled or ground flush to achieve uniform wall thickness and smooth surface finish.
- Solution Annealing: Tubes are annealed at 1050°C – 1150°C in a protective atmosphere (hydrogen or vacuum) to relieve cold work stresses, dissolve chromium carbides, and restore full corrosion resistance.
- Pickling & Passivation: Post-annealing, tubes are pickled in nitric-hydrofluoric acid mixture to remove oxide scale, followed by passivation treatment to establish a protective chromium oxide film.
- Final Dimensional Inspection: OD, WT, roundness, and straightness are verified using automated optical measurement systems.
- Coiling: Finished tube is wound onto a steel or aluminum spool at controlled tension to prevent deformation, kinking, or springback.
- Packaging & Dispatch: Coils are wrapped in moisture-proof polyethylene film, secured with steel banding, and placed on wooden pallets for export-grade shipping.
4.2 Key Process Controls
- Welding Parameter Monitoring: Real-time feedback control on voltage, current, and travel speed ensures consistent weld quality throughout production runs.
- Atmosphere Control: Annealing furnaces maintain dew point below −60°C to prevent re-oxidation and carbide precipitation.
- Traceability: Each coil is assigned a unique heat number and traceable to raw material mill certificates.
5. Applications
| Industry | Application | Recommended Grade |
|---|---|---|
| Food & Beverage | Hygienic process piping, CIP (Clean-in-Place) systems, brewing equipment | 304L, 316L |
| Pharmaceutical | Bioreactor piping, sterile transfer lines, cleanroom fluid systems | 316L, 304L |
| Petrochemical | Process piping, heat exchanger tubes, flare systems | 316, 321, 904L |
| Marine & Offshore | Seawater cooling systems, ballast piping, desalination plant components | 2205, 316 |
| Automotive | Exhaust system components, fuel lines, sensor housings | 321, 310S |
| Medical Devices | Surgical instrument shafts, endoscope tubing, implant housings | 304L, 316L |
| Architecture & Decoration | Handrails, balustrades, structural framing, decorative trim | 304, 316 |
| Aerospace | Fuel lines, hydraulic tubing, heat exchanger components | 316, 321, 904L |
| Energy | Solar thermal collectors, fuel cell manifolds, battery enclosure piping | 316, 2205 |
6. Quality Certifications
- ISO 9001:2015 — Quality Management System certification for production facilities
- ISO 14001:2015 — Environmental Management System certification
- EN 10204 3.1 — Third-party inspection and material certification per European standard
- ASME — American Society of Mechanical Engineers stamping qualification (where applicable)
- PED (Pressure Equipment Directive) 2014/68/EU — Conformity assessment for pressure-containing applications
- NSF/ANSI 61 — Drinking water system component certification (for 304L/316L grades)
- 3-A Sanitary Standards — Dairy and food processing equipment compliance
- Mill Test Reports (MTR) — Full chemical analysis and mechanical test results provided per coil
- NDT Reports — 100% ultrasonic or radiographic weld inspection reports available upon request
7. Unique Selling Points
Material Utilization: Coil configuration eliminates trim loss from cut-to-length pipe, achieving up to 98% material utilization rate — reducing cost per usable meter by 10–15% compared to straight-length alternatives.
- Precision Dimensional Control: Tolerance levels as tight as ±0.03 mm on wall thickness enable direct use in high-precision applications without secondary machining.
- Seamless Weld Quality: Full-penetration TIG welds with flush ground beads provide mechanical properties equivalent to seamless pipe, verified by 100% non-destructive testing.
- Flexible Order Quantities: Coil format accommodates both small-batch trial orders and large-scale production runs without minimum order quantity restrictions.
- Customization Capability: Non-standard OD, WT, surface finish, and delivery condition available through collaborative engineering with Wenzhou Jixing's technical team.
- Supply Chain Reliability: Located in Wenzhou — China's premier hub for stainless steel pipe manufacturing — the company leverages deep regional supply chain integration for competitive lead times and consistent quality.
- Full Traceability: End-to-end material traceability from mill heat number through final coil dispatch ensures compliance with aerospace, medical, and nuclear industry requirements.
8. Ordering Information
When placing an order for Wenzhou Jixing Metal Materials Co., Ltd. Stainless Steel Coil Tubes, customers should specify the following:
- Grade (e.g., 304L, 316L, 2205)
- Outer diameter and wall thickness (with required tolerance class)
- Surface finish (2B, BA, No. 4, Mirror)
- Delivery condition (Annealed, Pickled & Passivated)
- Coil inner diameter preference
- Applicable standard (ASTM, EN, GB, JIS)
- Required certifications and inspection reports
- Quantity (in meters or kilograms)
Wenzhou Jixing Metal Materials Co., Ltd. maintains a professional technical support team available to assist with material selection, specification compliance verification, and application engineering consultation.