Stainless Steel Coil Tube — Pressure-Tested & Leak-Proof Coiltube Product Series
1. Product Overview
The Stainless Steel Coil Tube (盘管, Coiltube) is a precision-engineered, continuously wound tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product series is specifically designed and qualified for applications demanding high-pressure resistance and superior sealing integrity. Each coil tube undergoes rigorous Hydrostatic Pressure Testing (耐压试验) and Leakage & Sealing Inspection (密封性检查) in accordance with international standards, ensuring zero-defect performance under demanding operational conditions.
The coiltube format offers significant logistical and fabrication advantages over straight-length tubing, enabling downstream users to minimize material waste through continuous cutting, reduce inventory handling complexity, and optimize nesting in automated forming and bending operations.
2. Material & Properties
2.1 Material Grades
- AISI 304 / 304L (UNS S30400 / S30403) — General-purpose austenitic stainless steel with excellent corrosion resistance and formability.
- AISI 316L (UNS S31603) — Enhanced chloride resistance and superior performance in aggressive chemical environments.
- AISI 321 (UNS S32100) — Stabilized austenitic grade with titanium addition for improved high-temperature resistance and resistance to intergranular corrosion.
- AISI 310S (UNS S31008) — Ultra-high-temperature grade suitable for extreme thermal cycling environments.
2.2 Mechanical Properties (Annealed Condition)
| Property | 304 / 304L | 316L | 321 | 310S |
|---|---|---|---|---|
| Tensile Strength (MPa) | ≥ 515 | ≥ 515 | ≥ 515 | ≥ 515 |
| Yield Strength (MPa) | ≥ 205 | ≥ 205 | ≥ 205 | ≥ 205 |
| Elongation (%) | ≥ 40 | ≥ 40 | ≥ 40 | ≥ 40 |
| Hardness (HBW) | ≤ 187 | ≤ 187 | ≤ 187 | ≤ 200 |
| Maximum Service Temperature (°C) | 870 | 870 | 900 | 1150 |
2.3 Chemical Composition (Typical, wt%)
| Element | C | Si | Mn | P | S | Cr | Ni | Mo | Ti |
|---|---|---|---|---|---|---|---|---|---|
| 304 | ≤ 0.08 | ≤ 1.00 | ≤ 2.00 | ≤ 0.045 | ≤ 0.030 | 18.0–20.0 | 8.0–10.5 | — | — |
| 316L | ≤ 0.03 | ≤ 1.00 | ≤ 2.00 | ≤ 0.045 | ≤ 0.030 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | — |
| 321 | ≤ 0.08 | ≤ 1.00 | ≤ 2.00 | ≤ 0.045 | ≤ 0.030 | 17.0–19.0 | 9.0–12.0 | — | 5×C to 0.70 |
3. Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | Φ6.0 mm – Φ50.8 mm (custom ranges available) |
| Wall Thickness | 0.5 mm – 3.0 mm (tolerance ±10%) |
| Coil Weight | 100 kg – 500 kg per coil (standard); up to 800 kg on request |
| Coil Inner Diameter (ID) | Φ150 mm / Φ200 mm / Φ300 mm (selectable) |
| Surface Finish | Bright Annealed (BA), Pickled & Annealed (PA), Commercial (2B) |
| Surface Roughness (Ra) | ≤ 0.5 μm (BA finish); ≤ 0.8 μm (PA finish) |
| End Condition | Plain end, beveled end, or threaded end (per customer specification) |
| Hydrostatic Test Pressure | 1.5× Working Pressure (minimum 30 MPa for thin-wall grades) |
| Sealing Inspection | 100% Helium Leak Testing or Pneumatic Pressure Hold Test |
| Coil Packaging | Steel banding, VCI (Vapor Corrosion Inhibitor) wrap, wooden pallet, seaworthy export packaging |
| Standards Compliance | ASTM A269, ASTM A213, ASME SA-213, GB/T 12771, EN 10216-5 |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube follows a rigorously controlled, multi-stage manufacturing pipeline:
- Material Selection & Ingot Casting — Virgin stainless steel billets are sourced from certified mills with full traceability documentation (Mill Test Certificates, MTCs).
- Piercing & Hot Rolling — Billets are heated to forging temperature (1150–1250°C) and pierced to form hollow blanks, followed by hot rolling to approximate target dimensions.
- Cold Drawing / Cold Rolling — The hot-rolled tube blanks are cold-drawn through precision-die tooling to achieve exact dimensional tolerances, superior surface finish, and enhanced mechanical properties.
- Solution Annealing — Tubes are annealed at 1050–1100°C in a controlled atmosphere (hydrogen or vacuum) furnace to relieve cold-work stresses, restore ductility, and achieve a uniform austenitic microstructure.
- Pickling & Passivation — Surface scale and oxide films are chemically removed via pickling, followed by passivation treatment to enhance corrosion resistance.
- Coil Winding — The straight-length tube is wound into coils using automated coiling equipment to maintain consistent coil geometry and prevent deformation or kinking.
- Hydrostatic Pressure Testing — Each coil tube undergoes 100% hydrostatic pressure testing at 1.5× the specified working pressure, with a minimum hold time of 30 seconds, in compliance with ASTM A269 Section 9.
- Sealing & Leakage Inspection — Pneumatic pressure hold tests or helium leak detection (sensitivity ≤ 1×10⁻⁶ Pa·m³/s) are performed to verify complete sealing integrity of weld seams and tube walls.
- Dimensional & Visual Inspection — Final inspection includes OD/wall thickness measurement (ultrasonic or micrometer), straightness verification, and surface defect screening via magnetic particle inspection (MPI) or eddy current testing (ECT).
- Packaging & Dispatch — Qualified coils are wrapped, strapped, and palletized for safe transport, with accompanying documentation including MTC, test reports, and certificates of compliance.
5. Applications
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. is deployed across a broad spectrum of industrial applications where pressure integrity and corrosion resistance are critical:
- Petrochemical & Oil/Gas Industry — Heat exchanger tubes, refinery piping, and process instrumentation lines.
- Food & Pharmaceutical Processing — Sanitary-grade piping for CIP (Clean-In-Place) and SIP (Sterilization-In-Place) systems, dairy equipment, and brewing lines.
- Power Generation — Boiler tubes, condenser tubes, and superheater elements in thermal and nuclear power plants.
- Automotive Industry — Exhaust system components, fuel lines, and turbocharger piping.
- Medical Devices — Endoscopic instrument tubing, surgical equipment, and dialysis machine components.
- Chemical Processing — Reactor internals, heat exchangers, and corrosive fluid transport lines.
- Construction & Architecture — Structural and decorative piping in high-end building projects.
- Marine & Offshore — Seawater piping, desalination systems, and subsea infrastructure.
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains an internationally recognized quality management infrastructure to ensure product reliability and regulatory compliance:
- ISO 9001:2015 — Quality Management System (QMS) certification.
- ISO 14001:2015 — Environmental Management System (EMS) certification.
- ISO 45001:2018 — Occupational Health and Safety Management System (OHSMS) certification.
- ASME "S" Stamp — Authorized for pressure-vessel and pressure-piping applications per ASME Boiler and Pressure Vessel Code (BPVC).
- EN 10204 3.1 — Third-party inspection and testing certification available upon request.
- CE Marking — Compliance with European Pressure Equipment Directive (PED 2014/68/EU).
- NACE MR0175 / ISO 15156 — Resistance to sulfide stress cracking (SSC) for sour service applications (316L grade).
- NSF/ANSI 61 — Drinking water system components compliance (food-grade grades).
7. Unique Selling Points
7.1 Comprehensive Pressure & Sealing Assurance — Unlike standard coil tube suppliers, every unit undergoes dual verification: hydrostatic pressure testing at 1.5× working pressure and 100% leakage inspection, providing customers with documented, traceable proof of pressure integrity for every coil delivered.
7.2 Coil Format Efficiency — The coiltube format eliminates butt-weld joints inherent in straight-length tubing, reducing potential leak points by up to 90% in continuous-run applications and cutting fabrication time and material waste significantly.
7.3 Full Traceability — Each coil is assigned a unique heat number and production batch identifier, enabling complete traceability from raw material ingot through to final inspection, supporting customer quality audits and regulatory requirements.
7.4 Customization Capability — Wenzhou Jixing offers flexible customization of dimensions, surface finishes, end treatments, and coil configurations to meet specific customer engineering requirements.
7.5 Competitive Export Infrastructure — Seaworthy export packaging, English-language technical documentation, and logistics coordination support global customer procurement efficiently.
8. Technical Reference Standards
| Standard Designation | Title | Relevance |
|---|---|---|
| ASTM A269 | Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for Chemical and Similar Severely Corrosive Services | Material & pressure test requirements |
| ASTM A213 | Standard Specification for Seamless Austenitic Chromium-Nickel Stainless Steel Tubes for Heat-Transfer and Similar Uses | Heat exchanger tube qualification |
| GB/T 12771 | Stainless Steel Seamless Tubes for Fluid Transport | Chinese national standard compliance |
| EN 10216-5 | Technical Delivery Conditions for Seamless Tubes of Stainless Steels — Part 5: Tubes for Heat Exchangers and Similar Applications | European standard compliance |
| ASME BPVC Section IX | Welding, Brazing, and Fusing Qualifications | Welded tube qualification |
| ISO 5208 | Plastics piping systems — Hydrostatic pressure test method ( |