316L Austenitic Stainless Steel Coil Tube — Low-Carbon Molybdenum-Bearing Grade for Corrosion-Critical Applications
Product Overview
The 316L Austenitic Stainless Steel Coil Tube is a premium-grade continuous tube product engineered for the most demanding corrosion-resistant service environments. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this coil tube combines the inherently superior corrosion resistance of the 316 series with the enhanced weldability and ductility of the "L" (low-carbon) variant, delivering a material solution that excels in pharmaceutical processing, food-grade fluid handling, seawater desalination systems, and high-purity water distribution networks.
As a coiled (continuous-length) tube format, the product offers significant advantages over straight-length tubing in terms of material utilization, reduced joint count, lower installation labor, and superior hydraulic performance — making it the preferred choice for long-run piping systems where minimizing connections is critical to system integrity.
Material & Metallurgical Properties
The 316L grade is an austenitic stainless steel alloy that incorporates both molybdenum (Mo) and reduced carbon content relative to standard 316. This dual-element formulation provides a synergistic combination of corrosion resistance and mechanical performance:
- Molybdenum Addition (2.0–3.0%): Significantly enhances resistance to pitting corrosion, crevice corrosion, and chloride-induced stress corrosion cracking (SCC) — critical for marine, chemical, and high-chloride environments.
- Low Carbon Content (≤0.03%): Prevents chromium carbide precipitation at grain boundaries during welding and heat exposure, effectively eliminating intergranular corrosion (IGC) — a common failure mode in standard 316 after welding.
- Austenitic Microstructure: Non-magnetic in the annealed condition, excellent formability, and superior toughness across a wide temperature range including cryogenic applications.
- Chromium Content (16.0–18.0%): Forms a robust, self-healing passive oxide film that provides baseline atmospheric and chemical resistance.
The combination of low carbon and molybdenum makes 316L the industry benchmark for applications where the tube must withstand both welding fabrication stresses and aggressive corrosive media simultaneously — a requirement that standard 316 cannot reliably meet.
Specifications
| Parameter | Specification |
|---|---|
| Material Grade | ASTM A270 TP316L / ASME SA-270 / EN 10217-7 1.4404 / JIS G3459 SUS316L |
| Chemical Composition (max) | C ≤ 0.03%, Si ≤ 1.0%, Mn ≤ 2.0%, P ≤ 0.045%, S ≤ 0.030%, Cr 16.0–18.0%, Ni 10.0–14.0%, Mo 2.0–3.0% |
| Tube Form | Coil (Continuous Length) |
| Manufacturing Method | Seamless / Welded (per customer specification) |
| Outer Diameter Range | Φ6 mm – Φ219 mm (custom sizes available) |
| Wall Thickness Range | 0.5 mm – 12 mm (custom thicknesses available) |
| Surface Finish | Pickled & Passivated (2B), Electro-polished, Matte, Bright Annealed |
| Coil Length | Up to 3000 m per coil (negotiable based on specification) |
| Tensile Strength | ≥ 485 MPa (0.2% Proof Stress ≥ 170 MPa) |
| Elongation | ≥ 40% (minimum) |
| Operating Temperature | -196 °C to +870 °C (continuous service) |
| Available Standards | ASTM A269, ASTM A270, ASME B36.19M, EN 10217-7, ISO 3506 |
| End Preparation | Plain end, Beveled end, Threaded end, Custom per drawing |
| Packaging | Wooden coil cradle / Steel frame with moisture-proof wrapping |
Manufacturing Process
Wenzhou Jixing Metal Materials Co., Ltd. employs a fully integrated manufacturing process to ensure consistent quality from raw material to finished coil:
- Raw Material Selection: Only certified 316L stainless steel billets or strip from accredited mills are sourced, with full chemical and mechanical traceability via mill test certificates (MTC).
- Piercing / Cold Forming: Seamless tubes are produced via hot piercing followed by cold drawing and rolling; welded tubes utilize precision cold-rolled strip with continuous TIG (GTAW) welding.
- Heat Treatment: Solution annealing at 1010–1150 °C followed by rapid water quenching to homogenize the austenitic microstructure and restore full corrosion resistance.
- Pickling & Passivation: The tube is treated with a nitric acid/hydrofluoric acid blend to remove scale and impurities, followed by passivation to establish a uniform, protective chromium oxide surface film.
- Dimensional Inspection: Automated ultrasonic thickness testing, optical diameter gauging, and roundness verification ensure every coil meets tight dimensional tolerances (±0.05 mm for OD, ±10% for wall thickness).
- Coiling & Packaging: Tubes are wound onto precision-matched coil cores, secured with stainless steel strapping, and packaged to prevent mechanical damage and surface contamination during transit.
Applications
The 316L Coil Tube is the material of choice in industries where contamination, corrosion, and system failure are intolerable:
- Pharmaceutical Industry: CIP/SIP piping, reactor feed lines, clean steam distribution, and purified water systems — where the low-carbon grade ensures no chromium carbide formation at weld joints that could leach into drug products.
- Food & Beverage Processing: Milk processing lines, brewing equipment, sugar syrup conveyance, and CIP loops — providing hygienic surfaces resistant to organic acids, lactic acid, and salt-based cleaning agents.
- Seawater Desalination (SWRO): High-pressure feed water piping, brine concentrate lines, and permeate distribution — where molybdenum's resistance to chloride pitting is essential in 3.5% NaCl environments.
- High-Purity Water Systems: Ultra-pure water (UPW) distribution in semiconductor fabrication, biotech cleanrooms, and laboratory installations — where surface purity and long-term metal ion stability are paramount.
- Chemical Processing: Acid and alkali handling, chemical dosing lines, and reactor effluent piping.
- Marine & Offshore: Seawater cooling circuits, ballast water systems, and subsea piping where halide corrosion is a persistent threat.
- Medical Equipment: Endoscope tubing, dialysis machine fluid lines, and surgical instrument housings.
Quality Certifications & Compliance
Every batch of 316L Coil Tube produced by Wenzhou Jixing Metal Materials Co., Ltd. is backed by rigorous quality assurance:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001 — Environmental Management System
- EN 10204 3.1 — Mill Test Certificates with full chemical analysis and mechanical test data for every heat lot
- CE Marking — Compliance with European Pressure Equipment Directive (PED) 2014/68/EU where applicable
- PED / ASME Stamp — Available for pressure-containing applications per customer requirement
- Third-Party Inspection: SGS, BV, or TÜV inspection available upon request
- Material Traceability: Full heat-number traceability from raw material mill through final coil delivery
Key Selling Points
Superior Dual Corrosion Resistance: The unique combination of low carbon (≤0.03%) and molybdenum (2.0–3.0%) delivers unmatched protection against both pitting corrosion in chloride environments and intergranular corrosion at weld zones — a dual threat that eliminates the need for post-weld re-heat treatment.
Continuous Coil Format: Reduces the number of butt welds by up to 90% compared to straight-length pipe, dramatically lowering leak risk, maintenance frequency, and total cost of ownership in hygienic and critical-service systems.
Hygienic Surface Quality: Available in electro-polished finish with Ra ≤ 0.4 μm surface roughness, meeting FDA, 3-A Sanitary, and EHEDG requirements for pharmaceutical and food-grade installations.
Full Traceability & Certification: Every coil ships with EN 10204 3.1 MTC, ensuring complete material provenance and regulatory compliance for audit-sensitive industries.
Custom Engineering: Flexible sizing, surface finishing, end preparation, and packaging options tailored to project-specific requirements.
Wenzhou Jixing Metal Materials Co., Ltd. — Your trusted partner in premium stainless steel coil tube solutions for the world's most demanding corrosion-critical applications.