316 Austenitic Stainless Steel Coil Tube — Chloride & Organic Acid Resistant
Product Overview
The 316 stainless steel coil tube is a premium continuous-length tubing solution engineered by Wenzhou Jixing Metal Materials Co., Ltd for demanding industrial applications where superior corrosion resistance is paramount. Classified under the austenitic corrosion-resistant grade family, this coil tube incorporates a deliberate 2–3% molybdenum (Mo) alloy addition that fundamentally elevates its resistance to chloride-induced pitting, crevice corrosion, and attack by organic acids — properties that distinguish it decisively from standard 304-grade alternatives.
Delivered in continuous coil configuration, this product eliminates butt-weld joints, reduces fabrication labor, and enables seamless integration into heat exchanger coils, serpentine piping systems, and custom-form tubing assemblies. The coil form factor offers maximum material utilization, minimal waste, and streamlined downstream processing for end-users across chemical, pulp & paper, and marine industries.
Material & Properties
Grade 316 — Austenitic Corrosion-Resistant Stainless Steel
- UNS Designation: UNS S31600 / S31603
- EN Designation: 1.4401 / 1.4435
- Key Alloying Element: 2.0–3.0% Molybdenum (Mo)
- Chromium Content: 16.0–18.0% Cr
- Nickel Content: 10.0–14.0% Ni
- Carbon Maximum: 0.08% C
Performance Characteristics
- Chloride Pitting Resistance: The molybdenum addition significantly raises the pitting resistance equivalent number (PREN ≈ 24–26), providing robust protection against localized corrosion in chloride-containing environments, including seawater, brines, and industrial process streams.
- Organic Acid Resistance: Demonstrates excellent resistance to acetic acid, formic acid, citric acid, and other organic acids commonly encountered in chemical processing and food-grade applications.
- Crevice Corrosion Resistance: Superior to 304 grade in tight crevice geometries such as flange gaskets, bolted joints, and heat exchanger tube-to-tubesheet welds.
- Non-Magnetic (Austenitic): Fully austenitic microstructure ensures non-magnetic properties, beneficial for electronics-adjacent applications and certain instrumentation contexts.
- Weldability: Excellent weldability with minimal distortion; suitable for all standard welding processes (TIG, MIG, resistance, laser).
- Temperature Range: Suitable for service from cryogenic temperatures up to approximately 870°C (1,600°F) in non-oxidizing atmospheres.
- Mechanical Properties (Annealed Condition): Tensile strength ≥ 515 MPa; Yield strength ≥ 205 MPa; Elongation ≥ 40%.
Specifications
| Parameter | Specification |
|---|---|
| Material Grade | ASTM A270 Type 316 / EN 10217-7 1.4401 |
| Product Form | Continuous Coil Tube (盘管) |
| Manufacturing Method | Seamless (Cold-Drawn) or Welded (Austenitic) |
| Outer Diameter (OD) | 3.0 mm – 108.0 mm (custom sizes available) |
| Wall Thickness | 0.30 mm – 6.0 mm |
| Coil Length | Custom (typically 50 m – 500 m per coil) |
| Surface Finish | Bright Annealed (BA) / Pickled & Passivated / Custom |
| Inner Diameter Tolerance | ±0.05 mm – ±0.10 mm (per AMS 5528 or customer spec) |
| OD Tolerance | ±0.05 mm – ±0.15 mm |
| Heat Treatment | Solution Annealed (1050°C – 1150°C) + Water Quench |
| Passivation | ASTM A967 Citric Acid or Nitric Acid Passivation |
| Coil Packaging | Wooden reel or steel drum with protective wrapping |
| Standards Compliance | ASTM A270, EN 10217-7, GB/T 14976, JIS G3459 |
Manufacturing Process
The production of 316 stainless steel coil tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorous multi-stage manufacturing protocol:
- Raw Material Selection: Certified 316-grade stainless steel billets or coils are procured from approved primary mills, with full chemical composition verification against ASTM/EN specifications.
- Piercing & Hot Rolling (Seamless Route): Billets are heated to forging temperature and pierced to produce seamless tube blanks. Alternatively, cold-rolled strip is used for the welded route.
- Cold Drawing / Cold Reduction: Tubes are drawn through precision tungsten carbide dies to achieve target OD, wall thickness, and dimensional tolerances. Multiple drawing passes may be employed for high-precision applications.
- Intermediate Annealing: Tubes are solution-annealed between drawing passes to relieve cold-work hardening, restore ductility, and refine grain structure.
- Final Dimensional Calibration: A mandrel drawing or rotary piercing pass ensures consistent bore diameter and roundness throughout the coil length.
- Final Solution Annealing: Tubes are heated to 1050–1150°C followed by rapid water quench to fully solutionize carbides and achieve the desired austenitic microstructure with maximum corrosion resistance.
- Pickling & Passivation: Surface scale is removed via acid pickling; a protective chromium oxide passive film is established per ASTM A967 to ensure long-term corrosion performance.
- Coiling & Inspection: Finished tube is coiled onto protective reels, with 100% visual inspection and sampling for dimensional, mechanical, and chemical verification.
Applications
The unique combination of molybdenum-enhanced corrosion resistance and coil-form versatility makes this 316 coil tube the industry-standard selection for the following sectors:
Chemical Processing Industry
- Reactor piping, heat exchanger coils, and process loops handling chlorinated compounds, sulfuric acid, and mixed-organic acid streams
- Petrochemical distillation columns and fractionation equipment
- Acid production and storage systems
Pulp & Paper Industry
- Black liquor evaporator tubes and heat recovery coils
- Chlorine dioxide (ClO₂) generation and delivery systems
- Bleach plant piping and chemical dosing lines
Marine & Coastal Environments
- Seawater cooling circuits, desalination plant heat exchanger coils
- Marine atmospheric exposure — HVAC condensate systems, coastal facility piping
- Shipboard plumbing and sanitary systems
Additional Applications
- Pharmaceutical and bioprocessing equipment (hygienic-grade finishes available)
- Food & beverage processing — dairy, brewing, and fermentation systems
- Environmental protection — flue gas desulfurization (FGD) and wastewater treatment
- Custom coil assemblies for automotive heat exchangers and HVAC components
Quality Certifications & Traceability
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring every coil tube shipment meets or exceeds international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001 — Environmental Management System Certification
- Full Material Traceability: Each coil is accompanied by a Mill Test Certificate (MTC) / EN 10204 3.1 Certificate documenting chemical composition, mechanical properties, heat treatment status, and dimensional verification.
- Third-Party Inspection: Available upon request — SGS, BV, or TÜV inspection and witnessing of production and final testing.
- Testing Methods: Spectroscopic chemical analysis (OES), hydrostatic pressure testing (100%), dimensional measurement (OD, ID, wall thickness, roundness), and surface finish verification.
- Corrosion Testing Available: Ferrite number testing, intergranular corrosion testing (ASTM A262 Practice E), and pitting resistance testing upon customer request.
Why Choose Wenzhou Jixing Metal Materials Co., Ltd?
"Molybdenum-Enhanced Protection, Coil-Form Versatility, Certified Quality."
- Grade-Specific Expertise: Specialized production of 316 and 316L austenitic stainless steel coil tubes with deep understanding of chloride and organic acid service requirements.
- Continuous Coil Advantage: Eliminates weld joints for superior leak-tight integrity; reduces fabrication time and cost by up to 30% compared to straight-length tube.
- Custom Engineering: Flexible to produce custom OD, wall thickness, coil length, and surface finish per customer specifications.
- Global Standards Compliance: Products manufactured to ASTM, EN, GB, and JIS standards, suitable for international project specifications.
- Reliable Supply Chain: Established partnerships with premium steel mills ensure consistent raw material quality and competitive lead times.