Stainless Steel Steam Dryer Coil Tube — Coiltube Series (Ref. No. 382)
Product Overview
The Stainless Steel Steam Dryer Coil Tube (Coiltube) is a precision-engineered coiled tubular component manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Designed specifically for integration into industrial steam drying systems, this coiltube serves as the primary heat exchange element, facilitating efficient thermal transfer between pressurized steam and the process medium. The product has been extensively studied in the context of steam dryer coil tube life extension research, with findings demonstrating that optimized material selection, manufacturing tolerances, and installation practices can significantly extend operational service life—often exceeding 80% improvement over conventional coil designs.
Coiltubes are supplied in continuous helical coil configurations, minimizing joint interfaces and reducing potential leakage points. The helical geometry maximizes surface-area-to-volume ratio, ensuring superior heat exchange efficiency within compact equipment footprints.
Material & Properties
Coiltubes are fabricated from high-grade austenitic stainless steels selected for their exceptional resistance to thermal fatigue, oxidation, and corrosion under high-temperature steam environments. The primary material grades include:
- SUS304 / AISI 304 / 06Cr19Ni10 — General-purpose grade offering balanced corrosion resistance and formability for moderate-temperature steam applications (up to 450°C).
- SUS316L / AISI 316L / 022Cr17Ni12Mo2 — Enhanced molybdenum-bearing grade providing superior resistance to chlorides, acidic condensate, and pitting corrosion in aggressive environments.
- SUS321 / AISI 321 / 06Cr18Ni11Ti — Titanium-stabilized grade engineered for elevated-temperature service (up to 870°C), offering resistance to intergranular corrosion and thermal stress cracking.
- SUS310S / AISI 310S / 06Cr25Ni20 — Ultra-high-temperature grade for extreme-duty steam drying applications, maintaining mechanical integrity up to 1100°C.
Key mechanical and physical properties of the coiltube material include:
- Tensile Strength: ≥ 520 MPa (SUS304), ≥ 570 MPa (SUS321)
- Yield Strength: ≥ 205 MPa (SUS304)
- Elongation: ≥ 40% (SUS304)
- Thermal Conductivity: 16.3 W/(m·K) at 100°C (SUS304)
- Thermal Expansion Coefficient: 17.3 × 10⁻⁶ /°C (SUS304)
- Maximum Service Temperature: 870°C (SUS321), 1100°C (SUS310S)
- Corrosion Resistance: Excellent resistance to atmospheric, aqueous, and steam-phase corrosion; resistant to stress corrosion cracking (SCC) in properly selected grades
Technical Specifications
| Parameter | Specification | Standard / Tolerance |
|---|---|---|
| Coil Tube Outer Diameter (OD) | Φ6 mm – Φ50 mm (custom sizes available) | ±0.15 mm |
| Wall Thickness | 0.5 mm – 3.0 mm | ±10% of nominal |
| Coil Mean Diameter (CMD) | Φ50 mm – Φ600 mm | ±1.0 mm |
| Coil Pitch (Turn Spacing) | 3 mm – 15 mm | ±0.5 mm |
| Coil Length (Per Unit) | Up to 12,000 mm (continuous coil) | ±20 mm |
| Number of Turns | Custom (typically 50 – 2,000 turns) | ±1 turn |
| End Preparation | Plain end, beveled end, threaded end, or flanged | Per customer drawing |
| Surface Finish | Pickled & passivated; Ra ≤ 0.8 μm (polished available) | ASTM A380 |
| Applicable Standards | ASTM A213 / A269, ASME B36.19M, EN 10216-5, GB/T 12771 | — |
| Pressure Rating | Up to 16 MPa (design-dependent) | ASME VIII Div.1 |
| Operating Temperature Range | -196°C to 870°C (grade-dependent) | — |
| Material Heat Treatment | Solution annealed (1050°C – 1150°C, water quench) | ASTM A240 |
Manufacturing Process
The production of stainless steel steam dryer coiltubes follows a rigorously controlled multi-stage manufacturing process to ensure dimensional accuracy, material integrity, and long-term service reliability:
- Material Selection & Incoming Inspection: Certified stainless steel seamless or welded pipe stock is received with full mill test certificates (MTC). Each batch undergoes spectroscopic verification (PMI — Positive Material Identification) to confirm chemical composition compliance.
- Pipe Cutting & End Preparation: Precision cutting to specified lengths with deburring and end-finishing to eliminate sharp edges that could induce stress concentration during coiling.
- Preforming & Straightening: Initial straightening and preforming of the pipe to eliminate residual bends and ensure uniform cross-sectional geometry prior to coiling.
- Coiling / Winding: The pipe is wound onto precision mandrels using CNC-controlled coiling machines. Critical process parameters—bending radius, pitch consistency, and springback compensation—are controlled to achieve target coil geometry within tolerance. Multi-axial forming techniques prevent ovality and wall thinning at bend apexes.
- Welding & Joining: Where continuous coil length requires splicing, orbital TIG (Tungsten Inert Gas) welding is employed with full penetration and internal backing gas protection to ensure weld integrity.
- Heat Treatment (Post-Coiling Annealing): Coiled tubes undergo stress-relief annealing to eliminate residual stresses introduced during forming. This is critical for preventing delayed stress corrosion cracking in service.
- Pickling & Passivation: Acid pickling removes surface oxide scale, followed by nitric or citric acid passivation to restore the chromium-rich passive film, ensuring maximum corrosion resistance.
- Dimensional & Non-Destructive Testing (NDT): Final inspection includes dimensional verification (OD, wall thickness, coil diameter, pitch), visual inspection, and NDT methods including eddy current testing (ECT) and dye penetrant testing (PT) for surface and near-surface defect detection.
- Packaging & Delivery: Coiltubes are packaged in moisture-proof wrapping with protective end caps to prevent mechanical damage and corrosion during transit.
Applications
Stainless steel steam dryer coiltubes from Wenzhou Jixing Metal Materials Co., Ltd. find extensive application across multiple industrial sectors:
- Industrial Steam Dryers: Primary heat exchange coils in batch and continuous steam drying systems for food, pharmaceutical, chemical, and textile processing.
- Pharmaceutical Equipment: Steam sterilization chambers (autoclaves), freeze-drying systems (lyophilizers), and clean-room HVAC coils requiring biocompatible, corrosion-resistant materials.
- Food Processing Industry: Steam jacketed kettles, pasteurization systems, and drying tunnels for dairy, meat, and grain products.
- Chemical Processing: Solvent recovery systems, distillation columns, and reactor heating coils handling aggressive chemical media.
- Textile Industry: Fabric drying cylinders, steam calendering systems, and textile finishing equipment.
- Power Generation: Steam trap systems, economizers, and auxiliary heating coils in power plant balance-of-plant equipment.
- Marine & Offshore: Steam heating coils for marine engine rooms and offshore platform process equipment in saltwater-exposed environments.
- Research & Development: Laboratory-scale steam drying apparatus and pilot-plant thermal test rigs.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring product reliability and regulatory compliance:
- ISO 9001:2015 — Quality Management System certification covering design, manufacturing, and delivery processes.
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices.
- ASME "S" Stamp — Certification for construction of unfired pressure vessels and components (where applicable).
- EN 10204 3.1 / 3.2 — Third-party inspection and material certification for critical applications.
- CE Marking — Conformity with European Union directives for machinery and pressure equipment.
- NACE MR0175 / ISO 15156 — Compliance for materials in hydrogen sulfide-containing environments (for offshore applications).
- Full Traceability — Each coiltube batch is traceable to raw material heat number via serialized documentation and batch records.
Unique Selling Points — Life Extension Advantages
"The findings of the Steam Dryer Coil Tube Life Extension Research demonstrate that properly engineered coiltubes can achieve service lives exceeding 10 years in continuous operation, compared to 3–5 years for inadequately specified alternatives."
- Extended Service Life: Advanced material selection and post-forming stress-relief treatments eliminate the primary failure modes—thermal fatigue cracking, intergranular corrosion, and stress corrosion cracking—thereby extending operational life by up to 80%.
- Reduced Maintenance Downtime: Superior corrosion resistance and dimensional stability minimize unplanned shutdowns for coil replacement, improving overall equipment effectiveness (OEE).
- Energy Efficiency: Precision coil geometry with tight tolerances ensures optimal steam-liquid contact and heat transfer coefficients, reducing steam consumption by 10–15% compared to loosely wound coils.
- Custom Engineering: Full customization of coil diameter, pitch, tube size, material grade, and end configurations to match specific dryer design requirements.
- Minimal Weld Joints: Continuous coil construction eliminates the need for multiple field-welded joints, reducing leak points and failure probability.
- Cost-Effective Lifecycle: Although initial material cost may be higher than carbon steel alternatives, the extended service life, reduced maintenance, and energy savings deliver superior total cost of ownership (TCO).
Summary
The Stainless Steel Steam Dryer Coil Tube (Coiltube) Series from Wenzhou Jixing Metal Materials Co., Ltd. represents a technically advanced solution for industrial steam drying applications. Backed by rigorous manufacturing standards, comprehensive quality certifications, and research-driven design optimization for life extension, this product delivers reliability, efficiency, and economic value across the full operational lifecycle of steam drying systems.