Stainless Steel Coil Tube (Coiltube) — Jacket Furnace Heating Application
Product Code: 1030 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
This technical specification provides a comprehensive academic-level description of the stainless steel coil tube (Coiltube) product, with particular emphasis on its application in jacket furnace heating systems. The content draws upon research findings related to the internal heat transfer characteristics of jacket furnace heating coil tubes, ensuring that the product description reflects both engineering rigor and practical applicability in high-temperature thermal processing environments.
Product Overview
The stainless steel coil tube (Coiltube) is a precision-engineered tubular product manufactured in continuous coiled form, specifically designed for demanding industrial applications involving thermal energy transfer. In jacket furnace heating systems — a critical component in petroleum refining, chemical processing, and power generation — coil tubes serve as the primary heat exchange medium, transferring thermal energy from combustion gases to process fluids through convective and conductive mechanisms.
Wenzhou Jixing Metal Materials Co., Ltd. produces stainless steel coil tubes that meet stringent international standards for dimensional accuracy, mechanical integrity, and corrosion resistance. These products are engineered to withstand the extreme thermal cycling, oxidative environments, and mechanical stresses inherent in jacket furnace operations, ensuring prolonged service life and consistent thermal performance.
Material & Properties
Material Grades
- Austenitic Stainless Steels: Type 304 (UNS S30400), Type 316 (UNS S31600), Type 321 (UNS S32100), Type 347 (UNS S34700)
- Super Austenitic Stainless Steels: Type 904L (UNS N08904), Alloy 20 (UNS N08200)
- Heat-Resistant Alloys: Alloy 600 (UNS N06600), Alloy 800 (UNS N08800), Alloy 800H (UNS N08810)
- Custom Grades: Available upon request for specialized thermal applications
Mechanical Properties (Typical Values for Type 321 Stainless Steel Coil Tube)
- Tensile Strength (UTS): ≥ 515 MPa (75 ksi)
- Yield Strength (0.2% Offset): ≥ 205 MPa (30 ksi)
- Elongation (at Break): ≥ 40%
- Hardness (HB): ≤ 187
- Operating Temperature Range: −196 °C to +1050 °C (−321 °F to +1922 °F)
- Thermal Conductivity (at 20 °C): 16.3 W/(m·K)
- Thermal Expansion Coefficient (20–100 °C): 17.3 × 10⁻⁶ /°C
Corrosion Resistance
The selected stainless steel grades provide exceptional resistance to pitting, crevice corrosion, and intergranular corrosion in aggressive environments. The chromium (Cr) content of ≥ 18% forms a self-healing passive oxide layer (Cr₂O₃), while the addition of molybdenum (Mo) and niobium (Nb) further enhances resistance to chloride-induced degradation and high-temperature sensitization, respectively.
Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | Φ6.0 mm – Φ219.1 mm (0.25" – 8.63") | ASTM A213 / A269 |
| Wall Thickness (WT) | 0.5 mm – 12.7 mm (0.020" – 0.500") | ASTM A213 / A269 |
| Coil Inner Diameter (ID) | Φ300 mm – Φ1500 mm (12" – 59") | Manufacturer's Specification |
| Coil Length (per Coil) | 5 m – 300 m (16 ft – 984 ft) | Custom Order Available |
| Surface Finish | Ba&P (Bright Annealed & Pickled), No. 1, No. 2B, No. 4 | ASTM A478 |
| End Condition | Plain, Beveled, Threaded, or Flanged | ASME B1.20.1 |
| Dimensional Tolerance (OD) | ±0.05 mm (±0.002") | ASTM A213 |
| Dimensional Tolerance (WT) | ±10% of nominal | ASTM A213 |
| Straightness Tolerance | ≤ 0.1% of tube length | Manufacturer's Specification |
| Maximum Service Pressure | Up to 40 MPa (5,800 psi) — grade dependent | ASME BPVC Section VIII |
| Maximum Service Temperature | Up to 1050 °C (1922 °F) — grade dependent | ASTM A213 |
| Heat Treatment Condition | Solution Annealed (1050–1150 °C, water/quench) | ASTM A213 |
| Coating / Lining | Optional: Ceramic coating, PTFE lining, or bare finish | Custom Specification |
| Welding Compatibility | TIG (GTAW), MIG (GMAW), Resistance Welding | ASME Section IX |
| Inspection | 100% Hydrostatic Test, Eddy Current (ECT), Visual Inspection (VT) | ASTM A213 / EN 10216 |
| Packaging | Wooden crate or steel banding with moisture-proof wrapping | ISO 4180 |
Manufacturing Process
Process Flow
- Raw Material Selection: Virgin stainless steel billets or slabs sourced from certified suppliers, verified through spectrographic analysis (OES/PMS) for chemical composition compliance.
- Hot Rolling: Billets are reheated to 1100–1200 °C and hot-rolled through sequential passes to achieve the desired semi-finished tube diameter and wall thickness. This step establishes the initial geometry and homogenizes the microstructure.
- Pierling & Mandrel Drawing: The hot-rolled tube is pierced and drawn over a mandrel to refine the inner diameter and achieve tighter wall thickness tolerances.
- Heat Treatment (Solution Annealing): Tubes are annealed at 1050–1150 °C in a protective atmosphere (argon or vacuum) followed by rapid quenching. This dissolves carbide precipitates, restores full austenitic structure, and maximizes corrosion resistance.
- Pickling & Passivation: Surface scale and oxide films are removed using mixed acid pickling (HNO₃ + HF), followed by nitric acid passivation to regenerate the protective chromium oxide layer.
- Cold Drawing / Cold Rolling (Optional): For applications requiring enhanced mechanical properties or tighter tolerances, cold working is performed to achieve work-hardening and dimensional precision.
- Coiling: The finished tube is coiled onto a precision mandrel using computer-controlled coiling equipment to maintain consistent coil diameter, layer alignment, and minimum surface damage.
- Quality Inspection: Each coil undergoes 100% hydrostatic testing, eddy current testing for wall thickness verification, visual inspection, and dimensional measurement.
- Packaging & Dispatch: Coils are wrapped, banded, and packed in export-grade wooden crates with documentation including mill test certificates (MTC), material traceability records, and inspection reports.
Process Quality Control Points
- In-line monitoring of rolling temperature, reduction ratio, and coiling tension
- Non-Destructive Testing (NDT) including Eddy Current Testing (ECT) and Ultrasonic Testing (UT)
- Chemical composition verification via Optical Emission Spectroscopy (OES) at each heat
- Microstructural examination per ASTM E3 with grain size evaluation
Applications
Primary Application: Jacket Furnace Heating Systems
Based on the research study "Research on Internal Heat Transfer Characteristics of Jacket Furnace Heating Coil Tubes", the stainless steel coil tube is specifically optimized for use as heating elements in jacket furnaces. In these systems, the coil tube acts as the heat transfer surface, absorbing radiant and convective heat from combustion gases and transferring it to the process fluid (typically crude oil, fuel oil, or chemical feedstock) flowing through the tube interior.
Key performance considerations identified through the research include:
- Internal Heat Transfer Coefficient: Optimized tube geometry (diameter, wall thickness, and surface roughness) enhances turbulent flow and increases the convective heat transfer coefficient (h_i), improving overall thermal efficiency.
- Thermal Stress Management: The coil tube must accommodate differential thermal expansion between the tube wall and surrounding refractory lining without cracking or deformation.
- Scale Formation Resistance: The austenitic microstructure and alloying elements inhibit oxide scale growth on the tube's inner surface, maintaining stable heat transfer performance over extended operating cycles.
- Pressure Drop Optimization: The coil geometry is designed to balance heat transfer enhancement with acceptable pressure drop (ΔP) across the heating zone, ensuring process fluid circulation without excessive pumping power.
Additional Industrial Applications
- Petroleum Refining: Heater tubes in crude oil distillation units, atmospheric and vacuum distillation furnaces, and reforming reactors
- Chemical Processing: Reactor heating coils, heat exchanger tubes, and process piping in chlor-alkali, polymer, and fertilizer plants
- Power Generation: Boiler tubes, superheater coils, and economizer elements in utility and cogeneration plants
- Petrochemical: Steam cracking furnace tubes, ethylene and propylene production heating systems
- Food & Pharmaceutical: Sanitary-grade heating coils (304/316L) in pasteurization, sterilization, and CIP (Clean-in-Place) systems
- Marine & Offshore: Subsea heating coils, seawater heat exchangers, and desalination plant components
- Automotive: Exhaust system components, catalytic converter substrates, and EGR (Exhaust Gas Recirculation) cooling coils
Quality Certifications
Applicable Standards
| Standard | Description |
|---|---|
| ASTM A213 / A213M | Standard Specification for Seamless Austenitic Stainless Steel Tubes for High-Temperature Service |
| ASTM A269 / A269M | Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for Chemical and Similar Severities |
| ASTM A478 | Standard Specification for Stainless Steel Products for Chemical and Similar Service |
| EN 10216-5 | Technical Delivery Conditions for Seamless Stainless Steel Tubes for Heat Exchangers and Heat Sinks |
| ISO 15530 | Stainless Steel Tubes — Technical Delivery Conditions for Tubes Intended for Heat Exchangers |
| ASME BPVC Section VIII | Pressure Vessel Code — Rules for Construction of Pressure Vessels |
| API 5CT | Specification for Casing and Tubing (for oil and gas industry applications) |
Company Certifications
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO 45001:2018 — Occupational Health and Safety Management System
- NADCAP — National Aerospace and Defense Contractors Accreditation Program (for aerospace-grade materials)
- API Monogram — American Petroleum Institute certification for oil and gas industry products
- CE Marking — European Conformity for products sold within the European Economic Area (EEA)
- PED (Pressure Equipment Directive 2014/68/EU) — Certification for pressure equipment intended for use in the EU
Unique Selling Points
1. Research-Validated Thermal Performance
This product line is developed with direct reference to published academic research on internal heat transfer characteristics in jacket furnace heating coil tubes. The tube geometry, material selection, and surface finish are optimized based on empirical correlations and computational fluid dynamics (CFD) modeling, ensuring superior thermal efficiency and reduced fouling tendency.
2. Precision Coiling Technology
Advanced CNC-controlled coiling equipment ensures uniform coil diameter, minimal inter-layer stress, and damage-free handling. This reduces field installation time and eliminates the risk of coil spring-back or deformation during deployment.