Stainless Steel Coil Tube — Oil Well Cooling Coil Furnace Application
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product specifically designed for high-temperature thermal processing applications, with particular emphasis on oil well cooling coil furnace systems. These coil tubes are formed from stainless steel strip material through cold-rolled and cold-drawn processes, producing continuous, tightly wound coil configurations that offer superior heat exchange efficiency, mechanical integrity, and corrosion resistance under extreme operating conditions.
Unlike conventional straight tubes, coil tubes provide significantly greater surface area per unit length, making them ideal for heat dissipation, thermal regulation, and fluid transport in oilfield production environments where temperature management is critical to operational safety and productivity.
Material & Properties
Material Grades
- Austenitic Stainless Steels: AISI 304 (UNS S30408), AISI 316 (UNS S31608), AISI 316L (UNS S31603)
- Duplex Stainless Steels: 2205 (UNS S31803), 2507 (UNS S32750)
- Heat-Resistant Grades: AISI 310 (UNS S31008), AISI 321 (UNS S32108)
Key Mechanical Properties
- Tensile Strength: 520–750 MPa (depending on grade and heat treatment)
- Yield Strength: 205–450 MPa
- Elongation at Break: ≥30% (annealed condition)
- Impact Toughness: ≥47 J at −40°C (Charpy V-notch)
- Thermal Conductivity: 14–20 W/(m·K) at 20°C
- Maximum Service Temperature: Up to 1050°C (Grade 310) / 870°C (Grade 316L)
Corrosion Resistance
- Excellent resistance to intergranular corrosion, pitting, and crevice corrosion
- Outstanding performance in chloride-containing environments typical of oilfield produced fluids
- Resistance to stress corrosion cracking (SCC) in halide solutions
- Long-term stability in high-temperature sour gas (H₂S/CO₂) environments
Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | Φ6.0 mm – Φ114.3 mm | ASTM A213 / EN 10216-5 |
| Wall Thickness (WT) | 0.5 mm – 8.0 mm | ASTM A213 / EN 10216-5 |
| Coil Winding Diameter | Φ100 mm – Φ2000 mm | Custom / ISO 4413 |
| Coil Length per Spool | 50 m – 500 m | Manufacturer Specification |
| Surface Finish | 2B / No. 4 / Electropolished (Ra ≤ 0.4 μm) | ASTM A403 |
| Heat Treatment | Annealed / Solution Treated / Pickled & Passivated | ASTM A240 |
| End Condition | Plain End / Beveled / Threaded / Socket Weld | ASME B16.11 |
| Tolerance on OD | ±0.05 mm (Precision) / ±0.10 mm (Standard) | ASTM A213 |
| Tolerance on WT | ±0.02 mm (Precision) / ±0.05 mm (Standard) | ASTM A213 |
| Operating Pressure | Up to 35 MPa (5000 PSI) | ASME B31.3 |
| Operating Temperature Range | −196°C to +1050°C | Grade-dependent |
Manufacturing Process
Process Flow
- Material Selection & Incoming Inspection: Cold-rolled stainless steel strip is sourced from certified mills and subjected to chemical composition analysis (OES), mechanical testing, and visual inspection per ASTM A666.
- Coil Winding (Cold Forming): The strip is precisely wound into helical coil configurations using CNC-controlled coiling machines, ensuring uniform winding pitch and dimensional accuracy.
- Welding (where applicable): Longitudinal welds are performed via Automatic Laser Welding (ALW) or TIG (Tungsten Inert Gas) welding with 100% Argon shielding, followed by internal deburring and weld bead flattening.
- Heat Treatment: Solution annealing at 1010–1150°C in a protective atmosphere (N₂ + H₂ or vacuum) to restore full austenitic microstructure and maximize corrosion resistance.
- Pickling & Passivation: Chemical cleaning using mixed acid (HNO₃ + HF) to remove scale and oxide films, followed by passivation treatment to establish a stable chromium oxide protective layer.
- Dimensional Verification: Full inspection of OD, wall thickness, roundness, and coil diameter using ultrasonic thickness gauging, laser micrometry, and coordinate measuring machines (CMM).
- Non-Destructive Testing (NDT): 100% visual inspection, dye penetrant testing (PT) per ASTM E165, and radiographic testing (RT) per ASTM E94 for critical weld joints.
- Coil Furnace Integration (Oil Well Cooling Application): The finished coil tubes are assembled into cooling furnace modules designed for oil well production systems, incorporating thermal expansion joints, insulation layers, and monitoring instrumentation.
Oil Well Cooling Coil Furnace — Design Rationale
The oil well cooling coil furnace represents a specialized application where stainless steel coil tubes are engineered to manage the thermal load of produced hydrocarbons. The helical coil geometry maximizes heat transfer surface area within a compact footprint, while the austenitic stainless steel construction ensures resistance to thermal cycling, corrosive produced water, and mechanical vibration inherent to wellhead environments.
Applications
- Oil Well Cooling Systems: Primary application in downhole and surface cooling coil furnaces for regulating produced fluid temperature prior to processing and transport.
- Heat Exchangers & Thermal Management: High-efficiency coil wound heat exchangers for refinery, petrochemical, and LNG processing facilities.
- Downhole Instrument Housing: Corrosion-resistant enclosures for downhole temperature and pressure gauges (TDG).
- Chemical Processing: Reaction vessels, condensers, and evaporators in pharmaceutical and food-grade applications.
- Power Generation: Boiler tubes, superheater coils, and condensate return systems in combined cycle power plants.
- Marine & Offshore: Ballast water treatment systems, seawater cooling circuits, and offshore platform piping.
Unique Selling Points
- Integrated Coil Furnace Design: Proprietary engineering experience in oil well cooling coil furnace systems, combining thermal optimization with mechanical robustness.
- Precision Dimensional Control: ±0.02 mm wall thickness tolerance ensures reliable fit-up in high-pressure oilfield assemblies.
- Extended Service Life: Duplex and super-austenitic grade options deliver 3–5× the service life of conventional carbon steel alternatives in sour service environments.
- Full Traceability: Each coil tube is accompanied by a material traceability certificate linking to mill heat numbers, heat treatment records, and NDT reports.
- Custom Engineering: Capability to design and manufacture coil geometries tailored to specific wellhead configurations and thermal load profiles.
Quality Certifications
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health & Safety Management
- API Q1 (Q90 1st Edition) — Quality Management System for Oil & Gas Industry
- NACE MR0175 / ISO 15156 — Materials for use in H₂S-containing environments
- ASME Section IX — Welding qualifications
- EN 10204 3.1 — Third-party inspection certificates available upon request
- CE Marking — Conformity with EU Pressure Equipment Directive (PED 2014/68/EU)
Compliance Standards
| Standard | Title | Applicability |
|---|---|---|
| ASTM A213 | Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for High-temperature Service | Material & Dimensions |
| ASTM A269 | Standard Specification for Austenitic Stainless Steel Welded, Cold-Formed Seamless Tube | Welded Tube Construction |
| EN 10216-5 | Non-alloy and Alloy Steel Tubes for Technical Purposes — Seamless Tubes for High Temperatures | European Conformity |
| ASME B31.3 | Process Piping | Pressure Design & Installation |
| API 5CT | Specification for Casing and Tubing | Oilfield Application Reference |
| GB/T 12771 | Stainless Steel Seamless Tubes for General Purposes | Chinese National Standard |
Conclusion
Wenzhou Jixing Metal Materials Co., Ltd. delivers premium-grade stainless steel coil tubes engineered for the demanding thermal and corrosion environments of oil well cooling systems. Leveraging advanced cold-forming technology, rigorous quality assurance protocols, and deep domain expertise in oilfield thermal management, the company provides solutions that ensure operational reliability, extended asset life, and compliance with international industry standards.