Stainless Steel Coil Tube (Coiltube) — Oil Field Heater Application
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
Product Category: Stainless Steel Coil Tube / Coiltube (盘管)
Reference Document: "Research and Application of Anti-Scale Technology for Oil Field Heater Coil Tubes" — Technical Learning and Application Report
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) produced by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular component specifically designed for high-temperature oil field heater applications. These coil tubes are formed into helical or serpentine configurations and are utilized as heat transfer elements within oil field heating furnaces (油田加热炉), where they facilitate the thermal processing of crude oil and related hydrocarbon fluids.
Coil tubes in oil field heaters are subjected to extreme operating conditions, including sustained high temperatures, thermal cycling, corrosive media exposure, and the formation of inorganic scale deposits. The integration of advanced anti-scale technology (防垢技术) into the design and material selection of these coil tubes represents a critical engineering advancement that significantly extends service life, improves thermal efficiency, and reduces maintenance downtime in upstream oil production operations.
This product line leverages Wenzhou Jixing Metal Materials Co., Ltd.'s expertise in stainless steel metallurgy and precision tube forming to deliver coil tubes that meet the rigorous demands of oil field thermal processing environments.
2. Material & Properties
2.1 Base Materials
The coil tubes are manufactured from high-grade austenitic stainless steel grades, selected for their superior corrosion resistance, high-temperature strength, and resistance to scale formation. Commonly utilized grades include:
- 304 Stainless Steel (UNS S30408 / AISI 304): General-purpose austenitic stainless steel with excellent oxidation resistance up to 870°C (1600°F). Contains approximately 18% Chromium (Cr) and 8% Nickel (Ni).
- 316 Stainless Steel (UNS S31608 / AISI 316): Enhanced corrosion resistance due to the addition of 2–3% Molybdenum (Mo), making it suitable for environments containing chlorides or sulfides commonly found in oil field applications.
- 310S Stainless Steel (UNS S31008 / AISI 310S): High-temperature austenitic grade with 25% Cr and 19% Ni, providing exceptional resistance to oxidation and thermal cycling at temperatures exceeding 1093°C (2000°F).
- 321 Stainless Steel (UNS S32108 / AISI 321): Titanium-stabilized austenitic stainless steel, resistant to intergranular corrosion (敏化) and suitable for sustained high-temperature service.
2.2 Key Material Properties
| Property | Specification / Typical Value |
|---|---|
| Chromium (Cr) Content | ≥ 17% (304/316); ≥ 24% (310S); ≥ 18% (321) |
| Nickel (Ni) Content | ≥ 8% (304/316); ≥ 19% (310S); ≥ 9% (321) |
| Molybdenum (Mo) Content | 2–3% (316 grade only) |
| Tensile Strength (UTS) | ≥ 520 MPa (75,000 psi) at room temperature |
| Yield Strength (0.2% Offset) | ≥ 205 MPa (30,000 psi) |
| Elongation | ≥ 40% (minimum) |
| Operating Temperature Range | −196°C to +1100°C (−321°F to +2012°F), grade-dependent |
| Thermal Expansion Coefficient | 16–18 × 10⁻⁶ /°C (20–1000°C) |
| Thermal Conductivity | 16.3 W/(m·K) at 100°C (304 grade) |
2.3 Anti-Scale Performance
The coil tubes incorporate advanced anti-scale technology (防垢技术) through the following mechanisms:
- Surface Passivation: A stable chromium oxide (Cr₂O₃) passive film forms naturally on the stainless steel surface, providing a barrier against scale nucleation and adhesion.
- Surface Treatment: Electropolishing (电化学抛光) or chemical passivation treatments are applied to achieve a surface roughness (Ra) of ≤ 0.4 μm, minimizing sites for scale attachment.
- Internal Coating Options: Optional ceramic or polymeric internal coatings can be applied to further inhibit scale formation (结垢) in aggressive chemical environments.
- Hydrodynamic Design: The coil geometry is engineered to maintain turbulent flow (湍流) conditions, reducing boundary layer thickness and inhibiting scale deposition.
3. Specifications
| Parameter | Specification |
|---|---|
| Product Type | Stainless Steel Coil Tube / Coiltube (盘管) |
| Available Outer Diameter (OD) | Φ19 mm – Φ89 mm (customizable) |
| Available Wall Thickness | 0.5 mm – 6.0 mm (customizable) |
| Coil Pitch (螺旋间距) | Custom; typically 25 mm – 150 mm |
| Coil Diameter | Custom; typically 200 mm – 1200 mm |
| Tube Length (per coil) | Up to 120 m (continuous forming capability) |
| Material Grades | 304, 304L, 316, 316L, 310S, 321, 347, 904L |
| Surface Finish | 2B, BA (Bright Annealed), Electropolished, Custom Ra values |
| End Preparation | Plain, Beveled, Threaded, Flanged (per customer specification) |
| Heat Treatment | Solution Annealing (固溶处理) at 1010–1150°C followed by water quench |
| Applicable Standards | ASTM A213, ASTM A269, ASME SA-213, GB/T 12771, EN 10216-5 |
| Maximum Design Pressure | Up to 10 MPa (1450 psi), grade and geometry dependent |
| Maximum Operating Temperature | Up to 1100°C (2012°F) for 310S grade |
4. Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous, multi-stage manufacturing process:
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Raw Material Selection & Inspection:
Stainless steel seamless tubes or welded tubes conforming to ASTM or ASME standards are procured and subjected to incoming quality inspection, including chemical composition analysis (光谱分析), mechanical testing, and dimensional verification.
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Precision Coiling (精密盘绕):
Flat or tubular stock is cold-formed or hot-formed into the required helical coil geometry using CNC-controlled coiling machines. The process ensures consistent coil pitch, diameter, and dimensional accuracy within ±0.5 mm tolerance.
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Welding (if applicable):
For welded coil tubes, longitudinal seams are joined using Automatic Submerged Arc Welding (SAW) or Gas Metal Arc Welding (GMAW). Weld quality is verified through radiographic testing (RT, 射线检测) or ultrasonic testing (UT, 超声波检测).
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Solution Annealing (固溶热处理):
The formed coil tubes are heated to 1010–1150°C and rapidly quenched in water to dissolve carbides, restore full austenitic structure, and achieve maximum corrosion resistance.
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Pickling & Passivation (酸洗钝化):
Post-annealing, the coil tubes are pickled in a nitric-hydrofluoric acid mixture to remove oxide scale, followed by passivation to restore and enhance the protective chromium oxide passive film.
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Anti-Scale Surface Treatment:
Electropolishing or specialized chemical treatment is applied to achieve ultra-low surface roughness and enhanced anti-scale performance, as validated by the research documented in the referenced technical study.
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Quality Control & Testing:
Each coil tube batch undergoes comprehensive testing including dimensional inspection, hydrostatic pressure testing (水压试验), and non-destructive testing (NDT) to ensure compliance with specified standards.
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Packaging & Delivery:
Finished coil tubes are carefully packaged to prevent mechanical damage and corrosion during transit, with accompanying material test certificates (MTC) and quality documentation.
5. Applications
The Stainless Steel Coil Tubes from Wenzhou Jixing Metal Materials Co., Ltd. are deployed in a wide range of industrial applications, with particular emphasis on oil field thermal processing:
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Oil Field Heater Furnaces (油田加热炉):
Primary application — coil tubes serve as heating elements for crude oil preheating, viscosity reduction, and flow assurance in upstream production facilities. The anti-scale technology significantly extends service intervals between maintenance shutdowns.
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Refinery Heat Exchangers:
Used as tube bundles in shell-and-tube heat exchangers for process heating and cooling in petroleum refining operations.
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Chemical Processing:
Coil tubes are employed in chemical reactors, evaporators, and condensers where resistance to aggressive chemical media is required.
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Power Generation:
Applied in superheater and reheater sections of boilers, as well as in waste heat recovery systems.
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Food & Pharmaceutical Industry:
Used in heat exchangers, pasteurizers, and sterilizers where sanitary-grade stainless steel coil tubes are mandated.
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Marine & Offshore Platforms:
Deployed in desalination systems, heating loops, and process equipment on offshore oil and gas platforms.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and certifications ensuring that all stainless steel coil tube products meet international standards:
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System certification ensuring consistent product quality and process control |
| ISO 14001:2015 | Environmental Management System certification for sustainable manufacturing practices |
| ISO 45001:2018 | Occupational Health and Safety Management System |
| ASTM A213 / ASME SA-213 | Standard specification for austenitic stainless steel seamless, cold-drawn tubing for high-temperature service |
| ASTM A269 / ASME SA-269 | Standard specification for austenitic stainless steel welded, cold-formed or seamless tubing and pipe for chemical and similar severe service |
| EN 10216-5 | European standard for welded austenitic stainless steel tubes for heat exchange and general heat transfer purposes |
| GB/T 12771 | Chinese national standard for stainless steel welded tubes for general application |
| API 5CT (where applicable) | American Petroleum Institute specification for casing and tubing (for oil field specific applications) |
Every production batch is accompanied by a Material Test Certificate (MTC) conforming to EN 10204 3.1 or 3.2 requirements, providing full traceability of chemical composition, mechanical properties, heat treatment records, and non-destructive testing results.
7. Unique Selling Points
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Advanced Anti-Scale Technology Integration:
Incorporating research-backed anti-scale solutions (防垢技术) derived from field-proven studies on oil field heater coil tubes, resulting in significantly reduced scale accumulation rates and extended operational intervals.
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Custom Engineering Capability:
Full customization of coil geometry (pitch, diameter, length), material grade, surface finish, and end preparation to match specific customer application requirements.
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High-Temperature Performance:
Grade 310S coil tubes deliver reliable performance at sustained temperatures up to 1100°C, making them suitable for the most demanding thermal processing environments.
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