Stainless Steel Coil Tube (盘管) — Truck-Mounted Well Washing Application
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd (温州吉兴金属材料有限公司) | Catalog No.: 1060
1. Product Overview
The Stainless Steel Coil Tube (盘管) produced by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered, continuously wound tubular product designed for demanding industrial applications, particularly in the oil, gas, and geothermal well servicing sector. Unlike conventional straight-length tubing, coil tubes are manufactured in a continuous helical configuration, enabling deployment from compact truck-mounted or skid-mounted equipment without the need for field jointing or threading. This design eliminates connection points that could serve as failure origins under high-pressure, high-temperature (HPHT) conditions, thereby significantly enhancing operational safety and reliability.
The product is specifically optimized for truck-mounted coil tube well washing devices (车装式盘管洗井装置), a field-proven technology for well cleaning, paraffin removal, sand management, and production stimulation in both onshore and offshore environments. The seamless integration of material integrity, geometric precision, and mechanical performance positions this coil tube as a critical component in modern well intervention workflows.
2. Material & Properties
2.1 Alloy Grades
The coil tube is available in a range of austenitic and duplex stainless steel grades selected for superior corrosion resistance, mechanical strength, and fatigue performance:
- ASTM A312 TP304 / TP304L — General-purpose austenitic grade offering excellent weldability and resistance to atmospheric and mild chemical corrosion.
- ASTM A312 TP316 / TP316L — Molybdenum-enhanced austenitic grade providing superior resistance to chlorides, sulfides, and acidic environments commonly encountered in well washing fluids.
- ASTM A312 TP321 / TP347 — Stabilized austenitic grades suitable for elevated-temperature service where intergranular corrosion resistance is critical.
- Duplex 2205 (ASTM A790) — High-strength duplex stainless steel offering a combination of high yield strength (~450 MPa) and exceptional resistance to chloride stress corrosion cracking (SCC).
2.2 Mechanical Properties
- Tensile Strength (UTS): ≥ 515 MPa (304/316); ≥ 620 MPa (Duplex 2205)
- Yield Strength (0.2% offset): ≥ 205 MPa (304/316); ≥ 450 MPa (Duplex 2205)
- Elongation at Break: ≥ 40% (austenitic grades)
- Hardness: ≤ 220 HV (annealed condition)
- Impact Energy (Charpy V-Notch, −40°C): ≥ 47 J (austenitic grades)
2.3 Corrosion Resistance
The material exhibits a minimum Pitting Resistance Equivalent Number (PREN) of 19 for 316L grade and 24 for Duplex 2205, ensuring robust performance in chloride-rich brine solutions, produced water, and chemical well washing agents. The passive chromium oxide film self-heals in the presence of oxygen, providing long-term protection against uniform and localized corrosion.
3. Technical Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (盘管) |
| Catalog No. | 1060 |
| Applicable Standards | ASTM A312, ASTM A790, ASME B36.19M, ISO 13679, GB/T 14976 |
| Outer Diameter (OD) | 12.7 mm – 76.2 mm (½" – 3") |
| Wall Thickness (WT) | 1.5 mm – 6.35 mm (⅛" – ¼") |
| Coil Length | Up to 3,000 m per coil (continuous, jointless) |
| Coil Inner Diameter (CID) | 1,200 mm – 2,500 mm (configurable per truck-mounted reel) |
| Pressure Rating | Up to 25 MPa (3,625 psi) depending on grade and wall thickness |
| Operating Temperature | −196°C to +650°C (austenitic); −196°C to +300°C (duplex) |
| Surface Finish | Pickled & Passivated (P&P), Ra ≤ 0.8 μm; optional electropolished Ra ≤ 0.4 μm |
| End Condition | Plain cut, chamfered, or pre-fitted with quick-connect couplings |
| Manufacturing Method | Seamless (hot-rolled / cold-drawn) or welded (ERW) — seamless preferred for HPHT service |
| Coating / Protection | None (bare stainless); optional PTFE-lined for abrasive slurry service |
| Material Certificates | EN 10204 Type 3.1 mill test certificates per coil |
4. Manufacturing Process
The production of high-quality stainless steel coil tubes follows a rigorous multi-stage manufacturing sequence:
- Raw Material Selection: Virgin stainless steel billets or continuous casting slabs are sourced from certified mills, with chemical composition verified via spectrographic analysis to ensure conformance to ASTM/EN specifications.
- Hot Rolling & Annealing: The raw stock is hot-rolled to approximate dimensions, followed by solution annealing at 1,050–1,150°C (austenitic) or 1,020–1,100°C (duplex) with rapid water quenching to dissolve carbides and restore full corrosion resistance.
- Cold Drawing / Cold Rolling: The annealed tubes are cold-drawn through precision tungsten carbide dies to achieve exact OD and wall thickness tolerances (±0.1 mm OD, ±0.05 mm WT). This process introduces beneficial strain hardening that increases yield strength by 20–40% while maintaining ductility.
- Intermediate Annealing: If cumulative cold work exceeds 40%, intermediate annealing is performed to prevent cracking and restore formability.
- Precision Coiling: The finished tubes are coiled onto precision-engineered reels using hydraulic tension control systems. The coiling tension is carefully managed to prevent ovality, kinking, or permanent deformation, ensuring the tube maintains its circular cross-section throughout the coil length.
- Pickling & Passivation: The coiled tubes undergo acid pickling (HNO₃/HF blend) to remove scale and surface contaminants, followed by passivation to establish a uniform chromium oxide protective layer.
- Non-Destructive Testing (NDT): Every coil undergoes 100% electromagnetic testing (ET) or ultrasonic testing (UT) for internal and external defect detection. Hydrostatic pressure testing at 1.5× the maximum working pressure is performed on each coil.
- Dimensional Inspection: OD, wall thickness, straightness (for cut lengths), and coil geometry are verified using laser profiling and automated measurement systems.
5. Applications
5.1 Well Washing & Well Cleaning
The primary application of this coil tube is in truck-mounted coil tube well washing devices, where the continuous, jointless tubing is deployed into production wells to deliver high-pressure cleaning fluids. The coil tube's inherent flexibility and fatigue resistance allow it to navigate wellbore deviations and negotiate directional changes without kinking or failure. This eliminates the risks associated with threaded or flanged connections that can leak or separate under cyclic loading.
5.2 Additional Industrial Applications
- Oil & Gas Production: Downhole injection of chemical treatment fluids, acidizing, and fracturing stimulation.
- Geothermal Energy: Circulation of working fluids in enhanced geothermal systems (EGS) where corrosion resistance is paramount.
- Chemical Processing: Transfer of aggressive chemicals in pharmaceutical, food, and semiconductor manufacturing.
- Heat Exchangers & Boilers: Coiled tube configurations for compact heat exchange surfaces in power generation and process industries.
- Hydraulic & Pneumatic Systems: High-pressure fluid conveyance in mobile equipment and industrial automation.
- Subsea Operations: Umbilical tubing and flow lines for offshore platform connections.
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and holds the following certifications:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- ISO 45001:2018 — Occupational Health & Safety Management System certification.
- NACE MR0175 / ISO 15156 — Compliance for materials used in sour (H₂S-containing) environments, ensuring resistance to sulfide stress cracking.
- API Spec Q1 / Q2 — Quality management for oil and gas products and services.
- EN 10204 3.1 — Third-party verified material test certificates for each production lot.
- CE Marking — Conformity with European Union regulatory requirements for pressure equipment (PED 2014/68/EU).
7. Unique Selling Points
- Jointless Continuous Design: The coil tube eliminates field connections, reducing leak points and failure risks by up to 95% compared to segmented tubing systems. This is a critical advantage in high-pressure well washing operations where connection integrity directly impacts personnel safety.
- Superior Fatigue Performance: The seamless, cold-drawn construction provides exceptional resistance to cyclic bending and vibration loads inherent in truck-mounted deployment systems, extending service life by 3–5× compared to welded alternatives.
- Truck-Mounted Integration Optimization: The coil geometry and reel dimensions are engineered specifically for integration with truck-mounted and skid-mounted deployment units, enabling rapid mobilization, reduced footprint, and faster well-to-well transit times.
- Grade Flexibility: Availability in multiple stainless steel grades (304, 316, 321, 347, Duplex 2205) allows customers to select the optimal material for their specific chemical environment, temperature range, and pressure requirements.
- End-to-End Traceability: Each coil is accompanied by a full material pedigree, including mill test certificates, heat numbers, chemical analysis reports, mechanical test data, and NDT records, ensuring complete traceability from raw material to final delivery.
- Custom Engineering Support: Wenzhou Jixing provides customized coil configurations, end-fitting solutions, and technical consultation to match specific well geometry and operational parameters.
8. Field Application Reference
The technical performance of this coil tube product is validated by field application research documented in the study "Field Application Research of Truck-Mounted Coil Tube Well Washing Devices" (《车装式盘管洗井装置的现场应用研究》). The research confirms that truck-mounted coil tube well washing systems achieve well cleaning efficiencies exceeding 90% with significantly reduced operational time and enhanced safety margins compared to conventional workover methods. The continuous tubing design demonstrated zero connection-related failures during extended field trials, validating the product's reliability in demanding downhole conditions.