Stainless Steel Heat Extraction Coil Tube — Model JX-CT Series
Product Overview
The JX-CT Series Stainless Steel Heat Extraction Coil Tube, manufactured by Wenzhou Jixing Metal Materials Co., Ltd., is a precision-engineered coiled piping product designed for high-temperature, high-pressure heat transfer applications in petrochemical refining and industrial process plants. The coil tube is formed by cold-bending or hot-forming continuous lengths of seamless stainless steel pipe into tightly wound helical configurations, optimizing thermal exchange surface area within compact spatial envelopes. This product line has been validated through rigorous field deployment at major refinery facilities, including heat extraction service in catalytic reforming and fluid catalytic cracking (FCC) units.
The fundamental design philosophy of the JX-CT coil tube addresses the critical challenge of extracting process heat from high-temperature streams while maintaining structural integrity under thermal cycling, mechanical vibration, and aggressive chemical environments. The helical geometry promotes turbulent flow characteristics, enhancing convective heat transfer coefficients by 30–50% compared to equivalent straight-pipe configurations.
Material & Properties
The JX-CT Series coil tubes are available in multiple stainless steel grades selected to match specific service conditions:
- ASTM A312 TP304 / TP304L — General-purpose austenitic stainless steel offering excellent corrosion resistance in oxidizing environments, suitable for temperatures up to 870 °C.
- ASTM A312 TP316 / TP316L — Molybdenum-bearing austenitic grade providing superior resistance to pitting and crevice corrosion in chloride-containing refinery streams, service temperature up to 870 °C.
- ASTM A312 TP321 / TP321H — Titanium-stabilized austenitic grade resistant to intergranular corrosion and thermal embrittlement, recommended for sustained service above 450 °C.
- ASTM A312 TP310 / TP310H — High-chromium, high-nickel austenitic grade for extreme-temperature heat extraction service exceeding 900 °C with outstanding oxidation resistance.
- ASTM A312 TP347H — Niobium-stabilized grade offering enhanced creep strength for prolonged high-temperature service in reformer and furnace applications.
Key mechanical properties at room temperature (representative values for TP316L seamless tube):
- Tensile Strength (UTS): ≥ 485 MPa (70 ksi)
- Yield Strength (0.2% offset): ≥ 205 MPa (30 ksi)
- Elongation (minimum): 40%
- Hardness (Brinell): ≤ 217 HB
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Outer Diameter (OD) | 12.7 mm – 159.1 mm (½" – 6") | ASTM A53 / ASME B36.19M |
| Wall Thickness | 1.5 mm – 12.7 mm (5/16" – ½") | ASME B36.19M |
| Coil Mean Diameter (CMD) | 300 mm – 3,000 mm | Custom / Customer-Specified |
| Coil Length (Straight Equivalent) | Up to 60 m per coil | — |
| Helix Pitch | 50 mm – 250 mm | Custom / Process-Defined |
| Number of Turns | 10 – 200 turns | Custom / Process-Defined |
| Bend Radius (Minimum) | 3D (D = Outer Diameter) | ASME B31.3 |
| Surface Finish (Internal) | Ra ≤ 0.8 μm (Electro-polished available: Ra ≤ 0.25 μm) | ASTM A269 / ASME BPE |
| Surface Finish (External) | Milled / Pickled & Passivated | ASTM A967 |
| Operating Temperature Range | −196 °C to +1,100 °C (grade-dependent) | ASME BPV Code Section VIII |
| Maximum Operating Pressure | Up to 35 MPa (5075 psi) | ASME B31.3 / EN 13480 |
| Heat Treatment | Solution Annealed (1050–1150 °C, water quench) | ASTM A312 |
| End Preparation | Plain / Beveled (ASME B16.25) / Threaded (NPT/BSP) | ASME B16.25 / ASME B1.20.1 |
| Welding Compatibility | GTAW / SBWT / Orbital TIG — autogenous or matching filler | ASME IX / EN ISO 13919 |
| Applicable Codes | ASME B31.3, EN 13480, GB/T 21832, NACE MR0175 | — |
Manufacturing Process
The production of JX-CT Series coil tubes follows a multi-stage, quality-controlled manufacturing sequence:
- Material Receiving & Verification — Incoming seamless stainless steel pipe is verified against mill test certificates (MTC, EN 10204 Type 3.1). Chemical composition is confirmed by optical emission spectrometry (OES); grain size and microstructure are examined per ASTM E112.
- Dimensional Inspection & Preparation — Pipe dimensions (OD, wall thickness, straightness) are measured using laser calipers and ultrasonic thickness gauges. Ends are prepared and deburred to specification.
- Coil Forming (Cold Bending or Hot Forming) — Cold bending is employed for coils with mean diameters ≥ 6D using CNC-controlled mandrel bending machines to prevent cross-sectional ovality. Hot forming is utilized for tight-radius configurations (CMD < 6D) with controlled interpass temperatures to avoid strain-induced martensitic transformation in metastable austenitic grades.
- Ovality & Geometric Control — Post-forming ovality is measured at multiple stations and maintained within 2% of nominal OD (per ASTM A312 tolerance). The coil pitch and turn-to-turn spacing are verified by coordinate measurement.
- Solution Heat Treatment (if required) — For coils subjected to significant cold work or hot forming, solution annealing is performed at 1050–1150 °C in a protective atmosphere furnace followed by controlled cooling to restore full austenitic microstructure and eliminate residual stresses.
- Pickling & Passivation — The coil is treated with a citric acid or nitric acid-based pickling solution to remove scale and oxidation, followed by passivation per ASTM A967 to establish a protective chromium oxide film (≥ 12% Cr surface enrichment verified by XRF).
- Final Inspection & Testing — Each coil undergoes visual inspection, dimensional verification, and hydrostatic pressure testing at 1.5× design pressure (per ASME B31.3). Non-destructive testing (eddy current per ASTM E309 or ultrasonic per ASTM E164) is performed on weld seams and critical regions.
- Packaging & Dispatch — Coils are wrapped in moisture-barrier film, placed in protective wooden or steel cradles, and shipped with full documentation including MTC, dimensional certificates, and NDT reports.
Applications
The JX-CT Series stainless steel heat extraction coil tubes are deployed in demanding thermal service across multiple industries:
- Petrochemical Refining — Heat extraction coils in catalytic reformer effluent coolers, FCC regenerator convection zones, delayed coker transfer lines, and hydrotreater high-pressure separators. The Lanzhou Refinery heat extraction coil tube application demonstrates proven performance in extracting process heat from hydrocarbon streams at temperatures exceeding 550 °C under sustained pressure.
- Steam-Generating Supercritical Units (SGSC) — Integral heat exchanger coils within steam drums for waste heat recovery in refinery gas recovery systems.
- Crude Oil Distillation Units (CDU) — Overhead line heat exchangers and vacuum distillation column thermosiphon coils.
- Chemical Processing — Reactor jacket coils and internal heat transfer elements in polymerization reactors, chlor-alkali processes, and specialty chemical synthesis.
- Power Generation — Waste heat boiler (WHEB) coil tubes in combined cycle power plants and industrial cogeneration systems.
- Food & Pharmaceutical — Sanitary-grade coil heat exchangers for pasteurization, sterilization (CIP/SIP), and thermal processing under FDA/3-A compliance requirements.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and compliance credentials:
- ISO 9001:2015 — Quality Management System certification covering design, manufacturing, and supply of stainless steel coil tubes.
- ISO 14001:2015 — Environmental Management System certification for environmentally responsible manufacturing practices.
- ISO 45001:2018 — Occupational Health & Safety Management System.
- ASME "S" Stamp — Authorized Manufacturer for pressure vessels and components (where applicable).
- NACE MR0175 / ISO 15156 — Compliance for sour service applications involving hydrogen sulfide environments.
- EN 10204 Type 3.1 — Third-party inspection and testing certificates for all production batches.
- API 5L / API 5CT — Material traceability and testing per American Petroleum Institute standards for refinery service.
- CE Marking (PED 2014/68/EU) — Conformity with European Pressure Equipment Directive for export applications.
Unique Selling Points
- Field-Validated Performance — The JX-CT coil tube design philosophy has been validated through comprehensive governance and optimization programs at major Chinese refineries, including the Lanzhou Refinery heat extraction coil tube remediation project, ensuring reliability under the most demanding process conditions.
- Customizable Geometry — Full parametric customization of coil mean diameter, pitch, number of turns, and end configurations to match specific process heat duty and spatial constraints.
- Wide Grade Selection — Availability across five primary austenitic stainless steel grades covering service temperatures from cryogenic to 1,100 °C, enabling optimal material-to-service matching.
- Precision Ovality Control — Proprietary CNC bending technology ensures cross-sectional ovality within 2%, maintaining uniform flow distribution and preventing localized stress concentrations at bend apexes.
- Full Traceability — Each coil tube is traceable to its original mill heat number with complete chemical, mechanical, and NDT documentation per EN 10204 Type 3.1.
- Integrated Surface Engineering — Option for internal electro-polishing to Ra ≤ 0.25 μm for sanitary applications, or external ceramic/plasma spray coatings for enhanced oxidation resistance in extreme-temperature service.
- Engineering Support — Dedicated technical engineering team provides thermal-hydraulic simulation (CFD), stress analysis (FEA per ASME B31.3), and fatigue life assessment for custom coil tube designs.
Note: All specifications listed are representative. Actual dimensions, tolerances, and material grades shall be confirmed through a formal purchase order and engineering agreement between the purchaser and Wenzhou Jixing Metal Materials Co., Ltd. The manufacturer reserves the right to modify specifications with prior notification where improvements in quality or compliance are achieved.