Stainless Steel Internal Heat Extraction Coil Tube (盘管 Coiltube)
1. Product Overview
The Stainless Steel Internal Heat Extraction Coil Tube (盘管 Coiltube, Catalog No. 1617) is a precision-engineered coiled piping component manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Specifically designed for internal heat exchange and thermal extraction applications, this coil tube is formed from high-grade austenitic stainless steel wire or seamless tube stock through advanced cold-drawing and coiling processes. The product serves as a critical component in heat exchangers, reactors, and thermal management systems where efficient heat transfer within confined internal geometries is paramount.
Internal heat extraction coils (内取热盘管) represent a specialized subset of coil tubes engineered to maximize surface-area-to-volume ratios within enclosed vessel configurations. These coils are integral to processes requiring precise temperature control, including chemical reactors, cryogenic systems, and industrial heat recovery units. The manufacturing and installation of such coils demand rigorous adherence to dimensional tolerances, material purity standards, and mechanical integrity requirements.
2. Material & Properties
2.1 Base Material Composition
The coil tube is fabricated from austenitic stainless steel conforming to recognized international standards. The primary material grades utilized include:
- SUS304 / AISI 304 / 06Cr19Ni10 — General-purpose corrosion-resistant grade with excellent formability
- SUS316L / AISI 316L / 022Cr17Ni12Mo2 — Enhanced molybdenum alloy for superior resistance to pitting and crevice corrosion
- SUS321 / AISI 321 / 06Cr18Ni11Ti — Titanium-stabilized grade for elevated-temperature service
- SUS310S / AISI 310S / 06Cr25Ni20 — High-temperature grade for extreme thermal environments
2.2 Mechanical Properties
| Property | SUS304 | SUS316L | SUS321 | SUS310S |
|---|---|---|---|---|
| Tensile Strength (抗拉强度), MPa (Min.) | 520 | 485 | 515 | 515 |
| Yield Strength (屈服强度), MPa (Min.) | 205 | 170 | 205 | 205 |
| Elongation (延伸率), % (Min.) | 40 | 45 | 40 | 40 |
| Operating Temperature Range (使用温度范围), °C | −196 to +870 | −196 to +870 | −196 to +1000 | −196 to +1150 |
| Thermal Conductivity (热导率), W/(m·K) at 20°C | 16.3 | 14.6 | 16.3 | 21.5 |
| Corrosion Resistance (耐腐蚀性) | Excellent | Superior (Molybdenum-enhanced) | Excellent (Ti-stabilized) | Outstanding (High-temperature) |
2.3 Chemical Composition (Typical, wt%)
| Element | C (Carbon) | Cr (Chromium) | Ni (Nickel) | Mn (Manganese) | Mo (Molybdenum) | Ti (Titanium) |
|---|---|---|---|---|---|---|
| SUS304 | ≤0.08 | 18.0–20.0 | 8.0–10.5 | ≤2.0 | — | — |
| SUS316L | ≤0.03 | 16.5–18.5 | 10.0–14.0 | ≤2.0 | 2.0–3.0 | — |
| SUS321 | ≤0.08 | 17.0–19.0 | 9.0–12.0 | ≤2.0 | — | 5×(C−0.02)–0.70 |
| SUS310S | ≤0.08 | 24.0–26.0 | 19.0–22.0 | ≤2.0 | — | — |
3. Specifications
3.1 Geometric Dimensions
| Parameter | Specification Range | Unit | Tolerance |
|---|---|---|---|
| Outer Diameter (外径) of Coil Tube | 6.0 – 32.0 | mm | ±0.15 |
| Wall Thickness (壁厚) | 0.5 – 3.0 | mm | ±10% |
| Coil Pitch (盘管节距) | 12.0 – 60.0 | mm | ±0.5 |
| Coil Diameter (盘管外径) | 150 – 1500 | mm | ±2.0 |
| Number of Turns (圈数) | 20 – 500+ | turns | ±1 |
| Total Coil Length (盘管总长) | 5 – 200 | m | — |
| Minimum Bending Radius (最小弯曲半径) | ≥ 3D | — | — |
| Surface Finish (表面光洁度) | Ra ≤ 0.8 (polished) / Ra ≤ 1.6 (standard) | μm | — |
| End Treatment (端部处理) | Flat cut / Threaded / Flanged / Beveled | — | — |
3.2 Performance Parameters
| Performance Indicator | Specification |
|---|---|
| Maximum Working Pressure (最大工作压力) | Up to 6.4 MPa (64 bar) |
| Hydrostatic Test Pressure (水压试验压力) | 1.5× Working Pressure |
| Heat Transfer Coefficient (传热系数) | 2000 – 15000 W/(m²·K) (depending on flow conditions) |
| Flow Velocity Range (流速范围) | 1.0 – 4.0 m/s (turbulent flow regime) |
| Pressure Drop per Unit Length (单位长度压降) | 0.5 – 5.0 kPa/m |
| Design Life (设计寿命) | ≥ 15 years (industrial service) |
4. Manufacturing Process
The manufacturing of internal heat extraction coil tubes follows a rigorous, multi-stage production workflow designed to ensure dimensional accuracy, metallurgical integrity, and surface quality. The process integrates traditional metal forming techniques with modern precision engineering controls:
4.1 Production Workflow
- Raw Material Inspection (原材料检验) — Incoming stainless steel wire or seamless tube is verified against mill test certificates (MTC/EN 10204 3.1), with spectroscopic analysis confirming chemical composition compliance.
- Pre-treatment & Annealing (预处理与退火) — Material is stress-relieved through controlled annealing (1050–1100°C) to achieve the desired austenitic microstructure and optimize cold-formability.
- Cold Drawing / Pipe Forming (冷拉拔/管材成型) — Stainless steel wire is cold-drawn through precision dies to achieve target outer diameter and wall thickness with tight tolerances. Alternatively, seamless tubes are drawn and calibrated.
- Coil Forming (盘管成型) — The formed tube is wound onto precision mandrels using CNC-controlled coiling machines. The coil pitch, diameter, and number of turns are programmatically controlled to meet exact specifications. Minimum bending radius of 3D is maintained to prevent wall thinning or ovality deformation.
- Welding (焊接) — Where continuous coils are required, tube segments are joined using Automatic Orbital TIG Welding (自动轨道TIG焊) with argon shielding. Weld quality is verified through visual inspection (VT) and, where required, radiographic testing (RT) or dye penetrant testing (PT).
- Post-forming Heat Treatment (成型后热处理) — Coils undergo solution annealing (固溶处理) at 1050–1100°C followed by rapid water quenching to restore full austenitic structure, eliminate residual stresses, and maximize corrosion resistance.
- Surface Finishing (表面处理) — Pickling and passivation (酸洗钝化) removes oxide scale and forms a protective chromium oxide layer. Optional polishing or electropolishing achieves mirror-finish surfaces (Ra ≤ 0.4 μm) for pharmaceutical or food-grade applications.
- Quality Inspection & Testing (质量检验与测试) — Comprehensive dimensional verification (caliper, micrometer, coordinate measuring machine), pressure testing, and material certification are performed prior to packaging.
- Packaging & Shipping (包装与运输) — Coils are wrapped in protective film, placed on wooden pallets or crates, and labeled with full traceability documentation.
4.2 Key Manufacturing Technologies
- Programmatic Coiling Control — CNC coiling systems ensure repeatable coil geometry with pitch variation ≤ ±0.5 mm across the entire coil length.
- Orbital TIG Welding (轨道TIG焊) — Automated welding with pulsed arc parameters produces weld beads with uniform penetration, minimal heat-affected zone (HAZ), and cosmetic quality suitable for food/pharma standards.
- Induction Heating Annealing — Localized heat treatment minimizes thermal distortion while achieving complete solution treatment of the coil.
- Online Dimensional Monitoring — Real-time laser displacement sensors monitor outer diameter and wall thickness during coiling, triggering automatic process adjustments for deviation correction.
5. Applications
Internal heat extraction coil tubes manufactured by Wenzhou Jixing Metal Materials Co., Ltd. find extensive application across multiple high-demand industries:
5.1 Primary Application Sectors
- Chemical & Petrochemical Industry (化工与石化行业) — Reactor internal coils for exothermic reaction temperature control, distillation column heat exchangers, and process fluid heating/cooling systems.
- Power Generation (发电) — Steam generator tubes, economizer coils, and condenser internal heat exchangers in thermal power plants.
- Pharmaceutical & Food Processing (制药与食品加工) — Sterilization heat exchangers, pasteurization coils, and CIP (Clean-in-Place) compatible heat transfer systems requiring hygienic-grade surfaces.
- Oil & Gas (石油与天然气) — Subsea heat exchangers, gas heater coils, and cryogenic process cooling systems.
- Heat Recovery Systems (余热回收系统) — Exhaust gas heat recovery coils, waste heat boiler internals, and thermal energy storage components.
- Refrigeration & Air Conditioning (制冷与空调) — Evaporator and condenser coils for industrial refrigeration systems and HVAC applications.
- Energy Storage (储能) — Thermal energy storage tank internal coils for concentrated solar power (CSP) and industrial waste heat utilization.
5.2 Typical Installation Configurations
- Horizontal Coil Installation (水平盘管安装) — Coils are mounted horizontally within vessel internals with support saddles at calculated intervals to prevent vibration-induced fatigue.
- Vertical Coil Installation (垂直盘管安装)