Stainless Steel Coil Tube (盘管) — Wenzhou Jixing Metal Materials Co., Ltd

Product Overview

The Stainless Steel Coil Tube (Product No. 1268) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered, helically wound tubular component designed for high-performance thermal exchange, chemical processing, and pipeline conveying systems. Unlike conventional straight-length tubing, the coil tube configuration maximizes surface area within a compact volumetric footprint, making it an indispensable component in heat exchangers, condensers, evaporators, and continuous conveyor pipeline systems.

This product line draws upon advanced mechanical analysis methodologies, particularly the Mechanical Analysis of the Straight Section in a Series-Coil Pipeline Continuous Conveyor, which provides critical insights into stress distribution, bending moment behavior, and fatigue life under cyclic loading conditions. The result is a coil tube product that delivers superior structural integrity and extended operational lifespan even in demanding industrial environments.

Material & Properties

The coil tube is fabricated from high-grade austenitic stainless steel, selected for its exceptional corrosion resistance, mechanical strength, and thermal stability. The primary material grades include:

• 304 Stainless Steel (UNS S30400) — General-purpose grade offering excellent resistance to atmospheric, chemical, and food-grade environments. Chromium content of 18–20% and nickel content of 8–10.5% provide robust passive film formation.
• 316 Stainless Steel (UNS S31600) — Enhanced molybdenum (2–3%) content confers superior resistance to pitting and crevice corrosion, particularly in chloride-rich and marine environments.
• 321 Stainless Steel (UNS S32100) — Titanium-stabilized grade suitable for high-temperature applications (up to 870°C) where intergranular corrosion resistance is critical.

Key Material Properties:

• Tensile Strength: ≥ 520 MPa (304), ≥ 515 MPa (316)
• Yield Strength: ≥ 205 MPa
• Corrosion Resistance: Equivalent to ASTM A270/A269 standards
• Operating Temperature Range: −196°C to +870°C (grade dependent)
• Surface Finish: Electropolished or passivated, Ra ≤ 0.4 μm
• Non-Magnetic: Austenitic structure (low residual magnetism after cold working)

Specifications

Parameter	Specification / Range
Product No.	1268
Product Name	Stainless Steel Coil Tube (盘管)
Material Grades	304, 304L, 316, 316L, 321, 310S, 904L, Duplex 2205
Outer Diameter (OD)	Φ3.0 mm – Φ50.0 mm
Wall Thickness	0.3 mm – 3.0 mm
Coil Diameter	Φ100 mm – Φ1200 mm
Coil Length	5 m – 200 m (continuous or custom)
Coil Pitch	1.5× OD – 5× OD (customizable)
Number of Turns	10 – 500 turns
Tolerance on OD	±0.05 mm (precision grade), ±0.1 mm (standard)
Tolerance on Wall Thickness	±10% of nominal
Surface Finish	Bright Annealed, Electropolished, Passivated, Matte
End Preparation	Plain cut, Beveled, Threaded, Flanged, Welded-in
Winding Direction	Left-hand (LH), Right-hand (RH), Double-wound
Applicable Standards	ASTM A269, ASTM A270, GB/T 12771, EN 10216-5, ASME B31.3
Maximum Operating Pressure	Up to 25 MPa (design dependent)
Delivery Condition	Coiled on wooden reel, shrink-wrapped, palletized

Manufacturing Process

The production of the Wenzhou Jixing Stainless Steel Coil Tube follows a rigorous, multi-stage manufacturing protocol to ensure dimensional accuracy, metallurgical integrity, and surface quality:

1. Raw Material Selection & Inspection:

   Virgin stainless steel coil stock is procured from certified mills and subjected to spectrographic analysis (OES) to verify chemical composition. Incoming material is inspected for surface defects, dimensional conformity, and mill certificates (EN 10204 Type 3.1).

2. Coil Straightening & Cutting:

   The stainless steel coil is fed through a precision straightening machine to eliminate residual curvature and stress. Lengths are cut to specified dimensions using high-speed shearing or laser cutting to ensure clean, burr-free edges.

3. Tube Forming & Seamless Drawing:

   For seamless tubes, the drawn tube method is employed where a mandrel is drawn through the coil stock, forming a continuous tube of uniform wall thickness. Alternatively, welded tube production utilizes high-frequency induction welding (HFW) with in-line seam inspection.

4. Precision Winding (Coiling):

   The formed tube is helically wound around a precision-machined mandrel using a CNC-controlled winding machine. The winding parameters — pitch, diameter, tension, and number of turns — are programmatically controlled to achieve exact geometric specifications. This stage is critical, as the winding process introduces residual bending stresses that must be carefully managed.

5. Stress Relief Annealing:

   The coiled tube assembly undergoes solution annealing in a protective atmosphere furnace (typically nitrogen or vacuum) at temperatures between 1050°C and 1150°C, followed by controlled cooling. This process eliminates residual stresses introduced during winding, restores full austenitic grain structure, and enhances corrosion resistance.

6. Mechanical Stress Analysis & Validation:

   Informed by the Mechanical Analysis of the Straight Section in a Series-Coil Pipeline Continuous Conveyor, each coil tube design undergoes finite element analysis (FEA) to evaluate bending moments, shear forces, and stress concentrations at the coil-to-straight transitions. This ensures the product meets fatigue life requirements under continuous conveying loads.

7. Surface Treatment & Finishing:

   The tube surface is cleaned via pickling and passivation (acid bath or electrolytic cleaning) to remove oxide scale and contaminants. Electropolishing may be applied for critical applications requiring Ra ≤ 0.4 μm surface roughness, such as pharmaceutical and food processing.

8. Quality Inspection & Testing:

   Comprehensive inspection includes dimensional measurement (OD, wall thickness, coil diameter), hydrostatic pressure testing, eddy current flaw detection, and visual examination of weld seams. Sampling is conducted in accordance with ASTM E1417 and EN 10228 standards.

9. Packaging & Dispatch:

   Finished coil tubes are mounted on export-grade wooden reels, protected with anti-corrosion wrapping, and palletized for shipment. Each unit is accompanied by a full material traceability certificate and test report.

Applications

The Wenzhou Jixing Stainless Steel Coil Tube finds extensive application across multiple high-demand industrial sectors:

• Heat Exchangers & Thermal Systems:

  Spiral-wound coil tubes serve as the primary heat transfer element in shell-and-coil heat exchangers, air coolers, condensers, and evaporators. The compact coil geometry provides high surface-area-to-volume ratios, enabling efficient thermal exchange in space-constrained installations.

• Pipeline Conveying Systems:

  As analyzed in the referenced mechanical study, coil tubes are integral components in series-coil pipeline continuous conveyors used in chemical plants, mining operations, and material handling systems. The coil configuration accommodates thermal expansion and mechanical vibration while maintaining structural continuity.

• Chemical Processing & Petrochemical Industry:

  316 and 316L grade coil tubes are employed in corrosive fluid handling, reactor cooling circuits, distillation columns, and acid storage systems where resistance to chlorides and sulfides is paramount.

• Food & Beverage Processing:

  Electropolished 304L coil tubes meet FDA and 3-A sanitary standards for use in dairy pasteurizers, beverage chillers, brewing equipment, and pharmaceutical CIP (Clean-in-Place) systems.

• Pharmaceutical & Biotechnology:

  Ultra-clean coil tubes with Ra ≤ 0.25 μm surface finish are used in sterile fluid transfer, bioreactor temperature control, and chromatography systems.

• Power Generation:

  Coil tubes are utilized in boiler feedwater heaters, turbine exhaust condensers, and nuclear cooling circuits where reliable performance under high temperature and pressure is essential.

• Automotive & Aerospace:

  Precision-wound stainless steel coil tubes serve as fuel lines, hydraulic circuits, and thermal management components in high-performance vehicles and aerospace applications.

• Oil & Gas Industry:

  Subsea coil tubing and downhole heat exchanger coils operate under extreme pressure and temperature conditions in offshore drilling and production platforms.

Quality Certifications

Wenzhou Jixing Metal Materials Co., Ltd maintains rigorous quality management systems and holds the following certifications and compliance credentials:

• ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and continuous improvement.
• ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
• ISO 45001:2018 — Occupational Health and Safety Management System certification.
• CE Marking — Conformity with European Union directives for pressure equipment (PED 2014/68/EU) and machinery safety.
• ASME / ASME Section IX — Welding procedure qualification in accordance with American Society of Mechanical Engineers standards.
• EN 10204 Type 3.1 — Inspection certificates issued by an authorized inspection representative confirming material compliance.
• Mill Test Certificates (MTC) — Full chemical and mechanical property verification for every batch of raw material and finished product.
• NACE MR0175 / ISO 15156 — Compliance with resistance to sulfide stress cracking for oil and gas applications.
• Third-Party Inspection — Available upon request from recognized bodies including SGS, Bureau Veritas, and TÜV.

Unique Selling Points

The Wenzhou Jixing Stainless Steel Coil Tube distinguishes itself through a combination of advanced engineering analysis, precision manufacturing, and comprehensive quality assurance:

• Engineering-Validated Design:

  Product designs are informed by rigorous mechanical analysis of coil-to-straight transition zones in continuous conveyor systems, ensuring optimized stress distribution and extended fatigue life beyond industry norms.

• Customizable Geometry:

  CNC-controlled winding enables fully customizable coil diameters, pitches, turn counts, and winding directions to match specific installation requirements — from tight-space heat exchangers to long-span conveyor systems.

• Full Material Traceability:

  Every coil tube is traceable from mill heat number through to finished product, providing complete supply chain transparency and facilitating rapid quality response.

• Multi-Grade Material Availability:

  From standard 304/316 to exotic grades including 904L, Duplex 2205, and Hastelloy, the product range accommodates the most demanding corrosion and temperature environments.

• Comprehensive Testing Protocol:

  Every production batch undergoes hydrostatic pressure testing, dimensional verification, surface inspection, and (where applicable) radiographic or ultrasonic flaw detection — exceeding minimum standard requirements.

• Global Compliance:

  Certifications spanning ISO, ASME, CE, EN, and NACE standards ensure seamless integration into international supply chains and regulatory frameworks.

Technical Notes

The mechanical behavior of coil tubes in continuous conveying applications warrants special attention. The straight sections connecting coil segments experience complex loading conditions including bending moments from fluid momentum, axial compressive forces from pipeline expansion, and cyclic fatigue from pump pulsations. Wenzhou Jixing's analytical approach — grounded in the Mechanical Analysis of the Straight Section in a Series-Coil Pipeline Continuous Conveyor — ensures that transition zones are