Stainless Steel Spiral Coil Tube (Coiltube) — Horizontal Spiral Coiling Machine Fabricated Product
Product Overview
The Stainless Steel Spiral Coil Tube (hereinafter referred to as "Coiltube") is a precision-engineered continuous tube product manufactured through a horizontal spiral coiling process. Produced by Wenzhou Jixing Metal Materials Co., Ltd, this product represents a sophisticated integration of advanced metallurgical forming technology and high-grade stainless steel material science. Unlike conventional straight tubes or standard U-bend coils, the spiral coil tube is formed using a Horizontal Spiral Coiling Machine (卧式螺旋盘管机), which ensures uniform curvature, consistent wall thickness, and superior dimensional accuracy throughout the entire coil length.
The product is classified under the Literature Study (文献学习) category, reflecting its development and optimization informed by rigorous academic research and engineering experience documented in the technical paper "Research and Application of Horizontal Spiral Coiling Machine" (《卧式螺旋盘管机的研制及应用》). This knowledge-driven approach distinguishes the product as a result of systematic process improvement and performance validation.
Material & Properties
The Coiltube is fabricated from high-grade austenitic stainless steel grades, selected for their outstanding combination of corrosion resistance, mechanical strength, and thermal stability. The following materials are typically available:
- 304 (UNS S30408) — General-purpose austenitic grade with excellent corrosion resistance and formability
- 316L (UNS S31603) — Enhanced molybdenum alloy for superior resistance to pitting and crevice corrosion in aggressive chemical environments
- 321 (UNS S32100) — Titanium-stabilized grade suitable for high-temperature applications with resistance to intergranular corrosion
- 310S (UNS S31008) — High-temperature grade with excellent oxidation resistance up to 1100°C
- 904L (UNS N08904) — Ultra-low carbon high-alloy grade for extreme chemical environments
| Property | 304 (UNS S30408) | 316L (UNS S31603) | 321 (UNS S32100) |
|---|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 515 | ≥ 520 |
| Yield Strength (MPa) | ≥ 205 | ≥ 170 | ≥ 205 |
| Elongation (%) | ≥ 40 | ≥ 40 | ≥ 40 |
| Maximum Service Temperature (°C) | 870 | 870 | 925 |
| Density (g/cm³) | 7.93 | 8.00 | 7.93 |
| Thermal Conductivity (W/m·K at 100°C) | 16.3 | 14.6 | 16.3 |
Specifications
| Parameter | Specification Range |
|---|---|
| Outer Diameter (OD) | Φ6 mm – Φ108 mm |
| Wall Thickness (WT) | 0.3 mm – 6.0 mm |
| Spiral Pitch (Helix Pitch) | Adjustable, typically 15 mm – 50 mm |
| Coil Diameter (Mean) | Φ200 mm – Φ2000 mm |
| Coil Length | Up to 500 m (continuous) |
| Surface Finish | 2B, BA (Bright Annealed), Mirror (#4, #8) |
| Surface Roughness (Ra) | ≤ 0.8 μm (BA); ≤ 0.2 μm (Mirror) |
| Dimensional Tolerance (OD) | ±0.05 mm (Precision grade) |
| Dimensional Tolerance (WT) | ±0.02 mm (Precision grade) |
| Coiling Temperature | Room temperature (cold forming) or 400–600°C (warm forming) |
| Helix Angle Accuracy | ±0.5° |
| Product Standard Reference | ASTM A213, ASTM A269, GB/T 14976, EN 10216-5 |
Manufacturing Process
The production of the Horizontal Spiral Coil Tube employs a proprietary multi-stage manufacturing process developed through extensive research and iterative optimization. The key stages are as follows:
-
Material Selection & Incoming Inspection
Raw stainless steel tube blanks are sourced from certified mills and subjected to spectroscopic analysis (OES), hardness testing, and dimensional verification prior to acceptance into production.
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Surface Preparation
Incoming tubes undergo mechanical cleaning, degreasing, and optional pickling and passivation to remove surface oxides, contaminants, and residual stresses.
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Horizontal Spiral Coiling (Core Process)
The tube is fed into the Horizontal Spiral Coiling Machine, where synchronized rotary and axial feed mechanisms guide the tube along a precise helical path. The machine employs:
- Programmable feed rate control for consistent pitch accuracy
- Multi-point rolling dies for uniform bending force distribution
- Real-time tension monitoring to prevent ovalization and wall thinning
- Computer Numerical Control (CNC) coordination of all motion axes
-
Post-Forming Stress Relief
Following coiling, the product may undergo controlled annealing (solution heat treatment at 1050–1100°C followed by rapid cooling) to relieve residual bending stresses, restore full austenitic microstructure, and maximize ductility.
-
Surface Finishing
Depending on application requirements, the coiltube receives BA (Bright Annealed) treatment in a hydrogen or nitrogen atmosphere, or mechanical polishing to achieve mirror surface finish.
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Final Quality Inspection
Comprehensive inspection includes dimensional measurement (OD, WT, pitch, coil diameter), hydrostatic pressure testing, visual examination, and optional eddy current testing for wall integrity.
Applications
The Spiral Coil Tube finds extensive use across multiple industrial sectors owing to its unique geometry, which provides high surface-area-to-volume ratios and efficient heat/mass transfer characteristics:
- Heat Exchangers — Shell-and-coil heat exchangers, spiral plate heat exchangers, and compact heat transfer devices in power generation and process industries
- Chemical Processing — Reactor internals, condensers, evaporators, and distillation columns where corrosion resistance is critical
- Pharmaceutical & Food Processing — Pasteurization coils, sanitary heat exchangers, and CIP (Clean-in-Place) compatible systems
- Oil & Gas Industry — Subsea heat exchangers, process cooling coils, and separator internals
- Biomedical Equipment — Dialysis machine heat exchangers, medical gas delivery systems, and sterilization equipment
- HVAC & Refrigeration — Compact evaporator and condenser coils for high-efficiency air conditioning systems
- Aerospace — Fuel cooling coils, hydraulic line assemblies, and thermal management systems
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring product conformity to international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001 — Environmental Management System
- ASME "S" Stamp — Pressure Vessel and Piping Components (where applicable)
- EN 10204 Type 3.1 — Third-party Material Test Certificates
- CE Marking — European Conformity for pressure equipment (PED 2014/68/EU)
- API Monogram — American Petroleum Institute certification for oil and gas applications
Unique Selling Points
1. Research-Driven Process Optimization: The horizontal spiral coiling machine utilized was developed through systematic academic research, resulting in superior geometric accuracy (±0.5° helix angle tolerance) and reduced material waste compared to conventional coiling methods.
2. Continuous Spiral Geometry: Unlike segmented or U-bend coil assemblies, this product is formed as a single continuous spiral, eliminating potential leak points at weld joints and ensuring uniform flow characteristics throughout the entire length.
3. Precision Dimensional Control: CNC-controlled forming ensures wall thickness variation of ≤ 0.02 mm across the entire coil, critical for applications requiring uniform heat transfer performance and predictable hydraulic resistance.
4. Customizable Configuration: Flexible adjustment of coil diameter, pitch, and total length enables tailored solutions for specific thermal-hydraulic design requirements.
5. Full Traceability: Each production batch is traceable from raw material mill certificate through final inspection, supporting regulatory compliance in pharmaceutical, aerospace, and nuclear industries.