Stainless Steel Coil Tube (Coiltube) for Water-Jacketed Heater Applications

Product Overview

The Stainless Steel Coil Tube (Coiltube) is a precision-engineered heat exchange component designed specifically for use in water-jacketed heating furnaces and industrial thermal processing systems. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this coiltube product is formed into continuous spiral or helical configurations to maximize heat transfer surface area within a compact footprint. The coiltube serves as the primary heat exchange medium, circulating coolant fluid (typically water or thermal oil) through the jacket system to regulate furnace temperature and protect the heating elements from overheating.

Coiltubes in water-jacketed heaters are subjected to extreme thermal cycling, chemical exposure, and mechanical stress. A critical operational concern is fouling and scaling (结垢) — the accumulation of mineral deposits, corrosion products, and thermal degradation residues on the inner and outer surfaces of the coil. Wenzhou Jixing's coiltube products are engineered with material selection, surface treatment, and geometric design optimized to minimize scaling formation, enhance cleanability, and extend service life under harsh operating conditions.

Material & Properties

The coiltube is fabricated from high-grade austenitic stainless steel grades selected for their superior corrosion resistance, thermal stability, and mechanical integrity at elevated temperatures. The following material grades are available:

Key Mechanical and Physical Properties:

Specifications

Parameter Specification
Product Name Stainless Steel Coil Tube (Coiltube)
Product Code No. 978
Outer Diameter (OD) Φ8 mm – Φ51 mm (custom sizes available)
Wall Thickness (WT) 0.5 mm – 3.0 mm
Coil Pitch (Helix Pitch) 15 mm – 80 mm (adjustable per application)
Coil Diameter Φ100 mm – Φ2000 mm
Tube Length per Coil 5 m – 500 m (continuous coil)
Material Grades SUS304, SUS316L, SUS321, SUS310S, SUS309S
Standard References ASTM A213, ASTM A778, GB/T 14976, EN 10216-5
Bending Radius ≥ 3D (3 times the outer diameter)
Surface Treatment 2B, BA, Electropolished, Passivated
End Preparation Plain, Beveled, Threaded, or Flanged
Maximum Operating Pressure Up to 2.5 MPa (design-dependent)
Operating Temperature Range -20°C to +870°C (grade-dependent)
Packaging Wooden pallet with moisture-proof wrapping

Manufacturing Process

The production of high-quality stainless steel coiltubes involves a multi-stage manufacturing process designed to ensure dimensional accuracy, mechanical integrity, and corrosion resistance:

  1. Raw Material Selection: Hot-rolled or cold-rolled stainless steel tubes are sourced from certified mills, with each batch verified through spectroscopic analysis (PMI) to confirm chemical composition compliance with the specified grade.
  2. Tube Straightening and Cutting: Tubes are precision-straightened and cut to required lengths using high-speed cutting equipment to minimize burr formation and dimensional deviation.
  3. Coiling / Helical Forming: The straight tube is fed through a CNC-controlled coiling machine that wraps the tube into a precise helical or spiral configuration. The coiling process employs progressive die sets and tension-controlled feed mechanisms to maintain uniform coil pitch and prevent tube ovalization or wall thinning at bends.
  4. Heat Treatment (if applicable): For certain applications requiring stress relief or grain stabilization, the coiltube undergoes solution annealing at 1050–1150°C followed by controlled cooling.
  5. Surface Finishing: Tubes may undergo electropolishing to achieve a smooth, low-surface-energy finish that resists fouling and scaling adhesion. Passivation treatment (using citric acid or nitric acid solutions) removes free iron and forms a protective chromium oxide layer.
  6. Quality Inspection: Each coiltube undergoes dimensional verification (OD, WT, coil pitch), hydrostatic pressure testing (typically at 1.5× design pressure), and visual inspection for surface defects, weld integrity, and geometric accuracy.

Applications

Stainless steel coiltubes from Wenzhou Jixing Metal Materials are deployed across a wide range of industrial heating and thermal processing systems:

Fouling and Scaling Mitigation — Key Engineering Considerations

A critical aspect of coiltube performance in water-jacketed heaters is the management of fouling and scaling (结垢). Fouling layers reduce heat transfer efficiency, increase pressure drop, and can lead to tube failure if left unaddressed. Wenzhou Jixing's engineering approach addresses scaling through multiple strategies:

Quality Certifications

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

Unique Selling Points

1. Expertise in Fouling-Resistant Design: Drawing from extensive industry knowledge of water-jacketed heater scaling mechanisms (水套加热炉盘管结垢), Wenzhou Jixing engineers coiltubes with geometric and surface characteristics specifically optimized to delay and minimize fouling — extending maintenance intervals and reducing total cost of ownership.