Stainless Steel Coil Tube — Paint Booth HVAC Coil Protection & Renovation Grade

Product Overview

The Stainless Steel Coil Tube (hereinafter referred to as "Coiltube") manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product specifically designed for application in paint booth air conditioning (HVAC) systems. This product addresses the critical challenge of corrosion resistance and thermal performance degradation encountered in aggressive chemical environments such as automotive and industrial painting facilities. The Coiltube serves as the core heat exchange element within air conditioning coils, ensuring reliable thermal regulation while withstanding prolonged exposure to solvent vapors, acid mist, and humidity.

Unlike conventional carbon steel or copper tubing used in standard HVAC applications, this stainless steel coil tube offers superior chemical inertness, extended service life, and reduced maintenance intervals — making it the preferred choice for paint booth environments where coating integrity and operational continuity are paramount.

Material & Properties

The Coiltube is fabricated from high-grade austenitic stainless steel, selected for its exceptional resistance to intergranular corrosion, pitting, and stress corrosion cracking in chloride-rich atmospheres.

Specifications

Parameter Specification
Nominal Outer Diameter (OD) φ6.35 mm / φ9.53 mm / φ12.70 mm (¼" / ⅜" / ½")
Wall Thickness 0.50 mm – 1.50 mm (customizable)
Coil Winding Diameter φ150 mm – φ300 mm (configurable per coil bundle design)
Coil Pitch (Row Spacing) 1.25 × OD – 1.5 × OD
Tube Length per Coil 2.0 m – 15.0 m (as required)
Surface Finish 2B (No. 4 Brushed) / BA (Bright Annealed) / Polished
Tolerance on OD ±0.05 mm
Tolerance on Wall Thickness ±10% of nominal
Applicable Standards ASTM A269 / A270; EN 10217-7; GB/T 12771; JIS G3459
End Condition Plain end / Flared / Threaded / Custom-fitted
Maximum Working Pressure 1.6 MPa – 4.0 MPa (dependent on OD and wall thickness)
Flow Medium Water, Glycol-water mixture, Refrigerant (R-134a, R-410A)

Manufacturing Process

  1. Raw Material Selection & Inspection: Stainless steel strip or seamless tube blank material undergoes spectroscopic analysis to verify chemical composition compliance with the specified grade. Incoming material must possess valid mill test certificates (MTC) conforming to EN 10204 Type 3.1.
  2. Coil Winding (Tube Bending): Precision CNC-controlled bending machines form the straight tube into the required coil geometry. The bending process is performed at controlled speeds to prevent work-hardening and micro-cracking at the bend apex. Minimum bend radius is maintained at ≥ 3 × OD to ensure structural integrity.
  3. Heat Treatment & Stress Relief: Post-forming annealing at 1050°C – 1100°C followed by controlled cooling restores full austenitic microstructure, eliminates residual stresses, and maximizes corrosion resistance (particularly critical for Grade 316L in chloride environments).
  4. Surface Treatment: Pickling and passivation remove oxide scale and form a protective chromium oxide layer. Optional electropolishing may be applied for enhanced surface smoothness (Ra ≤ 0.4 μm) to minimize fouling in fluid-carrying applications.
  5. Hydrostatic Pressure Testing: Each coil tube assembly is subjected to hydrostatic testing at 1.5 × maximum working pressure for a minimum of 60 seconds to verify weld integrity and absence of leakage paths.
  6. Dimensional Inspection: Coordinate measuring machines (CMM) and laser scanning verify coil geometry, pitch accuracy, and dimensional tolerances against the engineering drawing.
  7. Final Quality Assurance: Visual inspection, ultrasonic testing (UT) for wall thickness verification, and material certification compilation complete the quality assurance cycle.

Applications

The stainless steel coil tube from Wenzhou Jixing Metal Materials is engineered for demanding environments where conventional materials fail. Primary applications include:

Quality Certifications

Unique Selling Points

1. Superior Corrosion Resistance in Aggressive Environments: The austenitic stainless steel matrix, particularly Grade 316L with molybdenum enhancement, provides outstanding resistance to chloride-induced pitting and crevice corrosion — the primary failure mode of conventional HVAC coils in paint booth applications.

2. Extended Service Life: Field data indicates that stainless steel coil tubes in paint booth HVAC systems achieve service lives of 10–15 years compared to 3–5 years for copper or carbon steel alternatives, significantly reducing lifecycle costs.

3. Thermal Performance Stability: The non-reactive surface finish prevents scale formation and fouling, maintaining consistent heat transfer coefficients throughout the service life — critical for maintaining precise temperature and humidity control in paint application environments.

4. Customizable Geometry: Wenzhou Jixing Metal Materials offers flexible coil winding configurations (OD, pitch, length, row count) to integrate seamlessly with existing coil bundle designs or new HVAC system architectures.

5. Renovation Compatibility: Specifically engineered for retrofit applications where existing carbon steel or copper coils in paint booth HVAC systems require replacement with corrosion-resistant alternatives without major system modifications.

Technical Notes on Paint Booth Coil Protection & Renovation

Based on industry case studies and field experience documented in technical literature on paint booth HVAC coil protection and renovation, the following engineering principles govern the successful deployment of stainless steel coil tubes in these environments: