Stainless Steel Heating Coil Tube for Storage Tank Applications

Product Overview

The Stainless Steel Heating Coil Tube (Model Reference: JX-CT-1652) is a precision-engineered helical tube assembly designed for thermal management within industrial storage tanks (Storage Tank Heating Coil). Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this product serves as an integral heat transfer component in chemical processing, petrochemical, pharmaceutical, and food-grade storage systems. The coil tube is engineered to facilitate efficient thermal exchange between a heat medium (typically steam, hot water, or thermal oil) and the bulk liquid or semi-solid material contained within the storage vessel.

Unlike straight tube heat exchangers, the helical coil geometry maximizes the heat transfer surface area (Heat Transfer Surface Area) within a confined tank volume, enabling uniform temperature distribution while minimizing dead zones and thermal stratification. The product is designed in accordance with rigorous engineering calculations that account for fluid dynamics, thermal conductivity, pressure drop, and mechanical integrity under operational conditions.

Material & Properties

The coil tube is fabricated from austenitic stainless steel grades selected for their superior corrosion resistance, thermal stability, and mechanical durability under aggressive chemical environments. The following material options are available:

Key Mechanical Properties (Typical for 316L Grade):

Specifications

Parameter Specification / Range
Outer Diameter (O.D.) Φ12 mm – Φ159 mm (customizable)
Wall Thickness 0.8 mm – 6.0 mm
Coil Pitch (Helical Pitch) 20 mm – 200 mm (application-dependent)
Coil Diameter (Helical Diameter) Φ200 mm – Φ2000 mm
Coil Length (Total Unfolded Length) 1 m – 500 m
Maximum Operating Temperature –60°C to +450°C (316L); up to +870°C (321)
Maximum Operating Pressure 0.1 MPa – 6.3 MPa (design-dependent)
End Connections Welded, Flanged (ANSI/BS/EN), Threaded (NPT/BSP)
Surface Finish Pickled & Passivated (P&P), 2B, or Electropolished (Ra ≤ 0.4 μm)
Heat Medium Steam (Saturated/Live), Hot Water, Thermal Oil, Electric Trace
Applicable Standards ASTM A213, ASTM A269, ASME B31.3, EN 10217, GB/T 12771
Heat Treatment Solution Annealed (Solution Annealing), Stress Relieved

Manufacturing Process

The production of the heating coil tube follows a rigorous multi-stage manufacturing protocol to ensure dimensional accuracy, metallurgical integrity, and functional performance:

  1. Material Procurement & Inspection — Raw stainless steel tube stock is sourced from certified mills with full Material Test Reports (MTR, Mill Test Report) documenting chemical composition (Chemical Composition Analysis) and mechanical properties. Incoming inspection includes positive material identification (PMI, Positive Material Identification) via X-ray fluorescence (XRF, X-ray Fluorescence).
  2. Dimensional Preparation — Tubes are cut to calculated lengths based on thermal engineering computations. The coil geometry is determined through heat balance calculations (Heat Balance Calculation), including factors such as heat load (Heat Duty, Q), log-mean temperature difference (LMTD, Logarithmic Mean Temperature Difference), overall heat transfer coefficient (U-value), and allowable pressure drop (Pressure Drop, ΔP).
  3. Helical Coiling (Coil Forming) — Tubes are formed into helical shapes using precision coiling machinery. Cold coiling (Cold Forming) is employed for diameters below Φ50 mm; warm forming or hot forming may be utilized for larger diameters or thicker wall sections to prevent work hardening (Work Hardening) and cracking. Coil pitch and helical diameter are maintained within ±0.5% tolerance.
  4. Welding & Joining — Tube-to-fitting and tube-to-support welds are performed using Gas Tungsten Arc Welding (GTAW, TIG welding) or Automatic Orbital Welding (Orbital TIG Welding) with inert gas shielding (Argon, Ar). Weld procedures conform to ASME Section IX qualified welding procedures (WPS, Welding Procedure Specification). Welders are certified per AWS D1.6 or ISO 9606.
  5. Post-Weld Heat Treatment — Where required by code (e.g., ASME B31.3 for service temperatures above 425°C), post-weld heat treatment (PWHT) is conducted to relieve residual stresses (Residual Stress Relief) and restore corrosion resistance in the heat-affected zone (HAZ, Heat-Affected Zone).
  6. Pickling & Passivation — All welds and surfaces are subjected to pickling (using nitric/hydrofluoric acid blend) to remove weld scale and oxide, followed by passivation to establish a protective chromium oxide layer (Chromium Oxide Passive Film, Cr₂O₃).
  7. Pressure Testing & Non-Destructive Testing (NDT) — Hydrostatic pressure testing is conducted at 1.5× design pressure. NDT methods include Dye Penetrant Testing (PT, Penetrant Testing) and/or Radiographic Testing (RT, Radiographic Testing) for critical welds.
  8. Final Inspection & Packaging — Dimensional verification, surface finish inspection, and material traceability documentation are completed. Coils are packaged with protective end caps and desiccant to prevent atmospheric corrosion during transit.

Applications

The Stainless Steel Heating Coil Tube is deployed across a wide spectrum of industrial storage tank applications where thermal regulation is critical:

Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and holds the following certifications ensuring product conformity with international standards:

Unique Selling Points

Note: All specifications listed herein are typical values. Final product dimensions, material grade, and performance parameters are determined through collaborative engineering consultation between Wenzhou Jixing Metal Materials Co., Ltd and the end-user, based on site-specific thermal load requirements, operating conditions, and applicable code standards. Custom design and fabrication services are available upon request.