Titanium Coil Tube (Coiltube) — Titanium Heat Exchanger Coil

1. Product Overview

The Titanium Coil Tube (Coiltube) is a precision-engineered, continuous-length tubular component manufactured from high-purity titanium alloy, formed into a helical or serpentine coil configuration. Designed primarily for integration into shell-and-coil heat exchangers, this product delivers exceptional thermal conductivity, outstanding corrosion resistance, and superior mechanical integrity under extreme operating conditions. Wenzhou Jixing Metal Materials Co., Ltd. specializes in the production of titanium coil tubes conforming to international standards, serving demanding applications across the chemical, petrochemical, pharmaceutical, nuclear, and marine engineering industries.

Unlike discrete tube-in-tube assemblies, the coil tube offers a continuous, seamless flow path that maximizes heat transfer efficiency while minimizing pressure drop. The helical geometry inherently promotes turbulent flow, enhancing convective heat exchange and reducing fouling accumulation on internal surfaces.

2. Material & Properties

Titanium coil tubes are predominantly fabricated from commercially pure titanium grades (Grades 1, 2, and 4) or titanium alloys (e.g., Ti-6Al-4V, Ti-3Al-2.5V) selected based on the specific service environment. The following key material properties define the product's performance envelope:

• Corrosion Resistance: Titanium exhibits a self-passivating oxide layer (TiO₂) that provides exceptional resistance to chloride-induced stress corrosion cracking, sulfuric acid, hydrochloric acid, seawater, and a wide range of aggressive chemical media.
• Specific Strength: Titanium alloys deliver a strength-to-weight ratio approximately 1.5 times that of stainless steel, enabling lightweight yet structurally robust heat exchange assemblies.
• Thermal Conductivity: Commercially pure titanium (Grade 2) offers thermal conductivity of approximately 22 W/(m·K), while Ti-6Al-4V provides enhanced mechanical properties at the expense of slightly reduced thermal performance.
• Temperature Range: Operational temperatures extend from cryogenic conditions (−253 °C) to approximately 400 °C for commercially pure grades, with Ti-6Al-4V suitable up to 500 °C in non-oxidizing environments.
• Biocompatibility: Titanium's biocompatible nature makes it suitable for pharmaceutical and medical-grade processing applications.

3. Specifications

Parameter	Specification / Range
Material Grades	Commercially Pure Titanium (Grade 1, 2, 4); Ti-6Al-4V; Ti-3Al-2.5V; Ti-5Al-2.5Sn
Outer Diameter (OD)	6.35 mm (¼") to 50.8 mm (2")
Wall Thickness	0.5 mm to 3.0 mm
Coil Pitch	Customizable; typically 15 mm to 100 mm
Coil Length	Up to 150 m continuous coil (custom lengths available)
Tolerance on OD	±0.1 mm (standard); ±0.05 mm (precision)
Surface Finish	Mirror polish (Ra ≤ 0.2 μm); Industrial finish (Ra ≤ 1.6 μm)
Applicable Standards	ASTM B348, ASTM B861, ASME SA-348, EN 12449, GB/T 3620
Maximum Design Pressure	Up to 3.5 MPa (subject to grade and wall thickness)
Welding Process	TIG (GTAW) with argon gas shielding; laser welding for specialized applications
Coating / Surface Treatment	Anodizing available; passivation treatment standard

4. Manufacturing Process

The production of titanium coil tubes involves a multi-stage manufacturing sequence designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:

1. Raw Material Selection: Titanium sponge is refined via the Kroll process to achieve required purity levels, then converted into titanium ingots through vacuum arc remelting (VAR) or electron beam melting (EBM).
2. Hot Rolling & Extrusion: Titanium ingots are hot-rolled into billets and subsequently extruded into seamless tube blanks with controlled microstructure.
3. Cold Drawing: Extruded tubes undergo cold drawing through precision dies to achieve exact outer diameter and wall thickness tolerances, improving mechanical properties and surface finish.
4. Coil Forming: The straight tube is helically formed using CNC-controlled bending machinery that maintains constant bend radius and pitch without inducing plastic deformation, kinking, or wall thinning beyond acceptable limits.
5. Welding & Joining: Where coil sections require joining, Gas Tungsten Arc Welding (GTAW/TIG) is employed under inert gas shielding (argon or argon-helium mixture) to prevent oxidation of the weld zone. Weld parameters are optimized to minimize heat-affected zone (HAZ) width and residual stresses.
6. Heat Treatment: Solution annealing (typically 650–800 °C in vacuum or controlled atmosphere) is performed to relieve residual stresses and homogenize microstructure.
7. Surface Finishing: Mechanical polishing, chemical passivation, and optional anodizing treatments are applied to achieve specified surface roughness and enhanced corrosion resistance.
8. Non-Destructive Testing (NDT): Every coil tube undergoes ultrasonic testing (UT), radiographic testing (RT) of welds, and helium or pneumatic leak testing to ensure structural soundness.

5. Applications

Titanium coil tubes find critical application in the following industrial sectors:

• Petrochemical & Refining: Shell-and-coil heat exchangers for distillation columns, reboilers, and condensers operating in chloride-rich or acidic environments where carbon steel and stainless steel are insufficient.
• Desalination & Marine Engineering: Seawater coolers and preheaters in multi-stage flash (MSF) and reverse osmosis (RO) desalination plants, where titanium's immunity to chloride pitting is essential.
• Chemical Processing: Reactor cooling coils, acid heat exchangers, and evaporator systems handling sulfuric acid, hydrochloric acid, and mixed organic solvents.
• Pharmaceutical & Biotechnology: Bioreactor jackets, sterilization loops, and CIP (Clean-in-Place) systems requiring biocompatible, non-leaching materials.
• Nuclear Industry: Secondary coolant loops and waste treatment systems where radiation resistance and corrosion immunity are paramount.
• Aerospace: Lightweight heat exchangers for hydraulic fluid cooling and environmental control systems (ECS) where weight reduction is critical.
• Food & Beverage: Pasteurization, pasteurizer tubes, and brewing applications requiring hygienic-grade surfaces and resistance to organic acids.

6. Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems ensuring full traceability and compliance with international regulatory frameworks:

• ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
• ISO 14001:2015 — Environmental Management System compliance for sustainable manufacturing practices.
• ISO 45001:2018 — Occupational Health and Safety Management System.
• ASME "U" Stamp & "S" Stamp — Authorization for pressure vessel and heat exchanger component fabrication.
• EN 10204 Type 3.1 Test Certificates — Third-party verified material certification for each production lot.
• CE Marking — Conformity with European Directive 2014/68/EU (PED — Pressure Equipment Directive).
• Mill Test Reports (MTR) — Full chemical composition analysis, mechanical property verification (tensile strength, yield strength, elongation, hardness), and microstructural examination for every batch.
• NACE MR0175 / ISO 15156 — Compliance for sour service applications (H₂S environments).

7. Unique Selling Points

• Superior Corrosion Immunity: Titanium's passive oxide film provides unmatched resistance in aggressive chemical environments where conventional stainless steel alloys fail.
• Continuous Coil Geometry: The uninterrupted helical design eliminates internal weld joints, reducing leak risk and maximizing heat transfer surface area per unit volume.
• Low Fouling Characteristics: Smooth surface finish and turbulent flow regime minimize scale and biofilm accumulation, reducing maintenance intervals.
• Lightweight Construction: Density of titanium (4.51 g/cm³) is approximately 58% that of steel, enabling weight savings of 40–45% in overhead and mobile installations.
• Extended Service Life: Design life exceeding 25–30 years in demanding service conditions, offering superior total cost of ownership (TCO) despite higher initial material cost.
• Full Customization: Coil dimensions, pitch, length, and surface treatment are fully configurable to match specific thermal duty requirements and spatial constraints.

Note: All specifications are subject to engineering review based on specific application parameters. Wenzhou Jixing Metal Materials Co., Ltd. provides dedicated technical support for material selection, thermal design validation, and installation guidance to ensure optimal system performance and longevity.