UNS C68700 Longitudinal Grooved Tube | High Efficiency Heat Exchanger Tube
The UNS C68700 longitudinal grooved tube is a high-efficiency enhanced heat transfer tube manufactured with aluminum brass as the base material, featuring uniform longitudinal grooves processed on the inner or outer tube wall. It integrates the excellent corrosion resistance of UNS C68700 alloy with the heat transfer enhancement performance of longitudinal grooves, serving as a core component for heat exchangers and condensers under severe working conditions in marine engineering, power generation, petrochemical and other industries.
Base Material Characteristics: Core Advantages of UNS C68700 Aluminum Brass
UNS C68700 belongs to the copper-zinc-aluminum alloy series, with chemical composition: Copper 76%–79%, Aluminum 1.8%–2.5%, Arsenic 0.02%–0.1%, balance Zinc, and total impurities ≤ 0.3%.
Excellent Corrosion Resistance
Aluminum elements form a dense alumina passive film on the surface, resisting high-velocity seawater erosion, cavitation corrosion and flow-induced corrosion. Arsenic effectively inhibits dezincification corrosion, delivering a service life 5 times that of ordinary brass, and suitable for operating temperatures ranging from -163℃ to 150℃.
Superior Mechanical & Machinability
Tensile strength ranges from 380–450 MPa in annealed condition, and can reach 550–700 MPa after cold working, outperforming most traditional brass grades. Elongation is ≥35% for annealed temper and maintains 12%–20% for cold-rolled temper, balancing high ductility and work hardening capacity. Typical hardness is HB 80–120.
High Thermal Conductivity & Cost-Effectiveness
Thermal conductivity reaches approximately 105 W/(m·K), far higher than stainless steel. Its cost is only 52% of copper-nickel tubes, and the coating-free design greatly reduces subsequent maintenance costs.
Structural Design & Heat Transfer Enhancement Mechanism of Longitudinal Grooves
2.1 Structural Design
Continuous grooves are processed along the axial direction of the tube wall. Groove depth: 0.3–2 mm, groove width: 1–3 mm, groove quantity: 20–60 pieces (customized by outer diameter). A plain tube section of 150–200 mm is reserved at both ends for convenient welding and installation.
2.2 Heat Transfer Enhancement Principle
Longitudinal grooves raise the effective heat transfer area by 30%–80%, greatly improving heat transfer efficiency.
Grooves disrupt the fluid boundary layer, reduce the thickness of the laminar sublayer and increase turbulence intensity, boosting the convective heat transfer coefficient by 50%–120%.
Under condensation conditions, condensate liquid flows from groove peaks to groove valleys. Groove valleys act as drainage channels to accelerate condensate discharge, lowering thermal resistance and improving condensation heat transfer efficiency by over 40%.
Key Technical Parameters & Specifications
| Item | Parameter Range |
|---|---|
| Base Material | UNS C68700 |
| Outer Diameter | 19mm, 25mm, 32mm, 38mm (Customizable) |
| Wall Thickness | 1.0–3.0mm |
| Groove Depth | 0.3–2.0mm |
| Groove Quantity | 20–60 pieces |
| Length | 1.5–6.0m (Customizable) |
Core Application Scenarios
Performance Advantage Comparison
✔ Heat transfer coefficient increased by 50%–120%
✔ Pipe consumption reduced by 30%–50% under same heat transfer load.
✔ Thermal conductivity 3–4 times that of stainless steel
✔ Better seawater corrosion resistance with lower overall cost.
✔ Service life against corrosion increased by 5 times
✔ Improved resistance to dezincification and cavitation corrosion.
Comprehensive advantage summary: UNS C68700 longitudinal grooved tube solves industry pain points of fast corrosion, low heat transfer efficiency and high operating cost under harsh marine and industrial conditions. Supports industrial energy saving and long-term stable operation.
Installation & Maintenance Guidelines
Installation
Weld the plain tube sections at both ends with tube sheets by TIG welding or brazing; avoid overheating damage to the grooved area. Arrange tube bundles properly to prevent groove blockage.
Maintenance
Clean internal fouling regularly with low-pressure water (≤0.5 MPa); avoid hard brushes that may damage the passive film on the groove surface. Prolonged contact with strong oxidizing acid and alkali media is prohibited.
Conclusion
The UNS C68700 longitudinal grooved tube perfectly combines the high anti-corrosion performance of aluminum brass with the heat transfer enhancement of longitudinal grooves. It solves the industry pain points of fast corrosion, low heat transfer efficiency and high operating cost for heat exchange equipment under harsh marine and industrial conditions. As an ideal pipe material for high-efficiency heat exchange equipment, it supports industrial energy saving and long-term stable operation of production facilities.
* Data based on standard tests and application feedback. Custom specifications available upon request.