In high-salinity and corrosive environments, material selection is the thin line between operational success and catastrophic failure. C68700 Aluminum Brass (UNS C68700) has emerged as the industry standard for heat exchangers and marine engineering, offering a unique balance of corrosion resistance and mechanical durability.
This guide provides a professional technical breakdown for engineers and procurement managers looking to optimize their material performance.
1. What is c68700 material?
C68700 is a copper-zinc-aluminum alloy engineered specifically for severe corrosive conditions. What sets it apart is its ability to form a thin, protective, self-healing film on its surface when exposed to flowing seawater.
Standard Compliance: ASTM B111, ASME SB111.
Key Advantage: Superior resistance to "impingement" (high-velocity erosion) compared to standard brass.
2. Technical Specifications: Chemical & Mechanical
C68700 chemical composition
| Element | Content (%) | Role in the Alloy |
| Copper (Cu) | 76.0% - 79.0% | Base metal, providing thermal conductivity. |
| Aluminum (Al) | 1.8% - 2.5% | Critical: Forms the protective oxide layer. |
| Arsenic (As) | 0.02% - 0.06% | Effectively prevents dezincification. |
| Zinc (Zn) | Remainder | Enhances strength and machinability. |
C68700 Mechanical Properties (Typical for Tubes)
Tensile Strength: 450 - 600 MPa
Yield Strength: ≥ 150 MPa
Elongation: ≥ 35%
Thermal Conductivity: 100 W/(m·K) at 20°C
3. Why Global Buyers Choose C68700?
A. Exceptional Biofouling & Corrosion Resistance
C68700 is virtually immune to dezincification due to its precise arsenic content. It thrives in high-velocity brackish water and seawater, making it the preferred alternative to C44300 (Admiralty Brass) in aggressive environments.
B. Cost-Performance Ratio
While more expensive than standard brass (approx. 10-15% premium), ASTM B111 C68700 is significantly more affordable than Copper-Nickel (C70600) or Titanium alloys, providing an "optimized middle ground" for mid-to-high-end industrial projects.
C. Excellent Heat Transfer Efficiency
Its thermal conductivity is ideal for heat exchangers, ensuring maximum energy efficiency in desalination plants and power station condensers.
4. Critical Applications in Modern Industry
- Marine Engineering: Condenser tubes for ships, offshore oil rig piping, and seawater cooling systems.
- Power Generation: Heat exchanger tubes for nuclear and fossil fuel power plants.
- Desalination Plants: Evaporator tubes and distillation units.
- Oil & Gas: Distillation equipment and heat exchangers in refineries.
5. Processing & Fabrication Guide
1. Hot Forming: Best worked between 720°C and 800°C.
2. Cold Working: Excellent cold-working properties (deformation rate ≤60% suggested before annealing).
3. Welding: TIG or Laser welding is recommended. Pro Tip: Use Argon shielding to prevent aluminum oxidation during welding.
4. Surface Treatment: Chemical polishing or nickel plating can be applied to further extend service life in extreme acidity.
6. Procurement Insights: Supply Chain & Trends
Currently, the market demand for C68700 is surging in the Asia-Pacific and Middle East regions due to massive investments in desalination and green energy.
Buyer's Note: When sourcing ASTM B111 C68700 Tubes, ensure your supplier provides Eddy Current Testing (ECT) and Hydrostatic Testing reports. At Baohui Steel, we maintain a smart inventory system for standard dimensions (Outer Diameter 10-250mm), ensuring a stable lead time of 15-25 days.
Summary
C68700 Aluminum Brass is more than just a metal; it is a "Green Corrosion-Resistant" solution that fills the gap between low-end brass and high-cost titanium. Its environmental compatibility and high reliability make it the future of marine and energy cooling systems.
Email:baohui@bhsteelpipe.com
