Copper Nickel 95/5 Tubes are widely used in marine, offshore, and heat exchanger applications due to their excellent resistance to seawater corrosion and biofouling. These tubes are made from an alloy containing 95% copper and 5% nickel, which gives them strength, durability, and reliability in harsh environments. Understanding the right fabrication and welding techniques for these tubes is essential to maintain their performance and quality.

1. Understanding Copper Nickel 95/5 Tubes

CuNi 95/5 Tubes, also known as Copper Nickel 95/5 Tube C70400, have a fine balance of copper and nickel that provides high resistance to corrosion, especially in saltwater conditions. These tubes are commonly used in shipbuilding, desalination plants, and power generation systems. Their thermal conductivity and strength make them a preferred choice for heat exchangers and condensers.

2. Fabrication Techniques

Fabrication of Copper Nickel 95/5 Tubes requires precision and proper handling to avoid damage or contamination. Here are some key fabrication steps:

  • Cutting and Bending:
    Copper Nickel 95/5 Tubes can be cut using standard tools like tube cutters or saws. When bending, it’s important to maintain a proper radius to prevent cracking or flattening.

  • Forming:
    CuNi 95/5 Tubes can be easily formed into various shapes and sizes. Cold working is often preferred for small adjustments, while hot forming can be used for more complex shapes.

  • Cleaning:
    Before any welding or joining process, the tube surface must be thoroughly cleaned to remove oil, dirt, or oxides. This ensures a strong and clean joint.

3. Welding Techniques

Welding is one of the most critical stages in working with Copper Nickel 95/5 Tubes. The right technique ensures strength and corrosion resistance at the joints.

  • Welding Method:
    The most commonly used welding methods are TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) welding. These methods provide precise control and high-quality welds.

  • Filler Metal:
    A filler metal of similar composition, usually CuNi 70/30, is used to achieve strong and corrosion-resistant welds.

  • Pre-Weld Preparation:
    Before welding, the tube ends must be cleaned and aligned properly. Any contaminants like grease or dust can cause porosity or weak joints.

  • Welding Process:
    During welding, use argon or helium as shielding gas to prevent oxidation. It’s important to maintain steady heat input to avoid overheating or distortion.

  • Post-Weld Cleaning:
    After welding, the joint should be cleaned with a wire brush or acid solution to remove surface oxides and maintain corrosion resistance.

4. Testing and Inspection

After fabrication and welding, CuNi 95/5 Tubes undergo various inspections to ensure quality. These include:

  • Visual Inspection for surface defects or cracks.

  • Hydrostatic Testing to check pressure resistance.

  • Non-Destructive Testing (NDT) methods like ultrasonic or radiographic testing to ensure weld integrity.

5. Applications

Copper Nickel 95/5 Tubes are used in:

  • Marine piping systems

  • Heat exchangers and condensers

  • Desalination plants

  • Offshore platforms

  • Power plants

Conclusion

Proper fabrication and welding techniques are essential for maintaining the strength and corrosion resistance of Copper Nickel 95/5 Tubes. With correct preparation, welding methods, and inspection processes, CuNi 95/5 Tubes can deliver long-lasting performance in even the most demanding environments. Whether used in marine, industrial, or power applications, Copper Nickel 95/5 Tube C70400 continues to be a trusted choice for quality and durability.