What Is Copper Nickel Welding?

Definition

• Copper-nickel welding simply refers to the process of joining copper alloy metals through the use of extensive heat. The process, known as arc-welding, occurs when the extreme heat causes the metals to melt and conjoin upon cooling. Copper-nickel is a particular form of alloy metal used for various purposes. Copper and nickel are mutually soluble metals that weld together well and form a particularly tight bond.

Characteristics

• The characteristics of copper-nickel alloys make them a logical choice for certain types of projects, especially those involving seawater. Aside from their resistance to corrosion, they are also less subject to biofouling, or the accumulation of bacteria and other microorganisms. They also have a high level of thermal and electrical conductivity. These alloys tend to be particularly strong and resistant to various types of wear that would destroy other types of metal.

Grades

• The grade of a copper-nickel alloy is determined by the percentage of copper and nickel in each. The greater the percentage of nickel, the stronger the alloy. In marine service, two primary copper-nickel alloys are regularly used. One involves a mixture of 70 percent copper and 30 percent nickel, while the other is a mixture of 90 percent copper and 10 percent nickel. The 70-30 mixture is the stronger of the two, but the 90-10 mixture tends to be more common and is less expensive.

Cleanliness

• When using a copper-nickel alloy in the welding process, it is imperative to maintain the cleanliness of the metal to avoid potential problems later on. The presence of lead, sulfur and phosphorus can all cause the welded joints to crack. Oil and grease should be removed by a clean cloth as should other foreign elements that can cause contamination in the welding process.