Every year, worldwide usage of copper reaches more than 22 million tonnes, and this figure continues to rise as the demand increases. As a base metal, copper truly holds a significance in various industries, and so do its alloys bronze and brass. In the business of building boats and ships, a copper alloy that has stood the test of time is naval brass. The alloy is widely used in the fabrication of propellers, propeller shafts, rivets, and more.
Naval brass is officially denoted by its international standard name C464, and it is composed of approximately 60% copper, 39% zinc, and traces of tin. This alloy was first developed as an alternative to common brass when shipbuilders noticed rapid degradation and corrosion when exposed to saltwater. The introduction of tin in the naval brass alloy gave the metal a tougher surface and made it highly corrosion resistant in marine environments.
Working with the Alloy
Having a high copper content, C464 exhibits excellent heat and electrical conductivity. It has a high machinability, and is excellent for hot forging projects. For welding naval brass, most fabricators use gas-shielded arc processes. Aside from being intended for boats and marine applications, naval brass is also used in condensers, heat exchangers, bolts, and some aircraft parts.
Weaknesses of Naval Brass
Though brass is generally corrosion-resistant and strong, the metal still has its limitations. It can weather and change color over time. Naval brass is also prone to dezincification, which is the loss of the zinc content, leaving most of the copper behind. This can lead to structural cracks on the surface of the alloy.