This alloy is 96% copper and around 2 - 3% silicon. With very high corrosion resistance, it is commonly used in salt-water, fresh water, sewage, and atmospheric applications. It is quite durable and similar to low carbon steel in hardness. It is a popular alloy because of its combination of strength, ductility, corrosion resistance and weldability. It is commonly seen in architecture, marine applications, pumps and boilers.