Aluminium Bronze Valves

Aluminium bronzes are copper-base alloys with around 5% to 11% aluminium. Iron, nickel, manganese and silicon are often added to enhance its properties. Aluminium bronze valves are particularly resistant to corrosion by sea water where they are most frequently used.

Aluminium bronzes also have good resistance to sulphuric acid, sulphur dioxide and other combustion products and also show low rates of oxidation at high temperatures.

The most common alloys contain 8% to 11% of aluminium and around 5% each of iron and nickel. The result is more correctly known as a nickel aluminium bronze (or NAB for short) and is a duplex (two-phase) alloy with excellent strength and corrosion resistance. Typical specifications are ASTM B148 UNS C95800 or EN1982 CC333G.

In comparison with other alloys, NAB in sea water is superior to 316, duplex and super duplex stainless steels where pitting corrosion and crevice corrosion are concerned. In corrosion terms, it stands up well against super duplex stainless steels, and is more cost effective.