Admiralty brass erosion-corrosion

The heat-transfer quaUties of titanium are characterized by the coefficient of thermal conductivity. Even though the coefficient is low, heat transfer in service approaches that of admiralty brass (thermal conductivity seven times greater) because titanium s greater strength permits thinner-walled equipment, relative absence of corrosion scale, erosion—corrosion resistance that allows higher operating velocities, and the inherently passive film. 

The original saltwater condenser tube made of admiralty brass was found to be susceptible to erosion-corrosion at tube ends. Aluminum brass containing 2% aluminum was more resistant to erosion in saltwater. Inhibition with arsenic is necessary to prevent dezincification as in the case of admiralty brass. The stronger naval brass is selected as the tube material when admiralty brass mbes are used in condensers. Cast brass or bronze alloys for valves and fittings are usually Cu-Sn-Zn compositions, plus lead for machinability. Aluminum bronzes are often used as tube sheet and channel material for exchangers with admiralty brass or titanium tubes exposed to cooling water. 

Admiralty brass is not particularly resistant to erosion-corrosion. It should not be used in water flowing at velocities exceeding 2 m/s. They give good service as condenser tube materials in ships condensers. 

The superior performance of the inhibited admiralties, aluminum brass, aluminum bronzes, and copper-nickels over copper results from the combination of their corrosion product insolubility in seawater, erosion, and biofouling resistance. 

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