PREMATURE FAILURE OF A NICKEL ALUMINUM BRONZE VACUUM PUMP IN SEAWATER SERVICE

摘要

Nickel Aluminum Bronze (NAB) is frequently the material of choice for the fabrication of equipment such as pumps, valves, etc. for seawater service. In general, the corrosion performance of this alloy material in seawater is very satisfactory and its resistance to cavitation is excellent. However, component failures have been occasionally encountered. The present paper discusses the premature failure of a NAB Liquid Ring Vacuum Pump (LVRP) at the seawater treatment plant of the Kuwait Oil Company (KOC). The failure investigation consisting of metallographic examination of the alloy microstructure, hardness profiles, and SEM microprobe analysis indicated that the cause of failure was attributable to the use of a non-specific grade of NAB in an improperly heat treated condition and possibly operational parameters. The corrosion morphology indicated that cavitation and erosion-corrosion were the main damage mechanisms.