Development of Copper Alloys for Seawater Service from Traditional Application to State-of-the Art Engineering

Abstract

Abstract Since antiquity both wrought and cast forms of copper alloys have exhibited significant corrosion resistance in marine environments. Their properties have been developed and modified over the years to meet today’s exacting engineering challenges and continue to offer solutions to a range of industries requiring reliability in seawater including commercial and naval shipbuilding, offshore seawater-handling and firewater systems, and thermal desalination plants. This paper describes the range of copper alloys in marine service today and the evolution of applications which include ships' cannon and hull sheathing in 18th and 19th century and condenser and seawater piping requirements which spurred concentrated investigations in the 20th century. The latter led to the development and introduction of copper-nickels and nickel aluminum bronzes (NABs), which are now the most widely used marine engineering copper alloys. The direction of future developments is also discussed. Technically, the paper covers the influence of refined composition and/or heat treatment which have optimized the properties of copper-nickels and NABs in terms of localized corrosion and erosion-corrosion resistance. It also discusses the importance of correct commissioning and shut down procedures to ensure that the full capabilities of copper alloys are achieved.