Super duplex stainless steel sea water piping systems have been in use since 1991, generally with excellent results. However, there have been one or two problems at start-up for a few projects and a number of post weld surface treatments have been proposed to improve service performance. The paper describes the results of laboratory tests to investigate the effects of some of the treatments that have been
suggested. Some of these offered a substantial improvement to the critical pitting temperature, and the practicality of these is discussed in
relation to service experience. Keywords: Sea water, stainless steel, welding, pitting