Abstract
Stainless steels such as AISI Type 304 SS are being used for seawater piping applications due to their desirable mechanical properties and good weldability. However, they are susceptible to pitting and crevice corrosion in chloride bearing environments. Thus a new generation of highly alloyed stainless steels such as Avesta 254 SMO with high molybdenum contents has been developed for improved localised corrosion resistance in seawater. These steels are also susceptible to the formation of undesirable secondary phases such as sigma and chi which degrades both mechanical and corrosion properties. Alternatively, the main alloying element can be surface alloyed onto the surface of a suitable substrate by laser surface alloying. In this paper, austenitic stainless steel surface alloys of varying molybdenum contents have been formed on 304 SS by laser surface alloying and characterised by optical and scanning electron microscopy. The corrosion behaviour was ascertained by electrochemical and immersion tests.
