Corrosion behavior of electron beam welded duplex stainless steels

Abstract

The corrosion behavior of duplex stainless steels is strongly affected by the austenite-ferrite ratio. With regard to corrosion resistance as well as mechanical properties a balanced ratio between these two microstructural components is desired. Weld seams manufactured by electron beam welding (EBW) generally exhibit very high amounts of ferrite due to a strong loss of nitrogen during the welding process and a very high cooling rate, which can affect the corrosion behavior adversely. Significant improvements can be reached by varying the electron beam guidance and applying multi-beam technology. This paper considers the pitting corrosion as well as selective corrosion behavior of the welds as a function of the chosen process parameters during EBW. Comparisons with the corrosion performance of manual metal arc and tungsten inert gas welds are also made.