σ-phase morphologies and their effect on mechanical properties of duplex stainless steels

Abstract

Abstract The aim of the presented study is to investigate the influence of the different σ-phase morphologies on the mechanical, wear and corrosive behaviour of the duplex stainless steel 1.4462 (X2CrNiMoN 22 5 3). Different amounts of σ-phase were precipitated in tensile, impact strength, wear and corrosion samples by annealing at 750 °C, 850 °C and 938 °C. σ-phase shows a detrimental influence on the impact strength and the corrosion behaviour. To a very limited extent it can be used to slightly raise the strength under quasi-static load and to improve the wear resistance. Finally, it can be concluded that σ-phase has more unfavourable influences on the material' behaviour than advantageous ones. Therefore, it should be avoided in duplex stainless steels.