Laves phase precipitation and sigma phase transformation in a duplex stainless steel microalloyed with niobium.

Duplex stainless steels are used to replace austenitic in industrial applications, especially the chemical industry where corrosion resistance chloride-containing media is an important requirement. According literature, niobium has a great influence on transformation of phases these (ferrite, austenite and sigma). Given interest evaluating this property terms wear material, aim study was evaluate effect formation austenitic-ferritic steel SEW 410 Nr 1.4517 after heat treatment at 850ºC for 15, 30 60 minutes. The contents studied were 0.2; 0.5 1.5 wt%. Measurements microhardness, electrochemical tests saline solution containing 3.5% sodium chloride carried out. results show that increase content sigma phase leads hardness resistance, associated with decrease potential. Therefore, use austeno-ferritic recommended when factor be considered.