Thermal cycles experienced by a superduplex stainless steel SAF 2507 when is welded, can promote the precipitation of secondary phases which decrease the mechanical properties as well as the corrosion resistance. Due to the application of the duplex alloys in the petrochemical industry, the study of these alloys has become very important in order to predict its service behavior. The aim of this work is to study the microstructural changes in the superduplex stainless steel weld joint after applying the GTAW process under three interpass temperatures after the deposition of every single pass. The results showed that slow cooling rates promoted by the deposition of the subsecuent passes and the higher interpass temperature, promote the precipitation of sigma phase in the HAZ while rapid cooling rates promoted by the lower interpass temperature do not promote the sigma phase precipitation.
sigma phase; GTAW; thermal cycle; superduplex
