ESSC & DUPLEX 2019

SAF 2205 duplex stainless steel has good corrosion resistance, mechanical strength, weldability at relatively low price. But it is susceptible to sigma phase precipitation. The sigma phase is a hard and brittle intermetallic phase that occurs in the Fe.-Cr system. The temperature range from 600 to 950 °C is critical for the sigma phase precipitation. The effects of time and temperature on the intermetallic phase precipitation and phase transformations in SAF 2205 were investigated. The influence on mechanical properties was studied. The specimens were isothermally annealed at different temperatures from 600 to 750 °C for 1 min, 10 min, 100 min and 1000 min. The specimens were investigated by optical microscopy and ferritoscope measurements. Mechanical properties tensile strength, hardness and impact toughness were analyzed. The detrimental effect of sigma phase precipitation was studied.