Microstructure Evolution in the Segregation Area of S31254 Stainless Steel Plate

Effect of solution temperature on the microstructure evolution in the segregation area of S31254 superaustenitic stainless steel plate was investigated. Samples were heated in the range of 950 °C-1250 °C for 0.5 h and then quenched to room temperature. As the temperature was between 950 °C and 1050 °C, two different secondary particles precipitated and dispersed in matrix of the steel. When the solution temperature reached to 1150 °C, any second phases could not be observed by SEM. In addition, several precipitating phases in the different position including grain interiors, grain boundaries and three-joint grain boundary were identified as Chi phase and Sigma phase in the tested steel using TEM.