1981

Hänninen, Hannu; Minni, Erkki

Impurity segregation in austenitic stainless steels has usually been studied by using surface heating experiments in Auger electron spectrometer. Although direct studies of grain boundary segregation would be preferable, there is a difficulty of achieving intergranular fracture in these ductile materials in the Auger electron spectrometer. After hydrogen charging of the specimens the grain boundaries of sensitized austenitic stainless steels can be broken up. The compositions of grain boundaries in two sensitized austenitic stainless steels (AISI 304 and AISI 321) are obtained. Also the depth distribution of segregated species will be given, depicting the layered segregation profiles of phosphorus and sulfur. An example of impurity segregation at the interdendritic fracture surface of a hot crack in an austenitic stainless steel weld is also presented. Segregations of S, Nb and P are observed.