Grain boundary segregation of copper, tin and antimony in C-Mn steels at 900 degree C

The segregation of copper, tin and antimony to austenite grain boundaries at 900 degree C has been investigated in C-Mn steels using a scanning Auger microprobe (SAM). The specimens for microanalysis were prepared in a manner such that the prior austenite grain boundaries could be exposed by fracturing at room temperature in the UHV chamber of the SAM unit. Initial bulk concentrations ranged between 600 and 2600 ppm Cu, 50 and 360 ppm Sn and 8 and 35 ppm Sb. Significant enrichment of copper, tin and antimony was detected along the austenite grain boundaries. The grain boundary concentration of copper and tin was found to vary depending upon the initial bulk concentration while the average concentration of antimony at the grain boundaries was found to be approximately 1 at % for all of the heats studied.