Microstructure refinement after nitrogen enrichment and austenite decomposition in a low-alloyed steel studied by EBSD and Laser Confocal Scanning Microscopy
Résumé
EBSD orientation microscopy and Laser Scanning Confocal Microscopy are used to investigate the origins of the faster austenite decomposition kinetics and finer resulting microstructure, after nitrogen enrichment in low-alloyed steels. A previous interpretation is confirmed: precipitation of nitrides in austenite during enrichment promotes ferrite formation on cooling. Another origin is the refinement of austenite grains during the re-austenitization treatment, which is applied before the study of austenite decomposition, upon final cooling.