Gibson, J.L.; Jimenez, C.; Garcia De Andres, C.; Danon, C.A.; Luppo, M.I.: Evaluation of the Abnormal Grain Growth in an ASTM 213 Grade T91 Steel. Procedia Materials Science 8 (2015), p. 1118-1126
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A study of the austenite grain growth of an ASTM A213 T91 steel held at 1050ºC for increasing times is presented. The prior a ustenite grain size distribution (PAGSD) at various holding times was determined using scanning electron microscopy. Taking into account the critical role played by MX precipitates (M: metal, X: C and/or N) on grain growth, transmission electron microscopy on replicas was used to characterize the carbides or carbonitrides present during holding in austenite; thus, the particle size distribution and chemical composition of these precipitates were determined for each austenite holding time. Results indicate a change in the chemical identity of the MX precipitates –from V-rich to Nb-rich- during the first minutes of austenite holding, the M23C6 dissolution and the further austenite grain growth in a heterogeneous mode.