Grain size control is essential in achieving satisfactory mechanical properties in heat-treated low-alloy steels. It is well established that alloys containing pinning particles exhibit abnormal grain growth when heated in a given temperature range. This abnormal grain growth is characterized by the presence of a bimodal size distribution, that is, the presence of a number of larger grains in a matrix of otherwise relatively smaller grains. In the present work, a new model is derived to establish a relationship between the occurrence of abnormal grain growth and the precipitates size distribution. The latter is itself predicted using a model based on classical nucleation and growth theory. Comparison with experimental data shows satisfactory agreement and illustrates the need to account for the entire precipitates distribution when addressing abnormal grain growth.
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