Structure of Grain Boundaries and Mechanism of Stabilization of the Grain Structure of Steels by Step Heating to Austenization Temperatures

An analysis of the existing information on the structural state of grain boundaries in metals and the effect of impurities on grain growth during high-temperature heating is carried out. It is established that the heating rate in the interval of phase α→γ transformation has a great influence on the kinetics of growth of austenitic grain. Based on experimental and published data, a model is proposed that describes the mechanism of formation and growth of austenitic grains in steels upon heating at different speeds. It is concluded that slow heating of steel in the interval of phase α→γ transformation leads to the formation of grains with predominantly high-angle misorientation and adsorption at the boundaries of impurity atoms, which contributes to the stabilization of the grain structure