EFFECT OF 2ND-PHASE PARTICLES ON THE GRAIN-SIZE OF A MULTI-MICROALLOYED MEDIUM-CARBON STEEL

An experimental study on the grain growth of a medium carbon microallo yed steel with two levels of aluminum nitride (AIN) is carried out. Tw o types of precipitates (V-Ti carbonitrides and AlN) are expected in t he alloys selected. The effect of both particles on the final grain si ze is analyzed, and special emphasis is given to the appearance of abn ormal grain growth. The dependence of the volume fraction of particles and of their size on time and temperature is theoretically derived ac cording to simplified models. The particle sizes are also experimental ly determined and contrasted with the latter theoretical approaches. C lassical models of grain growth control are compared and that proposed by Rios proportionates the best agreement with experimental results. The effect of the heating rate, i.e. overprecipitation, is also qualit atively included in the analysis.