Influence of Cooling Rate and Austenite Grain Size on Nucleation of Ferrite

In this paper,influence of cooling rate and austenite grain on intragranular ferrite in non quenched and tempered medium carbon steel had been investigated by using high temperature quenching and high temperature phase change machine confocal microscope.Furthermore,the nucleation and growth of intragranular ferrite had been studied in order to provide the basis for smelting clean steel.Experimental results show that the cooling rate of 0.1 ℃/s can produce optimal equiaxial ferrite and the cooling rate affects the transformation temperature of ferrite.600 s holding time at quenching temperature can generate small size of austenite which is more suitable for ferrite nucleation at grain boundaries.