Austenite Grain Nucleation and Growth After Re-Austenitizing Pre-Quenched 0.56% C Steels

Austenite grain size has been shown to have a major effect on the fatigue and fracture resistance of high hardness steels. This study examines austenite nucleation and grain growth for pre-quenched 0.56% C steels. Specimens heated at selected rapid to slow heating rates to austenitizing temperatures of 850 to 1050 C for 1 to 1000 s were examined by scanning electron microscopy to characterize austenite nucleation and grain size. Austenite grain diameters in the range of <5 µm to >300 µm were observed.