Study of the effect of heat treatment on low cycle fatigue in AISI 4340 steel by acoustic emission

The effect of prior heat treatment on the mechanical properties, namely the characteristics of plastic deformation, crack initiation and crack propagation, in the low cycle fatigue of AISI 4340 steel was investigated. Also studied was the effect of the changes in microstructure due to heat treating on the fatigue properties using electron microscopy. Simultaneously, during fatigue tests, acoustic emission was used to determine the extent of …