Workhardening behaviour and microstructural analysis of failed austenitic manganese steel crusher jaws

Abstract

This study focussed on the work hardening behaviour and microstructure of austenitic manganese steel relative to premature failure of crusher jaws. Samples of sound and failed crusher jaws were taken, the change with depth from the working surface to the sample core was measured and their microstructures observed. The study revealed a sharp hardness gradient in the failed crusher jaws, and presence of large carbides at both the austenite grain boundaries and in the austenite matrix. The failure of crusher jaws was attributed to brittle fracture as a result of precipitates of carbides from the inability of precipitated carbides to absorb shock during impact working. Finally, we conclude that the failure occurred as a result of inadequate quenching operations during the manufacturing process that resulted in the formation of carbide precipitates which embrittle the austenitic manganese steel, reduce its ability to withstand shock and create a non uniform plastic flow as it is work hardening.