Modelling the mechanical behaviour of heat-treated AISI 52100 bearing steel with retained austenite

The mechanical properties of hardened AISI 52100 bearing steel such as flexural strength, microhardness and Young's modulus are considerably influenced by the austenite content retained in the microstructure. A microstructure-sensitive finite element simulation approach is presented which considers the effect of retained austenite to estimate the mechanical properties. The austenite grain size is derived as a function of austenitising temperature and holding time using a modified Arrhenius type equation. The simulation strategy involves division of the two-dimensional domain using triangular elements such that a group of six neighbouring triangular elements represented a hexagonal grain of calculated size. Material inhomogeneity is introduced by enforcing austenite properties to a fraction of the elements equal to the volume percent of retained austenite in the steel. The predictions from the simulation approach for 8% and 20% retained austenite volume fractions matched well with earlier experimental results.