Thermomechanical behaviour modelling and microstructure evolution of high Cr–Co–Mo aerospace bearing steel

Abstract

The microstructure evolution and hot-compressive behaviour of high Cr–Co–Mo bearing steel under different deformation conditions were investigated by dynamic recrystallisation (DRX) kinetics analysis and simulation. The results showed that the thermal deformation parameters and carbide dissolution have a great influence on the rheological properties and microstructure. The flow stress decreases with the increase of temperature and the decrease of strain rate. The grain boundary pinning effect is weakened by the dissolution of carbides into the matrix, resulting in the rapid growth of DRX grains. The processing map of high Cr–Co–Mo bearing steel was divided into five regions, and the most suitable processing parameters can be defined as the temperature range of 1000–1070°C and strain rate range of 0.01–0.003 s−1.

Investigation on Improved Hot Processing Map of Cr4Mo4Ni4V Aerospace Bearing Steel Based on Carbide Content

“…[17][18][19][20] Therefore, the regulation of carbide content is also a crucial role in bearing steel hot processing. Tang et al [21] proposed that, with the decrease of the strain rate and the prolongation of the high-temperature holding time, the nanoscale carbides gradually dissolve in the matrix. The grain boundary pinning effect is weakened by the dissolution of carbides into the matrix, resulting in the rapid growth of dynamic recrystallization (DRX) grains in the low-carbon high-alloy aerospace bearing steel.…”