Modeling of flow stress of 42CrMo steel under hot compression

The compressive deformation behavior of 42CrMo steel was investigated at temperatures from 850 C to 1150 degrees C and strain rates from 0.01s(-1) to 50s(-1) on a Gleeble-1500 thermo-simulation machine. The results show that the true stress-true strain curves exhibit peak stresses at small strains, then the flow stresses decrease monotonically until high strains, showing a dynamic flow softening. The stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zener-Hollomon parameter in an exponent-type equation. A revised model describing the relationships of the flow stress, strain rate and temperature of the 42CrMo steel at elevated temperatures is proposed by compensation of strain. The stress-strain relations of 42CrMo steel predicted by the proposed models agree well with experimental results. (C) 2008 Elsevier B.V. All rights reserved.