Deformation Behavior and Dynamic Recovery Kinetics of Ultrahigh Strength Steel BR1500HS at Elevated Temperature

Abstract

The flow behaviors of ultrahigh strength steel BR1500HS at elevated temperature were studied by performing hot tension tests at the temperatures of 773 K, 873 K, 1023 K and 1173 K, and strain rates of 0.01 s−1, 0.1 s−1 and 1 s−1 on a Gleeble 3500 thermo-mechanical simulator. The true stress-strain curves were obtained and their characteristics were analyzed. Relationships among the maximum stress, temperature and strain rate were described by means of the conventional hyperbolic sine equation. The average deformation activation energy in the whole deformation temperatures was determined as Q = 235.257 KJ/mol by regression analysis. Based on σ(dσ/dε) verse σ2 curves, the values of dynamic recovery (DRV) rate coefficient, r, saturated stress, σrec, and yield strength, σ0, under different deformation conditions were calculated. In order to estimate the DRV volume fractions, the modified Avrami type equation including r (r = 106.911351Z−0.059) as a function of the temperature compensating parameter, Z, was established, and then the effects of deformation conditions on the DRV kinetics were described in details.

Keywords

• ultrahigh strength steel
• flow behaviors
• deformation activation energy
• dynamic recovery
• 81.40.lm
• 83.10.bb
• 83.10.gr