Softening kinetics in the process of stress relaxation after hot deformation of HSLA steel

Abstract

The paper presents the results of investigations concerning the hot plastic deformation of HSLA steel, particularly the kinetics of static thermally activated processes. The influence of the parameters of hot deformation and the duration of isothermal holding on the process of soft annealing by the stress relaxation have been investigated. The tests were performed making use of the compression method, applying a simulator Gleeble 3800. The relaxation was tested during the isothermal holding after the hot compression of HSLA steel at the strain rate of 1.0 s −1 and temperature of 850-1200 • C. The results of softening kinetics have been gathered in static recrystallization-temperature-time (RTT) curves. It has been found that in the course of the isothermal holding of the steel there occurs a recovery and static and metadynamic recrystallization. The kinetics of these processes depends mainly on the temperature and degree of deformation of the investigated steel.