Interaction between Precipitation and Dynamic Recrystallization in HSLA-100 Microalloyed Steel

Strain induced precipitation in HSLA-100 steel was investigated by conducting hotcompression and relaxation tests at temperature range of 850C to 1100C and strain rate of 0.001s-1 to 1s-1. The absence of dynamic recrystallization at temperatures below 1000C was attributedto the influence of dynamic precipitation. The stress relaxation tests showed that strain inducedprecipitation is possible over a wide range of temperatures from 850C to 1050C. The startingand finishing times of precipitation were sensitive to temperature than strain rate. At temperaturerange of 950-1000C and strain rate of 0.1s-1 the lowest times for precipitation were observed. Thecombination of precipitation-time-temperature and recrystallization-time temperature diagramsshowed that at high temperatures and low strain rates, precipitation precedes dynamicrecrystallization, whereas at the opposite condition, dynamic recrystallization goes in advance. Thestarting and finishing times for dynamic precipitation were approximated about 40 percent lowerthat those for strain induced precipitation.

Keywords:

Hot deformation , Cu-bearing HSLA steel , Dynamic recrystallization , Hot compression , Stress relaxation