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

Strain induced precipitation in HSLA-100 steel was investigated by conducting hot compression and relaxation tests at temperature range of 850°C to 1100°C and strain rate of 0.001 s^-1 to 1s^-1. The absence of dynamic recrystallization at temperatures below 1000°C was attributed to the influence of dynamic precipitation. The stress relaxation tests showed that strain induced precipitation is possible over a wide range of temperatures from 850°C to 1050°C. The starting and finishing times of precipitation were sensitive to temperature than strain rate. At temperature range of 950-1000°C and strain rate of 0.1s^-1 the lowest times for precipitation were observed. The combination of precipitation-time-temperature and recrystallization-time temperature diagrams showed that at high temperatures and low strain rates, precipitation precedes dynamic recrystallization, whereas at the opposite condition, dynamic recrystallization goes in advance. The starting and finishing times for dynamic precipitation were approximated about 40 percent lower that those for strain induced precipitation.