Strain-Induced Precipitation in Nb and Nb-Ti Microalloyed Steel

The stress-relaxation method is used to monitor the strain-induced precipitation curves with thermo-simulation machine in Nb and Nb-Ti microalloyed steel.Meanwhile,the strain-induced precipitation process is also obtained with the aid of carbon replica technique under the TEM observation.The experimental results indicate that: there are three stages in the precipitation process and the addition of Ti to the Nb microlloyed steel will retard the progress of precipitation of Nb(C,N) under the condition of fully dissoution of specimen treated in the higher temperature.The particles will gradually possess the irregular shape from the circular shape with the increase of relaxation time.