Influence of Mechanical Deformation and Annealing on Kinetics of Martensite in a Stainless Steel

An attempt has been made to understand the kinetics concerning the manufacturing schedule of high strength 304 stainless steel comprising formation of strain-induced martensite in the course of cold rolling (25%) at 0 degrees C and its reversion during annealing in the temperature range of 300800 degrees C for 1h. Increase in reversion with increasing annealing temperature without any perceptible grain growth up to 800 degrees C has been demonstrated by the microstructural investigation. X-ray diffraction analysis has revealed that the 25% cold rolling has resulted in the formation of 20% deformation induced martensite which after annealing at 800 degrees C has been reduced to 8%. Different stages of reversion behaviour have been envisaged by carrying out differential scanning calorimetry. Activation energies of the reactions involved during reversion have been determined by Kissinger method. Results are compared and found to be in good agreement with the published data.