In the present study, the aluminized 22MnB5 Hot Press Forming (HPF) steel was deformed isothermally in the temperature range of 600-800 8C. The specimens were deformed with 0%, 10% and 30% engineering strain at a strain rate of 0.5/s. Mechanical stabilization of austenite during phase transformation was observed. The influence of strain rate was also studied. It was found that the martensite transformation was affected by the combined effect of mechanical stabilization and dynamic recovery. The influence of high temperature deformation on the final microstructure, microhardness and mechanical properties were studied. Deformation applied below 750 8C resulted in a significant decrease of the strength and the hardness. The ferrite fraction and morphology had a clear effect on the room temperature tensile fracture morphology.

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