The permanence of powder preform forged steels on higher order applications such as automobile, aerospace, ordnance industries with elevated temperature and strength is being sustained by implementing various heat treatment progresses. Different heat treatment schedules after the forged preforms of AISI 8620 steel produced through conventional powder metallurgy route were analysed for its mechanical strength, fractography, and microstructure properties. Green compacts were prepared in the pressure range of 540±10 MPa and sintered in the electrical muffle furnace at 1150±10◦ C for 120 min. Sintered compacts were hot upset forged into square cross section bars. Some bars were quenched in the water medium, and other sets of samples were cooled inside the furnace and in still air. Kinetics of the cooling velocities highly influences the tensile and impact properties improvement with determined microstructure and fractographic features.