International Journal of Engineering and Information Systems (IJEAIS)   Year: 2022 | Volume: 6 | Issue: 8 | Page No.: 1-9 AN INVESTIGATION OF THE RELATIONSHIP BETWEEN THE COOLING MODES AND MECHANICAL PROPERTIES OF AISI 5120 ALLOY STEEL Download PDF Meshref A. A., Mostafa S. S., Deyaa M. A., Emad B. A., Osman A. O. Abstract: In this work, three kinds of heat treatments namely full annealing, normalizing, and hardening are applied to investigate the effect of cooling modes the on the mechanical properties of the AISI 5120 alloy steel. Also, the fracture surface of the specimens after tensile testing has been studied. The results of this work reveal that the cooling in boiling water creates a 5120 steel alloy with high tensile properties and the high Vickers hardness number. Cooling in oil decreases the tensile properties and the Vickers hardness number for steel alloy 5120. This work indicates that, the tensile properties and the Vickers hardness number for steel alloy 5120 dependent on the cooling modes. The best cooling mode is the cooling in boiling water, as it posses the best combination of strength and ductility.