ABSTRACT

 In this research work the mechanical and microstructural property of medium carbon steel is determined based on the quenching medium employed on it. Three quenching mediums air, oil and water are studied to determine which better improves the hardness and wear resistance properties of the mild steel rods used in the study. The result and anafysis from the hrdne.sstest is compared with the hardness of the same steel material when it is not heat treated A mild steel , :,' bar of 16 mm diameter and 180 mm length each was usedfor this study. The stelroiY.s wer 1eated at an elevated temperatures of 700 °C, held at this temperature for 45 seco,d.. Tien different quenching techniques were used to bring down the temperarure of the metal to room temperature. The hardness of each specimen ofthe mild steel rod- air cooled (specimen A), ok cooled (specimen B) anl water cooled (specimen C) specimens were respectively determined and compared against the mild thit was not heat treated (specimen Z). The Rockwell hardness testing machine wa.used to determine thzardness of the various specimens. The water cooled mild steel proved to have a higher hardiiessvalue 79 HRB against all other quenching medium which had a hardness value of 77 HRR for specimen A, 73 HRB for specimen B and 71 HR.B for specimen Z hence th research revealed that the adoption of the water as a quenching medium better improves the hardness and wqr ysstance of medium carbon steel.