ABSTRACT

 In this research work the mechanical and microstructural proper' of medium carbon steel is a'eterminect based on the quenching medium employed on it. Three quenching mediums — air, oil and water arc studied to determine which better improves the hardness and wear resistance properties of the mild steel rods used in the study. The result and analysis from the hardness test is compared with the hardness of the same steel materi.21 when it is not heat treated. A mild sled bar of16mm diameter and 180 mm length each was useifor this study. The steel rods were 4eated at an elevated temperatures of 700 °C', held at this tenperature for 45 seconds. Then different quenching techniques were used to bring down the temperature of the metal to room temperature. The hardness of each specimen of the mild steel rod- air cooled 'specimen A), oil cooled (specimen B) and water cooled ("specimen C) specimens were respectively determined and compared against the mild steelbar that was not heat treated ('specimen Z). The Rocirwell hardness testing machine waused to determine the iardness of the various spechnens. The water cooled mild steel proved ía have a higher hardness value 79 HRB against all other quenching tnediuin which hada hardness value of 77 HRB for specimen A, 73 HRB for specimen B and 71 HRBJr specimen z. jlel7ee, this research rvealed that the adoption of the water as a quenching medium better iinpro icr the hardness and wear rsisrance of medium carbon steel.