ABSTRACT
This research work focus on the evaluation of water-based eggshells powder as a quenching medium for hardening medium steel. Medium carbon steel sample with original diameter of 12.00mm and gauge length of 50m was quenched in both the agitated and non-agitated water-based eggshell powder quenchant. The medium carbon steel samples were initially normalized and this was followed by austenitizing the samples at 930oC for 20 minutes which was eventually quench in both the agitated and non-agitated water-based eggshell powder quenchant. Hardness test was carried out on the as-quenched samples to determine the performance of the water-based eggshell powder quenchant which was compared with water and oil. Also, the specific latent heat of vaporization, cooling rates of all the selected quenching media and metallographic analysis was carried out for each as-quenched sample in the selected media. The results obtained show that water-based eggshell powder quenchant has a higher specific latent heat of vaporization than water. The microstructure of samples quenched in agitated water-based eggshell powder quenchant revealed complete transformation of the austenite into martensite and a good degree of hardness was obtained. Therefore, water-based eggshell powder quenchant can be used as a quenching medium for hardening steel.
