Ihom A.Paul^1,, Nyior G. Bem², Nor I. Justine³, Ogbodo N. Joy⁴

This work has investigated the possibility of utilizing egg shell waste which is a rich source of calcium carbonate as an enhancer or energizer in the case hardening of mild steel using organic solid wastes like sugar cane, melon shells and aracaceae flower droppings as the carbon source. The mild steel specimens were inserted in carburizing boxes containing the carburizing material and carburized at a temperature of 920°C for 5 hours. They were then quenched in water, after which they were prepared for hardness test using Rockwell hardness tester, and for microscopic examination. The result showed that the carbonaceous organic waste used improved the case hardness of the steel. The result also showed that egg shell containing carburizing material produced higher case hardness on the steel than those carburizing materials without egg shell. Sugar cane waste produced a case hardness of 45.1HRC, with egg shell the case hardness became 45.5HRC. Melon shell waste produced a case hardness of 47.8HRC, and with egg shell the case hardness became 52.6 HRC. This hardness corresponded to an effective case depth of 0.65mm. Aracaceae flower wastes produced a case hardness of 56 HRC on the mild steel this corresponded to an effective case depth of 0.7mm, with egg shell the case hardness became 56.6 HRC with an effective case depth of 0.75mm. The calculated total case depth based on carburizing parameters was 1.34mm. The effect of egg shell waste as an enhancer in the carburization of mild steel has been established the result of the work has clearly shown that egg shell waste can be used in place of calcium carbonate to improve on the hardness value of mild steel during carburization. The success of this work has created another outlet for reducing the waste burden attributed to these solid wastes

carburization, enhancer, egg shells, mild steel, organic solid wastes