Investigation of the Suitability of Periwinkle Snail Shells as Carburizing Material for the Surface Hardness Improvement of Low Carbon Steel

The carburization potential of periwinkle snail shells as a carburizing material for the surface hardness improvement of low carbon steel have been studied using the pack carburizing process. The carburizing process was carried out at the temperatures of 850 to 950⁰C at the soaking time interval of 30, 45 and 60minutes. The carburized steel specimens were quenched in water and then tempered at 200⁰C for half an hour to relieve the residual stresses introduced as a result of  quenching. Standard methods were adopted to determined the surface hardness and impact notched strength of the carburized and uncarburized test specimens. Micro-examination was also performed using standard metallographic techniques to observe the influence of the absorbed carbon on the microstructure of the carburized steel specimens. The results of the experiment clearly showed that the carburizing material greatly enriched the steel surface with carbon as exhibited by the surface hardness values. It was observed that the process variables (carburizing temperatures and soaking time) had  significant effect on the surface hardness and impact notched strength of the carburized steel specimens. The surface hardness of the carburized steel progressively increases while the impact notched strength remarkebly decreases with increase in carburizing temperature and soaking time. The peak surface hardness values of 53.7, 58.4 and 59.1 HRC were obtained at the caburizing temperature of 950⁰C for the soaking time of  30, 45 and 60minutes respectively. The uncarburized steel had the highest impact notched strength of 27J while the minimun impact notched  strength of 9J was obtained for the specimen carburized at 950⁰C for 60minutes soaking time.