Materials Science and Metallurgy Engineering. 2014, 2(3), 31-34DOI:
Abstract: The study “the effect of holding time on the hardness of mild steel case hardened with carburizing material energized by cow-bone” has been x-rayed. The mild steel specimens used for the study were carburized in the furnace at 900C at various holding times of 2 hrs, 4 hrs, 6 hrs, and 8 hrs, using 65% charcoal / 35% cow-bone as carburizing material. Hardness values were obtained using Vickers Micro-hardness Tester Machine, from the hardness values, hardness profiles were plotted. The result of the study clearly showed that the hardness of the carburized steel increased with increase in holding time. The hardness profile results were higher for higher holding time (surface hardness: 830 Hv for 2 hrs, 850 Hv for 4 hrs, 900 Hv for 6 hrs and 1000 Hv for 8 hrs) and also the plot of the profile for 8 hrs holding time was higher than that of 6 hrs, and that of 6 hrs was higher than that of 4 hrs, and in that order. This clearly showed that holding time has effect on the hardness of case hardened steel.