The efficacy of carburizing compounds with different carbon source and added industrial energizers for surface treatment of mild steel for mechanical property improvement

Abstract

‘’The Efficacy of Carburizing Compounds with Different Carbon Source and added Industrial Energizers for Surface Treatment of Mild Steel for Mechanical Property Improvement’’ has been studied. The research work involved material sourcing and carburizing compounds preparation. Five compounds were prepared in carburizing steel boxes in which mild steel specimens were embedded, covered and sealed with clay. Electric muffle furnace was used for the carburization process. The pack carburization boxes were inserted in the furnace at operational temperature of 920^oC and holding time of 8 hours. They were then removed and the specimens quenched in water. The specimens which were earlier on prepared by machining using lathe were cut into two and the cut-side was ground, polished and etched for metallographic analysis. For hardness test; the carburized specimens were not etched. The  result  of  the  work  showed  that carbon source determines the efficacy of the carbon material as a carburizing compound in pack carburizing. It was also noticed that charcoal alone produced case depth of 0.08 mm and surface hardness of 58.42HRC, while coal had case depth of 0.06 mm and surface hardness of 54.42 HRC under the same conditions of holding time and carburizing temperature. The addition of industrial chemical energizers drastically improved the efficacy of the carburizing compounds, but the combination of coal and charcoal to energizers did not lead to any synergistic effect in terms of high case depth and surface hardness. The best carburizing compounds were compounds C and D because of the presence of the energizers; they had surface hardness of 64.44 HRC and 64.39 HRC respectively. In the absence of energizers; the charcoal performed better than the coal.