Exploratory study on Carburisation of Mild Steel using Selected Agroforestry Wastes

Abstract

In the present work, exploratory study was conducted on selected agroforestry wastes as carbonaceous source for carburisation of mild steel in relation to conventional charcoal. Pulverised and carbonised coconut shell (CS), coconut bunch fruit (CBF), palm kernel shell (PKS) and palm kernel bunch fruit (PKBF) and their blends were combined in various proportions with CaCO3 for pack carburisation of mild steel. Carburisation was accomplished by heating the samples to 950 oC for 8 hoursfollowed by oil quenching and subsequent tempering at 450 oC and 550 oC, respectively. Microstructures in the agroforestry waste-carburised samples were similar to those obtained in charcoal carburised mild steel but with differential martensitic morphology and distribution. The hardness profile in the carburised samples correlated to the carbon potential of the carburising source in the trend PKS: 217.24Hv; CS: 203.32Hv; PKBF: 196.23Hv and CBF: 190.4Hv. Similar trend was obtained in the wear behaviour of the carburised samples. The impact strength of the selected agroforestry wastes compared favourably with the conventional charcoal and showed no correlation to the carbon potential. Whilst this study suggests that the selected agroforestry wastes are promising as carburising agents, a further investigation is imperative to determine the optimised carburising conditions as well as the technological framework for carbonisation of the wastes.