EFFICACY OF GRADED CARBON (COW BONES AND COAL DUST) AS MOULD ADDITIVES ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF GREY CAST IRON

The effect of carbonaceous additives (cow bones and coal dust) on microstructure and mechanical properties of grey cast iron was studied. The melt was prepared with selected cast iron scraps and superheated to 1550℃. With 0.1% inoculant (Fe-Si) was added to the stream to allow uniform dissolution of the inoculants in the melt. Hardness and tensile measurement were examined using Brinnel hardness (HBN) and Instron Tensiometer (1195) for tensile values (MPa) respectively. The microstructural properties of the produced cast were examined through scanning electron microscope attached with energy dispersion spectrometer (SEM/EDS). The morphology was examined through Nikon metallurgical microscope. From the Results, the hardest of the as-cast material and tensile strength was obtained from mould additives of 53 micron below for both additives but cow bone appears better which was supported by the microstructure given. From the hardness propagation, 437BHN was obtained on the average by mould with cow bone additive and lowest with coal dust additive with 409 BHN. The average ultimate tensile strength recorded in mould with cow bone was 212 MPa and 244 MPa in coal dust mould. In all the microstructures indicated significant amount of pearlite matrix, massive carbide and fine distorted graphite flakes which are factor for enhanced performance.