Browsing by Author "Oyetunji, A."

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Achievement of Nodules in Ductile Iron Having Sulphur Content Not Less Than 0.07% Weight
(Daffodil International University, 2014-07-01) Oyetunji, A.; Omole, S.O.
Scraps melt were analyzed with optical light emission spectrometer for chemical composition. The charge was prepared theoretically with carbon percent of 3.9 and silicon of between 2.1 and 2.8 percent after inoculation. 2 kg of CaCO3 (flux) was charged to aid removal of slag. The charges were heated to a tapping temperature of 1430° C. Temperature was monitored by inserting thermocouple in to the charges. The melt was desulphurised with 0.30 kg calcium carbide (CaC2) after the attainment of 1430°C. Three tappings were made tagged A, B and C into the prepared ladle via sandwich process. 3.5 %, 3.0 % and 2.0 % of ladle capacity (15 Kg) was the quantity of Mg used to treat melts A, B and C respectively. The treated melts were poured into the prepared sand moulds forming desired casting. The as-cast were analyzed again to determine its chemical compositions and found that carbon and silicon were not less than 2.0 and 1.0 % respectively. The casting was tested for hardness, tensile and micro structural evaluation. The microstructures revealed that as-cast tagged A and B formed nodular iron when etched with 2 % nital even with residual sulphur content of 0.075 % and 0.070% for A and B respectively. Cast produced from melt C revealed not a clear nodular cast iron. Emphasis is on casting A and B as we obtained nodules in A and B.
Investigation of Foundry Properties of Oshogbo and Saki Silica Sand Deposits
(Daffodil International University, 2013-07) Ayoola, W.A.; Oyetunji, A.; Adeosun, S. O.; Sekunowo, O. I.; Bodude, M. O.
The quality of moulding sand used in foundry usually exerts significant influence on cast properties. It is therefore imperative that the moulding characteristics of a green sand deposit are established prior to its application. This work compares the foundry properties of moulding sand from River Osun and Saki with a view to determining their suitability for casting household utensils. In addition, it also investigated the effect of termite hill activities on moulding sand. Samples of the sands were obtained from different locations within the deposits in Oshogbo and Saki respectively. AFS sieve analysis was performed on the sand to obtain 600 µm grain sizes. These compositions were later mixed in different proportions and then subjected to green and dry compression strengths, shatter index, permeability and moisture content tests. The results obtained indicated that Oshogbo sand deposit has superior green and dry compression strengths values of 16.35 kN/m2 and 14.49 kN/m2 over that of Saki which exhibited 9.3 kN/m2 and 8.3 kN/m2 respectively. The highest permeability of 193 ml/min was demonstrated by Saki compared with 79 ml/min by Oshogbo deposits while the difference in their moisture contents is insignificant. The shatter index of 64 % and 72 % was obtained for Oshogbo and Saki sands respectively. These results demonstrated the possible utility of both sands for making of sand casting moulds. However, Oshogbo deposit is recommended for its higher fraction of the 600µm grain being the preferred size with demonstrable foundry sand desired properties.