ACHIEVEMENT OF NODULES IN DUCTILE IRON HAVING SULPHUR CONTENT NOT LESS THAN 0.07% WEIGHT
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Abstract: 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 1430o 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 1430oC. 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.