Abstract:
The effect of stirring cavitation and calcium carbide addition on mechanical and electrochemical behavior of grey cast iron has been investigated. The study considered the percentage weight of calcium carbide and speed of cavitation introduced into the melt. 1.0 wt. %, 1.5 wt. % and 1.5 wt. % of calcium carbide and cavitation speed of 180 rpm, 240 rpm and 300 rpm were used respectively in studying the mechanical and electrochemical behaviour. Control samples of varied percentage weight of calcium carbide were produced, without cavitation. Tensile, hardness, wear, microstructural analysis and corrosion tests were used to characterize the samples. The UTS of the grey cast iron increase as the speed of cavitation increases on increase in the addition of 𝑤𝑡.% CaC2 except at 1.0 wt. % CaC2 where the UTS decreases as the speed of cavitation increases. Hardness values of the cavitated samples increases with increase in speed of the stirrer and increase in the CaC2 addition. A decrease in hardness values were observed in cavitated samples as compared to control samples especially at 1.5wt. % and 2.0wt.%CaC2. Impact energy at 1.5𝑤𝑡.% CaC2 addition and moderate cavitation starts the increasing and extends to 2.0wt. % additive up to maximum value of 1.29844J before failures were observed. Influence of variation of the cavitation speed shows an increase in the wear resistance of the samples as the speed decreases. The micrographs of control samples showed that as the CaC2 addition rate increases the graphite morphology changes from type D to type A graphite flakes with few areas of ferrite phase and carbide particles in a pearlitic structure. In acidic medium, the corrosion rate of the sample shows that the control sample will perform better than the cavitated samples. In saline, the control samples show a high corrosion rate as compare to the cavitated samples.
