Browsing by Author "Owolabi, Oluwasegun Biodun"
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Item Effect of welding variables on mechanical properties of low carbon steel welded joint(Advances in Production Engineering & Management, University of Maribor, 2014) Talabi, Segun Isaac; Owolabi, Oluwasegun Biodun; Adebisi, Jeleel Adekunle; Yahaya, TaiwoThis paper discussed the effect of welding variables on the mechanical prop-erties of welded 10 mm thick low carbon steel plate, welded using the Shield-ed Metal Arc Welding (SMAW) method. Welding current, arc voltage, welding speed and electrode diameter were the investigated welding parameters. The welded samples were cut and machined to standard configurations for tensile, impact toughness, and hardness tests. The results showed that the selected welding parameters had significant effects on the mechanical properties of the welded samples. Increases in the arc voltage and welding current resulted in increased hardness and decrease in yield strength, tensile strength and impact toughness. Increasing the welding speed from 40-66.67 mm/min caused an increase in the hardness characteristic of the welded samples. Initial decrease in tensile and yield strengths were observed which thereafter increased as the welding speed increased. An electrode diameter of 2.5 mm provided the best combination of mechanical properties when compared to the as received samples. This behaviour was attributed to the fact that in-creased current and voltage meant increased heat input which could create room for defect formation, thus the observed reduced mechanical properties.Item Review on Oxide Formation and Aluminum Recovery Mechanism during Secondary Smelting(Journal of Castings and Materials Engineering, 2018) Osoba, Lawrence Opeyemi; Owolabi, Oluwasegun Biodun; Talabi, Segun Isaac; Adeosun, Samson OluropoThe remelting, refining, and casting process of aluminum alloys often generate aluminum dross containing primarily oxides and nitrides of aluminum and entrapped metallic aluminum at the surface of the molten metal as a result of reactions within the furnace atmosphere at elevated temperatures. The handling of dross is an expensive but necessary activity during aluminum smelting. Furthermore, the amorphous Al2O3 oxide film formed on the pure molten aluminum surface due to the liquid metal randomly distributed atoms is impermeable to the diffusion of aluminum metal and oxygen. In amorphous materials, there is a low mobility of the charge carriers and an absence of preferred diffusion paths. This film can transform to crystalline Al2O3 by nucleation and grows with time and opportunity. This review discusses the mechanism of oxide formation and the aluminum metal recovery processes.