FACULTY OF TECHNOLOGY
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Item Corrosion behavior of nickel plated low carbon steel in tomato fluid(2009-06) Oluwole, O. O.; Olawale, O."This research work investigated the corrosion resistance of nickel plated low carbon steel in tomato fluid. It simulated the effect of continuous use of the material in a tomato environment where corrosion products are left in place. Low carbon steel samples were nickel electroplated at 4V for 20, 25, 30 and 35 mins using Watts solution.The plated samples were then subjected to tomato fluid environment for for 30 days. The electrode potentials mV (SCE) were measured every day. Weight loss was determined at intervals of 5 days for the duration of the exposure period. The result showed corrosion attack on the nickel- plated steel, the severity decreasing with the increasing weight of nickel coating on substrate. The result showed that thinly plated low carbon steel generally did not have any advantage over unplated steel. The pH of the tomato solution which initially was acidic was observed to progress to neutrality after 4 days and then became alkaline at the end of the thirty days test (because of corrosion product contamination of the tomato)contributing to the reduced corrosion rates in the plated samples after 10 days. Un-plated steel was found to be unsuitable for the fabrication of tomato processing machinery without some form of surface treatment - thick nickel plating is suitable as a protective coating in this environment. "Item Corrosion behavior of 18/8 stainless steel and nickel-plated low carbon steel in cassava fluid(2009) Oluwole, O. O.; Atanda, P. O.; Odekunbi, O. A.; Odegbaju, E."This research work investigated the corrosion resistance of nickel- plated medium carbon steel and 18/8 stainless steel in cassava fluid (i.e. containing hydrogen cyanide). It simulated the effect of continuous use of the materials in a cyanide environment where corrosion products are left in place. Low carbon steel sample was nickel electroplated at 4V for 35 minutes. The plated sample, the unplated and the 18/8 stainless steel were then subjected to a cassava fluid environment for thirty days. The electrode potentials, in mV (SCE), were measured every day. Weight loss was determined at intervals of 5 days for duration of the exposure period. The result showed little corrosion attack on the nickel-plated steel on the fifth and tenth days which quickly dropped to zero by the 15th day and remained at the passive state till the 20th day when corrosion picked up again increasing steadily, linearly until the end of the test day. Corrosion of the 18/8 stainless steel was very low as well decreasing till the last day of the test. The pH of the cassava solution which initially was acidic because of the cyanide content in the cassava was observed to progress to neutrality within five days and to alkalinity at the end of the thirty days test (because of corrosion product contamination of the cyanide). Un-plated steel was found to be unsuitable for the fabrication of cassava processing machinery because of the very high corrosion rate.18/8 stainless steel was found suitable for use in this environment. The renewed corrosion activity on nickel plated steel after the 20th day (pH=12) of continuous use in cyanide environment makes it unsuitable for use. "Item Corrosion behavior of nickel plated medium carbon steel in cocoa liquor(Pacific Journal of Science and Technology, 2009-11) Oluwole, O. O.; Olorunfemi, O.This research work investigated the corrosion resistance of nickel plated medium carbon steel in cocoa liquor. It simulated the effect of continuous use of the material in a cocoa liquor environment where corrosion products are left in place. Medium carbon steel samples were nickel electroplated at 4V for 20, 25, 30, and 35 mins. using Watts solution. The plated samples were then subjected to a cocoa liquor environment for 30 days. The electrode potentials mV (SCE) were measured every day. Weight loss was determined at intervals of 5 days for the duration of the exposure period. The result showed maximum corrosion rate on the nickel-plated steels to be 0.05mm/yr throughout the 30 days. duration of the test while corrosion rate in the un-plated steel was observed to be 0.36mm/yr at the end of 30 days. Generally, it was observed that the thicker the nickel coating, the lower the corrosion rate. The pH of the cocoa liquor was acidic throughout the thirty days test duration. Nickel plating is suitable as a protective coating for mediumcarbon steels in cocoa liquor environment.Item Stress loops effect in ductile failure of mild steel(2009) Oluwole, O. O.A simulation study of effect of stree on mild microstructure has revealed stress loops at areas of stress application which are believed to be the root cause of the ductile failure morphology (cup and cone) in ductile alloys under plane strain conditions. The area of concerntration of these stress loops were obsrved to be that of subsequent instability (or necking) observed in mild steel and other materials of low friction (flow) stress. Shear stress loops with angular bearing of 45 o to the tensile axis were observed to instigate both the failure site and shear morphology in these materials. In plane stress conditions, shear was seen to be that of a wave shape running obliquely to area of stress application resulting in oblique necking observed in thin mild steel sheets.Item Finite element modeling of heat transfer in salt bath furnaces(2009) Oluwole, O. O.; Atanda, P. O.; Imasogie, B. I."Heat flow patterns in two salt bath furnaces were studied in this work using finite element(FE) analysis. The implications of the heat flows on long term stability of furnace performance were evaluated. One design had a purely silica brick back-up after the embedded heating element with asbestos and glass-wool fiber insulation just before the outer steel shell. The other had an additional air-gap insulation formed by cylindrical steel belts with spacers placed after the silica back-up. It was observed that the design with additional air-gap insulation had tremendous insulation effect, necessitating a drastic thinning down of the silica brick thickness and glass wool fiber. "Item Engineering research for self-reliance-modeling and simulation perspective(2009) Oluwole, O. O."Engineering research is a sine-qua-non for development of new products, new production processes, hence production lines in the quest for self reliance in any economy. Modeling and simulation is a veritable tool for such research and development. This paper presents the multifaceted use of modeling and simulation as decision tools for engineering facet of an economy drawing examples from two different engineering disciplines- Metallurgical and Civil. "Item Comparative study of corrosion behaviour of galvanized steel and coated Al 3103 roofing sheets in carbonate and chloride environments(2009) Oloruntoba, D. T.; Oluwole, O. O.; Oguntade, E. O.This work studied the comparative corrosion behaviour of Al3101 and galvanized steel roofing sheets in 1M, 0.5M and 0.3M solutions of sodium carbonate and sodium chloride. Samples of the aluminium and galvanized sheets were subjected to the different environments for thirthy days. The electrode potentials, in mV(SCE), were measured everyday. Electrode potential measuremets were taken everyday for thirty consecutive days. Weight loss or gain measurements were taken every three days for the duration of the exposure period. The results showed sodium chloride environment had higher corrosive effects on the galvanized roofing sheet than sodium carbonate environment while the reverse was true for aluminium sheets. Also, galvanized steel roofing corroded more than aluminium roofing in both carbonate and chloride environments. Corrosion of galvanized steel roofing was continous throughout the exposure period in all the environment used. Galvanized steel roofing sheet is not good material for roofing in carbonated and chloride environments or in industrial environments where chloride or carbonate contamination is possible.Item Effect of thermomechanical working on the strengthening of some austenitic steel grades(Elsevier, 2009) Omotoyinbo, J. A.; Oluwole, O. O."This work studied the effects of degrees of warm-split rolling at different temperatures on the strengths of three different grades of austenitic steels (chrome–manganese, chrome–manganese with Ni and Mo additions, chrome–nickel with Mn and Mo additions). The results were compared with cold-rolling effects on the steel grades. The tensile, hardness and impact strengths of the rolled products were obtained. The results showed that thermomechanical working remarkably influenced the properties of the alloys. The trend in property change was dictated by both the degree and temperature of deformation. It was concluded that warm deformation at 350 _C and degree of deformation between 20% and 30% enhanced the plasticity values (toughness and ductility) of the alloys. "Item Adaptation of Ushafa clay, Abuja, as a suitable replacement for bentonite in the foundry industry(2008) Atanda, P. O.; Oluwole, O. O.; Ogale, O. T.This work investigated the possible use of Ushafa clay in Abuja, Nigeria as a suitable replacement for bentonite clay in foundry use. Moulding sand mixes with compositions of 8,10 and 13%. Ushafa clay, silica sand and 5,7,8,9,10 and 11% coal dust additives were mulled. From each mix, cylindrical specimens were prepared and subjected to permeability, shatter index, compression and shear strength tests . The results from the Ushafa mix were compared with results from bentonite mixes. The results showed that moulding sand compositions having 13%. Ushafa clay, and coal dust additions of 8% produced specimens with good permeability, dry strength, green strength and collapsibility for foundry use. This work has confirmed the possible use of Ushafa clay as suitable replacement for bentonite binder in foundryItem Working properties of some selected refractory clay deposits in South Western Nigeria(2008) Omotoyinbo, J. A.; Oluwole, O. O."Working properties of some clay deposits in Ekiti State, Nigeria were investigated with a view to determine their suitability for use as refractory bricks. The samples were collected from three different commercial pottery clay centers in Ekiti State; they are Ara, Awo and Isan. Two varieties were collected from both Ara and Isan, which are named Ara 1, Ara 2, and Isan 1, Isan 2 respectively while only one type was collected from Awo. The clay samples were crushed, pulverized, sieved and their chemical compositions were determined. The clay samples were treated separately as well as blended together in different proportions and moulded into bricks. The bricks were dried and fired to 1050°C. Tests for refractoriness, thermal shock resistance, shrinkage, thermal expansion; bulk density, porosity, and compressive strength were carried out on each batch specimen. The results showed that Ara 2 and Ara 1, 2 combined in equal proportions displayed the highest thermo chemical stability. They also possess comparatively high cold crushing strength, and high thermal shock resistance, but definitely not the highest. The apparent porosity of all the batch specimens was found to be high as well as the bulk densities, while the shrinkage of all the specimens were low. It was concluded that 100% Ara 2, and a blend of Ara 1 and 2 in equal proportions, are most suitable for production of crucibles, and furnace lining for non ferrous metals processing, such as Aluminium, Lead and Bronze. "