Browsing by Author "Oluwole, O. O."

Now showing 1 - 20 of 53

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 foundry
Aluminium anode activation research- a review
(2012) Idusuyi, N.; Oluwole, O. O.
The aim of this paper is to review aluminum anode formulation and activating elements till date and discuss the possibility of further work based on recent trends in the use of nano or agro based materials. The performance of aluminum anodes is largely dependent on alloy composition and a good understanding of the relationships between the metallurgy and the anodic response of the alloys. Recent researches show that microalloying aluminum anodes with certain metallic composite oxides can significantly improve anode life and reduce costs. Suggestions for further work are also presented.
Coal-fired power systems: oppportunities and challenges in the development of superalloys for boiler systems
(2011) Oluwole, O. O.
Coal fired power systems are still integral part of energy generation in many countries. The fact that this scenario will remain for quite sometime has accentuated the pursuit of clean coal initiatives (CCPI) aimed at getting to near zero(NZE)the carbon emissions in coal power generation. One of the major challenges in development of clean coal technology is in the area of materials technology for the development of boiler/steam turbine and Integrated Gasification Combined Cycle (IGCC) systems. As the most critical component in the construction of boiler systems, the superheater tubes have to undergo the most severe service conditions and must meet Stringent requirements with respect to fireside coal-ash corrosion/erosion, steamside oxidation and spallation, along with creep strength, thermal fatigue strength, and weldability. This paper presents the challenges of developing novel superalloys for these systems and the methods being advanced to overcome the problems.
Comparative analysis of analytical and graphical upperbound solutions for 4-high reversing aluminium cold-rolling sheet mill
(Scientific & Academic Publishing, 2012) Oluwole, O. O.; Adewumi, A. D.
Upper bound solutions to a 4-High reversing aluminium cold-rolling sheet mill was obtained in this work using both analytical and graphical methods. The upper bound method was applied to the rolling of an Al 1200 sheet from 7mm to 0.6mm in six passes. It was observed that both methods were very effective in predicting upper bound load value with the graphical method giving a higher value using input velocity values from industry. However, it was observed that the graphical method becomes very difficult to use when sheet thicknesses become very small.
Comparative analysis of analytical and graphical upperbound solutions for 4-high reversing aluminium cold-rolling sheet mill
(Scientific & Academic Publishing, 2012) Oluwole, O. O.; Adewumi, A. D.
Upper bound solutions to a 4-High reversing aluminium cold-rolling sheet mill was obtained in this work using both analytical and graphical methods. The upper bound method was applied to the rolling of an Al 1200 sheet from 7mm to 0.6mm in six passes. It was observed that both methods were very effective in predicting upper bound load value with the graphical method giving a higher value using input velocity values from industry. However, it was observed that the graphical method becomes very difficult to use when sheet thicknesses become very small.
Comparative study of corrosion behaviour of nickel and gold plated carbon steels used as ornamentals in saline environment
(Science and Academic Publishing, 2012) Oluwole, O. O.; Garus-Alaka, W.; Ajide, O. O.
This study investigated the corrosion resistance of plated and unplated steels useful as ornamentals in saline environment. Nickel plating of carbon steel was done in watts solution for 25minutes with a current density of 3 Adm-3 at 60oC. The nickel plated carbon steel was later gold plated for 20 minutes with a current density of 0.2 Adm-3 at 50oC . The plated and unplated carbon steels were immersed in saline environment for 360 hours. Weight loss was taken every 24 hours in order to evaluate corrosion penetration rate (CPR). The results obtained showed that plated carbon steel generally offers a better corrosion resistance than the unplated one. Corrosion of ornamentals is equally gaining importance especially coated ornamentals. The use of nickel for ornamentals is gaining more prominence over silver rising due to its shiny surface and its cost. The use of nickel plated ornamentals just as gold plated ornamentals are being patronized will surely become common place due to affordability for the generality of people. However, the effects of everyday corrosive fluids from kitchen salt and low acidic media on the durability of the coatings need to be established. Carbon steel is the natural substrate used in ornamental coatings .The results also showed that a small thickness of gold plated carbon steel exhibited better corrosion resistance in saline environment. More also, gold plated carbon steel is found to be more suitable and reliable candidate material than nickel plated carbon steel in this environment although with higher costs.
Comparative study of corrosion behaviour of nickel and gold plated carbon steels used as ornamentals in saline environment
(Science and Academic Publishing, 2012) Oluwole, O. O.; Garus-Alaka, W.; Ajide, O. O.
This study investigated the corrosion resistance of plated and unplated steels useful as ornamentals in saline environment. Nickel plating of carbon steel was done in watts solution for 25minutes with a current density of 3 Adm-3 at 60oC. The nickel plated carbon steel was later gold plated for 20 minutes with a current density of 0.2 Adm-3 at 50oC . The plated and unplated carbon steels were immersed in saline environment for 360 hours. Weight loss was taken every 24 hours in order to evaluate corrosion penetration rate (CPR). The results obtained showed that plated carbon steel generally offers a better corrosion resistance than the unplated one. Corrosion of ornamentals is equally gaining importance especially coated ornamentals. The use of nickel for ornamentals is gaining more prominence over silver rising due to its shiny surface and its cost. The use of nickel plated ornamentals just as gold plated ornamentals are being patronized will surely become common place due to affordability for the generality of people. However, the effects of everyday corrosive fluids from kitchen salt and low acidic media on the durability of the coatings need to be established. Carbon steel is the natural substrate used in ornamental coatings .The results also showed that a small thickness of gold plated carbon steel exhibited better corrosion resistance in saline environment. More also, gold plated carbon steel is found to be more suitable and reliable candidate material than nickel plated carbon steel in this environment although with higher costs.
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.
The contribution of eutectic liquid film to the TMAZ microfissuring in intertia friction welded PM RR1000 superalloy
(The Nigerian Institution of Mechanical Engineers, 2010) Oluwasegun, K. M.; Olorunniwo, O. E.; Oluwole, O. O.
The microstructure of the base alloy and thermomechanical affected zone (TMAZ) of inertia friction welded powder metallurgy (PM) RR1000 were examined by the use of standard metallogrphic techniques involving optical, analytical scanning transmission electron microscopes equipped with energy dispersive spectometer and an electron probe micro analyser. It was discovered that liquation of grain boundary phases present in the pre-weld alloy resulted in the formation of eutectic type ƴ-ƴ1 solute rich liquid film predominant in the TMAZ regions whic contributed significantly to micro fissuring during welding. It was found that apart from the effect of rapid precipitation of ƴ particles on the TMAZ cracking as has been widely reported, constitutinal liquidation of ƴ particles was a notable part of liquidation process which promoted the susceptibility of TMAZ to microcracking.
Corrosion analysis of nickel and gold plated carbon steel ornamentals in sulphuric acid meduim
(2012) Oluwole, O. O.; Garus-Alaka, W.; Ajide, O. O.
This study investigated the corrosion resistance of Nickel and Gold plated carbon steels ornamentals in 0.5mol/dm3Suphuric acid(H2SO4) medium. Nickel plating of carbon steel was done in watts solution for 25minutes with a current density of 3 A/dm3 at 60oC. The nickel plated carbon steel was later gold plated for 20 minutes with a current density of 0.2A/dm3 at 50oC.The plated and unplated carbon steels were exposed to H2SO4 environment for 15 days. The weight loss was taken every 24 hours in order to evaluate corrosion penetration rate(CPR). The results obtained showed that plated carbon steel generally offered a better corrosion resistance than the unplated carbon steels. The conclusion that can be drawn from this study is that Nickel plated carbon steel is found to be more reliable material to be used as ornamentals than gold plated carbon steel in H2SO4 enviroment
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. "
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. "
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.
Corrossion behavioir of zinc plated 1018 steel in tomato fluid
(2010) Oloruntoba, D. T..; Oluwole, O. O.; Awheme, O
"This research work investigated the corrosion resistance of zinc plated 1018 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. 1018 steel samples were zinc electroplated at voltages between 0.5V to 0.9V for 5 to 20minutes.The plated samples were then subjected to tomato fluid 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 corrosion attack on the zinc- plated steel, the severity increasing with the increasing weight of zinc coating on substrate. The result showed that thinly plated 1018 steel generally did not have any advantage over unplated steel and were quickly stripped of their zinc plating with resultant corrosion of the underlying steel substrate. Heavily zinc-plating steel was observed to offer some form of protection for the plated steel.The pH of the tomato solution which initially was acidic was observed to progress to neutrality after 5 days and then became slightly 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 day. Zinc coating of 1018 steel was found to be unsuitable for the fabrication of tomato processing machinery in this environment.
Development of a field-portable digital potentiostat
(2012) Oluwole, O. O.; Adegoke, T. O.; Ajide, O. O.
The use of potentiostats for corrosion rate studies and activation polarization is very crucial because the weight loss method is limited in corrosion studies. However, commercial potentiostats are expensive for most end users. For these reasons, it was desirable to design and build an inexpensive field-portable potentiostat to interface with electrochemical cell. This paper present the proceeudre and design principles of a portable, digital and inexpensive potentiostat, its construction and testing PROTEUS software was used in the design of the different components of the potentiostate and simulation of the tested in a corrosion cell in which a mild steel working electrode (WE) was immersed in 5% NaCl solution. Ag/ AgCl exchange current density (io of mild steel, |Fe/Fe2) of 1.5 X10-6 A/ cm2, standard potential of ,mild steel (Eo mildsteel) of -0.42V and corrosion penetration rate (CPR) at io of 9.18x10-7 cm/hr and Taffel β value of 0.13V was obtained for mild steel in 5% NaCl solution. The values of OCP, ioEo, CPR and β were consistent with values obtained form literature.
Development of Mathematical Equation for fraction of solid in AlSi7Mg Alloy solidification simulation
(2007) Oluwole, O. O.; Oluwadare, G. O.; Afonja, A. A.
Thermodynamic data is made use of in calculating fraction of metal solidified in solidification simulation. However, thermodynamic data for many industrial alloys in their solidification ranges are not available for most practicing engineers. It is thus desirable to develop reliable equations that can be used in calculation fraction of metal solidified for solidification simulation. This work has developed an equation to calculate fraction of metal solidified for AlSi7Mg alloy solidifying under fast cooling conditions using generated values from thermodynamic data.
Earing characteristics of cold-rolled and temper annealed aluminium 1200
(Asian Network for Scientific Information, 2006) Aderibigbe, D. A.; Oluwole, O. O.; Olorunniwo, O. E.; Atanda, P. O.; Ogundare, O.
Earing characteristics of deep-drawn cold-rooled and temper-annealed 1200 was studied at high deformation levels of 75,85,and 90% cold rolling. The relationshp of earing with varying degrees of cold roll was studied and the effect of different annealing temperatures on earing. Hardness, ductility and strength variations with earing were also studied. Earing was at an aneeal-temperature. The relationship of earing to hardness, ductibility and strength properties were observed to follow the same pattern. Hardness, ductility and strength properties of cold-rolled and temper-annealed Aluminium 1200 at lowest eaaring did not necessarily correspond to the materials lowest hardness, highest ductility or lowest strength respectively and were found to vary for varying degrees of cold-roll.
Effect of draw ratio and sheet thickness on earing and drawability of Al1200 cups
(2010) Oluwole, O. O.; Anyaeche, C. O.; Faola, O. V.
"The effect of blank/punch diameter ratio (draw ratio) in deep drawing on earing for different gauges of Al 1200 sheet was studied. Using 60, 62, 64 and 65mm diameter circle blanks and 33mm diameter punch die, fully annealed Al 1200 sheets of gauge thicknesses 0.6 to 2.0mm were subjected to deep drawing on an ErrichsenR cup drawing machine. The results showed that with increase in sheet thickness, the smaller is the draw ratio that would draw the sheet. For 0.6-0.9mm sheet thickness, cups were drawn with draw ratios of 60/33 to 65/33. For sheet thicknesses of 1.2-1.58mm, only 60/33 and 62/33 draw ratios were observe to draw cups. Earing was observed to generally increase with increasing draw ratio using the same sheet thickness. It was also observed that for thinner sheets (0.6-0.9mm), using the same draw ratio, earing increased with increasing sheet thickness. For thicker sheets (1.2-1.58mm) earing was observed to decrease with increasing sheet thickness. After that, there was an increase for deep-drawn 2mm thick sheet. Higher draw ratios were observed to draw deeper cup depths with minimal earing. The depth of jcups drawn with 65/33 draw ratio was observed to be about 28% more than those drawn with 60/33 draw ratio with an increase in earing of only 0.84% for 0.6mm thick sheet and 1.2% for 0.9mm thick sheets. Earing was also observed to increase by 1.64% for the 2mm thick sheet that had undergone grain growth over the fine grained one. "
The effect of A5TB refiner on the fatigue strength of 6063Al alloy
(2010) Ibitoye, S. A.; Adeleke, A. A.; Oluwole, O. O.; Tiamiyu, A. O.; Ode, E. B
The study focuses on the influence of aluminium titantium boron (ASTB) master alloy on the fatigue behaviour at 6063Al alloy. Cylindrical cast rods of 6063Al containing different proportions of A5TB ranging from 0-0.11 wt% were produced and were machined to conform to a standard fatigue specimen. The test specimens prepared were tested for fatique strength at various stress levels, and results obtained were compared. The resistance to fatique failure was observed to decrease as the stress level increased. It was also noted that irrespective of stress level, the optimum fatique strength was obtained when the A5TB content was about 0.06 wt%. It was found that 6063Al alloy to which A5TB master alloy have been added was most suitable for the design of components meant to operate under cyclic loading at low stresses below about 3.02KN/m2.
Effect of cold drawn deformation on mechanical properties of low carbon steel due to changes in grain size
(2011-09) Raji, N. A; Oluwole, O. O.
The effect of grain size on the mechanical properties of cold-drawn low carbon steel was investigated. Low carbonsteel specimen cold-drawn to 20%, 25%, 40% and 55% as applicable for the manufacture of 4 inches, 3 inches,21/2 inches and 2inches nail were obtained. The study was aimed at providing experimental result for the understanding of grain size effects which occur with increasing degree of cold-drawn deformation in low-carbon steel used for nail manufacture.The micrographs of steel were obtained using optical microscopy(OM) observation for 20%, 25%,40% and 55% degrees of drawn deformation. From the OM micrographs the counting method as stated in the ASTME E112 standard for grain size was used to determine the grain size of the steel on the micrograph at the different degrees of deformation. The tensile strength, yield strength, brinnel hardness, and toughness of the materials were obtained from mechanical tests. It was shown that the tensile strength, yield strength, toughness and hardness follow quite closely the hall-petch equation.