Department of Metallurgical and Materials Engineering

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Browsing Department of Metallurgical and Materials Engineering by Author "Adeyemi, M.B"

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  • Item
    Open Access
    Effects of Bath Temperature on Cooling Rate, Mechanical Properties and Microstructure of Medium Carbon Steel during Quenching Operations
    (Journal of Energy Technologies and Policy, 2015) Agboola, J.B.; Abubakre, O.K.; Mudiare, E.; Adeyemi, M.B
    The effects of variations of bath temperatures of Selected Nigerian Vegetable oils on cooling rates, mechanical properties and microstructure of the quenched steel samples were investigated in this work. Cooling curves at different bath temperatures have been experimentally determined. From the cooling curves, the cooling ability variations were then analysed. The results obtained show that increasing bath temperatures increased the cooling rates of the quenched steel. These cooling rates are found to enhance mechanical strength with limited ductility of the quenched carbon steel. The hardness and tensile strength for palm kernel quenched sample increased from 40.8 HRC to 43 HRC. However, percentage elongation and impact values decreased from 0.28% to 0.21% and 9.5 N/mm2 to 7.5 N/mm2 respectively as bath temperature increases from 35 °C to 100 ºC. The results also showed that the microstructure of the quenched steel samples can be changed and significantly improved by varying the bath temperature. Reasons for variation in mechanical properties and microstructure are discussed
  • Item
    Open Access
    Effects of Velocity of Impact on Mechanical Properties and Microstructure of Medium Carbon Steel during Quenching Operations
    (Scientific Research Publishing Inc. (Engineering), 2015-07-17) Agboola, J.B.; Abubakre, O.K.; Mudiare, E.; Adeyemi, M.B
    Theoretical analysis of the effects of the velocity of impact using suitable heat transfer equations expressed in forms of finite difference method was developed and used to determine their effects on the characteristic cooling parameters during the quenching process. Various velocities of impact obtained by varying the heights of specimen drops were also used to experimentally determine their effects on characteristic cooling parameters and mechanical properties of medium carbon steel using water as the quenching medium. At a height of drops of 0.5 m, 1.0 m, 1.5 m, and 2.0 m, the tensile strength of the material is 410.4, 496.12, 530.56, and 560.40 N/mm2 respectively. The corresponding hardness values are 42.4, 45.2, 46.2, 50.5 HRC respectively. It is found that as the velocity of impact increases, the maximum cooling rate increases. Hardness and ultimate tensile strength also increase. There are good agreements between theoretical and experimentally determined values of critical cooling parameters of water during quenching operations.
  • Item
    Open Access
    Performance Assessment of Vegetable Oil and mineral oil blends during heat treatment of Medium Carbon Steel
    (International Journal of Microstructure and Materials Properties, 2016) Agboola, J.B.; Abubakre, O.K.; Edeki, M.; Adeyemi, M.B
    A comparative study was carried out to investigate the suitability of some selected Nigerian vegetable oils as alternative quenchant to SAE40 engine oil for industrial heat treatment of Medium Carbon steels. The study involved the characterization of physicochemical properties and fatty acid profile of cottonseed oil, palm kernel oil, neem seed oil and palm oil. The quenching performance of these vegetable oils was conducted at quenchant bath temperatures of 34˚C, 50˚C, 70˚C, and 100˚C. SAE40 engine oil (Standard quenchant) and tap water served as control. The effect of cooling rates of the quenching media on mechanical properties and microstructure of the quenched steel samples were investigated. The results obtained show that the different vegetable oils have different viscosity and viscosity-temperature behaviour just as their molecular structures were different. The mechanical properties of the as-quenched specimens in these oils show that the hardness of steel quenched in palm kernel oil was highest at 40.85HRC. As received sample absorbed the highest amount of energy (183 J) before fracture while the sample quenched in water absorbs the least energy (28 J). Hence vegetable oil is suitable as an alternative quenchant to petroleum-based SAE40 engine oil for quenching medium carbon steels, without cracking or distortion, the most suitable among them being palm kernel oil.