DESIGN AND CONSTRUCTION OF DUAL–POWERED HEAT TREATMENT FURNACE
The Importance of materials in industries cannot be overemphasized in the recent advancement of material development for automobiles, aerospace, oil and gas industry, etc. as it has been found to be a veritable tool in improving specific desired properties of metals. The exorbitant cost of heat treatment furnace which is mainly attributed to its imported nature has been responsible for its dearth in the material science laboratory of our Universities. The epileptic nature of power supply in country has also made it imperative to look inward and develop an alternate power source for furnaces in use in the university. As the country expends so much of her wealth on importation and equally clamouring for more local content, it is imperative that Engineers in Training and Engineers come up with solutions to the national problem. This work was aimed at designing and constructing a dual powered heat treatment furnace for the Department of Mechanical Engineering Laboratory, University of Ibadan.
After extensive literature review, Gas was settled for as the alternate power source for electricity due to its relative availability. Having made conceptual designs using SolidWorks, the most viable design was selected with decision matrix. Design Calculations were made with mild steel considered as the charge material as it is the most available ferrous metal/ alloy. The minimum insulation thickness, adiabatic flame temperature of butane, and heat of combustion were calculated Chrome steel was used as the crucible due to its high melting point and especially its passivation ability. The Crucible was designed to be a truncated cone to allow for circulation of hot combustion gases. The final design has a wall thickness of 46 mm; made up of an outer shell thickness of 2 mm steel plate, a Fire Clay -Kaolin based Insulation thickness of 44mm.A furnace height of 402 mm was generated.
The design and construction of a dual powered heat treatment furnace using the adopted methodology was achieved. Upon Testing, the constructed heat treatment furnace which has the capacity of 0.00675 m3 capable of containing 53.06 kg of mild steel, attained a temperature of 400 C in 11 minutes, thus an average heating rate of 36.3 C/ min while powered using a blower based gas burner and an average heating rate of 5.3 C/ min while powered by electricity, the furnace has the ability to switch power source in case of unavailability of electricity and back to electricity in case of restoration. Furnace lost energy can be recovered through recuperation. The furnace which can be used to heat treat ferrous and non ferrous metals alike can be adapted for melting as the crucible is positioned in a vertical direction.