07-11-2012, 12:17 PM
Design Analysis of an Electric Induction Furnace for Melting Aluminum Scrap
Design Analysis of an Electric Induction.pdf (Size: 76.13 KB / Downloads: 130)
Abstract
The advancement of any nation technologically has been influenced and elevated by the extent to which it can usefully harness and convert its mineral resources. The productions of metal in foundries and in all human lives have also become a general practice. Different melting techniques are in practice with different energy sources. The cleanliness and availability of electrical energy sources in Nigeria is of paramount importance to its use in foundries, hence the need for this design. This paper deals principally with the mechanical and electrical requirements for induction furnace production. The mechanical aspect gives consideration to the geometrical components, cooling system, and the tilting mechanism. The electrical aspect deals with the furnace power requirement to make it functional. The design was achieved through consideration of relevant theories and their practical application.
Introduction
In the production of mineral resources, the melting of metals has become one of the tremendous industrial practices in the forefront. This is because metals are versatile elements whose fields of application are very wide in human lives.
Of all metals, iron production has developed substantially, such that different types of furnaces ranging from blast furnaces, open-hearth furnaces, to converters and electric furnaces for steel production are in use today worldwide. Here in Nigeria, Ajaokuta Steel Company and Delta Steel Company are examples of steel making companies that use these types of furnaces.
Aluminum being the most abundant metallic element, forming about 8% of the solid portion of the earth’s crust, is rarely available as rich ores. Hence most countries are dependent on supplies of it being imported. Nigeria, for instance, uses aluminum in all aspects of human endeavor (Abubakre 2001), be it transportation, machine components, cooking utensils alloying etc.
Basic Components
The induction furnace consists basically of a crucible, inductor coil, and shell, cooling system and tilting mechanism.
The crucible is formed from refractory material, which the furnace coils is lined with. This crucible holds the charge material and subsequently the melt. The choice of refractory material depends on the type of charge, i.e. acidic, basic or neutral. In this design a neutral refractory is use and based on effectiveness, availability and practical application in Nigerian foundries, zirconium oxide (ZrO2) is implored. The durability of the crucible depends on the grain size, ramming technique, charge analysis and rate of heating and cooling the furnace.
The inductor coil is a tubular copper coil with specific number of turns. An alternating current (A.C) passes through it and magnetic flux is generated within the conductor. The magnetic flux generated induces eddy currents that enable the heating and subsequently the melting process in the crucible. In order to eliminate electrical breakdown the turns are insulated by wrapping with mica tape, this serve as a good insulator.
Conclusion
The development of this project from the theoretical aspects to its practical application is of immense contribution to the development of Nigerian foundry technology and to enhance availability of spare parts. The Induction furnace design and subsequently its fabrication should be promoted considering the abundant power sources, less maintenance cost and labor requirements.