Aluminium Shots and Notch bars
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by: U Konapure
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Southern Ferro is a Public Limited Company , established in 1972 having rolling mills, structure steel , ingot manufacturing. The company is Managed by Technocrats.
We manufacture Aluminium shots/Notch Bars according to IS-1253:1992 Aluminium for use in Iron & Steel manufacture- specification
IS-1253:1992 Aluminium for use in Iron & Steel manufacture- specification
4.2 Aluminium Grade 1 is normally suitable for use in manufacture of mild steel and low alloy steels,where as Grade2 is normally required for manufacture of Alloy Steel & Special Steels.
The Company also manufactures Aluminium Shots and Notch Bars (1Kg piece).
SHORT TECHNICAL NOTE:
On use of Aluminium for deoxidation of molten steel.
The main sources of Oxygen in steel making are as follows:
• Oxygen Blowing (Example : Basic Oxygen Furnace (BOF)
• Oxidizing stages used in steel making processes (Example: Electric Arc Furnace)
• Atmosphere Oxygen dissolved in liquid steel during pouring operation.
• Oxidizing Refractory (Lining of furnaces and Ladles)
• Rusted and wet scrap, G.I.Scrap.
Solubility of Oxygen in molten steel is 0.23% at 1700 deg. C. However it decreases during cooling down and then in drops sharply in solidification reaching 0.003% in the Solid steel.
Oxygen liberated from the solid solution oxidizes the steel components (C, Fe, alloying elements) forming gas pores (blow holes) and non metallic inclusions entrapped within the ingot structure. Both blow holes and inclusions adversely affect the Steel quality.
Preliminary deoxidation is achieved mainly by adding Fe-Si in the Furnace or ladle in the final stage of melting. However the effectiveness of the deoxidizer tends to fade with time and deoxidation of the complete volume of melt is difficult to achieve. Therefore, the deoxidizers should be added continuously in Spruce/cenre column while pouring.
Final deoxidation of steel in steel making is most commonly done by Metallic deoxizers like Manganese, Silicon and Aluminum; Aluminium being the most powerful deoxidizer. AS IT HAS A HIGH AFFINITY FOR OXYGEN, HIGH SOLUBILITY IN STEEL, LOW COST, READY AVAILABILITY AND EASE OF ADDITION TO MOLTEN METAL. Theoretically, the equilibrium constant at 1600 deg.C for MG 1.318, Si 4.518 and Al 13.018.
However, it has been found that when an excessive amount of Aluminium is added, generally above about 0.08%, Aluminium nitride embrittlement of the resultant casting tends to occur.
Aluminium and Si are uncreactive additive which melts but does not boil at the temperature of the molten steel. Therefore, turbulence is required to dissolve and mix the aluminium through the steel. In Bottom Pouring for Ingots, therefore, these shots should be added in the Centre Column so that when the molten steel falls, it creates a turbulence for effective and continous deoxidation. Better results are achieved if the shots are mixed with some Fe-Si which gives retardation to the aluminium for better mixing and homogenization with molten steel for effective deoxidation.
About the Author
Southern Ferro Ltd. (Aluminium Division) Industrial Estate, Gokul Road, Hubli - 580030 Karnataka,INDIA Phone: +91 - 836 - 2330024/25 +91 - 836 - 4252282 Fax: +91 - 836 - 2331429 Email: southern.alu2011@gmail.com southernfero@gmail.com alu@southernferro.com Website : www.southernferro.com Contact Person: U.S. Konapure Conatct No: +91 - 93798 - 29014
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