This article deals with description of "induction melting furnace aod and/or ladle refining furnace" methods to make construction and alloy steel and tells its advantage over old methods.
The use of medium frequency induction melting furnaces for producing casting has been a world-renowned process for ages. But production of structural steel, alloy steel and stainless steel through "Induction Melting Furnace AOD and/or Ladle Refining Furnace" route is relatively a new concept.
Engineering industry has grown by leaps and bounds during the last decade the world over, and so has generation of steel scrap. Electric Arc Furnaces were used for re-melting of this scrap to convert the same into saleable steel products. But four major factors went against the electric arc furnaces - high capital cost, high operational cost, week electricity grids and long gestation period. Besides, most of such scrap has been available locally and its transportation to a distant place is a costly affair. The consumption of structural steel in any city has grown up for development of the city through construction ofroads, buildings, bridges, plants and machinery, et al. Therefore, it became imperative for the country to have some alternative route to re-melt the steel scrap, as and where available,economically, for local consumption.
Electrotherm redefined the scrap re-melting process by economising the cost of installation, cost of operation and gestation period through induction melting furnace - ladle refining furnace route. Induction furnaces in India have replaced over 600 electric arc furnaces during late 1980s and early 1990s. Electrotherm has made Mini Steel plants of as small as 30.000 TPA to as large as 500.000 TPA capacities economically viable through induction furnaces.
Induction furnaces are now widely used, not only in India but also in other Asian, African and Middle Eastern countries as well, to re-melt steel scrap. Control of chemical composition, especially carbon, was a difficult task in induction furnaces as oxygen blowing was not advisable, and the only means to have carbon under prescribed limit was by using selected and graded scrap. Now carbon reduction has also become easier in induction furnaces, without oxygen lancing, by using calculated quantity of Direct Reduced Iron (DRI). Refining, alloy addition and superheating is then carried out in DC Plasma Ladle Refining Furnace to produce high quality structural steel and alloy steel.
Steel plants striving to produce stainless steel have got very efficient and convenient equipment from Electrotherm in the form of Metal Refining Konverter (MRK). MRK is essentially decarburising equipment for most effective production of stainless steel and several grades of low carbon alloy steel. Indias largest stainless steel producer Shah Alloys Ltd., Ahmedabad happens to be the largest stainless steel producer in the world through induction - MRK - LRF route. Electrotherm has supplied 4 induction furnaces of 20-tonne, two MRKs of 20-tonne and two MRKs of 50-tonne capacities to Shah Alloys. Electrotherms clients through Induction -MRK -LRF - CCM rolling mill route are successfully producing difficult grades of 200 series stainless steel sheets up to 0.35 mm in India.
Today, India produces around 50 million tonnes of steel per annum and the plants done by Electrotherm are contributing around 12 to 14 million tonnes. Many plants have been installed for using up to 80% DRI for producing various grades of steel through induction melting furnaces economically as DRI is a cheaper raw material, and some time the only raw material available.
Electrotherm has successfully executed turnkey projects in different parts of the world for Mini Steel Plants of various capacities and is now executing Integrated Steel Plants consisting of DRI plant, SMS and rolling mill starting with iron ore and coal as the main raw materials to produce rolled steel products. At the moment. Induction Melting Furnace Ladle Refining Furnace combination is the most effective route to produce high quality steel from scrap/DRI economically.
|Posted : 8/12/2005|