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Metal Industries
Published in Charles E. Baukal, Industrial Combustion Pollution and Control, 2003
Salama and Desai [42] studied electric induction heating and gas metal heating in forging applications. The following market factors were considered: workpiece size (temperature uniformity of large workpieces and the need to reheat partially forged products from large workpieces), product run (frequency of changes in shape and size of the workpieces for short-run products), quality tolerance (surface defects), and energy price. The first two factors were considered to be the most important. The two extremes of gas furnace sophistication were chosen to compare against electric induction: the slot furnace with low efficiency (4-25%) and low capital cost, and the rotary hearth furnace with high energy efficiency (2CM5%), but high capital cost (almost five times higher than that of the slot furnace). Electric induction furnaces have high efficiency (45-55%), but even higher capital costs (nearly 6.5 times the cost of a slot furnace). The gas-fired rotary hearth furnace is comparable to the electric induction furnace. A great advantage of the electric induction furnace is better product quality because of reduced surface defects. Therefore, the most important recommended area for research is to reduce scale formation in gas-fired systems. One method would be to use indirect heating with radiant tube burners.
Life cycle impacts of induction furnace technology for crude steel production: case study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Aysegul Avinal, Pinar Ergenekon
Ferrous scrap is converted into steel in EAF and IF plants. Although EAF and IF have the same processing steps, they differ in the operating principle of the furnace and in the amount of scrap fed into the furnace. In EAF, steel is produced by directly melting ferrous scrap materials with an arc created by a graphite electrode (European Commission 2013). During the induction furnace operation, the melting heat is generated by the currents induced by the electromagnetic field created by a water-cooled copper coil placed inside the furnace body (Centre for Science and Environment 2012). There are several operational and environmental advantages for IFs, such as high flexibility in alloys and melting regimes, short melting times, lower environmental loads, good process control, high thermal efficiency, and homogeneous melting of the metal. Nonetheless, the disadvantages of induction furnaces are high quality – more expensive scrap charging requirement, high investment cost for installation, lower melting capacities (below 15 tonnes per hour), and heat losses in the water-cooled induction coil (European Commission 2005). In 2019, 67.8% of the steel was produced from scrap in Turkey, while the rate of steel production from scrap was 41.3% in the European Union and around 28% worldwide (Worldsteel Steel Statistical Yearbook 2020). Production at IF plants in Turkey constitutes 2% to 5% of the total steel production. Steel production in induction furnaces in India, which is the second largest steel producer in the world, is around 30% (Indian Bureau of Mines 2018). In China, the world’s largest steel producer, 53% of the steel is produced in BOFs and 47% in arc furnace facilities. However, steel production in induction furnace plants has started to increase in recent years (Bedarkar and Dalal 2020).