Browsing by Author "Iparraguirre, J. A."
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Item Alloying elements liquid addition to optimize secondary metallurgy(2018-01-01) Jimbert, P.; Iturrondobeitia, M.; Fernandez-Martinez, R.; Barbero, J. I.; Serna, M.; Eguizabal, D.; Oncala, J. L.; Artola, A.; Iparraguirre, J. A.; Arteaga, A.; PROMETAL; SG; CIRMETALDuring the last years, numerous secondary metallurgical technologies have been developed. The present study presents a new technology based on adding all the alloying elements in liquid state. In this new process, a molten bath of the appropriate composition is made with alloying elements and deoxidants (in an induction furnace). This molten alloy is introduced into the liquid steel at the beginning of secondary metallurgy. With this new process, in addition to improving the mixing between alloy elements and steel, its final objective is to improve the process of secondary metallurgy in order to: reduce the time of secondary metallurgy, reduce the temperature of the steel liquid, use cheaper alloying elements, improve steel cleaning by reducing the addition of inclusions by ferroalloys, thus improving steel quality, increasing the efficiency of ferroalloys and increasing productivity. All this would result in lower energy consumption due to the reduction of electric furnace times and temperatures.To achieve this goal, the first experiments with 100kg castings at laboratory scale have been performed, and the results are presented here below. Castings with solid and liquid addition of the alloying elements have been made and, the performance of the elements, the use of ferroalloys of different qualities and the final solidification microstructure have been analyzed for the 95Cr6 alloy, obtaining similar results in both processes. A more complex alloy (40NiCrMo4) has also been investigated to analyze the performance of other elements like Ni and Mo. The results obtained with both alloys indicate that the viability and the necessary requirements for a future adaptation to the industrial environment of this new technology are feasible. Tests on an industrial scale are necessary for a real estimation of the savings and environmental improvements that would lead to the industrialization of this new technology.Item New developments in hybrid use of induction and plasma heating technologies for melting and holding ferrous and non-ferrous alloys(World Foundry Organization, 2014) Eguizabal, D.; Cobos, L.; Iparraguirre, J. A.; Rodriguez, P.; Arocena, I.; CIRMETAL; Tecnalia Research & InnovationIn the following decade Europe will invest huge efforts to save energy and resources in energy intensive industrial processes. Foundry industry is one of the most energy intensive industries in the world and reducing this energy usage is a primary goal for the sector. The metal casting industry is heavily dependent on natural gas and electricity, and growing interest in energy efficiency has been driven by the impacts of energy cost volatility. Over the years, the foundry industry has been looking for an energy efficient rapid melting furnace with reduced losses from oxidation and contamination. The employ of hybrid heating technologies for foundry industry processes should be seen as one of the most innovative and efficient alternatives of the last years in the sector. This Research has the objective of assess the effect of hybridizing induction and plasma heating technologies in energy consumption for melting and holding ferrous and non-ferrous alloys. Tests have been carried out in a 125 litres capacity prototype using a plasma torch of 200 kW and an induction coil of 300 kW as maximum heating power. The materials used at these trials are commonly used at Aluminium and Cast Iron foundry industry, and the use of low-cost scraps has been specifically tested too. The main objective of the tests has been to measure the global energy consumption of melting and holding at casting temperature industrial alloys. An additional effect of the use of induction-plasma heating consists in increased melting rate. According to the methods presented, the energy supplied to the induction furnace and plasma device as well as melting duration counted from switching on the induction and plasma to overheating of the liquid metal to casting temperature was measured. It was found in next to industrial conditions that induction-plasma melting rate was significantly higher as compared to the single induction melting process. In the same way, the energy consumption is lower. The research carried out under these next to industrial conditions (1 ton of steel capacity furnace) has shown that the use of plasma torch in hybrid heating system with an induction furnace is effective, improves energetic indices of the melting process and increases the output of the induction furnace.