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Calvet N.,CIC ENERGIGUNE | Dejean G.,CNRS PROMES | Unamunzaga L.,IK4 Azterlan | Py X.,CNRS PROMES
ASME 2013 7th Int. Conf. on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology, ES 2013 | Year: 2013

The ambitious DOE SunShot cost target ($0.06/kWh) for concentrated solar power (CSP) requires innovative concepts in the collector, receiver, and power cycle subsystems, as well as in thermal energy storage (TES). For the TES, one innovative approach is to recycle waste from metallurgic industry, called slags, as low-cost hightemperature thermal energy storage material. The slags are all the non-metallic parts of cast iron which naturally rises up by lower density at the surface of the fusion in the furnace. Once cooled down some ceramic can be obtained mainly composed of oxides of calcium, silicon, iron, and aluminum. These ceramics are widely available in USA, about 120 sites in 32 States and are sold at a very low average price of $5.37/ton. The US production of iron and steel slag was estimated at 19.7 million tons in 2003 which guarantees a huge availability of material. In this paper, electric arc furnace (EAF) slags from steelmaking industry, also called "black slags", were characterized in the range of temperatures of concentrated solar power. The raw material is thermo-chemically stable up to 1100 °C and presents a low cost per unit thermal energy stored ($0.21/kWht for ΔT=100 °C) and a suitable heat capacity per unit volume of material (63 kWht/m3 for ΔT=100°C). These properties should enable the development of new TES systems that could achieve the TES targets of the SunShot (temperature above 600 °C, installed cost below $15/kWht, and heat capacity ≥25 kWht/m3). The detailed experimental results are presented in the paper. After its characterization, the material has been shaped in form of plates and thermally cycled in a TES system using hot-air as heat transfer fluid. Several cycles of charge and discharged were performed successfully and the concept was validated at laboratory scale. Apart from availability, low-cost, and promising thermal properties, the use of slag promotes the conservation of natural resources and is a noble solution to decrease the cost and to develop sustainable TES systems. Copyright © 2013 by ASME.


Eguskiza S.,IK4 Azterlan | Niklas A.,IK4 Azterlan | Fernandez-Calvo A.I.,IK4 Azterlan | Santos F.,IK4 Azterlan | Djurdjevic M.,Nemak Linz GmbH
International Journal of Metalcasting | Year: 2015

The production of high quality parts for automotive and aircraft industries requires both improved melt processing and effective control tools which can assure the melt quality in terms of Si modification before casting. Thermal analysis is a highly interesting metallurgical quality control tool, well suited for use in casting plants as it is easy to handle and provides quick results. In this work, the effect of strontium fading on eutectic silicon modification and on the solidification curve of an A356 and A319 alloy was studied. Eutectic silicon modification was assessed by image analysis of characteristic features of the silicon particles. A correlation with the cooling curve parameters at the eutectic arrest was established. Copyright © 2015 American Foundry Society.


Niklas A.,IK4 Azterlan | Bakedano A.,IK4 Azterlan | Orden S.,TQC Technologies | da Silva M.,Fundacio Privada ASCAMM | And 3 more authors.
Materials Today: Proceedings | Year: 2015

Primary AlSi10MnMg alloy is widely used for manufacturing of high ductility VPDC castings. This alloy combines low Fe with high Mn level to guarantee good ductility. Secondary alloys are cheaper but they contain a higher Fe content, which is detrimental to the ductility. Microadditions based on Mn have been found very effective in formation of less harmful α- iron compounds. In this study the effect of microstructure and casting defects on mechanical properties has been investigated in secondary alloy with 0.62%Fe and moderate Mn. Mechanical properties similar to the primary alloy were obtained when specimens were free from casting defects. © 2015.


Zarrabeitia G.,IK4 Azterlan | Suarez R.,IK4 Azterlan
International Journal of Metalcasting | Year: 2013

IK4-Azterlan is a metallurgical research centre with broad experience in casting and solidification technologies for cast iron, steel and aluminium alloys. The entity provides basic and applied research transfer by close collaboration with foundry industries and other universities and (research) centres. As a member of the IK4-Research Alliance, Azterlan is engaged in long-term activities studying and modeling solidification in casting process, liquid metal treatment procedures and the development of new alloys with enhanced performance. Other fields of interest for IK4-Azterlan are on the use of artificial intelligent networks for solving foundry problems and the development of metal quality predictive tools. Copyright © 2013 American Foundry Society.


Aguado E.,IK4 Azterlan | Uribe U.,IK4 Azterlan | Natxiondo A.,Veigalan Studio 2010 SLU | Fernandez-Calvo A.I.,IK4 Azterlan | And 2 more authors.
71st World Foundry Congress: Advanced Sustainable Foundry, WFC 2014 | Year: 2014

During the last years, new technologies have been developed in order to reduce the environmental pollution and preserve resources. For this reason, the light weight concept has aroused highly interesting in the transportation industry, particularly, in the development electric and hybrid vehicles. One of the actions was to replace some components made of steel or cast iron by other made of aluminium casting. However, some components cannot be replaced only by aluminium and need to be combined with steel in order to achieve the desired mechanical characteristics. Therefore, there is great interest in developing processes to manufacture aluminium/steel hybrid structures that present a good bond. This work is a comparative study of different interfaces of S355J2H steel insert in AlSi7Mg aluminium casting. To develop this research, a range of processing conditions for improving the bond strength between steel insert and aluminium alloy were carried out. Before casting, different chemical, thermal and mechanical treatments were applied to the steel insert: As-received condition, pre-heating, shot blasting, pickling, hot dip aluminizing, hot dip galvanizing, zinc coating. The steel/AlSi7Mg interfaces were characterized by optical microscopy (LOM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). Special attention was paid to study the interface failure position and the intermetalic phases and compounds formed in the reaction action zone. The interface shear strength has been assessed by the push-out test, and the results have been correlated with microstructural observations at the interfaces. Copyright 2014 World Foundry Organization.

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