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Prat J.,ASK Chemicals | Artola G.,IK4 Azterlan | Trillo G.,IK4 Azterlan | Izaga J.,IK4 Azterlan
72nd World Foundry Congress, WFC 2016 | Year: 2016

Foundry sector, as a whole, has incorporated relevant technological advances into productive processes. Nevertheless, the specific field of feeding system design criteria hasn't improved in the same proportion. The use of simulation tools doesn't always come together with the optimization of key indicators. Part rework costs remain unchanged, yield values hardly reach 50% and the metallurgy of the processed alloys is kept under nearly unchangeable principles. With this starting point, a deep review of the feeding systems that are employed for the manufacture of cast steel components is carried out, to lead in the end, to the identification and assessment of the metallurgical advantages that can be exploited in the most thermally affected zones and to the net/gross yield optimization. A complex variable matrix has been defined and studied, taking into consideration high added value materials, their metallurgy both in liquid and solid state, novel feeding devices such as core-risers, riser-paddings and EXACTCAST™ (patented) mini-risers, and advanced simulation concepts. The most important achieved results are exposed which, taking advantage of the new feeding technologies, allow reaching yields over 75%, with an optimized metallurgical quality in the final product. © 2016, The WFO (The World Foundry Organization Ltd). All rights reserved.


Artola G.,IK4 Azterlan | Artola G.,University of Navarra | Gallastegi I.,IK4 Azterlan | Izaga J.,IK4 Azterlan | And 2 more authors.
International Journal of Metalcasting | Year: 2017

Austempered ductile iron (ADI) grades are standardized, and the requirements of current international standards (EN 1564-12/ASTM A897-15) are given terms of conventional mechanical properties, such as hardness and tensile strength. Nevertheless, these properties do not show the real potential of the ADI grades. In order to promote the use of ADI parts in place of other materials, this work proposes a comparison between GJS-900-8 and GJS-1200-3 grades, both in terms of conventional and advanced mechanical properties, employing stress intensity factors and critical CTODs (Crack Tip Opening Displacement). This study is completed with mechanical fatigue testing, so that it can be shown that the service life of ADI parts is comparable to that given by other heavier and more expensive options. © 2016 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.


Niklas A.,IK4 AZTERLAN | Bakedano A.,IK4 AZTERLAN | Orden S.,IK4 AZTERLAN | Nogues E.,Fundacio Eurecat | And 2 more authors.
Key Engineering Materials | Year: 2016

Primary AlSi10MnMg alloy is the most widely used alloy for manufacturing of vacuum assisted high pressure die castings (VPDC) with high ductility requirements. In this alloy, die soldering is avoided by a high Mn level (0.5-0.6 wt. %) while Fe is kept low (< 0.25 wt. %). Such combination guarantees that the Al-Fe-Mn-Si intermetallic compounds are of the α-iron rich polyhedral or Chinese script type, which is less harmful to the ductility. However, secondary alloys are cheaper and their production requires less energy than the one of primary alloys. The higher amount of Fe, a common impurity in secondary alloys, reduces ductility but also die soldering and thus manufacturing costs. Microadditions based on Mn are known to be very effective in transforming the harmful needle/platelet shaped β-compounds into α-iron compounds with a less harmful morphology. In this work a secondary alloy with 0.60 wt. % Fe and different Mn microadditions has been cast in test parts with different wall thicknesses using VPDC technology. The Mn content of the new alloy has been optimized. Mechanical properties of the optimised alloy have been determined in different heat treatment conditions and been compared to the corresponding AlSi10MnMg primary alloy. Mechanical properties similar to those of the primary alloy have been achieved. © 2016 Trans Tech Publications, Switzerland.


Aguado E.,Engineering and Foundry Processes | Baquedano A.,Engineering and Foundry Processes | Uribe U.,IK4 Azterlan | Fernandez-Calvo A.I.,Engineering and Foundry Processes | Niklas A.,Engineering and Foundry Processes
Materials Science Forum | Year: 2013

The necessity of preserving resources and to reduce environmental pollution makes light weight concepts highly interesting for the transportation market, with light weight being essential for newly developed electric and hybrid vehicles. However, some components cannot be replaced only by aluminium, but 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. In the present work a range of processing conditions for improving the bond strength between S355J2H steel inserts and AlSi7Mg casting alloy were investigated. Before casting, different chemical, thermal and mechanical treatments were applied to the steel insert: As-received condition, preheating, shot blasting, pickling, hot dip aluminizing, hot dip galvanizing, zinc coating and nickel/copper plating. The steel/AlSi7Mg interfaces were characterized by optical microscopy (LOM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). Special attention was paid to the presence of defects, formation of oxides and/or intermetallic phases in the reaction 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. Combinations of different insert treatments were also investigated. © (2013) Trans Tech Publications, Switzerland.


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.


Monzon-Gracia A.,INFUN | Sertucha-Perez J.,IK4 AZTERLAN | Serrallach-Perarnau J.,INFUN | Suarez-Creo R.,IK4 AZTERLAN
Dyna (Spain) | Year: 2013

Current understanding about the influence of several alloying elements on mechanical properties of steels and cast irons and more precisely on ductile cast irons is still incomplete. On the other hand, an increasing demand to develop innovative and cheap cast iron alloys with improved mechanical properties and potential application on high performance components is also observed. Crankshafts used to manufacture high-power engines for big vehicles are a proper example of this demand. The present work is devoted to study the effect of several chemical alloying elements on the structural and mechanical properties of fully pearlitic ductile cast irons. An optimized combination of C, Si, Cu, Mn Mo and Cr contents has leaded to develop a new methodology for preparing as-cast ductile irons with more homogeneous matrices, tensile strength values even higher than 1000 MPa and elongation values higher than 4%.


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.


Fernandez-Calvo A.I.,IK4 AZTERLAN | Lizarralde I.,IK4 AZTERLAN | Eguskiza S.,IK4 AZTERLAN | Santos F.,Veigalan Estudio 2010 S.L.U. | Niklas A.,IK4 AZTERLAN
71st World Foundry Congress: Advanced Sustainable Foundry, WFC 2014 | Year: 2014

Thermal analysis has been used for decades for melt control before casting aluminum alloys. However, obtaining a good grain refinement in a standard cup does not ensure that the grain refinement is correct in real parts which may solidify at very different cooling rates. For this study, the effect of cooling rate on AlSi7Mg alloy with different metal qualities in terms of grain refinement was tested. A mathematical model has been built for prediction of grain size in aluminium castings, knowing the following parameters: grain refining potential of the melt, evaluated by using thermal analysis (Thermolan-Al system) and cooling rate of the selected zone in the casting, evaluated in terms of DAS by metallographic measurement or simulation tools. The model was first developed by the correlation between nucleation potential in term of grain size measured on the standard thermal analysis cup with those obtained in cylindrical test parts with various diameters cast in sand moulds. It was found possible to set up a formula for the grain size of the cylindrical test parts as a function of their modulus and of the nucleation potential evaluated on the standard thermal cups. A correlation between modulus and DAS (metallographic and simulation prediction) is established also for the cylinders. The new model has been validated in steering knuckles cast with melts having different grain refining potential. Good correlations, with R2 factors ranging from 0.85 to 0.91 were obtained when comparing measured grains sizes with the corresponding calculated values in cylinder casting and steering knuckles. Thus a simple thermal analysis of the melt prior to casting allows to predict if the desired grain size will be obtained at different locations of the part or if corrective actions must be taken in order to improve the grain refinement potential of the melt. Copyright 2014 World Foundry Organization.

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