Veigalan Estudio 2010 SLU

Durango Bizkaia, Spain

Veigalan Estudio 2010 SLU

Durango Bizkaia, Spain

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Alonso G.,R and D of Metallurgical Processes | Larranaga P.,R and D of Metallurgical Processes | De La Fuente E.,R and D of Metallurgical Processes | Stefanescu D.M.,Ohio State University | And 2 more authors.
International Journal of Metalcasting | Year: 2017

The importance of the nucleation and growth phenomena that controls the solidification of castings on the mechanical properties and soundness of cast iron cannot be overemphasized. The graphite nucleation mechanism is directly related to the carbon content of the iron and the inoculation treatment. To further understand these phenomena, interrupted solidification experiments were conducted on spheroidal graphite irons at three different levels of carbon equivalent (4.0, 4.2, 4.4), with and without the addition of a commercial inoculant. A detailed scanning electron microscopy investigation was carried out to analyze and quantify the possible nucleation sites at different solid fractions, as well as the influence of the inoculant in their formation. Thermodynamic software was used to evaluate the probability of formation of the compounds. A detailed discussion on the differences in nucleation of graphite between the beginning and end of solidification is provided. © 2016 American Foundry Society.


Patent
Casa Maristas Azterlan and Veigalan Estudio 2010 S.L.U. | Date: 2017-07-05

The present invention discloses a hybrid aluminium bronze alloy that presents the following chemical composition (percentages expressed by weight with respect to the total weight of the alloy): Al: 6 - 9%; Fe: 5.0 - 14%; Ni: 2.0 - 7%; Cr: 0.5 - 2.8%; C: 0.01 - 0.20%; Mn <3%; Zn <0.5%; Si <0.2%; Sn<0.3%; P <0.3% Cu in balance and further impurities in an amount of less than 0.5%. The invention also discloses a process for the manufacturing of this hybrid aluminium bronze alloy. Additionally the invention also discloses a process for submitting this alloy to a thermochemical surface treatment process, and the obtained thermochemically surface treated alloy. Finally the invention refers to the uses of these alloys.


Alonso G.,Area Ingenieria | Stefanescu D.M.,Ohio State University | Stefanescu D.M.,University of Alabama | Larranaga P.,Area Ingenieria | Suarez R.,Veigalan Estudio 2010 SLU
International Journal of Cast Metals Research | Year: 2016

While the manufacture of compacted graphite (CG) iron castings has seen significant expansion over the recent years, the growth of CG during iron solidification is still not fully understood. In this work, effort was expanded to experimentally reveal the evolution of graphite shape during early solidification and its relationship to the solid fraction. To this purpose, interrupted solidification experiments were carried out on hypereutectic irons with three magnesium levels. The graphite shape factors were measured and analysed as a function of chemical composition and solid fraction. Scanning electron microscopy was carried out to establish the fraction of solid at which the transition from spheroidal graphite (SG) to CG occurs. It was confirmed that solidification started with the development of SG for all CG irons. The SG-to-CG transition was considered to occur when the SG developed a tail (tadpole graphite). The findings were integrated in previous knowledge to attempt an understanding of the solidification of CG iron. © 2016 Informa UK Limited, trading as Taylor & Francis Group.


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.


Alonso G.,ID y Procesos Metalurgicos | Stefanescu D.M.,Ohio State University | Suarez R.,Veigalan Estudio 2010 SLU | Loizaga A.,ID y Procesos Metalurgicos | Zarrabeitia G.,ID y Procesos Metalurgicos
International Journal of Cast Metals Research | Year: 2014

The paper introduces a new linear displacement analysis (LDA)/thermal analysis (TA) experimental device for measuring linear displacement during the solidification of cast iron. The experimental device comprises a sand mould encased in a steel shell that prevents mould wall movements. Thus, only the linear displacement caused by the shrinkage or expansion of the metal is recorded by the transducers. Two quartz rods introduced directly at different heights into the liquid metal and connected to two transducers record the linear displacement during the liquid-solid transformation and subsequent cooling. Two thermocouples positioned at the same height with the quartz rods allow for the concomitant TA and LDA and thus for the direct correlation between expansion/contraction and the temperature change during solidification events such as graphite formation. The LDA device was used to study the differences in the solidification mechanisms of irons with different graphite morphologies (lamellar, compacted/ vermicular and spheroidal) at carbon equivalent in the range of 3·7-4·4%. The analysis included the LDA and TA curves and full metallographic characterisation of the cast irons. In general, graphite expansion increased as the graphite shape changed from lamellar, to compacted and then to spheroidal. The most important process variables are the magnesium and carbon contents. Higher Mg residual and C in the iron produced more graphite expansion. Compacted graphite (CG) iron was particularly sensitive to the Mg residual. Indeed, the high Mg CG irons exhibited similar graphite expansion to that of spheroidal graphite (SG) iron, while the low Mg CG iron expansion was closer to that of the lamellar graphite (LG) iron. Graphite expansion increased for all data with the time interval over which graphite expansion occurred. It also increased with both carbon and carbon equivalent. The time for graphite expansion increased noticeably with the carbon content of the iron. It did not depend on the graphite shape. By combining TA and LDA, it was possible to plot the evolution of graphite expansion as a function of the fraction solid and thus to understand the kinetics of graphite expansion. The amount of expansion available at the end of solidification was quantified. Such data, when correlated with process variables, will be useful in decreasing microshrinkage and in producing riserless compacted and SG irons. © 2014 W. S. Maney & Son Ltd.


Alonso G.,Ingenieria | Stefanescu D.M.,Ohio State University | Stefanescu D.M.,University of Alabama | Suarez R.,Veigalan Estudio 2010 SLU | And 2 more authors.
71st World Foundry Congress: Advanced Sustainable Foundry, WFC 2014 | Year: 2014

The expansion and contraction processes that occur during the cooling of liquid iron and its subsequent solidification are the primary cause of microshrinkage formation in castings. Of particular interest is graphite expansion which can compensate the shrinkage produced by the solidification of austenite. Thus, a better understanding of these processes is a key objective in the engineering of castings free of shrinkage defects. The paper introduces a combined Linear Displacement Analysis (LDA)/Thermal Analysis (TA) experimental device for measuring the linear displacement during the solidification of cast iron. The experimental device comprises a steel shell surrounding the test mold. In one approach the shell is rigid and prevents mold wall movements. In this way, only the linear displacement caused by the shrinkage or expansion of the metal is recorded by the transducers. In a second approach, the shell can freely move in to horizontal directions, allowing mold expansion. Two quartz rods introduced into the liquid metal and connected to transducers record the linear displacement during the liquid-solid transformation and subsequent cooling. Thermocouples positioned at the same height with the quartz rods allow for the concomitant LDA and TA, and thus for the direct correlation between expansion /contraction and the temperature change during solidification events such as graphite formation. The LDA device was used to study the differences in the solidification mechanisms of irons with different graphite morphologies (lamellar, compacted/vermicular and spheroidal), at three different levels of carbon equivalent, to give hypoeutectic, eutectic and hypereutectic composition. It was found that graphite expansion increases with the carbon content and the magnesium residual. Spheroidal graphite iron had the highest expansion. Compacted graphite iron had slightly higher expansion than lamellar graphite iron. A method was developed to evaluate the expansion as a function of fraction solid evolved. The unrestrained mold experiments proved that to insure results consistency, experiments should be conducted with restrained molds.


Patent
Casa Maristas Azterlan and Veigalan Estudio 2010 S.L.U. | Date: 2016-06-01

1. A method to control the ausferritic as-cast microstructure in iron parts with sections of different thicknesses, which comprises:a) Calculate the cooling rate for the maximum and minimum thermal moduli considering an air cooling.b) Calculate the minimum cooling rate needed to avoid the pearlitic nose, as a function of different contents of Ni, Cu and Mo (CR_(min)).c) Select one of the compositions with a minimum cooling rate (CR_(min)) lower than the cooling rate for the maximum thermal modulus.d) Calculate the eutectoid temperature (T_(eutectoid)) as a function of the thermal modulus for the composition selected, for all the different thermal moduli of the part.e) Calculate the shake-out temperature (T_(shakeout)) for all the different thermal moduli of the part.f) Identify if T_(shakeout) for the minimum thermal modulus is over the eutectoid temperature (T_(eutectoid)) calculated in d) and if T_(shakeout) for the maximum thermal modulus is below the solidus temperature (T_(solidus)).


Patent
Veigalan Estudio 2010 S.L.U., Thermal Quality Control Technologies S.L.U. and Casa Maristas Azterlan | Date: 2014-07-02

The present invention discloses a method for the manufacturing of ausferritic ductile iron alloy which comprises the following steps: (i) casting a melt of a ductile iron alloy in a mould; (ii) solidification of the casting in the mould and subsequent cooling until the casting temperature is between 800C and 950C; (iii) shaking out the casting at said temperature between 800C and 950C; (iv) cooling the casting until the temperature of the casting reaches a value between 275C to 450C with a high enough cooling rate in order to avoid the pearlitic nose; (v) introducing the casting in an insulating material and leaving the casting inside for a period of time until a completely ausferritic microstructure is obtained. The invention also discloses the ausferritic ductile iron alloy produced by the present method.


Patent
Veigalan Estudio 2010 S.L.U. and Casa Maristas Azterlan | Date: 2014-09-10

The invention relates to a method for predicting at least one first characteristic parameter of a structure of a part (100) cast in an aluminium alloy, comprising:i) by means of a thermal analysis technique recording a solidification curve of said alloy in a standard thermal analysis cup and obtaining a plurality of second characteristic parameters of said solidification curve of the alloy;ii) obtaining said first characteristic parameter of the structure of the part using a pre-established equation that relates at least one of a plurality of first characteristic parameters of the structure of the part to the thermal modulus, MODULUS, and to at least one of said plurality of second characteristic parameters of the solidification curve, wherein the thermal modulus, MODULUS, is calculated on the basis of a DAS parameter according to the following equation: where a and b are constants, and the DAS parameter is the secondary dendrite arm spacing of the structure of the part.


Patent
Veigalan Estudio 2010 S.L.U., Thermal Quality Control Technologies S.L.U. and Casa Maristas Azterlan | Date: 2014-07-02

The present invention relates to a method for controlling if the amount of active magnesium in a treated melt is above or below a certain level which comprises the following steps: (i) providing a thermal analysis cup with tellurium, a thermocouple, a metallic cap, and a controlled amount of a neutralizing mixture of sulfur and FeSi, said mixture comprising: a) from 0.07 to 0.25 wt% of FeSi in respect of the weight of the test sample of the treated liquid iron which is poured into it in the next step (ii), and b) a number of equivalents of sulfur which is the same as the number of equivalents of active magnesium which correspond to the said certain level to be determined, (ii) pouring into the thermal analysis cup treated melt; (iii) recording a cooling curve and (iv) identifying according to the shape of the curve, if the test sample has solidified at the graphite eutectic or at the carbide eutectic. The present invention relates also to a thermal analysis cup for use in said method.

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