Microstructural optimization of unalloyed ductile cast irons with a ferritic matrix used in the manufacture of wind turbine rotors

The aim of this work was the microstructural optimization of cast irons with nodular graphite for the manufacture of wind turbine hubs, paying preferential attention to the geometry and distribution of graphite spheroids to ensure the required mechanical properties for this application. The target was pursued based upon microstructure-properties correlation, in an environment of great competitiveness and exigency marked by current international standards. The methodology followed consisted of the generation of knowledge from tailor-made industrial castings, followed by the analysis of their microstructures, in order to extract valuable conclusions for the production process through the use of statistical analysis. The approach method employed was a Fractional Design of Experiments (DOE) with 7 factors, 16 experiments and resolution IV. The samples from each experiment were cubes of identical geometry, and designed to match a surface-to-volume module equal to 4 cm (1.57 in) found as the highest values in real hubs of 3 MW power wind turbines. It is concluded that the use of nodulizers with traces of lanthanum favour the reduction of the volume fraction of pearlite, although La has proved not to promote the spherical shape of primary graphite. The negative effect of pre-inoculants containing SiC on the spheroidal morphology of graphite has also been verified, and also that low-Mn bearing scrap favours graphite formation and the reduction of the volume fraction of pearlite, in spite of being a carbide forming element. The whitening effect of Mn was minimized with low carbon equivalent melts

Hydrometallurgical extraction of Al and Si from kaolinitic clays

Herein is presented the results of a study on the hydrometallurgic extractionand recovery of aluminum and silicon by leaching of kaolinitic clays with HF. Thestudied extraction parameters were: temperature, reaction time, solid/liquid ratio,concentration, and precipitating agent mass. In the leaching process, mineraldissolutions near 100% were obtained when working at 348 K, solid/liquid ratio2% w/v, HF 12% v/v, for 120 minutes. The HF leach liquor generated from thedissolution of kaolinitic clays contains H2SiF6 and H3AlF6. Studies were conductedto recover the two valuable fluorides as K2SiF6 and Na3AlF6 by precipitation withalkaline salts from the leach liquor. Phases of precipitated fluorides were identifiedby XRD and surface morphology by SEM. The purity of the K2SiF6 precipitate was98.8%, whereas for Na3AlF6, it was 89.3%. Also, both synthesized solids are ofhigh commercial value due to their industrial applications.Fil: Pinna, Eliana Guadalupe. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Suarez, Daniela Silvana. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Rosales, Gustavo Daniel. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Rodriguez, Mario Humberto. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin

Conservation of the european mining and metallurgical heritage. Part 2

In the June 1999 issue of the CIM Bulletin an inventory of Mining Museums Across Canada was published. Because museums are an important educational tool and a touristic attraction, it is a pleasure to have professors Octavio Puche Riart and Luis Felipe Mazadiego Martinez respond to our invitation to write about the European mining and metallurgical museums. Part 1 of this article appeared in the May 2000 issue

Emissions from pre-Hispanic metallurgy in the South American atmosphere

Peer reviewedPublisher PD

THE IMPORTANCE OF THE COST INFORMATION IN MAKING DECISIONS

The cost information system plays an important role in every organization within the decision-making process. An important task of management is to ensure the control over operations, processes, activity sectors, and not ultimately on costs. Although in reaching the goals of an organization compete many control systems (production control, quality control and stocks control), the cost information system is important because it monitors the results of the others. The detailed analysis of costs, the calculation of production cost, the loss quantification, the estimating of work efficiency provides a solid basis for the financial control.decisions, costs, users, financial

NUMERICAL EVALUATION OF LOADED CREDIBILITY

An original paper, which describes techniques for estimating premiums for risks, containing a fraction (a part) of the variance of the risk as a loading on the net risk premium.esscher premium, variance premium, the linearized credibility formula.

Biography of César Rubio y Muñoz (Cáceres, 1858-Madrid, 1931), President of the 14th International Geological Congress (Madrid, Spain, 1926)

The mining engineer César Rubio, before joining the Geological Survey of Spain, worked in numerous Spanish mining districts, in which he introduced important innovations. His main contributions being the director of the Geological Survey of Spain was the research of the Catalonian potassium salts deposits and the organization of the XIV International Geological Congress, which took place in Madrid in 1926

Estudio de la rugosidad superficial de implantes dentales de titanio blastinizados mediante microscopía electrónica de barrido en 3D

Una de las actividades más importantes en el estudio de los implantes dentales de Ti c.p. se encuentra enfocada al uso de modificaciones superficiales mediante métodos físicos o químicos, debido a que ensayos in vivo han puesto de manifiesto que ciertas superficies rugosas producen una mejor fijación por osteoaposición de hueso que la correspondiente a superficies lisas, por lo que resulta necesario realizar una adecuada caracterización de la rugosidad de los mismos. Una gran variedad de tratamientos superficiales son utilizados para incrementar la rugosidad de los implantes dentales de Ti c.p.. De todos ellos, el más utilizado es el blastinizado. En éste, las partículas abrasivas son arrastradas por una corriente de aire hasta impactar con el material siendo algunas de las diferentes variables operativas del proceso el tamaño de partícula y la presión. Existe una gran variedad de parámetros que describen la topografía de las superficies entre los cuales se encuentran los grupos de parámetros de amplitud, híbridos y funcionales. La correcta elección de los parámetros más significativos dependerá de las características del tratamiento superficial utilizado y del objetivo del estudio realizado. En el presente trabajo se realiza una caracterización, por microscopía electrónica de barrido 3D, de la superficie de muestras de Ti c.p. sometidas a diferentes condiciones de blastinizado, proporcionadas por una empresa fabricante de implantes dentalesFil: Kang, Kyung W.. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Pereda, Maria D.. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Lemos, Adriana. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Bilmes, Pablo David. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Bonetto, Rita Dominga. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Scarano, Mariano. Kinetical SRL Insumos Medicos; Argentin

THE ROLL OF FINANCIAL ASSISTANCE IN THE IMPLEMENTATION OF ENVIRONMENTAL POLICY

The paper analyses the roll of the main external funds in the environmental protection. These investments represent an important place in the economic growth and in the same time contribute to the achievement of the objectives of the environmental policy, taking into account the demands imposed by the adhering (65% out of the integration costs are environment costs), finally reducing the gaps between European Union and Romania. However the quality of the environment determines regional attractiveness and as such is a local factor for investment.financial assistance, European Union, environmental policy, European integration