Nonterrestrial utilization of materials: Automated space manufacturing facility

Four areas related to the nonterrestrial use of materials are included: (1) material resources needed for feedstock in an orbital manufacturing facility, (2) required initial components of a nonterrestrial manufacturing facility, (3) growth and productive capability of such a facility, and (4) automation and robotics requirements of the facility

Numerical modelling of cold crucible induction melting (CCIM) process and fabrication of high value added components of titanium and its alloys

This dissertation concerns the development of a numerical modelling of cold crucible induction melting (CCIM) and the fabrication of high value added components of titanium and its alloys. Titanium and its alloys have emerged as a very attractive metal for numerous applications: medical prostheses, aerospace industry, automotive industry, power generation, sport equipment, and marine engineering. The reason lie in their attractive properties, such as excellent biocompatibility, high specific strength, excellent corrosion resistance, excellent high temperature creep resistance, and good fracture toughness. However, the application of titanium is often limited by its relatively high cost. This high cost of titanium makes casting very attractive route. However, is it difficult to cast these alloys by conventional casting techniques because of the titanium reactivity at high temperatures, which reacts with the crucible and mould components. The CCIM process is currently the most effective means of melting these alloys. The CCIM is an innovative process to melt high melting point reactive materials such as titanium alloys. The melting and casting of the material is performed in vacuum or in a protective atmosphere in order to prevent any contamination of the charge. Moreover, a water cooled segmented crucible is used instead of a ceramic crucible to avoid any kind of reaction among the charge and the crucible. The magnetic field generated by an external coil penetrates through the slits of the crucible and generates induced currents in the charge, which are responsible of melting it due to Joule heating. The drawbacks of this process are the poor efficiency due to great percentage of heat that is removed by the cooling system and the small superheat of the melt, which can cause solidification problems. In this dissertation, we have selected the CCIM process to melt and cast titanium alloys. The aim of this dissertation consists on increasing the scientific knowledge about the CCIM process by means of both a numerical and an experimental approach. The main part of the dissertation focuses on the development of a numerical modelling of CCIM to optimize of the main parameters of the process. The task of optimizing melt superheat faces the challenge of finding optimal combination of crucible height to diameter ratio, number of inductor turns, crucible design, current strength, and frequency. Variation of any of the after mentioned factors influences the shape of melt meniscus and, as a result, flow pattern and energy balance. The second part deals with the set-up of an installation of CCIM and the fabrications of titanium components. As a result of the present work some goals have been achieved, being the most important: a) Development of numerical modelling of CCIM, b) setting up of a CCIM installation, and c) casting of titanium parts.Tesi honek “Cold crucible induction melting (CCIM)” prozesuaren simulazio numerikoaren gainean eta prozesu honen bidez titaniozko balio erantsi altuko osagaiak ekoizteko modua tratatzen du. Titanioak eta bere aleazioek interes handia sortu dute aplikazio industrial askotan: mediku protesiak, aeronautika, automozioa, energia generazioa, kirol ekipamendua eta itsas ingeniaritza. Arrazoia bere ezaugarri erakargarrietan errotzen da: biokonpatibilitate bikaina, erresistentzia espezifiko altua, korrosioaren aurkako erresistentzia ezin hobea, tenperatura alturako isurpenaren aurkako erresistentzia paregabea eta hausturaren aurkako erresistentzia. Hala ere, bere kostu altuak bere aplikazioak murrizten ditu. Galdaketa-prozesuek kostu txikiagoko produktuetara daramate. Hala ere, zaila da aleazio hauek galdaketa prozesu konbentzionalekin urtzea, tenperatura handitan erreaktibotasun handia daukate eta. CCIM prozesua aleazio hauek galdatzeko prozesu eraginkorren arten dago gaur egun. CCIM prozesua material erreaktiboak urtzeko prozesu berritzailea da. Bai urtze bai galdaketa hutsean edo atmosfera babesle baten egiten da materialaren erreakzioa saihesteko. Gainera, ohiko zeramikozko arragoen ordez segmentudun kobrezko arragoa erabiltzen da. Kanpoko harilak sortutako kanpo magnetikoa arragoaren arteketatik barneratzen da eta indukziozko korronteak sortzen ditu kargan, karga bera urtuz Joule beroketagatik. Prozesu honen arazoak efizientzia eskasa (hozte sistemak xurgatzen duen beroagatik) eta solidotzearazoak eragin ditzakeen gainberotze txikia dira. Tesi honetan, CCIM prozesua aukeratu dugu titaniozko aleazioak galdaketa prozesuaren bidez fabrikatzeko. Tesi honen helburua CCIM prozesuaren gaineko ezaguera zientifikoa handitzean datza bai ikuspegi teorikoa bai ikuspegi esperimentala erabiliz. Tesiko alderdi nagusia prozesuaren parametro nagusiak optimizatzeko CCIM prozesuaren zenbakizko modelizazioaren garapenaran gainean tratatzen du. Gainberotze tenperatura optimizatzeko zeregina arragoaren altura diametro ratioa, harilaren espira kopurua, arragoaren diseinua, korrontea eta frekuentziaren balio optimoa aurkitzean datza. Aipatutako faktoreen edozein aldaketek meniskoaren egoeran eragiten du, eta ondorioz, jariakinaren patroian eta energi balantzean. Tesiaren bigarren atalak CCIM instalazio bat abiarazteaz eta titaniozko osagaiak fabrikatzeaz dihardu. Lan honen emaitz garrantzitsuenak hurrengokoak dira: a) CCIM prozesuaren modelo numerikoaren garapena. b) CCIM prozesuaren instalazio baten abiaraztea. c) Titaniozko piezen galdaketa.Esta tesis trata sobre el desarrollo de un modelo numérico del “cold crucible induction melting (CCIM)” y la fabricación de componentes de alto valor añadido de titanio y sus aleaciones mediante este proceso. El titanio y sus aleaciones se han convertido en un metal muy atractivo para numerosas aplicaciones: prótesis médicas, industria aeroespacial, industria de automoción, generación de energía, deporte e ingeniería marina. La razón radica en sus propiedades atractivas, tales como excelente biocompatibilidad, alta resistencia específica, excelente resistencia a la corrosión, excelente resistencia a la fluencia a alta temperatura y buena resistencia a la fractura. Sin embargo, la aplicación de titanio es a menudo limitada por su coste relativamente alto. Los procesos de fundición conducen a productos de menores costes. Sin embargo, es difícil fundir estas aleaciones por técnicas de moldeo convencionales, debido a la reactividad de titanio a altas temperaturas, que reacciona con el crisol y molde. El proceso CCIM es actualmente el medio más eficaz de fusión de estas aleaciones. El CCIM es un proceso innovador en la que la fusión y colada del material se realiza bajo vacío o dentro de una atmósfera protectora y donde se utiliza un crisol refrigerado segmentado de cobre en vez de los habituales crisoles cerámicos para evitar cualquier tipo de reacción entre la carga y el crisol. El campo magnético generado por una bobina externa penetra a través de las ranuras del crisol y genera corrientes inducidas en la carga, las cuales son las responsables de la fusión debido al calentamiento Joule. Los inconvenientes de este proceso son la baja eficiencia debido al gran porcentaje de calor que se elimina por el sistema de refrigeración y el pequeño sobrecalentamiento del metal fundido, que puede causar problemas de solidificación. En esta tesis, hemos seleccionado el proceso CCIM para fundir y colar las aleaciones de titanio. El objetivo de esta tesis consiste en aumentar el conocimiento científico sobre el proceso CCIM tanto de un modo numérico como un modo experimental. La parte principal de la tesis se centra en el desarrollo de un modelo numérico de CCIM para optimizar de los principales parámetros del proceso. La tarea de optimizar sobrecalentamiento se enfrenta al reto de encontrar la combinación óptima de la altura del crisol a diámetro, número de espiras del inductor, diseño del crisol, intensidad de corriente y frecuencia. La variación de cualquiera de los factores mencionados influye en la forma del menisco del metal líquido y, como resultado, el patrón del fluido y el balance de energía. La segunda parte trata de la puesta en marcha de una instalación de CCIM y la fabricación de componentes de alto valor añadido de titanio. Como resultado de este trabajo se han logrado algunos objetivos, siendo los más importantes: a) Desarrollo de modelos numéricos del CCIM. b) Puesta a punto de una instalación CCIM. c) Fundición de piezas de titanio

Radioactive scrap metal decontamination technology assessment report

Within the DOE complex there exists a tremendous quantity of radioactive scrap metal. As an example, it is estimated that within the gaseous diffusion plants there exists in excess of 700,000 tons of contaminated stainless steel. At present, valuable material is being disposed of when it could be converted into a high quality product. Liquid metal processing represents a true recycling opportunity for this material. By applying the primary production processes towards the material`s decontamination and re-use, the value of the strategic resource is maintained while drastically reducing the volume of material in need of burial. Potential processes for the liquid metal decontamination of radioactively contaminated metal are discussed and contrasted. Opportunities and technology development issues are identified and discussed. The processes compared are: surface decontamination; size reduction, packaging and burial; melting technologies; electric arc melting; plasma arc centrifugal treatment; air induction melting; vacuum induction melting; and vacuum induction melting and electroslag remelting

Materials review for improved automotive gas turbine engine

The potential role of superalloys, refractory alloys, and ceramics in the hottest sections of engines operating with turbine inlet temperatures as high as 1370 C is examined. The convential superalloys, directionally solidified eutectics, oxide dispersion strenghened alloys, and tungsten fiber reinforced superalloys are reviewed and compared on the basis of maximum turbine blade temperature capability. Improved high temperature protective coatings and special fabrication techniques for these advanced alloys are discussed. Chromium, columbium, molybdenum, tantalum, and tungsten alloys are also reviewed. Molbdenum alloys are found to be the most suitable for mass produced turbine wheels. Various forms and fabrication processes for silicon nitride, silicon carbide, and SIALON's are investigated for use in highstress and medium stress high temperature environments

Volume 56 - Issue 6 - January, 1946

https://scholar.rose-hulman.edu/technic/1161/thumbnail.jp

Projects at the Western Environmental Technology Office. Quarterly technical progress report, July 1, 1995--September 30, 1995

The goal of this project is to demonstrate the technical and economic feasibility of commercializing a biotechnology that uses plants to remediate soils, sediments, surface waters, and groundwaters contaminated by heavy metals and radionuclides. This technology, known as phytoremediation, is particularly suited to remediation of soils or water where low levels of contaminants are widespread. Project objectives are to provide an accurate estimate of the capability and rate of phytoremediation for removal of contaminants of concern from soils and groundwaters at Department of Energy (DOE) sites and to develop data suitable for engineering design and economic feasibility evaluations, including methods for destruction or final disposition of plants containing contaminants of concern. The bioremediation systems being evaluated could be less expensive than soil removal and treatment systems, given the areal extent and topography of sites under consideration and the investment of energy and money in soil-moving and -treating processes. In situ technology may receive regulatory acceptance more easily than ex situ treatments requiring excavation, processing, and replacement of surface soils. In addition, phytoremediation may be viable for cleanup of contaminated waters, either as the primary treatment or the final polishing stage, depending on the contaminant concentrations and process economics considerations

Book of abstracts of the 14th International Symposium of Croatian Metallurgical Society - SHMD \u272020, Materials and metallurgy

Book of abstracts of the 14th International Symposium of Croatian Metallurgical Society - SHMD \u272020, Materials and metallurgy held in Šibenik, Croatia, June 21-26, 2020. Abstracts are organized in four sections: Materials - section A; Process metallurgy - Section B; Plastic processing - Section C and Metallurgy and related topics - Section D

Research and development work on non-ferrous minerals, metals and alloys at the National Metallurgical Laboratory

THE phenomenal growth of non- ferrous metals and their multitude alloys for a wide range of service conditions witnessed in this century by the world had its impact on India in a big way, only in the last two decades. The non- ferrous metal production was only limited to some prod-uction of copper, lead, antimony and aluminium in the coun-try, of which recent years have seen over ten-fold increase in the case of aluminium production in view of large bauxite reserves in various areas. More recently zinc production has also been started at two new factories one each in the public and private sector--the former at Udaipur based on Zawar zinc mines and the latter at Alwaye based on imported zinc concentrates. Active steps are already underway to start indigenous production of magn-esium on a semi commercial scale at Jamshedpur based on NML developed know- how and also to start another plant for production of copper with foreign technical know- how at Khetri in Rajasthan