The thermocyclic fatigue behavior of the low-melting solder 43Sn/43Pb/14Bi has been investigated and compared to that of standard 60Sn/4OPb solder via metallographic analysis (using scanning electron microscopy) and evaluation of the degree of fatigue development (using a fatigue scale as a function of thermocycles). Specimens were subjected to shearing strains imposed by several hundred fatigue thermocycles. Both solder types fatigue by the same microstructural failure mechanism as described by other workers. The mechanism is characterized by a preferential coarsening of the solder joint microstructure at the region of maximum stress concentration where cracks originate.

No description available.

This thesis studied the iron smelting technology of Southwest China. It introduces the natural and human environment of Southwest China and gives a systematic review on the important archaeological sites of Southwest China. A total of 75 iron smelting related sites of Southwest China were surveyed. Five of these sites were excavated and studied in detail including the furnace structures, smelting related materials and their smelting process. A statistical study of over 5,100 iron objects (and bronze and iron bi-metallic objects) in published excavation reports was carried out to understand the pattern and statistical distribution of iron objects excavated in Southwest China. This was followed by metallographic analysis of 66 samples taken from 42 iron objects and slags (mostly from the Lijiaba site, and from the Qiaogoutou site). The slag samples (from the Xuxiebian site) helped to identify the bowl-shaped furnaces, that discovered at the iron smelting sites of Southwest China, as refining furnaces. The results of the metallographic studies helped to characterise the range of technologies that developed in Southwest China primarily during the Han dynasty (202BC-220AD). According to these studies, some issues such as the origin and development of technology, the labourers’ identities, the origin of the blacksmiths, and the management and policy of iron production in Southwest China are discussed.

After carbon, phosphorus is the most commonly detected element in archaeological iron. The typical phosphoric iron range is 0.1wt% to 1wt%P. The predominant source of phosphorus in iron is the ore smelted. Around 60% of economic UK rock iron ore formations contain over 0.2%P. Under fully reducing conditions, both in liquid-state (cast iron) and solid-state bloomery smelting (direct reduction) processes, such rock ores would be predicted to produce phosphoric iron, and bog iron ores even more so. Ore-metal-slag phosphorus ratios for bloomery iron are derived here, by means of: laboratory experiments; full-scale experimental bloomery smelting; and analysis of remains from three Medieval and two Late Roman-Iron Age iron production sites in England and the Netherlands. Archaeological ore, slag, metal residues (gromps), and iron artefacts were analysed by metallography, SEM-EDS, EPMA, and XRD. The effects of forging and carburising on phosphoric iron were studied by experiment and artefact analysis. The ore to slag %P ratio for solid-state reduction was determined to range from 1:1.2 to 1: 1.8. The ore to metal %P ratio varied from 1:0.2 to 1:0.7-1.4, depending on furnace operating conditions. Archaeological phosphoric iron and steel microstructures resulting from non-equilibrium reduction, heat treatment, and mechanical processing are presented to define the technology of early phosphoric iron. Microstructures were identified by a combination of metallography and chemical analysis. The phosphoric iron artefacts examined appear to be fully functional objects, some cold-worked and carburised. Modern concepts of 'quality' and workability are shown to be inapplicable to the archaeological material.

Resumo: Este trabalho teve como objetivo o desenvolvimento das técnicas fundição de semicubos do trem de pouso principal do cargueiro C-115 Buffalo da Força Área Brasileira, pelo processo de fundição de liga de magnésio em moldes de areia a verde para atender as necessidades emergenciais nas atividades de apoio logístico, tático e transporte. Por ser um item estrutural cujas exigências em relação às propriedades de engenharia e segurança são rigorosas, foi necessário o desenvolvimento de técnicas de fundição diferenciadas para a obtenção do modelo com suas respectivas superespessuras de contração e usinagem; ângulos de saída; sistemas especiais de canais de alimentação; molde preparado com areia sintética, bentonita, enxofre, ácido bórico e água; magnésio, alumínio, zinco e alumínio-manganês de grau metalúrgico para a obtenção da liga; tratamento e refino do banho metálico, técnica de vazamento com frentes de alimentação simétricas; controle de qualidade por meio de inspeção visual, análise da composição química e metalográfica das fases e constituintes da liga, ensaios mecânicos e radiográficos para qualificação do fundido, conforme padrões aeronáuticos. Os ensaios apresentaram resultados cujos valores obtidos foram comparados com os padrões aeronáuticos internacionais, permitindo viabilizar a transferência desse desenvolvimento para o processo produtivo de forma a atender necessidades emergenciais e estimular a evolução do setor aeronáutico do País. / Abstract: This work had as objective the development of the techniques of semicubes casting of the main landing gear of the C-115 Buffalo freighterm from Brazilian Air Force, by the process of magnesium alloy casting in green sand molds to attend to the emergent necessities in the activities of logistic, tactical support and air service. The creation of the Project of Nationalization of Aeronautical Components was necessary for the maintenance of the operationalization of the aircraft and to prevent the collapse of the fleet. Aeronautical wells are a structural item whose requirements in relation to the security and engineering properties are rigorous, it was necessary the development of differentiated techniques of casting for the attainment of the model with its respective superthicknesses contraction adn machining; pattern draft; special gate systems; mold prepared in synthetic sand, bentonite sand, sulphur, acid boric and water; magnesium, aluminium, zinc and aluminum-manganese of metallurgical degree for obtention of the alloy; treatment and refining of the metallic bath, pouring technique with symmetrical fronts of feeding; quality control by means of visual inspection, analysis of the chemical and metallographic composition of the phase and mechanical and radiografic constuent of the alloy, assays for qualification of the casting, as aeronautical standards. The assays had presented resulted whose gotten values had been compared with international aeronautical standards, allowing to make possible the transference of this devolopment for the productive process to pay attention to emergency necessities and to stimulate the evolution of the aeronautical sector of the Country. / Orientador: Valdir Alves Guimarães / Coorientador: Francisco Cristovão Lourenço de Melo / Banca: Carlos Kiyan / Banca: Mirian de Lourdes Noronha Motta Melo / Mestre

Made available in DSpace on 2014-06-11T19:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-03-06Bitstream added on 2014-06-13T20:18:25Z : No. of bitstreams: 1 souzafilho_mp_me_guara.pdf: 3830984 bytes, checksum: 7c2960cef5b04e4cbf20952bbc3f0443 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho teve como objetivo o desenvolvimento das técnicas fundição de semicubos do trem de pouso principal do cargueiro C-115 Buffalo da Força Área Brasileira, pelo processo de fundição de liga de magnésio em moldes de areia a verde para atender as necessidades emergenciais nas atividades de apoio logístico, tático e transporte. Por ser um item estrutural cujas exigências em relação às propriedades de engenharia e segurança são rigorosas, foi necessário o desenvolvimento de técnicas de fundição diferenciadas para a obtenção do modelo com suas respectivas superespessuras de contração e usinagem; ângulos de saída; sistemas especiais de canais de alimentação; molde preparado com areia sintética, bentonita, enxofre, ácido bórico e água; magnésio, alumínio, zinco e alumínio-manganês de grau metalúrgico para a obtenção da liga; tratamento e refino do banho metálico, técnica de vazamento com frentes de alimentação simétricas; controle de qualidade por meio de inspeção visual, análise da composição química e metalográfica das fases e constituintes da liga, ensaios mecânicos e radiográficos para qualificação do fundido, conforme padrões aeronáuticos. Os ensaios apresentaram resultados cujos valores obtidos foram comparados com os padrões aeronáuticos internacionais, permitindo viabilizar a transferência desse desenvolvimento para o processo produtivo de forma a atender necessidades emergenciais e estimular a evolução do setor aeronáutico do País. / This work had as objective the development of the techniques of semicubes casting of the main landing gear of the C-115 Buffalo freighterm from Brazilian Air Force, by the process of magnesium alloy casting in green sand molds to attend to the emergent necessities in the activities of logistic, tactical support and air service. The creation of the Project of Nationalization of Aeronautical Components was necessary for the maintenance of the operationalization of the aircraft and to prevent the collapse of the fleet. Aeronautical wells are a structural item whose requirements in relation to the security and engineering properties are rigorous, it was necessary the development of differentiated techniques of casting for the attainment of the model with its respective superthicknesses contraction adn machining; pattern draft; special gate systems; mold prepared in synthetic sand, bentonite sand, sulphur, acid boric and water; magnesium, aluminium, zinc and aluminum-manganese of metallurgical degree for obtention of the alloy; treatment and refining of the metallic bath, pouring technique with symmetrical fronts of feeding; quality control by means of visual inspection, analysis of the chemical and metallographic composition of the phase and mechanical and radiografic constuent of the alloy, assays for qualification of the casting, as aeronautical standards. The assays had presented resulted whose gotten values had been compared with international aeronautical standards, allowing to make possible the transference of this devolopment for the productive process to pay attention to emergency necessities and to stimulate the evolution of the aeronautical sector of the Country.

After carbon, phosphorus is the most commonly detected element in archaeological iron. The typical phosphoric iron range is 0.1wt% to 1wt%P. The predominant source of phosphorus in iron is the ore smelted. Around 60% of economic UK rock iron ore formations contain over 0.2%P. Under fully reducing conditions, both in liquid-state (cast iron) and solid-state bloomery smelting (direct reduction) processes, such rock ores would be predicted to produce phosphoric iron, and bog iron ores even more so. Ore-metal-slag phosphorus ratios for bloomery iron are derived here, by means of: laboratory experiments; full-scale experimental bloomery smelting; and analysis of remains from three Medieval and two Late Roman-Iron Age iron production sites in England and the Netherlands. Archaeological ore, slag, metal residues (gromps), and iron artefacts were analysed by metallography, SEM-EDS, EPMA, and XRD. The effects of forging and carburising on phosphoric iron were studied by experiment and artefact analysis. The ore to slag %P ratio for solid-state reduction was determined to range from 1:1.2 to 1: 1.8. The ore to metal %P ratio varied from 1:0.2 to 1:0.7 ¿ 1.4, depending on furnace operating conditions. Archaeological phosphoric iron and steel microstructures resulting from non-equilibrium reduction, heat treatment, and mechanical processing are presented to define the technology of early phosphoric iron. Microstructures were identified by a combination of metallography and chemical analysis. The phosphoric iron artefacts examined appear to be fully functional objects, some cold-worked and carburised. Modern concepts of 'quality' and workability are shown to be inapplicable to the archaeological material.

This diploma thesis deals with the automation of the electropolishing process, which is per-former as the last step in the preparation of metallographic samples intended for observation in an electron microscope. A complete hardware design of a single-purpose machine has been developed, which provides the automatic preperation of up to six samples per insertion. There was the design of a manipulator for sample handling together with chemically re-sistant sample holder suitable for automatic operation as a part of solution. The design of the whole machine was developed with regard to the safety of the operator. The thesis includes detailed 3D model of the device and the desing of an application for measurement in the LabVIEW. It describes the future working process of the machine, including a description of a software for controlling the machine and sending process data of each sample to the to the database in accordance with the principles of industry 4.0. In the conclusion, the achieved results and the proposal of further steps necessary for the realization of the machine are for-mulated.

Neste trabalho foram realizados experimentos de soldagem circunferencial em tubos de aço inoxidável super duplex UNS S32750, com diâmetros de 19,05 mm e 48,20 mm. Foram executadas soldas utilizando-se diversos parâmetros de soldagem num equipamento MIG com controle CMT&reg Cold Metal Transfer. Os cordões de solda foram avaliados por inspeção visual e dimensional, além dos ensaios de tração e microdureza Vickers, bem como a análise microestrutural em conjunto com análise de precipitação de fases, a qual foi realizada em acordo com a prática A da norma ASTM A923, e ensaio de corrosão conforme a prática A da norma ASTM G48 em conjunto com a norma ASTM A923. Os resultados indicaram que a soldagem do tubo com diâmetro de 19,05 mm apresentou cordão de solda com dimensões inaceitáveis conforme norma, tendo sido esta condição atribuída a utilização de um elevado diâmetro do arame para as condições (parâmetros) usadas de soldagem. A soldagem do tubo com diâmetro de 48,20 mm apresentou falta de penetração nas condições empregadas, quando soldado pelo processo CMT&reg convencional. No caso da utilização do CMT&reg combinado com arco pulsado, em condições que geraram maior aporte de calor durante a soldagem, assim obteve-se penetração total da junta e acabamento superficial adequado. Os resultados indicaram que a soldagem utilizando o processo CMT&reg combinado com arco pulsado, nas condições (parâmetros) empregados geraram bom acabamento superficial, aliado propriedades mecânicas compatíveis, atendendo exigências de normas, bem como uma microestrutura balanceada e alta resistência à corrosão. / This study carried out circumferential welding experiments in UNS S32750 Super Duplex Stainless Steel tubes using diameters of 19,05 mm and 48,20 mm. Welds were performed using various welding parameters on a MIG machine with Cold Metal Transfer&reg CMT control. The weld joints were evaluated by visual and dimensional inspection in addition to the Vickers microhardness and traction tests, as well as the microstructural analysis in conjunction with phase precipitation analysis, which was performed according to practice A of ASTM A923, and corrosion test in accordance with practice A of ASTM G48 in conjunction with ASTM A923. The results indicated that welds performed in pipes with a diameter of 19.05 mm showed a weld joint with unacceptable dimensions according to the standard, this condition being attributed the use of a high wire diameter for the welding conditions used. Welding performed for pipes with a diameter of 48.20 mm showed a lack of penetration under the conditions employed when welded by the conventional CMT&reg process. In the case of the use of CMT&reg combined with pulsed arc, under conditions that generated greater heat input during welding, this resulted in total penetration of the joint and adequate surface finish. The results indicated that welding using the CMT&reg process combined with pulsed arc, under the conditions (parameters) employed generated good surface finish, combined mechanical properties, meeting standards requirements, as well as a balanced microstructure and high resistance to corrosion.

Neste trabalho foram realizados experimentos de soldagem circunferencial em tubos de aço inoxidável super duplex UNS S32750, com diâmetros de 19,05 mm e 48,20 mm. Foram executadas soldas utilizando-se diversos parâmetros de soldagem num equipamento MIG com controle CMT&reg Cold Metal Transfer. Os cordões de solda foram avaliados por inspeção visual e dimensional, além dos ensaios de tração e microdureza Vickers, bem como a análise microestrutural em conjunto com análise de precipitação de fases, a qual foi realizada em acordo com a prática A da norma ASTM A923, e ensaio de corrosão conforme a prática A da norma ASTM G48 em conjunto com a norma ASTM A923. Os resultados indicaram que a soldagem do tubo com diâmetro de 19,05 mm apresentou cordão de solda com dimensões inaceitáveis conforme norma, tendo sido esta condição atribuída a utilização de um elevado diâmetro do arame para as condições (parâmetros) usadas de soldagem. A soldagem do tubo com diâmetro de 48,20 mm apresentou falta de penetração nas condições empregadas, quando soldado pelo processo CMT&reg convencional. No caso da utilização do CMT&reg combinado com arco pulsado, em condições que geraram maior aporte de calor durante a soldagem, assim obteve-se penetração total da junta e acabamento superficial adequado. Os resultados indicaram que a soldagem utilizando o processo CMT&reg combinado com arco pulsado, nas condições (parâmetros) empregados geraram bom acabamento superficial, aliado propriedades mecânicas compatíveis, atendendo exigências de normas, bem como uma microestrutura balanceada e alta resistência à corrosão. / This study carried out circumferential welding experiments in UNS S32750 Super Duplex Stainless Steel tubes using diameters of 19,05 mm and 48,20 mm. Welds were performed using various welding parameters on a MIG machine with Cold Metal Transfer&reg CMT control. The weld joints were evaluated by visual and dimensional inspection in addition to the Vickers microhardness and traction tests, as well as the microstructural analysis in conjunction with phase precipitation analysis, which was performed according to practice A of ASTM A923, and corrosion test in accordance with practice A of ASTM G48 in conjunction with ASTM A923. The results indicated that welds performed in pipes with a diameter of 19.05 mm showed a weld joint with unacceptable dimensions according to the standard, this condition being attributed the use of a high wire diameter for the welding conditions used. Welding performed for pipes with a diameter of 48.20 mm showed a lack of penetration under the conditions employed when welded by the conventional CMT&reg process. In the case of the use of CMT&reg combined with pulsed arc, under conditions that generated greater heat input during welding, this resulted in total penetration of the joint and adequate surface finish. The results indicated that welding using the CMT&reg process combined with pulsed arc, under the conditions (parameters) employed generated good surface finish, combined mechanical properties, meeting standards requirements, as well as a balanced microstructure and high resistance to corrosion.