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Estudo das brasagens de WC-Co/AgCu/a?o H13 e WC-Co/AgCUNi/a?o H13 utilizando metaliza??o mec?nica / Study of brazing of WC-Co/AgCu/H13 steel and WC-Co/AgCuNi/H13 steel using mechanical metallizationTeixeira, Wendel Anderson Dantas 30 November 2016 (has links)
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Previous issue date: 2016-11-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Interfaces Metal-WC-Co est?o presentes em opera??es de perfura??o de po?os de petr?leo, onde se utilizam brocas tric?nicas de insertos cer?micos duros. A a??o combinada de corte, esmagamento e desagrega??o de rochas causa a degrada??o das brocas de perfura??o. A degrada??o est? relacionada com o desgaste, fratura total ou parcial do corpo da broca ou dos insertos, choque t?rmico e corros?o. Tamb?m o deficiente encaixe mec?nico dos insertos cer?micos nos cones da broca pode originar o seu destacamento provocando uma s?rie de danos ? broca. O aprimoramento no processo de produ??o de interfaces metal-cer?mica pode eliminar ou minimizar algumas das falhas acima mencionadas nas brocas tric?nicas, otimizando o seu tempo de vida ?til, e portanto, reduzindo o custo m?trico de perfura??o. A brasagem ? uma t?cnica extensivamente utilizada para uni?o de metais e cer?micos, podendo ser uma excelente alternativa ao processo comum de encaixe mec?nico de ?pressfitting? dos insertos cer?micos no corpo de a?o da broca. A metaliza??o das superf?cies WC-Co ? utilizada para melhorar a molhabilidade e ades?o de sistemas M/C. Neste trabalho, pretendeu-se avaliar o efeito da temperatura de brasagem em uni?es de insertos WC-6Co com a?o H13 utilizando ligas de adi??o com base no eut?tico 72Ag28Cu, em um forno com uma condi??o de alto v?cuo. A caracteriza??o mec?nica, microestrutural e morfol?gica das uni?es geradas foi avaliada em ensaios de flex?o de 3 pontos, MEV-EDS e DRX. Os melhores resultados de resist?ncia mec?nica foram encontrados para os sistemas brasados a 880?C com liga de adi??o eut?tica AgCu. / Metal-WC-Co interfaces are present in oil well drilling operations, where tricone drill bits with hard ceramic inserts play an important role. The combination of cutting, crushing and breaking up of rocks results in the degradation of tricone drill bits by wear, total or partial rupture of the drill bit body or the ceramic inserts, thermal shock and corrosion. In addition, the improper pressfitting of the ceramic inserts on the bit body may cause its total detachment, and promote serious damages to the drill bit. The improvement on the production process of metal-ceramic interfaces can eliminate or minimize some of above-mentioned failures presented in tricone drill bits, optimizing their lifetime and so reducing drilling metric cost. Brazing is a widely established technique to join metal-ceramic materials, and may be an excellent alternative to the common mechanical press fitting process of hard ceramic inserts on the steel bit body for tricone drill bit. The metallization of WC-Co surfaces is used to improve the wetting and adhesion of the M/C system, when a liquid phase is present during the brazing process. In this work, the effect of brazing temperature was studied on WC-6Co and H13 steel couples, using 72Ag28Cu eutectic based brazing alloys inside a furnace under high vacuum. Mechanical and microstructure caracterization of the interfaces produced was analysed by 3 point flexural tests, SEM-EDX and XRD techinques.d, and the interfaces produced were analysed by SEM-EDX. Better results for mechanical strenght were found for the systems brazed at 880?C using AgCu eutectic braze alloy.
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