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Estudo das variáveis que afetam a tenacidade e a ductilidade do aço PH13-8Mo utilizado na indústria aeronáutica
(Universidade Federal de São Carlos, 2012-10-27) Moreno, Rômulo Fernandes; Ishikawa, Tomaz Toshimi; https://lattes.cnpq.br/5726055117451807
Precipitation Hardening Stainless Steel PH13-8Mo is a high strength steel used in the aerospace industry. Beyond the high strength, this grade has relatively high toughness and ductility for the strength achieved. The aerospace industry is increasingly asking for high strength materials with higher toughness and ductility than the actual limits required. Villares Metals, manufacturer of specialty steels and alloys, supplies the 13-8 steel (Villares grade N4534QA) for the aerospace industry like Embraer and ELEB (landing gear manufacturer of Embraer aircrafts). Although Villares 13-8 steel meets the international and the aerospace specifications, is characteristic of this company to improve its products and follow the new requirements of the customers and the market. Thus, is of its interest to produce the 13-8 steel with higher toughness and ductility. Therefore, the objective of this work is to study the variables which affect the 13-8 steel toughness and ductility aiming to produce it with improved properties. It were studied the effect of the alloying and residual elements, steelmaking process (remelting), hot forming process (forging and rolling) and heat treatment process. The verification of these effects was verified through tensile and impact Charpy V tests.
Ocorrência de nitrato em águas subterrâneas na Unidade de Gerenciamento de Recursos Hídricos Tietê-Jacaré
(Universidade Federal de São Carlos, 2012-10-27) Casagrande, Lucas Antonio Ribas; Salvador, Nemésio Neves Batista; https://lattes.cnpq.br/9930582531600560; https://lattes.cnpq.br/0069984164515170
Agricultural practices present themselves as potentially polluting to groundwater. The recharge areas, where the aquifers tend to be more vulnerable, are under important agricultural areas, and there are not many researches that evaluate the impact of agricultural activity on groundwater quality. The occurrence of high nitrate concentrations, as an effect of the intensive use of fertilizers and nitrogen-rich agricultural products, along with the disposal of agro-industrial residues on the ground, such as nitrogen-rich vinasse, are some of the biggest concerns due to agricultural activity. Considering the existence of extensive areas of sugar cane production, as well as the need for preserving the recharge areas occurring at the Water Resources Management Unit nº 13 (Tietê-Jacaré), this research has as its main goal the accomplishment of a survey and systematization, from water quality existing data, of nitrate occurrence in Serra Geral, Bauru and Guarani Aquifer Systems groundwater, at the Tietê- Jacaré hydrographic basin. Thus, the existing data from groundwater quality monitoring performed by the São Paulo State Environmental Agency were consolidated, for the nitrate parameter, and, moreover, there had been analyzed results from groundwater analyses, for the Nitrate parameter, of a total of 151 private deep wells located in agricultural areas at the Tietê-Jacaré basin, registered at the São Paulo State Water Department. The integrated data, grouped for each Aquifer, has been submitted to basic statistics analysis, calculating its averages, medium, maximum and minimums. The medium ones were used as a reference, for comparison to the orientating values of quality reference, prevention and intervention. Of general form, from the results of the existing analyses, it is observed that the Nitrate concentrations are low, finding higher values in wells that take water from Bauru and Serra Geral Aquifers. None of the raised concentrations were above the national drinking water standard, however, the occurrence of nitrate concentrations above the prevention value deserves attention, indicating alteration on natural balance, mainly for human influence. The wells and their nitrate concentrations were located on a Tietê-Jacaré land use map, through which the ones located in sugar cane areas were identified. The nitrate data for those wells on sugar cane production areas were submitted, separately, to another basic statistics analysis, calculating the averages, medium, maximum and minimum, for comparison with the other wells located in areas with different land use types. On average, the concentrations of the wells in sugar cane area are higher than the concentrations for other wells, especially for the Bauru and Guarani Aquifers. In general, there are increasing concentrations throughout time, indicating the need for continuous monitoring for the nitrate parameter, beyond the establishment of preventive actions to avoid nitrate pollution.