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Advisor(s)
Abstract(s)
O trabalho apresentado permitiu estudar a corrosão em diferentes tipos de aços. Para uma compreensão de todos os fenómenos adjacentes a este processo, começou-se por referir alguns conceitos básicos da electroquímica, da corrosão e da metalurgia. Abordaram-se as diferentes formas de corrosão existentes, enfatizando a corrosão por picadas e intersticial, e também se referiram algumas metodologias para proteger os metais.
Após expor todos estes conceitos mencionou-se o mundo dos pipelines, onde a corrosão pode originar acontecimentos catastróficos caso seja negligenciada. Fez-se referência à história destas estruturas, ao fenómeno de corrosão que as atinge e ao modo de prevenir e avaliar a gravidade da corrosão.
Neste trabalho estudou-se, em solução de NaCl e em solução de H2SO4, os aços inoxidáveis 304L e 316L, geralmente usados para transporte ou armazenamento de fluidos a altas temperaturas; os aços S275 e S355, usados em aquedutos ou outras estruturas adjacentes aos mesmos; e também os aços X52 e X70, usados nos pipelines que transportam gás ou óleo para todo o mundo.
O objectivo deste trabalho foi identificar quais as amostras destes aços que são mais susceptíveis de serem corroídas. Concluiu-se, através de testes de polarização anódica e de imersão, que o aço inoxidável 316L é o mais resistente, apresentando-se o aço carbono X52 no extremo oposto.
This work allowed the study of corrosion on different types of steels. For an understanding of all phenomena surrounding this process, we began to mentioned some basic concepts of electrochemistry, corrosion and metallurgy. It was shown some forms of corrosion, emphasizing the pitting and crevice corrosion, and also mentioned some methods to protect metals. After exposing all these concepts, we show the world of pipelines, where corrosion may cause catastrophic events if neglected. References were made to the history of these structures, to the corrosion phenomenon that affects them and also how to prevent and assess the severity of this event. In this work we studied, in NaCl and H2SO4 solutions, three types of steels, such us: the 304L and 316L stainless steels, usually used for transportation or storage of fluids at high temperatures; steels S275 and S355, used in aqueducts or other structures nearby, and also X52 and X70 steels, used in gas or oil pipelines worldwide. The aim of this study was to identify which samples of these steels are more likely to be corroded. It was concluded through anodic polarization and immersion tests, that the 316L stainless steel is the toughest, and in the other end, the carbon steel X52 was the less resistance.
This work allowed the study of corrosion on different types of steels. For an understanding of all phenomena surrounding this process, we began to mentioned some basic concepts of electrochemistry, corrosion and metallurgy. It was shown some forms of corrosion, emphasizing the pitting and crevice corrosion, and also mentioned some methods to protect metals. After exposing all these concepts, we show the world of pipelines, where corrosion may cause catastrophic events if neglected. References were made to the history of these structures, to the corrosion phenomenon that affects them and also how to prevent and assess the severity of this event. In this work we studied, in NaCl and H2SO4 solutions, three types of steels, such us: the 304L and 316L stainless steels, usually used for transportation or storage of fluids at high temperatures; steels S275 and S355, used in aqueducts or other structures nearby, and also X52 and X70 steels, used in gas or oil pipelines worldwide. The aim of this study was to identify which samples of these steels are more likely to be corroded. It was concluded through anodic polarization and immersion tests, that the 316L stainless steel is the toughest, and in the other end, the carbon steel X52 was the less resistance.
Description
Mestrado em Engenharia Química - Ramo Optimização Energética na Indústria Química
Keywords
Corrosão Polarização anódica Ensaio de imersão Aços Corrosion Anodic polarization Immersion test Steels
Citation
Publisher
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto