Estudo da influência do tratamento térmico a laser nas características dos aços avançados de alta resistência dual phase 600 e transformed induced plasticity 750
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Data
2016-03-22
Autores
Amorim, Marcelo Soares [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os aços avançados de alta resistência são de importância na indústria moderna da mobilidade. Na indústria automobilística, por exemplo, é previsto que o uso destes materiais cresça de maneira acentuada nos próximos anos. Algumas características destes materiais podem ser melhoradas por meio de tratamento térmico, seja ele em toda a extensão do produto ou em partes específicas para as quais se deseja um dado comportamento mecânico. Neste trabalho se propôs a investigação inicial do efeito de um tratamento térmico local por radiação laser, uma forma controlada de adição de energia, nas propriedades mecânicas e na microestrutura de dois destes materiais. Os materiais estudados foram os aços dual phase (DP 600) e o transformed induced plasticity (TRIP 750), e a contribuição pretendida aqui foi prover informações sobre a interação entre a radiação laser e os materiais de estudo, dentro de determinados parâmetros de processamento térmico. Para a caracterização dos materiais, conforme recebidos e após os tratamentos térmicos a laser propostos, foram realizados ensaios metalográficos, de difratometria de raios-X, de dureza e de tração. Verificou-se que, para a faixa de parâmetros de processo experimentada, houve mudanças significativas nas características dos materiais estudados, notadamente um aumento na dureza superficial, alcançando valores correspondentes ao dobro dos relativos aos materiais sem tratamento, nos limites de escoamento, com aumentos de até 15% com relação ao material-base, e de resistência, com aumentos até cerca de 30% com relação ao material-base. Por outro lado, verificou-se uma diminuição no alongamento específico dos materiais, quando submetidos a ensaios de tração, de até 80% com relação aos materiais sem tratamento térmico.
The advanced high strength steels are of importance in modern mobility industry. In the automotive industry, for example, it is anticipated that the use of such materials will be increased in the near future. Some characteristics of these materials can be improved through heat treatments, considering the entire mass of the product or in specific regions of a part, for which it is necessary a particular mechanical behavior. This work focused on the initial investigation of a local heat treatment by laser radiation, a controlled form of energy addition, in the mechanical properties and microstructure of two of these materials. The studied materials are the dual phase steel (DP 600) and the transformed induced plasticity steel (TRIP 750), and the desired contribution here was to provide information about the interaction between the laser radiation and the studied materials for a given range of thermal processing parameters. To characterize the materials as received and after proposed laser heat treatments, metallographic evaluation, X-ray diffraction, and hardness and tensile tests were performed. It was found that, for the range of process parameters investigated, there were significant changes in the characteristics of the materials, notably an increase in surface hardness, reaching values corresponding to twice of those for materials without treatment, in the yield limits, with increases of up to 15% with respect to the base material, and strength limits, with increases up to about 30% with respect to the base material. On the other hand, there was a decrease in the elongation of materials, when subjected to tensile tests, up to 80% in comparison to materials without heat treatment.
The advanced high strength steels are of importance in modern mobility industry. In the automotive industry, for example, it is anticipated that the use of such materials will be increased in the near future. Some characteristics of these materials can be improved through heat treatments, considering the entire mass of the product or in specific regions of a part, for which it is necessary a particular mechanical behavior. This work focused on the initial investigation of a local heat treatment by laser radiation, a controlled form of energy addition, in the mechanical properties and microstructure of two of these materials. The studied materials are the dual phase steel (DP 600) and the transformed induced plasticity steel (TRIP 750), and the desired contribution here was to provide information about the interaction between the laser radiation and the studied materials for a given range of thermal processing parameters. To characterize the materials as received and after proposed laser heat treatments, metallographic evaluation, X-ray diffraction, and hardness and tensile tests were performed. It was found that, for the range of process parameters investigated, there were significant changes in the characteristics of the materials, notably an increase in surface hardness, reaching values corresponding to twice of those for materials without treatment, in the yield limits, with increases of up to 15% with respect to the base material, and strength limits, with increases up to about 30% with respect to the base material. On the other hand, there was a decrease in the elongation of materials, when subjected to tensile tests, up to 80% in comparison to materials without heat treatment.
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Palavras-chave
Caracterização mecânica, Tratamento térmico a laser, Aços avançados de alta resistência, Aços multifásicos, Mechanical characterization, Laser heat treatment, Advanced high strength steels, Multiphase steels