Interação do hidrogênio no aço duplex 2205 recozido e envelhecido após laminação a frio

• Ano de defesa: 2021
• Autor(a) principal: Loyslene Rabelo Fernandes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ENG - DEPARTAMENTO DE ENGENHARIA METALÚRGICA; Programa de Pós-Graduação em Engenharia Metalúrgica, Materiais e de Minas; UFMG
• Palavras-chave em Português: Aço inoxidável duplex; Fragilização por hidrogênio; Absorção de hidrogênio; Difusividade do hidrogênio; Fratura frágil; Engenharia metalúrgica; Metalurgia física; Aço inoxidável; Aço - Teor de hidrogênio; Aço - Tratamento térmico
• Link de acesso: http://hdl.handle.net/1843/49716

Duplex stainless steels (DSS) belong to a group of high-alloy steels consisting of a twophase microstructure of ferrite and austenite. These alloys offer an attractive combination of properties, including high mechanical strength combined with good corrosion resistance and ductility. Its application has been growing; being used mainly in maritime transport, petrochemical, nuclear and pulp and paper industries. However, these materials can fail during their useful life when exposed to certain media. Samples of DSS 2205 were received in the homogenization annealing condition (1050ºC for 300 s and cooling in water), were cold rolled at 60% reduction and annealed at 1100ºC for 2 h and aged at 850ºC for 24 h. Then they were charged with hydrogen. Melt extraction analyzes were applied to quantify hydrogen in steel. In situ tensile and bending tests with simultaneous hydrogen charged were used to assess the instability caused by this element. Deformation-induced martensite in austenite occurred in the tensile test in samples without loading. The microstructure was characterized by optical microscopy, scanning electron, transmission electron, electron backscatter diffraction and x-ray diffraction. The ferrite (α), austenite (), sigma (), chi () and carbide (M23C6) phases were identified. The DSS showed a considerable reduction in ductility, considering only 5% elongation in the aged state. Melt extraction revealed a microstructure hydrogen content of up to 50 ppm by weight for the annealed condition, while for the aged sample it was 10 ppm by weight. Due to the high-volume fraction of intermetallic phases and hydrogen charged, the fracture surfaces were characterized as intergranular.