"Influência do Processamento Termomecânico sobre a Formação de Bandas de Cisalhamento e Propriedades Magnéticas de um Aço de Grão Não Orientado com 3%Si" / "Influência do Processamento Termomecânico sobre a Formação de Bandas de Cisalhamento e Propriedades Magnéticas de um Aço de Grão Não Orientado com 3%Si"

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

02/02/2010

RESUMO

Non-oriented silicon steels are soft magnetic materials widely used in equipments for electricity generation and distribution. The obtaining of both high magnetic induction and low magnetic loss has been subject of research for the improvement and development of new nonoriented silicon steels. These works have focused on the development of alloys with lower contents of residuals and thermomechanical processes that produce grain sizes and crystallographic orientations appropriate to the final product. This project studied the effect of thermomechanical processing on the formation of shear bands and on the magnetic properties of a non-oriented silicon steel with 3.0wt% Silicon. The samples were submitted to hot rolling, cold rolling and final annealing at 1020 C. Properties such as magnetic loss, magnetic induction and permeability were measured in the final samples. The structural evolution was assessed by optical metallography with determination of grain size and by crystallographic orientation analysis with X-ray diffraction and EBSD (Electron Back- Scattering Diffraction). The presence of shear bands was evaluated by light microscopy of samples submitted to annealing at intermediate temperatures, from 620 to 780 C. The volume fractions of fiber and texture components were determined, as well as ODF (Orientation Distribution Function). It was found that the larger the hot band grain size the lower was the g fiber volume fraction and the higher was the h fiber volume fraction at the final annealing. The increasing cold reduction contributed strongly to this result. The magnetic properties could be benefited from the optimization of crystallographic texture. The best combination of microstructure, due to the intense generation of shear bands, crystallographic texture, due to higher nucleation of grains with Goss and Cube orientations from these bands, and magnetic properties was achieved for the samples hot rolled at 1000 and 1120 C to the thickness 1.8 and 1.4 mm, and this combination was more evident to the thickness 1.4 mm.

ASSUNTO(S)

aço ao silício de grão não-orientado bandas de cisalhamento textura cristalográfica propriedades magnéticas non-oriented silicon steel texture magnetic properties engenharia de materiais e metalurgica shear bands

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