Efeito do envelhecimento entre passes durante a laminação a frio sobre as propriedades magnéticas do aço silício de grão orientado de alta permeabilidade

Abstract

The effects of inter-pass ageing temperature during cold rolling on structure, magnetic properties and mechanical properties of high permeability grain oriented electrical steel was studied. The samples were processed in a single-stage cold rolling to 0.27 mm thickness, with 88 % reduction, without and with inter-pass ageing treatment in the temperature range of 100~300 °C for 10 minutes at intermediate gauges of 1.0 mm, 0.7 mm and 0.5 mm in order to determine the magnetic properties. To determine the changes in mechanical properties due to strain ageing, the samples underwent overlapped ageing, after pre-strain by rolling, under the same conditions of inter-pass ageing and then were subjected to tensile test in thicknesses of 1.0 mm, 0.7 mm and 0.5 mm. The effect of strain ageing was more pronounced in the thickness of 0.7 mm and the largest variation in yield strength was at 200 °C in all evaluated thicknesses. At this temperature the largest amount of orientation after primary recrystallization was also observed, as well as the smallest final grain size and consequently the best results of core loss. The magnetic induction had almost no alterations, indicating that the texture was not affected by inter-pass ageing treatment.