Effect of stress-relief annealing on microstructure, texture and hysteresis curve of mechanically cut non-oriented Fe-Si steel

The effect of stress-relief annealing at 780 °C for 2 h on microstructure and texture in the cut edge zone as well as hysteresis curve of a mechanically cut non-oriented Fe-Si steel with 0.5 mm thickness and medium silicon content was investigated. The results from electron backscatter diffraction (EBSD) analysis revealed that the annealing resulted in a significant decrease in dislocation densities and low-angle boundary (LAGB, 2°≤ θ ≤ 15°) percentages, and refined the grain sizes from both the upper surface and the lower surface as result of the occurrence of grain recrystallization. The annealing also caused a drastic increase in volume fraction of λ fiber ({001}〈uvw〉) component, and led to an obvious decrease in that of γ fiber ({001}〈uvw〉) component. Microstructure and texture evolution from the upper surface is evidently different from that from the lower surface. The single sheet testing results showed that the annealing improved the hysteresis loops dramatically regardless of the variations of the cutting length per mass. The possible main reasons for the microstructure, texture, and hysteresis loop evolution due to the annealing were discussed in detail.