Analyses of texture memory, surface-effect-induced transformation texture and variant selection in low graded electrical steels

Abstract

This study investigates the retaining of both {100} texture and topographic structure of columnar grains in cast slabs of industrial low graded electrical steels in terms of texture memory and variant selection. In addition, phase transformation treatment is conducted on industrial low graded electrical steels to explore the possibility of producing {100} texture by surface effect. The results show that the texture memory in columnar grains of cast slab can be explained by the directional cooling and internal thermal stress. The abundant Σ3 grain boundaries of small equiaxed grains within coarse columnar grains are detected, which can reduce transformation strain effectively. After phase transformation annealing, {111} and {100} texture memories with equiaxed grains in recrystallization type are resulted in commercial sheets due to the presence of P and Al elements which restrict surface-effect induced transformation texture. In comparison, strong {100} texture and columnar grains are formed in a laboratory-melt sheet as surface effect induced transformation texture by preferred nucleation at surface and preferred growth into sheet centre layer.