INSTABILITY OF SECONDARY RECRYSTALLIZATION CAUSED BY EXCESSIVE COLD-ROLLING REDUCTION IN FE-3-PERCENT-SI ALLOY

Secondary recrystallization of an Fe-3%Si alloy containing AIN and MnS as inhibitors with heavy cold rolling before primary recrystallization annealing was investigated with special reference to poor secondary recrystallization. Excessive cold-rolling reduction produces smaller primary recrystallized grains with higher intensity of {100}[025] oriented grains and higher possibility for {100}[025] oriented grains associated with Sigma 5 coincidence boundaries. Specific grain growth of the {100}[025] primary recrystallized grain before the onset of secondary recrystallization is considered to cause the poor secondary recrystallization by reducing the driving force of secondary recrystallization. It may be essential for this unstable secondary recrystallization that the two equivalent orientations of the {100}[025] oriented grains which increase with increasing cold-rolling reduction have the Sigma 5 coincidence orientation relationship with each other.