Annealing kinetics of cold-rolled plain carbon steels

Softening of rimmed steel during batch annealing is due to recrystallization, grain growth and carbide coarsening. The post-recrystallization softening process is used commercially to control product quality and its kinetics can be characterized by an apparent activation energy. This parameter is shown to increase with decreasing carbon content owing to the influence of carbide particle dissolution on the grain growth rate. The latter effect is suppressed by low manganese and high sulphur contents because of the formation of fine manganese sulphide precipitates. The apparent activation energy of softening can be applied to improve the economics of industrial batch annealing.