Dynamic Recrystallization of Ferrite and Microstructure Formation during Intercritical Rolling of Low Carbon Steel

Abstract

Ferrite microstructure has been investigated in low carbon steel, hot-rolled in intercritical range by laboratory mill with various rolling reductions and temperatures.The results obtained are as follows:
(1) Dynamic recrystallization of ferrite is confirmed to take place in 0.17%C-1.35%Mn steel intercritically rolled 80% through the experimental results that elongated ferrite microstructures consist of polygonal recrystallized grains and the incubation time for static recrystallization after dynamic recovery is longer than the time experimentally required for quenching operation to fix the microstructure.
(2) In low carbon rimmed steel, rolling conditions for the complete dynamic recrystallization of ferrite are confined to those with high reduction and high temperature.
(3) The dynamically recrystallized ferrite structure is less liable to change by heat treatment after rolling than dynamically recovered ferrite.
(4) The rolling temperature at which the deformation resistance takes minimum value shifts to lower temperature as the rolling reduction increases. It is explained by the occurrence of dynamic recrystallization of ferrite.
(5) Texture of the material containing dynamically recrystallized ferrite at midthickness is randomized, while material containing deformed or recovered ferrite shows well developed texture with {100}<011> orientations as main component.