Abstract

MILLAN, J et al. Recrystallization orocess during the annealing of a 0,04%c al-killed steel. Rev. Fac. Ing. UCV [online]. 2005, vol.20, n.1, pp.17-31. ISSN 0798-4065.

The recrystallization process of a commercial 0.04%C Al-killed steel, cold rolled up to 80% subjected to a annealing heat treatment at variable heating rates was evaluated in the present study. For this purpose, samples were isothermally annealed at various heating rates (12ºC/h, 20ºC/h, 40ºC/h and 650ºC/min) and then soaked at 700ºC for 15 hours. The microstructural evolution of the samples followed by optical microscopy, scanning and transmission electron microscopy, showed that the recrystallization process took place between 600 and 650ºC for the samples heated at low rates (12ºC/h, 20ºC/h and 40ºC/h), and the grain structure developed was the so called “pancake” type. The grain size for these samples showed an insignificant growth during the holding stage at 700ºC. On the other hand, with the samples heated at 650ºC/min, the recrystallizaction occurred on reaching 700ºC, the grain structure was more equiaxial and the grain size changed appreciably during the holding stage. The spheroidization process of cementite occurred in significant amounts during the holding stage at 700ºC. The precipitation and coarsening of AlN particles were also evaluated during the holding stage at 700ºC.

Keywords : Recrystallization; AlN precipitates; Pancake structure.