Cross-rolling mediated microstructure and texture evolution in severely cold-rolled and annealed ultrafine pearlite

Abstract

Effect of cross-rolling on the evolution of microstructure and texture in pearlite was investigated in the present work. For this purpose, near pearlitic steel was cold-rolled to 95% reduction by unidirectional cold-rolling (UCR) and different cross-rolling routes. The UCR processed material showed a predominantly lamellar structure, while the microstructure development in selected cross-rolled materials was featured by the presence of profuse shear bands and severely bent lamellae. While the UCR processed materials showed the presence of the typical RD (//〈110〉) and ND (//〈111〉) fibers, the texture formation in different cross-rolled materials was featured by the strong presence of a {001}〈110〉 component of the RD-fiber. The presence of the prominent {001}<110 > component could be explained by the stability of this component under cross-rolling. Recrystallization resulted in progressive spheroidization of the cementite. The pinning of the high angle boundaries by the cementite particles hindered the long-range migration of boundaries, thus inhibiting typical discontinuous recrystallization but favoring a recovery dominated softening process. The recrystallization textures in different cross-rolled materials were featured by the retention of deformation texture, namely the prominent {001}<110 > component of the RD-fiber, which amply corroborated a recovery dominated mechanism. Extended annealing resulted in the onset of abnormal grain growth in selected cross-rolled materials, which appeared to affect the microtexture, while the global texture remained mostly unaffected.