Recrystallization Behavior and Texture Formation of Rapidly Annealed Cold-Rolled Extralow Carbon Steel Sheets

Abstract

The influence of a heating rate up to 1000 C/s on recrystallization behavior and texture formation of an extralow carbon steel sheet was investigated. To discuss the experimental results of this investigation, a mathematical model for predicting recrystallization behavior was developed. An analysis using the model shows that the heating rate influences the apparent thermal activation energy of recrystallization. At a higher heating rate, C dissolved from cementite and AlN precipitated during heating decreases and as a consequence the apparent thermal activation energy is lower. This can also be a valid explanation for the fact that recrystallization of a steel sheet coiled at low temperature is retarded.The main orientations of the recrystallization texture are weakened if the heating rate is increased. This tendency has already been observed at the initial stage of recrystallization. If the specimen is heated slowly up to the initial stage of recrystallization, the decrease in the intensity of the main orientations is reduced even though the heating rate subsequently increases. This result indicates that, concerning formation of the recrystallization texture, the heating rate mainly influences the nucleation process.

The Effect of Ultrafast Heating in Cold-Rolled Low Carbon Steel: Recrystallization and Texture Evolution

“…The pinning effect of carbon atoms on the dislocation structure is claimed to play a significant role in slowing the recrystallization and decreasing the ferrite recrystallized fraction at the same heating temperatures. Similar findings are reported by Stockemer and Vanden Brande [14] and Senuma et al [15]. It is also reported that the recrystallization is completed before the onset of austenite formation in low and very low carbon steels, as well as in interstitial free (IF) steel [16].…”

“…It is also reported that the recrystallization is completed before the onset of austenite formation in low and very low carbon steels, as well as in interstitial free (IF) steel [16]. Results on the texture evolution during fast and ultrafast heating of ULC steel and low carbon steel heating have been published elsewhere [4][5][6][7]14,15,17,18]. The orientation measurements do not show significant deviations from {111}<uvw> ND fiber [19,20], suggesting that the recrystallization textures in ferrite are practically independent of the heating rate.…”

“…The effect of UFH rates on the recrystallization of cold-rolled ultra-low carbon (ULC) steel during continuous heating (anisothermal conditions) was the subject of a number of studies in recent years [10][11][12][13][14][15]. Ferry et al [11] and Muljono et al [12] reported faster recrystallization kinetics when UFH rates are applied in comparison to conventional heating rates.…”

Present Status and Future Prospects of Simulation Models for Predicting the Microstructure of Cold-rolled Steel Sheets

“…The parameter b is the function of temperature, reduction in cold rolling and initial grain size, and n is a constant that varies from 1 to 4 depending on the growth behavior of the recrystallizing grains. Equation (3) Recent research on the prediction of the recrystallization behavior of cold-rolled extra-low-carbon steel sheets using a JMAK-type equation 6) is introduced in the following. Figure 3 shows the recrystallization behavior of steel samples coldrolled to 80% and subsequently heated with various heating rates.…”

Present Status and Future Perspective of Models for Predicting Microstructure of Cold Rolled Steel Sheets

“…Influence of the heating rate on the recrystallization behavior of an extralow carbon steel sheets cold rolled to 80%. 7) Experimental data were compared with the result calculated. …”