|Spoluautoři MAUBANE Rorisang|
The influence of Mn content on austenite recrystallization during roughing and early finishing of low C-high Nb-Ti steels has been investigated using multi-pass rolling simulations. Stress analysis was used to study the austenite softening behaviour. The ferrite microstructure after the first finishing pass was examined. The flow stress during roughing is unaffected by the Mn content, but increases with Nb content. Sufficient strain accumulation, coupled with low Zener-Hollomon, Z, values during roughing produce extensive dynamic recrystallization, DRX, and grain refinement in low and high Mn steels. The location of an intermediate water cooling facility is important for complete softening if partial, static recrystallization dominates during roughing. It becomes less critical for conditions favouring rapidly completed dynamic and/or metadynamic recrystallization. For a finishing entry temperature of 1000ºC, a low Mn content reduces the extent of recrystallization. Softening is completely suppressed at 900ºC, irrespective of Mn content. Low Mn contents produce coarser ferrite grains that are relatively insensitive to roughing conditions.