Sl. Semiatin et al., A SIMPLE-MODEL FOR CONVENTIONAL HOT-ROLLING OF SHEET MATERIALS, Metallurgical and materials transactions. A, Physical metallurgy andmaterials science, 25(8), 1994, pp. 1681-1692
Temperature transients during the bare hot rolling of sheet materials
have been modeled using a simple one-dimensional, finite-difference he
at-transfer approach. The model addresses heat losses associated with
(1) the transfer of the sheet from the reheat furnace to the rolling m
ill and (2) the actual rolling operation itself. The former step compr
ises heat losses primarily through radiation and the latter through ch
illing of the hot workpiece in contact with the cooler rolls. The prin
cipal output of the model is the temperature field through the thickne
ss of the sheet. The usefulness of the model was gaged through an inve
stigation of the effect of temperature transients on the hot-rolling b
ehavior of Ti-6Al-4V sheet. Specifically, the effect of temperature tr
ansients on rolling pressure and development of nonuniform microstruct
ure was determined. Over the entire temperature range studied, the rol
ling pressure for Ti-6Al-4V was found to be dependent only on the aver
age temperature of the workpiece within the roll gap, irrespective of
metastable phase transformations that may have accompanied the deforma
tion process itself. The one-dimensional heat-transfer model was also
successful in explaining the occurrence of the nonuniform microstructu
res produced during rolling at nominal (furnace) temperatures near the
beta transus.