Identifying Production Conditions
for Ultrafine Grained Steel Sheets on Hot Strip Mill

Abstract

We identified the conditions needed to produce ultrafine grained steel in a hot strip mill using a simulation model for microstructure evolution. The following conditions are necessary.
-high-reduction-level rolling at each latter stand of the finishing mill
-strong cooling just after rolling
Low-temperature and continuous high-reduction-level rolling in hot strip mills suppresses static recovery between rolling stands, owing to the low-temperature rolling and the short time interval between rolling stands. Consequently, the effect of the high reduction level of one pass enables the strain in the steel to accumulate, resulting in ferrite-generating nucleation, and ultrafine grained steel is produced by the strong cooling after rolling.