Effect Of Intermediate Table Insulation Technics On Microstructure After Rolling During Hot Tandem Rolling

The different heat conservation technics on intermediate table between roughing and finishing of hot strip mills have direct effects on behavior of phase change and microstructure.This paper combining practical production conditions of hot tandem rolling in WuHan Iron and Steel Corporation studies the effect of heat conservation technics on intermediate table on behavior of phase change and microstructure as to Q235 during cooling process after rolling. By dilatometric test, Laboratory experiments were carried out on Thermecmastor----Z thermal simulation machine, continuous cooling transformation curves(dynamic CCT curve) of overcooling austenite of studied steel grade were measured on conditions of different heat conservation technics on intermediate table and certain deforming technics; Each sample was grinded, polished and corroded, through optical microscope, we could observe their microstructure, change of microstructure was studied on condition of different heat conservation technics on intermediate table; Using CCT curves that were established, effects on behavior of phase change and microstructure in terms of different deforming technics and technics of heat conservation were studied, laws of effect were also analyzed. The results indicate CCT curves move right-lower direction and grain size becomes large as heat conservation time prolonging; The higher heat conservation temperature is, the more dramatic effects on austenite grain is. The results of study will provide references to optimizing intermediate table insulation system during hot tandem rolling.