Comparison of recrystallization behaviour of cold deformed acicular ferrite produced by conventional processing and direct strip casting

The effect of initial microstructure on the recrystallization behaviour of low carbon (LC) steel was investigated. Steel strip (0.05 wt.% C) of 2-mm thickness was heat treated to produce an acicular ferrite (AF) microstructure from coarse austenite. The AF material and a strip-cast (SC) material of similar chemistry produced by twin roll casting were cold rolled to 50%, 70% and 90% reduction, and annealed for various times in the temperature range 580–680 °C. The evolution of microstructure during recrystallization was studied by optical microscopy and electron backscatter diffraction (EBSD) in the SEM. The initial microstructure was found to have a substantial influence on the recrystallization behaviour. AF recrystallized at a substantially faster rate than SC due to a higher level of solute Mn causing substantial solute drag effects.