Refinement of ferrite-pearlite structures through transformation from heavily deformed austenite in a low carbon Si-Mn steel

In a low-carbon Si-Mn steel without any other alloy ing elements, an ultra-fine ferritepearlite microstructure with a ferrite grain size of 2.3 μm was created through thermomechanical treatment. The feature of the process was one-pass heavy reduction at a low temperature in unrecry stallized austenite region followed by controlled cooling at 10 K/s. Crystallographic orientation of each ferrite grain was randomly distributed and most of the grain boundaries were high-angle ones.