Study on the Evolution of Banded Structure during the Slow Cooling Process

Through slow cooling experiments at a rate of 0.05 °C s −1 on hot‐rolled and homogenized samples for 1, 2, and 4 h, combined with analysis using optical microscopy, electron backscatter diffraction, and electron probe X‐ray microanalysis, the evolution of the banded structure, austenite grain size, and element segregation is studied. The following conclusions are drawn: During the slow cooling process, within the two‐phase region temperature range, proeutectoid ferrite nucleates and grows in a regular banded pattern, ultimately forming a banded structure composed of ferrite and martensite/pearlite. The hot‐rolled samples exhibited significant segregation bands of C and Mn both before and after slow cooling. Homogenization treatment results in a slight increase in austenite grain size, while elemental segregation gradually decreases. After the slow cooling experiment, the sample homogenized for 1 h still exhibits a banded structure, but with increased band width and reduced ordering. With further increases in homogenization time, the banded structure gradually disappears.