Morphology of Widmanstätten and Bainitic Ferrites

The morphologies of isothermally transformed Widmanstatten and bainitic ferrites in a low carbon low alloy steel have been investigated by means of optical and electron microscopies. In the steel investigated, the Widmanstatten ferrite grains nucleated from the ferrite grain boundary allotriomorphs in the temperature range between 625 and 600 o C, while the bainitic ferrite laths nucleated directly at the austenite grain boundaries below 580 o C. The formation of both Widmanstatten and bainitic ferrites accompanies sharp surface reliefs