Orientation relationship and variant pairing in bainite of low carbon steels depending on thermomechanical treatment

Crystallographic peculiarities of bainite were investigated in two low carbon microalloyed steels as a function of the parent austenite deformation and the cooling rate. The study was focused on the orientation relationship (OR) between parent austenite and bainitic ferrite and on the paring among probable orientation variants of the bainitic blocks. For the steels studied a common dependency of the OR on the parameter, characterizing the relative position of the transformation temperature within the bainite transformation temperature range, has been obtained. The same remains valid for the variant paring, though the dependency turns out to be more complex in case of ausforming.