Hot deformation influence on pearlite formation suppression at trip steels

Abstract

Trip steel multiphase microstructure is made up by polygonal ferrite matrix, bainite and significant fraction of retained austenite. Pearlite formation during thermomechanical processing disable sufficient retained austenite fraction stabilisation. Therefore pearlite formation is undesirable in TRIP steels. It is known that strain moves position of transformation curves to the left side toward to shorter times in CCT diagrams, however the transformation time reaction on hot deformation isn’t fully explicit in TRIP steels. The influence of hot deformation on formation of pearlite was investigated by thermomechanical rolling in this paper. Experimental TRIP steels step samples were rolled. Four different strains were achieved on single sample during single pass due to step shape of sample. Microstructures of single steps of step samples were evaluated after rolling. Suppression of pearlite formation by means of strain magnitude was evaluated.