Study of microstructure and microtexture of modified 9Cr–1Mo steel subjected to high deformation

The Nb–V modified 9Cr–1Mo ferritic steel is an extremely important structural material in the power industry. Present work is focused on how the microstructure, microchemistry and microtexture of this steel evolve during high degree of deformation, starting from the normalized and tempered condition. While the microstructure and microchemistry are analyzed using analytical transmission electron microscopy, the microtexture analysis is carried out using the electron back-scatter diffraction (EBSD) technique. High degree of cold rolling leads to the formation of forests of dislocations and cellular structure of ferritic matrix. The carbides were found to retain their morphology and chemistry after 88% cold work. Analysis of misorientation angles was used to derive the grain boundary character of the normalized and tempered steel and the deformed steel. Analysis of fiber texture reveals that deformation in the material does not lead to predominance of any particular fiber which is useful from fabrication point of view.