Effect of thermomechanical processing schedule on the texture and microstructure of pipeline grade API X80 microalloyed steel

Abstract

The presence of micro alloying constituents like Ti, Nb in microalloyed steel enhances its mechanical properties through grain size control and precipitation strengthening. The strengthening capability of microalloying additions can be fully utilized by choosing proper thermomechanical processing (TMP) schedule. The TMP schedule needs to be designed based on determination of critical temperatures of transformation in steel including no recrystallisation temperature (i.e ., Tnr) of microalloyed steels. The TMP was carried out on API X80 grade pipeline steel using Gleeble® 3800 Thermal mechanical simulator. The samples were deformed in plain strain condition at three different temperatures (860, 950 and 1050°C) by keeping other deformation parameters constant. The deformation temperature was chosen based on CCT and Tnr determination studies. The deformed samples were examined in EBSD and TEM to obtain the texture and microstructural information. It is also observed that formation of acicular ferrite and bainite microstructures in these steel is very much dependent on the deformation strain levels in the austenite matrix prior to transformation. The grain boundary misorientation angle distribution obtained from EBSD analysis can be a very important parameter to distinguish the different microstructural constituents apart from grain shape and image quality. Effect of thermomechanical processing schedule on the texture and microstructure of pipeline grade API X80 microalloyed steel (PDF Download Available). Available from: https://www.researchgate.net/publication/303524095_Effect_of_thermomechanical_processing_schedule_on_the_texture_and_microstructure_of_pipeline_grade_API_X80_microalloyed_steel [accessed Nov 15 2017].