TEXTURE CONTROL IN PIPELINE STEELS BY THERMO-MECHANICAL CONTROL PROCESSING
The texture evolution in pipeline steel is studied as a function of the thermo-mechanical processing parameters –rolling tem- perature and cooling rate after the finish rolling stage carried out with equal rolling reduction per pass.. The austenite recrystallization and grain growth during thermo-mechanical control processing (TMCP) of a pipeline steel grade are described and analysed in terms of precipi- tation state progress. Two stage controlled rolling (roughing and finishing) was carried out on a laboratory rolling mill for a set of complet- ed and interrupted schedules. Subsequent to rolling, two different cooling routes were used water quenching and accelerated water cooling (ACC) together with coiling simulation. From the combination of transmission electron microscopy (TEM) observations, detailed texture analysis and inductively coupled plasma-mass spectroscopy (ICPMS) precipitates quantification, consistent correlations between precipita- tion state and microstructure at every stage of TMCP can be recognized. The formation of specific transformation textures was explained via appropriate texture models that describe both formation of transformation and recrystallization textures in the austenite.