Influence of Selected Parameters of the Thermomechanical Rolling Process of HSLA Steel on the Transformation of Austenite into Ferrite

Abstract

The study analyzed two selected representative HSLA steels rolled at the Krakow branch of ArcelorMittal Poland S.A. The aim of the analysis was to determine the effect of parameters such as strain and cooling rate on the onset temperature of the transformation from austenite to ferrite. Dilatometric tests were carried out, followed by strain dilatometry. The cooling rate was varied and its relationship with the temperature of the beginning of austenite to ferrite transformation (Ar3) was determined. In the second part of the study, the subject literature was analyzed to find out how quickly the Ar3 temperature could be calculated. The available equations for calculating the Ar3 temperature were checked. However, the results of the calculations were not consistent enough to use these equations in the actual process. Therefore, the authors decided to develop their own equation – the proposed solution allows the calculation of the Ar3 temperature for the two selected HSLA steels mentioned above with an accuracy of several degrees and a correlation of more than 90%.