from the conferences organized by TANGER Ltd.
Universal plastometer Gleeble 3800, which is installed at the Regional materials science and technology centre at the VSB - Technical University of Ostrava was used for investigation of possibility of grain refinement of low-carbon steel. Through dilatometric tests of the investigated steel performed at various heating and cooling rates, the transformation temperatures Ar1, Ar3, Ac1 and Ac3 were determined. These temperatures were employed at the proposal of two following types of experiments, performed to refine a prime grain of the examined steel. The first set of the tests contained an annealing off the examined steel with a cyclical change of the temperature. It was found by metallographic analysis of the annealed samples that the samples annealed at the temperatures of 880 and 530 °C with the dwell of one second at the annealing temperature, and cooled down or heated up at the rate of 10 °C·s-1 showed finer grain even after one cycle. Increase of the number of cycles caused a decrease of ferritic grain. The second set of the test contained a cyclic deformation of the examined steel, which consisted of combination of pressure and tension at the given temperature. The deformation temperature, the size of the absolute strain, the dwell time between the individual cycles and the number of the individual cycles were chosen as variable parameters. Metallographic analysis of each cyclically deformed sample proved that the selected parameters of deformation did not lead to the required refinement of microstructure of the examined steel.
Keywords: Grain refinement, temperature of phase transformation, cycling of temperature, cycling of deformation, plastometer Gleeble 3800© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.