FEATURES OF KINETICS OF DESTROYING AUSTENITE AND THE REGULARITIES OF FORMATION OF THE С82DCr STEEL STRUCTURE DURING CONTINUOUS COOLING

One of the main tasks of modern metal science is the creation of scientific bases for controlled direction of the processes of structure formation in metals in order to achieve the best combination of the complex properties of finished products. Purpose. Investigation of the kinetics of the decay of austenite, as well as the regularities in the formation of the structure of C82DCr steel during continuous cooling with different rates from an elevated heating temperature. Results. The kinetics of the transformations was studied and a continuous cooling transformation diagram (CCTD) of the decomposition of supercooled austenite of alloyed chromium steel C82DCr (EN ISO 16120-2: 2011) was constructed, during cooling from a temperature of 1040 °C. When constructing the CCTD, the differential thermal analysis method was used, using a reference sample. The most effective intervals of air cooling rates have been established, which make it possible to form at least 90 % of sorbit in the rolled product structure, exclude the release of the excess phase (cementite secondary), and the appearance of structures formed by intermediate and shear mechanisms. The results of the research have been industrialized when developing the cooling mode for wire rod with a diameter of 8.0...12.0 mm from steel C82DCr on the Stelmor line in the flow of a continuous fine-wire mill 320/150.