Plastometric Study of Hot Formability

P. Kawulok, I. Schindler, R. Kawulok, S. Rusz, P. Opěla, J. Kliber, M. Kawuloková VSB – Technical University of Ostrava, Faculty of Metallurgy and Materials Engineering, Czech Republic Z. Solowski, K.M. Čmiel Třinecké železárny a.s., Czech republic Formability of hypereutectoid C-Mn-Cr-V steel in hot condition was investigated with use of plastometric methods. A wide range of deformation temperatures 1 300 640 °C for hot tensile tests was proposed with use of nil-strength temperature (NST), determined by special plastometric method, and as well as with use of the calculated temperatures of phase transformations during heating of the investigated steel. Ultimate tensile strength of the investigated steel was increasing exponentially with the decreasing deformation temperature. Ductility of the investigated steel in hot condition increased with the increasing deformation temperature up to the temperatures ranging from 1 150 to 1 250 °C, after which a sharp decline of formability took place in investigated material.