EFFECT OF DEFORMATION CONDITIONS ON THE TRANSFORMATION OF MICRO-ALLOYED MEDIUM-CARBON FORGING STEELS

The CCT diagrams of three medium-carbon steels without and with microalloying by vanadium and titanium were constructed by applying direct cooling of as-deformed austenite. Deformation parameters corresponding to those of industrial forging were varied with a laboratory simulation technique by using the plane strain hot compression test. The effect of microalloying, deformation, and deformation temperature on the amount of structural substituents was quantified. For practical application of the study the as-forged controlled cooling conditions were determined to achieve the desired bainite-free ferritic-pearlitic microstructure with beneficial mechanical properties.