MODELING THE FLOW BEHAVIOR OR A MEDIUM-CARBON MICROALLOYED STEEL UNDER HOT-WORKING CONDITIONS

The constitutive equations for the flow behavior of a commercial 0.34 pct C-1.5 pet Mn-0.7 pet Si-0.083 pet V-0.018 pet Ti microalloyed stee l were determined. For this purpose, uniaxial hot compression tests we re carried out over a wide range of strain rates (10(-4) to 10 s(-1)) and temperatures (1123 to 1423 K). In combination with models develope d in the literature, the experimental results permit the flow stress o f the present steel to be predicted within +/-5 pet. It is shown that the classical constitutive equations must be modified to take the grai n size into account, particularly when the latter is below 30 mu m.