The influence of chemical composition on peak strain of deformed austenite in low alloy and microalloyed steels

Using hot torsional tests, the influence of the most common elements in low alloy steels (C, Mn, Si, Mo) and in microalloyed steels (Ti, V, Nb) on peak strain has been studied. At the temperatures (900, 1000 and 1100 degrees C) and strain rates (0.544, 1.451, 3.628 and 5.224 s(-1)) at which the tests were carried out all the elements remained in solution during deformation with the exception of titanium which was in part previously precipitated. In these conditions, the results indicate that C, Si and Mn have hardly any influence on the value of peak strain (epsilon(p)) while Mo, V, Ti and particularly Nb considerably increase its value. The study has been completed with the modelling of epsilon(p) as a function of the Zener-Hollomon parameter and the austenite grain size for all the steels studied, showing the quantitative influence of the different alloying elements.