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 i n 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 an d 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 so lution during deformation with the exception of titanium which was in part previously precipitated. In these conditions, the results indicat e that C, Si and Mn have hardly any influence on the value of peak str ain (epsilon(p)) while Mo, V, Ti and particularly Nb considerably incr ease its value. The study has been completed with the modelling of eps ilon(p) as a function of the Zener-Hollomon parameter and the austenit e grain size for all the steels studied, showing the quantitative infl uence of the different alloying elements.