Effect of austenite grain boundary mobility on hardenability of steels containing vanadium

Abstract

AbstractA correlation has been established between the rate of grain boundary migration during austenitisation and the hardenability of steels containing 0·2–0·3%C, 1·5–1·7%Mn, up to 0·35% V, and small additions of Al or Ti. Interaction between the austenite grain boundaries and pinning particles was investigated using transmission electron microscopy and segregation to the austenite grain boundaries was examined using Auger electron spectroscopy. It has been concluded that the velocity of grain boundary migration during austenitisation influences the extent of equilibrium segregation to the austenite grain boundaries which, in turn, affects the hardenability. Pinning of the austenite grain boundaries enabled the potential hardenability effect of the alloying elements to be increased. Mechanisms have been discussed for the ways in which segregation, particularly of V, occurs to pinned or immobilised austenite grain boundaries, and the conditions by which most effective grain boundary pinning can be achieved have been considered. Some technological implications have been suggested.MST/804