Austenite grain growth in medium and high-carbon steels microalloyed with niobium

Abstract

The influence of niobium (0.03 <wt.-% Nb <0.10) on the grain growth of austenite has been studied in carbon steels (0.4 < wt.-% C < 0.8). The temperature of the start of rapid grain growth for the niobiumbearing steels has been correlated with the size and the number of niobium carbonitride precipitates dispersed in the matrix. It has been found that this temperature depends only on the amount of Nb dissolved during the forging treatment preceding the austenitizing treatment. The results agree with the theory of Gladman and Pickering.