The Effect of Aging of Super-Cooled Austenite on the Properties of Hardened High Speed Steel

Abstract

In the previous report, (N.K.G. Vol. 16 (1952) p. 328) the authors concluded that the super-cooled austenite of high speed steel precipitates carbides prior to γ→α transformation. The present report is on the experimental results and discussions on the actual influences of such carbide precipitation on the properties of hardened high speed steel. A sample is austenitized at 1300° and quenched in a metal bath of 600°, kept in the bath for a duration of time and then quenched in oil. Such specially quenched specimen contains no residual austenite, and in tempering shows no secondary hardening. The causes of these differences of properties, between the samples which were normally quenched and specially quenched, were studied by the usual metallurgical methods.