A New Method of Determining Austenite Grain Size and the Observation of Transition of Austenite Grain Boundary by Repeated Heating and Cooling

Abstract

If the specimen of mild steel of which surface is polished as flatly as a mirror, is carburized with weak carburizer, the graphite is deposited along the grain boundary of austenite. Applying this phenomena, we found a new method of determining austenite grain size, called “graphite method”, which was simpler and speedier than other methods. And the transition of austenite grain boundary by heating and cooling through A₁ point was also observed.