Analysis of the austenite grain size distribution in plain carbon steels

The aim of this paper is to report methods for measuring the austenite grai n size in plain carbon steels, including the estimation of the three dimens ional grain size distribution. Prior austenite boundaries are revealed usin g a number of quenching and etching techniques. The grain size is measured by standard manual procedures and by the use of image analysis equipment. R esults from these measurement methods are compared and systematic errors ar e identified. A correction is proposed to account for the systematic error in the measurement of the two dimensional grain size distribution by the us e of image analysis. Methods for the estimation of the three dimensional gr ain size distribution are compared. It is concluded that the method propose d by Matsuura and Itoh is the most versatile.