Astm: E562-19e1

) represents the total volume of a specific phase divided by the total volume of the material. While we live in a three-dimensional world, measuring 3D volumes directly inside an opaque metal is destructive and incredibly difficult. ASTM E562 solves this by using —the science of interpreting 3D structures from 2D cross-sections. Stereological math proves that the point fraction ( Ppcap P sub p

. Unlike simple area estimation, ASTM E562 is a statistical method. Before counting, the user must choose a desired statistical precision, known as the Percent Relative Accuracy (%RA). This choice dictates the total number of point "hits" (and thus the number of fields to analyze) needed to achieve that confidence level. astm e562-19e1