Posted by kelly on February 23, 2010 at 15:12:57:
In Reply to: macro etch ratings posted by Stuart Alexander on January 18, 2010 at 08:28:53:
Several series of photographs (Plate-I & Plate-II) of etched specimens are presented in two groups in the ASTM E381 specification.
Plate I—is for three different conditions: (1) Subsurface conditions; (2) Random conditions; and, (3) Center segregation. ...Hence the S, R, and C ratings with numbers attached.
Plate II—Ungraded series showing various other conditions.
Larger Number of each S, R, and C mean a more severe segregation condition.
You need to purchase these plates from ASTM so that you can make the comparisons.