There are a number of microscopic test methods that have been developed to determine the non-metallic inclusion content rating of wrought steel.  

The most common microscopic inclusion ratings performed for steel in the US are ASTM E45 Methods A and E, also referred as JK inclusion rating.  These methods place inclusions into one of several composition-related categories (Type A – Sulfides, Type B – Aluminates, Type C – Silicates, Type D – Globular Oxides).  These types of inclusions are referred to as “indigenous inclusions”.  The microscopic methods are not intended for assessing the content of “exogenous inclusions” (those from entrapped slag or refractories).  Microanalytical techniques such as energy dispersive X-ray spectroscopy (EDS) may be used to aid in determining the nature of the inclusion.

Materials with very low inclusion contents may be more accurately rated by automatic image analysis, which permits more precise microscopic ratings.  We employ an automated image analysis system by Clemex Technologies, which provides standardized programming that conforms to many of the following specifications.