I am going to run into some trouble because of interpretion differences of the ASTM E45. My understanding is, that the visual appearance of inclusions using 100x magnification is relevant for classification A - D . Others however, insist upon that any knowledge about the nature of the inlusions must be taken into account.
For example: at 100x magnification inlusions can be classified to D according to their visual appearance (round and dark); at 500x they look like sulfides (grey and longish). I know that the material has sulfides. The acceptance limit is A thin 1 and D thin 1.5.
Is it a must to use higher magnifications to resolve inclusion types?