This International Standard lays down guidelines for the macroscopic examination of steel by etching with strong mineral acids. The method has very wide application. Selection of the type and concentration of the reagent, the temperature of the reaction and the conditions of surface preparation of the test piece make it possible to achieve the required aim. NOTE— Depending on the conditions of surface preparation of the test piece, and on the etching process, this macroscopic examination does not always make it possible to distinguish on the one hand porosities from segregations, and on the other hand cracks from lines of inclusions or segregations.