This European Standard specifies the general requirements for the micrographic determination of content of non-metallic inclusions of metallic materials for aerospace applications. It also gives tables of standard acceptance criteria for particular steel types. It shall be applied when referred to in the EN technical specification or material standard unless otherwise specified on the drawing, order or inspection schedule. This European Standard is mainly applicable to steel but may be used on other metallic materials. This European Standard is not normally applicable to austenitic corrosion resisting steel, other than precipitation hardening, or to free-machining steel unless invoked in the material standards.