Due to the constantly increasing requirements for steels applied in the aerospace industry, a reliable characterisation of nonmetallic inclusions steadily gains importance. Out of the different described methods for inclusion analysis, the focus of this thesis lies on automated SEM/EDX investigations. On the basis of first analyses, an inclusion cluster consisting of 25 different inclusion classes especially adapted to the steel grade PH 13-8 Mo is developed which permits an inclusion categorisation over the whole process flow. Next to the comparison with a similar analysing method (P-SEM) and the variation of several influential parameters, the representativeness of this method and the applicability of the inclusion cluster on a different steel grade is tested. The results underline the potential of this analysing method.