Prepared sample which is used for the metallographic examination of metallic materials and their alloys.Sample taking starts with the selection of the sample material and the specification of the specimen level. For the detailed illustration of structures and/or inclusions and defects, several parallel and/or crossing specimen levels should be examined.
The metallographic specimens must be large enough; 15·15·10 mm can be assumed as empirical formula . Metallographic specimens are taken directly from the casting (for the examination of casting defects), from cast samples (taking the standard wall thickness into account) and from samples which have been used for the determination of mechanical properties.
If structural defects are examined, metallographic specimens taken directly on the defective surface are not suited and cannot be interpreted; the specimens should always be taken perpendicular to the surface.Since the high magnification of the sample under the microscope only allows for a very low depth of sharpness, the sample surface must be completely flat and polished (see Metallographic specimen preparation).